Conservative Treatment using Blood Flow Restriction in Individuals with Complete Anterior Cruciate Ligament Rupture: Protocol for a Randomised Clinical Trial

Conservative Treatment using Blood Flow Restriction in Individuals with Complete Anterior Cruciate Ligament Rupture: Protocol for a Randomised Clinical Trial | Research Square window.SnipcartSettings = { analytics: { enabled: false } }; (function() { var accessVector = localStorage.getItem('access_vector') || ''; window.dataLayer = window.dataLayer || []; if (accessVector) { window.dataLayer.push({ user: { profile: { profileInfo: { snid: accessVector } } } }); } })(); (function(w,d,s,l,i){w[l]=w[l]||[];w[l].push({'gtm.start':new Date().getTime(),event:'gtm.js'});var f=d.getElementsByTagName(s)[0],j=d.createElement(s),dl=l!='dataLayer'?'&l='+l:'';j.async=true;j.src='https://www.googletagmanager.com/gtm.js?id='+i+dl;f.parentNode.insertBefore(j,f);})(window,document,'script','dataLayer','GTM-K279D39R'); Browse Preprints In Review Journals COVID-19 Preprints AJE Video Bytes Research Tools Research Promotion AJE Professional Editing AJE Rubriq About Preprint Platform In Review Editorial Policies Our Team Advisory Board Help Center Sign In Submit a Preprint Cite Share Download PDF Study protocol Conservative Treatment using Blood Flow Restriction in Individuals with Complete Anterior Cruciate Ligament Rupture: Protocol for a Randomised Clinical Trial Alexios Pitsillides, Antonis Constantinou, Christos Karagiannis, and 1 more This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-6940729/v1 This work is licensed under a CC BY 4.0 License Status: Published Journal Publication published 01 Dec, 2025 Read the published version in Journal of Orthopaedic Surgery and Research → Version 1 posted 9 You are reading this latest preprint version Abstract Background Inadequate long-term outcomes are common following both surgical and non-surgical management of anterior cruciate ligament (ACL) rupture. Emerging evidence suggests that a bracing protocol may facilitate ligamental healing; however, a period of immobilization can induce muscle atrophy. This study aims to investigate potential benefits of adding blood flow restriction (BFR) training to the conservative treatment of ACL rehabilitation. Methods This is a double-blinded, two-arm randomised clinical trial. Participants in the intervention group will follow an exercise protocol using BFR training, while participants in the control group will follow the same protocol with sham BFR. Both groups will follow the same splint protocol. Individuals aged between 18 and 40 years with an acute or subacute complete ACL tear confirmed by imaging will be eligible to participate. Discussion Emerging evidence suggests that a conservative period of joint immobilisation, positioning the knee reduces the distance between the two torn ligament ends, may promote ACL healing after a complete rupture. However, brace use can result in muscle atrophy. BFR exercises may play an important role during this period of immobilisation and restricted movement. Positive results of exercise under BFR, in combination with a brace, can serve as an alternative treatment for participants with acute or subacute complete ACL tear, potentially reducing recovery time or even avoiding surgery. Trial registration: This protocol was approved by the Cyprus National Bioethics Committee (ΕΕΒΚ/ΕΠ/2024/70) and registered on ClinicalTrials.gov (Registration number: NCT06727344). Anterior cruciate ligament Complete rupture Blood flow restriction training Ligamental healing Bracing protocol Clinical trial Figures Figure 1 1. Background Anterior cruciate ligament (ACL) reconstruction is a widely practiced surgical intervention for ACL ruptures, particularly among athletes. However, current evidence suggests that reconstruction does not guarantee a full return to pre-injury function [ 1 ]. Approximately 80% of participants resume sports participation post-surgery, yet only 65% return to their pre-injury performance levels, and merely 55% reach a competitive standard [ 1 ]. Consequently, many individuals report reduced quality of life following surgery, and the risk of developing post-traumatic osteoarthritis remains elevated [ 2 ]. These limitations highlight the need to explore alternative treatment strategies, particularly those that promote intrinsic healing of the ACL. Unlike other knee ligaments, the ACL demonstrates limited spontaneous healing capacity, although the mechanisms underlying this difference remain unclear. A recent systematic review indicated that proximal ACL ruptures may possess a greater regenerative potential than mid-substance tears, suggesting a role for conservative management strategies [ 3 ]. Such approaches may include structured bracing to reduce knee laxity, progressive joint strengthening, early mobilisation, and load-bearing as tolerated [ 3 ]. In contrast a prolonged period of immobilization might result in muscle atrophy. In this context, Blood Flow Restriction (BFR) training emerges as a promising adjunct to conservative rehabilitation. BFR involves applying external pressure via inflatable cuffs to partially occlude arterial blood flow and fully restrict venous return during low-load resistance exercises [ 4 ], [ 5 ], [ 6 ]. This technique has demonstrated muscle hypertrophy and strength gains comparable to those observed with high-load resistance training, making it particularly suitable for early rehabilitation phases when high loads are contraindicated [ 4 ], [ 5 ], [ 6 ]. Objective : The aim of this study is to evaluate the effectiveness of BFR training in individuals with complete ACL rupture. Specifically, the study compares a conservative intervention involving bracing and BFR training with an identical bracing protocol combined with sham BFR (placebo) training, to assess the added value of BFR in functional recovery and joint stability. We hypothesise that the participants in the BFR group would experience less atrophy, reduced pain, higher functionality levels and better quality of life. 2. Methods 2.1 Study Design A double-blind, two-arm Randomised Clinical Trial (RCT) will be conducted. Participants in the intervention group will undergo an exercise protocol using BFR training, while participants in the control group will follow the same exercise protocol but with sham BFR training. Both groups will follow the same brace protocol. This RCT is registered at ClinicalTrials.gov (Registration number: NCT06727344) and was designed in accordance with the SPIRIT Statement for clinical trial protocols [ 7 ]. Reporting of the exercise interventions will follow the Consensus on Exercise Reporting Template (CERT) checklist [ 8 ]. 2.2 Eligibility criteria Individuals aged between 18 and 40 years will be eligible to participate in the study. The main inclusion criterion is the presence of an acute (0–4 days) or subacute (5–14 days) ACL tear confirmed by Magnetic Resonance Imaging (MRI) [ 9 ]. Participants must be able to read and communicate fluently in Greek and be willing to keep their injured leg immobilised for the period specified in the study protocol. To be included in the study, a signed eligibility form must be submitted to the principal investigator by the participant's personal and/or treating physician. The form outlines all medical conditions that preclude the study participation. Exclusion Criteria: Participants will be excluded from the study if they present with any of the following: Cardiovascular conditions: coronary artery disease, unstable hypertension, peripheral vascular disease, deep vein thrombosis, blood clotting disorders, cardiopulmonary diseases, atherosclerotic vessels, myocardial ischaemia, left ventricular dysfunction, haemophilia, vascular endothelial dysfunction, venous insufficiency, or Marfan syndrome [ 10 ]. Musculoskeletal injuries: recent muscle injuries or fractures, postoperative oedema, open fractures or wounds, neurological limitations or clinical or MRI evidence of concomitant injuries that require surgery (e.g. an unstable bucket-handle meniscal tear). Lifestyle-related conditions: Body Mass Index (BMI) > 25, diabetes, dyslipidaemia, or unwillingness to discontinue nutritional supplements during the intervention period [ 10 ]. Pregnancy [ 10 ] Family medical history: thromboembolic events, atrial fibrillation, heart failure, or cancer [ 10 ]. Medications use: current use of medications that increase blood clotting, including hormones and contraceptives [ 10 ]. Contraindications to BFR: presence of open wounds or serious skin conditions such as allergies to the cuff material identified during the initial evaluation study. 2.3 Interventions Prior to any intervention, at the beginning of the first session, all participants will have a familiarisation session with both the exercise protocol and BFR procedure. For exercise protocol familiarisation, participants will perform few repetitions of each exercise without the BFR device. For BFR familiarization, the cuff will be applied, and the calibration process will be conducted. All exercises will be paced using a metronome set at 60 beats per minute (bpm), with each muscle contraction phase (concentric or eccentric) lasting 2 seconds [ 11 ]. The participants will be seated facing a screen to follow the rhythm, which will be provided as an acoustic and visual stimulus. Both physiotherapists delivering the intervention will be trained to ensure consistency. The intervention period will be 12 weeks divided in 5 Phases as illustrated in Fig. 1. 2.3.1 Intervention Group The intervention group will consist of participants with acute (0–4 days) or subacute (5–14 days) ACL tears who meet the eligibility criteria. Participants in this group will follow the splint-use protocol [ 11 ]. 2.3.1.1 Splint use protocol. During the first three weeks (Phase 1), the knee will be immobilised at 90° using a splint (E-sense ROM Knee brace – Ref: RS3000). Participants will perform non-weight-bearing ambulation with the assistance of walking aids, as needed based on age and mobility level. In the fourth and fifth week (Phase 2), the range of motion of the splint will be adjusted to 60–90° and 30–90°, respectively, while non-weight-bearing ambulation continues. During the sixth week (Phase 3), the splint will allow full flexion and 0° extension, thus preventing hyperextension of the joint. From the seventh week onwards (Phase 4), the splint will be removed and full weight-bearing without restrictions will be permitted. Table 1 outlines the intervention protocol in terms of weight-bearing status and brace use. Table 1 Postoperative Weight-Bearing and Knee Brace Protocol by Rehabilitation Phase Phase Week Weight bearing and brace 1 1–3 Use of brace with knee immobilized at 90 ο . Non weight bearing. Use of walking aids. 2 4–5 4th: Brace at 60–90 o . 5th: Brace at 30–90 o Non weight bearing. Use of walking aids. 3 6 Brace from 0 ο to full flexion (avoiding hyperextension). Partial weight bearing. Use of walking aids. 4 7–10 Full weight bearing. End of brace use. End of walking aids use. 5 10–12 Full weight bearing. 2.3.1.2 BFR training protocol. Regarding the exercise programme, during Phase 1, participants will perform seated isometric quadriceps and hamstring contractions guided by a visual stimulus from an electronic hand dynamometer. For each exercise, participants will complete a total of 75 repetitions divided into four sets (30, 15, 15, 15) at 30% of the maximum strength of the uninjured leg. The scheme of 75 repetitions is suggested as sufficient volume to lead to adaptations and thus repetitions to failure may not be needed [ 9 ]. The required cuff pressure to achieve complete vascular occlusion of the lower extremity will be measured at rest, with the participant seated at the edge of an examination bed —as during exercises of Phase 1 and 2, due to dependence on body posture[ 12 ]. The cuff will be positioned on the most proximal part of the thigh [ 10 ]. An automated, personalised tourniquet device (MAD-UP Pro system, Angers, France) will be used to calculate each participant’s occlusion pressure. This device has acceptable accuracy and high reliability [ 12 ]. Both groups will follow the same exercise protocol and parameters. The intervention group pressure will be set at 80% and for sham group at 15%. Phases 1 and 2 will be performed using the installed settings of the device labelled as “free” mode, due to the inability of the device to recognise any movement below approximately 60 o . From Phase 3 onward, the installed “rehabilitation” settings will be used.[ 12 ], [ 13 ]. In Phase 2, the exercise protocol will be maintained as in Phase 1. Additionally, the "sliding" exercise will be introduced where the heel is dragged on the bed causing knee flexion, along with the skateboard sliding exercise in a seated position within the allowed range of motion. The exercise parameters (volume of repetitions, sets, execution speed, breaks) will remain unchanged. In Phase 3, single-leg squats of up to 60° will be incorporated, while exercise parameters will remain unchanged. In Phase 4, the exercise protocol will be modified. Participants will begin with 5 min on a stationary bike (without BFR), and quadriceps/hamstring isometrics will be replaced with resistance exercises for knee extension and flexion seated on the edge of a bed using KEISER device to set the ideal resistance. Sliding and single-leg squats will be performed with an increased range of motion (up to 90°), and a 30 cm step climb will be added. The exercise parameters will remain consistent with previous phases. In Phase 5 (final phase), gait retraining on a treadmill for 5 min and Y-balance exercises will be introduced, both without BFR. Rest intervals between sets will be 30 s, and the interval between exercises will be 1 min. The intervention group will perform the exercise programme with lower-extremity BFR. The cuff pressure will be reduced to 10% (minimum allowed by device) during the rest intervals. The execution speed of the exercises will be 2 s for contraction, followed by 2 s of release. All isometric exercises will be held for 3 s. Cryotherapy and anti-inflammatory medication will be prohibited to minimise impairment of the acute inflammatory response [ 11 ]. Participants will be encouraged to hydrate well, perform calf pump exercises (included in home exercise plan) and take Rivaroxiban 10 mg for the first 8 weeks (prescribed by their doctor) as Deep Vein Thrombosis (DVT) risk mitigation strategy. The use of paracetamol will be allowed in cases of intolerable pain but will be reported to the principal physiotherapist at each session. Table 2 presents in detail the exercise protocol our intervention. Table 2 Injured Leg Exercise Protocol Phase Exercise Position Equipment Parameters Required time (min) 1 Quadriceps isometric (with biofeedback) Seated, knee at 90 o Hand-held dynamometer (Kinvent) 4 sets with a total of 75 reps (30,15,15,15) at 30% of healthy leg peak force. 5.25 Hamstrings isometric (with biofeedback) Prone, knee at 90 o Hand-held dynamometer (Kinvent) 4 sets with a total of 75 reps (30,15,15,15) at 30% of healthy leg peak force. 5.25 Time required to complete phase: Exercises 10.5 min, 4 min breaks. 14.5 2 Quadriceps isometric (with biofeedback) Seated, knee at 90 o Hand-held dynamometer (Kinvent) 4 sets with a total of 75 reps (30,15,15,15) at 30% of healthy leg peak force. 5.25 Hamstrings isometric (with biofeedback) Prone, knee at 90 o Hand-held dynamometer (Kinvent) 4 sets with a total of 75 reps (30,15,15,15) at 30% of healthy leg peak force. 5.25 Heel slide Laying on a bed Sock 4 sets with a total of 75 reps (30,15,15,15) 5.25 Heel slide seated with leg on a skateboard Chair Skateboard 4 sets with a total of 75 reps (30,15,15,15) 5.25 Time required to complete phase: Exercises 16 min, 6.5 min breaks. 27.5 3 Semi – squats up to 60 ο Standing Chair 4 sets with a total of 75 reps (30,15,15,15) at 30% of healthy leg peak force. 6.5 Time required to complete phase: Exercises 22.5 min, 8.5 min breaks. 36 4 Knee extension Seated KEISER 4 sets with a total of 75 reps (30,15,15,15) at 30% of healthy leg peak force. 6.5 Knee flexion Prone KEISER 4 sets with a total of 75 reps (30,15,15,15) at 30% of healthy leg peak force. 6.5 Step Standing Step 30cm 4 sets with a total of 75 reps (30,15,15,15) at 30% of healthy leg peak force. 6.5 Stationary bike * Seated Stationary bike 5 min 5 Time required to complete phase: Exercises 36.5 min, 12 min breaks. 53.5 5 Gait retraining * Standing Walkway 5 min 5 Balance exercise (Υ test)* Standing Tape 5 reps at each direction 5 Time required to complete phase: Exercises 58.5 min, 14 min breaks. 77.5 Generally: break within sets 30 sec, break between exercises 1 min. Pressure deflated during breaks. Exercise execution speed 2 sec concentric 2 sec eccentric. Hold at isometric exercises 3 sec. * = Exercise without BFR 2.3.1.3 Home based program. Participants of both groups (BFR and Sham-BFR) will receive the same, home-based, exercise programme, via a mobile platform that will allow monitoring of compliance. Additionally, the platform will ensure correct exercise execution through instructional videos and specific exercise parameters. Such intervention has been reported to improve participants compliance and improve clinical outcomes in ACL post-surgery patients [ 13 ]. During Phase 1, exercises will include seated hip flexion, hip extension, hip adduction, abduction using a red resistance band or a ball. Each exercise will be performed as three sets of 10 repetitions, twice daily. These exercises will be selected to preserve as much muscle strength as possible in the muscle groups around the knee, specifically the hip. The position in which the exercises will be performed will be chosen for convenience due to the splint. During the Phase 2, glides will be added to the programme. In the 3rd phase, single-leg sit-ups of up to 45° will be introduced. During the 4th and 5th phases, all hip exercises (flexion, extension, abduction, and adduction) will be performed using a higher resistance band (blue bands). Slides and sit-ups of up to 45° will be performed up to 90°. Exercise volume and frequency will remain identical. Load progression will be achieved through the increase of band resistance. Resistance will be determined by the band colour. All participants will be provided with the necessary equipment (bands). Detailed description is presented in Table 3 . Table 3 Home Exercise Programme and Exercise Parameters. Phase Exercise Position Equipment Parameters 1 Hip abduction Seated Chair Red band 3 sets of 10 reps Hip extension Standing (single leg) Chair 3 sets of 10 reps Hip flexion Seated Chair Red band 3 sets of 10 reps Hip adduction Seated Chair Red band 3 sets of 10 reps Heel raises Seated Chair 3 sets of 10 reps 2 Same as Phase 1 plus: Heel slides – according to pain Supine Bed 3 sets of 10 reps 3 Same as Phase 2 plus: Partial squat up to 45 o Standing Chair 3 sets of 10 reps 4–5 Hip abduction with band Standing Chair Blue band 3 sets of 10 reps Hip adduction with band Standing Chair Blue band 3 sets of 10 reps Hip extension with band Standing Chair Blue band 3 sets of 10 reps Hip flexion with band Standing Chair Blue band 3 sets of 10 reps Heel raises Standing Chair Blue band 3 sets of 10 reps Squats up to 90 o Standing Chair Blue band 3 sets of 10 reps Heel slides Supine Bed 3 sets of 10 reps 2.3.2 Control Group The sham BFR protocol will mirror the intervention group’s exercise programme, except that sham pressure settings will be applied using the MAD-UP system [ 14 ]. Since the minimum allowable pressure on the device is 10%, the sham group’s cuff pressure will be set at 15%. This allows the therapist to deflate the cuff by 5% during breaks mimicking the procedure used in the intervention group, where the cuff is inflated during exercise and deflating during breaks. 2.4 Outcome Measures The outcome measures will be divided into three main categories. The first category will include measures for assessing the functionality and structure of the knee. The second category will consist of participant self-assessment questionnaires, and the third will focus on questionnaires evaluating the participant's quality of life [ 11 ]. Initial measurements will be conducted upon participant enrolment and will include magnetic resonance imaging (MRI), Lachman test, arthrometry, strength, swelling, Lysholm scale, Tegner scale, pain, balance, single-leg hop and exercise pain. At the beginning of each Phase, strength, swelling, and pain will be reassessed by the physical therapist responsible for each group. Final measurements will be taken at the conclusion of the intervention period and will include all baseline measurements. 2.4.1 Functionality and Structure 2.4.1.1 Strength (Primary Outcome) Strength is the primary outcome, given its importance in long-term functional recovery following ACL injuries. Isokinetic strength assessment is the most recommended procedure for measuring strength and identifying deficits/differences in ACL injuries. This method has demonstrated satisfactory reliability and validity [ 15 ]. Due to the immediate use of a splint, strength assessment will be performed using a handheld electric dynamometer (Kinvent). This tool is considered reliable and valid instruments to assess muscle strength in clinical settings because of its ease of use, cost, compact size and portability [ 16 ]. The handheld dynamometer seems to be a reliable option (ICC values above 0.90) to measure knee extension muscle strength, particularly when two measurements are taken, and their average is used [ 17 ]. During Phase 1 and 2 “Sitting Knee Extension at 90 o ” and “Prone Knee Flexion at 90 o ” as described in Kinvent Physio mobile application will be implemented to identify the ideal exercise load. The sitting knee extension and prone knee flexion are isometric tests for the evaluation of the maximum neuromuscular capacities of the quadriceps and hamstrings at 90 o of flexion, respectively. The procedures are well described and standardized within the application, ensuring consistency. These tests are widely used to quantify knee extensors strength in participants with ACL reconstruction [ 17 ]. Due to the locked position of the knee (90 o ) any maximal isometric effort of the injured limb could result in high anterior shear force, damaging any newly formed fibers. Thus, at Phase 1 and 2 the participant will be asked to perform isometric knee extension and flexion to failure. Then Holten diagram will be implemented to identify One Repetition maximum (1RM). At Phases 3 to 5 the Holten diagram with a submaximal weight will be used to the injured leg. To have comparability during the initial assessment strength will be evaluated with both procedures. Measurements during the intervention period will be taken by the principle physical therapists at the beginning of each phase. 2.4.1.2 Magnetic Resonance Imaging Each participant will undergo and initial and a final examination. MRI will be used to confirm ACL tears initially and reevaluate them at the end of the intervention period. The radiologist interpreting the images will be asked to grade the injury using the Anterior Cruciate Ligament Osteoarthritis Score (ACLOAS) system, a reliable tool for evaluating acute ACL ruptures and assessing tissue continuity [ 18 ]. The radiologist will also measure the cross-sectional area of ​​the knee muscles in anatomic position. All MRI scans will be performed at a designated radiology centre (OPSIS Medical Imaging Nicosia) that has agreed to evaluate participants as required for the study. The radiologist will be blinded to allocation to reduce assessment bias. The initial MRI will be conducted through the National Health System, as this is the standard procedure for the injury to be confirmed. The final MRI scan will be provided free of charge to our participants by the radiology centre. 2.4.1.3 Anterior Tibial Translation Knee laxity will be assessed by measuring the anterior displacement of the tibia relative to the femur using the arthrometer (Lachmeter) only at the initial and final assessments. This device provides a user-friendly and economical solution for quantifying anterior tibial displacement. Its validity and reliability have been studied in relation to the classic KT-1000 arthrometer, with satisfactory validity and reliability results [ 19 ]. The measurement will be conducted using the Lachman test, with the participant in a supine position and the knee slightly flexed, supported on a cushion to standardize the procedure. The arthrometer will be positioned with one fixed end on the thigh and the other end on the shin. The meter will then be pressed until it touches the shin and is reset. From this initial position, three measurements will be performed for each leg by applying anterior traction to the shin. The average of the three measurements will be considered as the final result [ 19 ]. 2.4.1.4 Balance To evaluate this parameter, measurements will be performed using a star execution test (SET). During the test, participants will attempt to reach the maximum distance with one leg while balancing on the other. The SET is a closed kinetic chain exercise that stimulates a single-leg squat and t assesses strength, proprioception, neuromuscular control, and range of motion in the hip, knee, and ankle. This test is considered reliable [ 19 ], [ 20 ], [ 21 ]. Balance will be measured only post-intervention due to the participants’ inability to stand on the affected leg due to the injury. Both limbs will be assessed to identify any dominance-related asymmetry. 2.4.1.5 Single-Leg Hop The second outcome measure of dynamic stability will be the single-hop test. After familiarisation, the participants will perform three attempts to achieve the maximum distance with one leg. For a jump trial to be considered valid, participants must maintain balance upon landing. This test is considered reliable and valid [ 22 ], [ 23 ]. For both dynamic tests, three attempts will be made after familiarisation, and the average score will be recorded. Single-Leg Hop will be measured only post-intervention due to the inability of the participant to stand on the affected leg due to the injury. Both limbs will be assessed to identify any limb dominance. 2.4.1.6 Oedema Knee circumference will be measured at the middle of the patella with the participant in the supine position and the knee fully extended. Measurements will be taken in centimetres and rounded to the nearest decimal place 0.1 cm. This measurement will be assessed during the initial assessment and then again once full knee extension is allowed according to the protocol. Knee circumference is a reliable method for assessing oedema in patients with ACL injuries [ 24 ] 2.4.1.7 Pain intensity Pain intensity will be assessed using the Visual Analogue Scale (VAS), in addition to the Lysholm pain subscale. Participants will rate their pain on a scale from 0 (no pain) to 10 (worst imaginable pain). Pain measurements will be recorded in an Excel file by the group physiotherapist at the beginning of each phase. The file will be transferred to the main investigator only after the completion of the intervention period [ 25 ]. 2.4.1.8 Exercise Discomfort Discomfort experienced during exercise will be recorded using the VAS methodology. The participants will report the degree of discomfort they experienced at the end of each session, describing it as a number from 0 (no discomfort) to 10 (maximum discomfort), similar to the pain measurement. Measurements will be recorded at the end of every session (Exercise discomfort). Exercise discomfort has previously been reported to be less in patients undergoing surgery with the use of BFR [ 26 ]. Thus, we will examine the effectiveness of BFR in inducing hypoalgesia in our study population. 2.4.2 Self-assessment Questionnaires 2.4.2.1 IKDC Scale The International Knee Documentation Committee (IKDC) scale is a subjective assessment of participant functionality. It is divided into three subcategories in which participants rate the symptoms, athletic activity, and knee functionality. The IKDC is recommended for individuals with ACL injuries for several reasons. It offers a reduced response time, sufficient internal consistency, and high levels of reliability and validity [ 27 ]. The scale has been standardised in the Greek population[ 28 ] 2.4.2.2 Lysholm Scale The Lysholm scale is a self-assessment questionnaire comprising subscales that assess pain, knee locking, swelling, stair climbing, squatting, and support requirements. The scale ranges from 0 (greatest disability) to 100 (least possible) [ 29 ]. 2.4.2.3 Tegner Scale The Tegner scale is a self-assessment scale for participant activity. The score ranges from 0 (sick leave or sedentary) to 10 (participation in high-level competition). Both the Lysholm and Tegner scales were validated for use in the Greek population with good results [ 29 ]. 2.4.3 Quality of Life Assessment Quality of life assessment largely covers how the injury affects the participant physically, emotionally, and socially—parameters that should not be underestimated or ignored in this specific injury. To assess quality of life, ​the EQ-5D questionnaire will be used [ 30 ]. The questionnaire consists of five categories (mobility, self-care, usual activities, pain, and anxiety/depression). The participant will rate each category with a score (level) from no problems to extreme problems. Each level will correspond to a 1-digit number. The results of each level are then combined to create a 5-digits number that describes the patient’s health state. This questionnaire is valid and reliable for use with participants with ACL injuries [ 31 ]. 2.5 Participant timeline The intervention period is expected to begin with subject recruitment on July 1, 2025, and will last for nine months (until April of 2026). Then two months will be spent on statistical analysis and results followed by another two months for writing and manuscript preparation for publication submission. Our study will have two main assessment points (baseline and at the end) with four minor assessment points at the beginning of each phase. 2.6 Sample Size The sample size was calculated based on quadriceps strength data, with (4G Power software (Version 3.1) [ 32 ]. Sample size was calculated based on the results of a previous relevant study [ 33 ]. The effect size (ES) was set at 1.16 using Cohen’s method. To achieve a power of 80% and an alpha level of 0.05, 20 participants (10 per group) are required. To account for a 10% dropout rate per group, a total of 22 participants are deemed necessary. 2.7 Recruitment Participants will be recruited through a combination of digital and professional outreach strategies. Specifically, targeted advertisements will be disseminated via social media platforms (e.g., Facebook, Instagram) to reach a broad audience of potential candidates within the appropriate age and demographic range. In parallel, formal invitation letters and study information sheets will be distributed to healthcare professionals, including general practitioners, orthopedic surgeons, and physical therapists, encouraging them to refer eligible patients. This dual recruitment approach aims to maximize participant reach and ensure the inclusion of individuals who meet the study’s eligibility criteria. 2.8 Randomization and Blinding This will be a double-blind study. To achieve assessor blinding, ensure allocation concealment and prevent selection bias, we will perform the sealed envelope randomization method (SNOSE). To minimize the limitations of this technique [ 34 ] the procedure will adhere to relevant instructions [ 35 ]. Thus, we will cut an aluminium foil into 44 pieces of the same width and twice the height of the envelope. Then, the carbon paper will be cut into 44 sheets at the size of the envelope and will be separated into 2 sets of 22 sheets. On each set, “BFR group” or “Control group” will be written. Then each carbon paper will be folded, covered with foil and then placed in the envelope, each envelope will be signed on its top. Initially, the measurements will be performed by the principal investigator, who will thus, not know the group assignment of each participant. The radiologist evaluating the MRIs will not have access to the subject’s allocation and thus will be blinded to allocation too. Participants in the control group will be training with the same BFR device but with different parameters under sham conditions. Only the physiotherapist of the specific group will have access to the relevant details. 2.9 Data collection Data collection will take place on the premises of the European University Cyprus before the randomization and beginning of any intervention (baseline) and immediately after (post-intervention). Each prospective participant will undergo an initial assessment, and baseline measurements will be recorded by the principal investigator. The MRI scans will be evaluated by a specialist both at baseline and post intervention period. During the intervention period, strength, swelling and pain will be assessed by the physical therapist of each group. Each physical therapist will maintain an excel file with all his patient’s initials, measurements and group. Those files will be given to the main assessor after the intervention period competition to achieve blinding of the assessor. 2.10 Data management Participants details will be kept in an Excel file saved on main investigator’s computer. The place will be accessible only to him. Participant files will be maintained in storage five years after the end of the study. In any files or documents that contain any personal information the initials of each participant will be used. The only data that will be given to anyone beyond the main researcher will be the contact list, containing the name and the contact details of each participant. The investigator that will hold this contact list will be principal for the communication during the intervention period ensuring that any within study communication does not affect blinding. 2.11 Statistical Analysis Statistical analysis will be conducted on an intention-to-treat (ITT) basis, including all participants as randomized, regardless of adherence to the intervention protocol. Baseline demographic and clinical characteristics will be summarized descriptively to assess comparability between groups. The normality of continuous variables will be assessed using the Shapiro–Wilk test. Descriptive statistics will be presented for all outcome variables (MRI, anterior tibial translation (ATT), balance, single-leg hop (SLH), oedema, resting pain, exercise pain, IKDC scale, Lysholm scale, Tegner scale, and ACL-QoL at baseline and post-intervention. Continuous variables will be reported as means and standard deviations, and categorical variables as frequencies and percentages, both at baseline and post-intervention. Between-group comparisons at baseline will be performed using independent t-tests for continuous variables and chi-square tests for categorical variables. To evaluate intervention effects, independent t-tests will be used to assess between-group differences at post-intervention. Additionally, two-way mixed ANOVA will be conducted for each dependent variable to examine the effects of time (baseline vs. post-intervention), group (intervention vs. control), and their interaction. A significance level of 5% (p < 0.05) and 95% confidence intervals will be applied throughout. All participants will be analysed in their assigned groups, regardless of adherence or dropout, to preserve the benefits of randomization. All analyses will be performed using IBM SPSS Statistics version 21 (IBM Corp., Armonk, NY, USA). 2.12 Adverse events Any adverse events will be recorded. Once an adverse event is identified by the group physiotherapist an independent investigator will be notified. He will be responsible to inform the main assessor who will decide if the participant can continue. All adverse events will be kept in an Excel file and will be published with the rest of the results. A relevant study reported 2 below knee DVT (before DVT prophylaxis was added to the protocol) [ 11 ]. To minimize the possibility of such an adverse event our protocol follows the same DVT risk mitigation strategies (hydration, calf pump exercises and Rivaroxiban 10 mg for the first 8 weeks). 2.13 Protocol amendments Any necessary amendments will be done through an interpointed investigator. Communication between assessor and physiotherapists or participants will only be done through him in a way that study blinding is not affected. 2.14 Confidentiality All records that contain names or other personal identifiers will be locked in the main investigator’s office. All documents will be destroyed upon study publication. 2.15 Declaration of interest All authors have completed the ICMJE uniform disclosure form at http://www.icmje.org/disclosure-of-interest/ and declare: no support from any organisation for the submitted work; no financial relationships with any organisations that might have an interest in the submitted work in the previous three years; no other relationships or activities that could appear to have influenced the submitted work. . 3. Discussion Emerging evidence suggests that one of the primary barriers to ACL healing is the physical separation between the two ruptured ends of the ligament, which may prevent the natural restoration of fibre continuity. Based on this understanding, we propose that a conservative period of joint immobilisation in a flexed knee position—designed to minimise the gap between the torn ends—may facilitate an optimal environment for spontaneous ligament healing. However, prolonged use of a knee brace and joint immobilisation can contribute to significant muscle atrophy, particularly in the quadriceps. To mitigate this adverse effect, the incorporation of BFR training during the immobilisation period may offer a viable solution. BFR exercises have been shown to stimulate muscle hypertrophy, and strength gains even at low training intensities, making them particularly suitable for use in patients with limited mobility or weight-bearing capacity. The present study will be the first to investigate the effects of BFR exercise as part of a completely conservative rehabilitation programme. Additionally, will be the first to evaluate the potential benefits of the method in matter of healing of the ligament. In case of positive results, the suggested methodology might provide an alternative to surgical intervention as conservative management of the completely ruptured ACL. In conclusion, we propose that a rehabilitation protocol combining joint immobilisation with BFR exercise presents a promising conservative approach for individuals with acute, complete ACL tears. This integrated strategy could potentially support ligament healing, preserve muscle mass, and ultimately reduce overall recovery time, offering an alternative to immediate surgical intervention in selected cases. Abbreviations ACL, anterior cruciate ligament ACLOAS, Anterior Cruciate Ligament OsteoArthritis Score BFR, blood flow restriction ES, effect size IKDC, International Knee Documentation Committee MRI, magnetic resonance imaging SET, star execution test VAS, Visual Analogue Scale ATT, Anterior Tibial Translation ACLR, anterior cruciate ligament reconstruction RCT, Randomised Controlled Trial CERT, Consensus on Exercise Reporting Template DVT, Deep Vein Thrombosis ITT, Intention To Treat Declarations Ethics approval and consent to participate This protocol was approved by the Cyprus National Bioethics Committee (ΕΕΒΚ/ΕΠ/2024/70) and registered on ClinicalTrials.gov (Registration number: NCT06727344).Participation will be entirely voluntary, and all potential participants will receive comprehensive verbal and written information regarding the study’s purpose, methodology, potential benefits, and possible side effects. Those who agree to participate will be required to provide written informed consent before the trial commences and will be explicitly informed of their right to withdraw at any time without providing a reason. Consent for publication Not applicable Availability of data materials Materials described in the manuscript, including all relevant raw data, will be available to any scientist wishing to use them for non-commercial purposes, without breaching participant confidentiality. Our results will be published as supplementary files using a code instead of participant names. The code will be relevant to only two indirect identifiers (treatment and series) ensuring anonymization [36] . For example, the first patient who joined the intervention group will receive the code “BFR-1” in published supplementary files. Competing interests The authors declare that they have no competing interests. Funding This research received no external funding. Authors’ contributions AP: Conceptualisation, Writing, review and editing, Methodology, and statistical analysis KG: Conceptualisation, review and editing, Methodology, statistical analysis, and supervising. AK : Conceptualisation, review and editing, Methodology and supervising. CK: Conceptualisation and review. All authors read and approved the final manuscript. Acknowledgements: All MRIs will be conducted at OPSIS diagnostic center after a relevant agreement. For the purposes of our study E-sense ROM Knee brace – Ref: RS3000 will be used. All participants will receive a discount due to a relevant agreement with local distributor (Orthohouse). References Ardern CL, Taylor NF, Feller JA, Webster KE. Fifty-five per cent return to competitive sport following anterior cruciate ligament reconstruction surgery: An updated systematic review and meta-analysis including aspects of physical functioning and contextual factors, Br J Sports Med , vol. 48, no. 21, pp. 1543–1552, Nov. 2014, 10.1136/bjsports-2013-093398 Lie MM, Risberg MA, Storheim K, Engebretsen L, Øiestad BE. What’s the rate of knee osteoarthritis 10 years after anterior cruciate ligament injury? An updated systematic review, Br J Sports Med , vol. 53, no. 18, pp. 1162–1167, Sep. 2019, 10.1136/bjsports-2018-099751 Pitsillides A, Stasinopoulos D, Giannakou K. Healing potential of the anterior cruciate ligament in terms of fiber continuity after a complete rupture: A systematic review, Oct. 01, 2021, Churchill Livingstone . 10.1016/j.jbmt.2021.06.003 Pearson SJ, Hussain SR. A Review on the Mechanisms of Blood-Flow Restriction Resistance Training-Induced Muscle Hypertrophy. Sports Med. 2014. 10.1007/s40279-014-0264-9 . 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Sep., Measurement properties for muscle strength tests following anterior cruciate ligament and/or meniscus injury: What tests to use and where do we need to go? A systematic review with meta-analyses for the OPTIKNEE consensus, Br J Sports Med , vol. 56, no. 24, pp. 1422–1431, 2022, 10.1136/BJSPORTS-2022-105498 Stark T, Walker B, Phillips JK, Fejer R, Beck R. Hand-held dynamometry correlation with the gold standard isokinetic dynamometry: A systematic review. PM R. May 2011;3(5):472–9. 10.1016/J.PMRJ.2010.10.025 . Ferreira IC, Souza MA, Júnior MA, Silveira-Nunes G, Barbosa MA, Barbosa AC. Validity of a portable hanging scale to assess the isometric muscle strength during knee movement, J Bodyw Mov Ther , vol. 28, pp. 433–438, Oct. 2021, 10.1016/J.JBMT.2021.06.004 Roemer FW, Frobell R, Lohmander LS, Niu J, Guermazi A. Anterior cruciate ligament osteoarthritis score (ACLOAS): Longitudinal MRI-based whole joint assessment of anterior cruciate ligament injury. Osteoarthritis Cartilage. 2014;22(5):668–82. 10.1016/j.joca.2014.03.006 . Ganko A, Engebretsen L, Ozer H. The rolimeter: a new arthrometer compared with the KT-1000. Knee Surg Sports Traumatol Arthrosc. 2000;8(1):36–9. 10.1007/S001670050008 . Munro AG, Herrington LC. Between-session reliability of the star excursion balance test, Physical Therapy in Sport , vol. 11, no. 4, pp. 128–132, Nov. 2010, 10.1016/j.ptsp.2010.07.002 Dobija L, et al. Measurement properties of the Star Excursion Balance Test in patients with ACL deficiency. Phys Ther Sport. Mar. 2019;36:7–13. 10.1016/J.PTSP.2018.12.010 . Bolgla LA, Keskula DR. Reliability of lower extremity functional performance tests. J Orthop Sports Phys Ther. 1997;26(3):138–42. 10.2519/jospt.1997.26.3.138 . Höher J, et al. A Single-Leg Vertical Hop Test Is an Effective Tool to Measure Functional Performance after Anterior Cruciate Ligament (ACL) Reconstruction. Appl Sci (Switzerland). Apr. 2024;14(8):3143. 10.3390/APP14083143/S1 . Soderberg GL, Ballantyne BT, Kestel LL. Reliability of lower extremity girth measurements after anterior cruciate ligament reconstruction. Physiother Res Int. 1996;1(1):7–16. 10.1002/PRI.43 . Boonstra AM, Schiphorst Preuper HR, Reneman MF, Posthumus JB, Stewart RE. Reliability and validity of the visual analogue scale for disability in patients with chronic musculoskeletal pain, Int J Rehabil Res , vol. 31, no. 2, pp. 165–169, Jun. 2008, 10.1097/MRR.0B013E3282FC0F93 Hughes L et al. Sep., Examination of the comfort and pain experienced with blood flow restriction training during post-surgery rehabilitation of anterior cruciate ligament reconstruction patients: A UK National Health Service trial, Phys Ther Sport , vol. 39, pp. 90–98, 2019, 10.1016/J.PTSP.2019.06.014 Svantesson E et al. Jul., Clinical Outcomes After Anterior Cruciate Ligament Injury: Panther Symposium ACL Injury Clinical Outcomes Consensus Group., Orthop J Sports Med , vol. 8, no. 7, p. 2325967120934751, 2020, 10.1177/2325967120934751 Koumantakis GA, Tsoligkas K, Papoutsidakis A, Ververidis A, Drosos GI. Cross-cultural adaptation and validation of the International Knee Documentation Committee Subjective Knee Form in Greek. J Orthop Traumatol. Jun. 2016;17(2):123–9. 10.1007/S10195-015-0362-Y/TABLES/3 . Panagopoulos A, et al. Cross-Cultural Adaptation of the Greek Versions of the Lysholm Knee Scoring Scale and Tegner Activity Scale. Cureus Jul. 2020. 10.7759/cureus.9372 . Kontodimopoulos N, Pappa E, Niakas D, Yfantopoulos J, Dimitrakaki C, Tountas Y. Validity of the EuroQoL (EQ-5D) Instrument in a Greek General Population. Value Health. Dec. 2008;11(7):1162–9. 10.1111/J.1524-4733.2008.00356.X . Svantesson E et al. Aug., Clinical outcomes after anterior cruciate ligament injury: panther symposium ACL injury clinical outcomes consensus group, Knee Surgery, Sports Traumatology, Arthroscopy , vol. 28, no. 8, pp. 2415–2434, 2020, 10.1007/s00167-020-06061-x Faul F, Erdfelder E, Lang A-G, Buchner A. G*Power 3: a flexible statistical power analysis program for the social, behavioral, and biomedical sciences. Behav Res Methods. May 2007;39(2):175–91. 10.3758/bf03193146 . Vieira de Melo RF, Komatsu WR, de Freitas MS, Vieira de Melo ME, Cohen M. Comparison of Quadriceps and Hamstring Muscle Strength after Exercises with and without Blood Flow Restriction following Anterior Cruciate Ligament Surgery: A Randomized Controlled Trial. J Rehabil Med. Nov. 2022;54(3):jrm00337. 10.2340/jrm.v54.2550 . Clark L, Dean A, Mitchell A, Torgerson DJ. Envelope use and reporting in randomised controlled trials: A guide for researchers. Res Methods Med Health Sci. Jan. 2021;2(1):2–11. 10.1177/2632084320957204/ASSET/ACC3A881-A394-416E-9D5A-D8573279BB8F/ASSETS/IMAGES/LARGE/10.1177_2632084320957204-FIG1.JPG . Doig GS, Simpson F. Randomization and allocation concealment: a practical guide for researchers, J Crit Care , vol. 20, no. 2, pp. 187–191, Jun. 2005, 10.1016/J.JCRC.2005.04.005 Hrynaszkiewicz I, Norton ML, Vickers AJ, Altman DG. Preparing raw clinical data for publication: Guidance for journal editors, authors, and peer reviewers. Trials. Jan. 2010;11(1):1–5. 10.1186/1745-6215-11-9/TABLES/1 . Additional Declarations No competing interests reported. Cite Share Download PDF Status: Published Journal Publication published 01 Dec, 2025 Read the published version in Journal of Orthopaedic Surgery and Research → Version 1 posted Editorial decision: Revision requested 12 Jul, 2025 Reviews received at journal 11 Jul, 2025 Reviews received at journal 01 Jul, 2025 Reviewers agreed at journal 29 Jun, 2025 Reviewers agreed at journal 29 Jun, 2025 Reviewers invited by journal 23 Jun, 2025 Editor assigned by journal 23 Jun, 2025 Submission checks completed at journal 23 Jun, 2025 First submitted to journal 20 Jun, 2025 You are reading this latest preprint version Research Square lets you share your work early, gain feedback from the community, and start making changes to your manuscript prior to peer review in a journal. As a division of Research Square Company, we’re committed to making research communication faster, fairer, and more useful. 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Also discoverable on Platform About Our Team In Review Editorial Policies Advisory Board Help Center Resources Author Services Accessibility API Access RSS feed Manage Cookie Preferences © Research Square 2026 | ISSN 2693-5015 (online) Privacy Policy Terms of Service Do Not Sell My Personal Information {"props":{"pageProps":{"initialData":{"identity":"rs-6940729","acceptedTermsAndConditions":true,"allowDirectSubmit":false,"archivedVersions":[],"articleType":"Study protocol","associatedPublications":[],"authors":[{"id":476218466,"identity":"1e6dad4e-60ea-40bf-b0eb-d7adb44ac26a","order_by":0,"name":"Alexios Pitsillides","email":"data:image/png;base64,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","orcid":"","institution":"European University Cyprus","correspondingAuthor":true,"prefix":"","firstName":"Alexios","middleName":"","lastName":"Pitsillides","suffix":""},{"id":476218467,"identity":"929cc861-03d1-422b-a43a-068fce4e7e34","order_by":1,"name":"Antonis Constantinou","email":"","orcid":"","institution":"European University Cyprus","correspondingAuthor":false,"prefix":"","firstName":"Antonis","middleName":"","lastName":"Constantinou","suffix":""},{"id":476218468,"identity":"da63bb8c-bfab-4649-8687-1de30beb963f","order_by":2,"name":"Christos Karagiannis","email":"","orcid":"","institution":"European University Cyprus","correspondingAuthor":false,"prefix":"","firstName":"Christos","middleName":"","lastName":"Karagiannis","suffix":""},{"id":476218469,"identity":"afd849f0-e4bd-407e-9c1b-a15837d662d5","order_by":3,"name":"Konstantinos Giannakou","email":"","orcid":"","institution":"European University Cyprus","correspondingAuthor":false,"prefix":"","firstName":"Konstantinos","middleName":"","lastName":"Giannakou","suffix":""}],"badges":[],"createdAt":"2025-06-20 17:08:07","currentVersionCode":1,"declarations":"","doi":"10.21203/rs.3.rs-6940729/v1","doiUrl":"https://doi.org/10.21203/rs.3.rs-6940729/v1","draftVersion":[],"editorialEvents":[{"content":"https://doi.org/10.1186/s13018-025-06285-y","type":"published","date":"2025-12-01T15:57:17+00:00"}],"editorialNote":"","failedWorkflow":false,"files":[{"id":85642887,"identity":"2fb68331-cacf-40bc-add5-c0847386316c","added_by":"auto","created_at":"2025-06-30 08:04:41","extension":"jpg","order_by":1,"title":"Figure 1","display":"","copyAsset":false,"role":"figure","size":55386,"visible":true,"origin":"","legend":"\u003cp\u003eSee image above for figure legend.\u003c/p\u003e","description":"","filename":"Picture1.jpg","url":"https://assets-eu.researchsquare.com/files/rs-6940729/v1/46c83b9d60cd2dc0b7ff570a.jpg"},{"id":97723803,"identity":"89debb4a-2786-425c-b516-77306e6115cc","added_by":"auto","created_at":"2025-12-08 16:07:02","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":1195316,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-6940729/v1/9aae1f1a-d254-465d-9e56-4c09181468a7.pdf"}],"financialInterests":"No competing interests reported.","formattedTitle":"Conservative Treatment using Blood Flow Restriction in Individuals with Complete Anterior Cruciate Ligament Rupture: Protocol for a Randomised Clinical Trial","fulltext":[{"header":"1. Background","content":"\u003cp\u003eAnterior cruciate ligament (ACL) reconstruction is a widely practiced surgical intervention for ACL ruptures, particularly among athletes. However, current evidence suggests that reconstruction does not guarantee a full return to pre-injury function [\u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e]. Approximately 80% of participants resume sports participation post-surgery, yet only 65% return to their pre-injury performance levels, and merely 55% reach a competitive standard [\u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e]. Consequently, many individuals report reduced quality of life following surgery, and the risk of developing post-traumatic osteoarthritis remains elevated [\u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e].\u003c/p\u003e \u003cp\u003eThese limitations highlight the need to explore alternative treatment strategies, particularly those that promote intrinsic healing of the ACL. Unlike other knee ligaments, the ACL demonstrates limited spontaneous healing capacity, although the mechanisms underlying this difference remain unclear. A recent systematic review indicated that proximal ACL ruptures may possess a greater regenerative potential than mid-substance tears, suggesting a role for conservative management strategies [\u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e3\u003c/span\u003e]. Such approaches may include structured bracing to reduce knee laxity, progressive joint strengthening, early mobilisation, and load-bearing as tolerated [\u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e3\u003c/span\u003e]. In contrast a prolonged period of immobilization might result in muscle atrophy.\u003c/p\u003e \u003cp\u003eIn this context, Blood Flow Restriction (BFR) training emerges as a promising adjunct to conservative rehabilitation. BFR involves applying external pressure via inflatable cuffs to partially occlude arterial blood flow and fully restrict venous return during low-load resistance exercises [\u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e4\u003c/span\u003e], [\u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e5\u003c/span\u003e], [\u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e6\u003c/span\u003e]. This technique has demonstrated muscle hypertrophy and strength gains comparable to those observed with high-load resistance training, making it particularly suitable for early rehabilitation phases when high loads are contraindicated [\u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e4\u003c/span\u003e], [\u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e5\u003c/span\u003e], [\u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e6\u003c/span\u003e].\u003c/p\u003e \u003cp\u003e \u003cb\u003eObjective\u003c/b\u003e:\u003c/p\u003e \u003cp\u003eThe aim of this study is to evaluate the effectiveness of BFR training in individuals with complete ACL rupture. Specifically, the study compares a conservative intervention involving bracing and BFR training with an identical bracing protocol combined with sham BFR (placebo) training, to assess the added value of BFR in functional recovery and joint stability. We hypothesise that the participants in the BFR group would experience less atrophy, reduced pain, higher functionality levels and better quality of life.\u003c/p\u003e"},{"header":"2. Methods","content":"\u003cdiv id=\"Sec3\" class=\"Section2\"\u003e \u003ch2\u003e2.1 Study Design\u003c/h2\u003e \u003cp\u003eA double-blind, two-arm Randomised Clinical Trial (RCT) will be conducted. Participants in the intervention group will undergo an exercise protocol using BFR training, while participants in the control group will follow the same exercise protocol but with sham BFR training. Both groups will follow the same brace protocol. This RCT is registered at ClinicalTrials.gov (Registration number: NCT06727344) and was designed in accordance with the SPIRIT Statement for clinical trial protocols [\u003cspan citationid=\"CR7\" class=\"CitationRef\"\u003e7\u003c/span\u003e]. Reporting of the exercise interventions will follow the Consensus on Exercise Reporting Template (CERT) checklist [\u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e8\u003c/span\u003e].\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec4\" class=\"Section2\"\u003e \u003ch2\u003e2.2 Eligibility criteria\u003c/h2\u003e \u003cp\u003eIndividuals aged between 18 and 40 years will be eligible to participate in the study. The main inclusion criterion is the presence of an acute (0\u0026ndash;4 days) or subacute (5\u0026ndash;14 days) ACL tear confirmed by Magnetic Resonance Imaging (MRI) [\u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e9\u003c/span\u003e]. Participants must be able to read and communicate fluently in Greek and be willing to keep their injured leg immobilised for the period specified in the study protocol.\u003c/p\u003e \u003cp\u003eTo be included in the study, a signed eligibility form must be submitted to the principal investigator by the participant's personal and/or treating physician. The form outlines all medical conditions that preclude the study participation.\u003c/p\u003e \u003cp\u003eExclusion Criteria: Participants will be excluded from the study if they present with any of the following:\u003c/p\u003e \u003cp\u003e \u003cul\u003e \u003cli\u003e \u003cp\u003eCardiovascular conditions: coronary artery disease, unstable hypertension, peripheral vascular disease, deep vein thrombosis, blood clotting disorders, cardiopulmonary diseases, atherosclerotic vessels, myocardial ischaemia, left ventricular dysfunction, haemophilia, vascular endothelial dysfunction, venous insufficiency, or Marfan syndrome [\u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e10\u003c/span\u003e].\u003c/p\u003e \u003c/li\u003e \u003cli\u003e \u003cp\u003eMusculoskeletal injuries: recent muscle injuries or fractures, postoperative oedema, open fractures or wounds, neurological limitations or clinical or MRI evidence of concomitant injuries that require surgery (e.g. an unstable bucket-handle meniscal tear).\u003c/p\u003e \u003c/li\u003e \u003cli\u003e \u003cp\u003eLifestyle-related conditions: Body Mass Index (BMI)\u0026thinsp;\u0026gt;\u0026thinsp;25, diabetes, dyslipidaemia, or unwillingness to discontinue nutritional supplements during the intervention period [\u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e10\u003c/span\u003e].\u003c/p\u003e \u003c/li\u003e \u003cli\u003e \u003cp\u003ePregnancy [\u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e10\u003c/span\u003e]\u003c/p\u003e \u003c/li\u003e \u003cli\u003e \u003cp\u003eFamily medical history: thromboembolic events, atrial fibrillation, heart failure, or cancer [\u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e10\u003c/span\u003e].\u003c/p\u003e \u003c/li\u003e \u003cli\u003e \u003cp\u003eMedications use: current use of medications that increase blood clotting, including hormones and contraceptives [\u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e10\u003c/span\u003e].\u003c/p\u003e \u003c/li\u003e \u003cli\u003e \u003cp\u003eContraindications to BFR: presence of open wounds or serious skin conditions such as allergies to the cuff material identified during the initial evaluation study.\u003c/p\u003e \u003c/li\u003e \u003c/ul\u003e \u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec5\" class=\"Section2\"\u003e \u003ch2\u003e2.3 Interventions\u003c/h2\u003e \u003cp\u003ePrior to any intervention, at the beginning of the first session, all participants will have a familiarisation session with both the exercise protocol and BFR procedure. For exercise protocol familiarisation, participants will perform few repetitions of each exercise without the BFR device. For BFR familiarization, the cuff will be applied, and the calibration process will be conducted. All exercises will be paced using a metronome set at 60 beats per minute (bpm), with each muscle contraction phase (concentric or eccentric) lasting 2 seconds [\u003cspan citationid=\"CR11\" class=\"CitationRef\"\u003e11\u003c/span\u003e]. The participants will be seated facing a screen to follow the rhythm, which will be provided as an acoustic and visual stimulus. Both physiotherapists delivering the intervention will be trained to ensure consistency. The intervention period will be 12 weeks divided in 5 Phases as illustrated in Fig.\u0026nbsp;1.\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003cdiv id=\"Sec6\" class=\"Section3\"\u003e \u003ch2\u003e2.3.1 Intervention Group\u003c/h2\u003e \u003cp\u003eThe intervention group will consist of participants with acute (0\u0026ndash;4 days) or subacute (5\u0026ndash;14 days) ACL tears who meet the eligibility criteria. Participants in this group will follow the splint-use protocol [\u003cspan citationid=\"CR11\" class=\"CitationRef\"\u003e11\u003c/span\u003e].\u003c/p\u003e \u003cdiv id=\"Sec7\" class=\"Section4\"\u003e \u003ch2\u003e2.3.1.1 Splint use protocol.\u003c/h2\u003e \u003cp\u003eDuring the first three weeks (Phase 1), the knee will be immobilised at 90\u0026deg; using a splint (E-sense ROM Knee brace \u0026ndash; Ref: RS3000). Participants will perform non-weight-bearing ambulation with the assistance of walking aids, as needed based on age and mobility level. In the fourth and fifth week (Phase 2), the range of motion of the splint will be adjusted to 60\u0026ndash;90\u0026deg; and 30\u0026ndash;90\u0026deg;, respectively, while non-weight-bearing ambulation continues. During the sixth week (Phase 3), the splint will allow full flexion and 0\u0026deg; extension, thus preventing hyperextension of the joint. From the seventh week onwards (Phase 4), the splint will be removed and full weight-bearing without restrictions will be permitted. Table\u0026nbsp;\u003cspan refid=\"Tab1\" class=\"InternalRef\"\u003e1\u003c/span\u003e outlines the intervention protocol in terms of weight-bearing status and brace use.\u003c/p\u003e \u003cp\u003e \u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab1\" border=\"1\"\u003e \u003ccaption language=\"En\"\u003e \u003cdiv class=\"CaptionNumber\"\u003eTable 1\u003c/div\u003e \u003cdiv class=\"CaptionContent\"\u003e \u003cp\u003ePostoperative Weight-Bearing and Knee Brace Protocol by Rehabilitation Phase\u003c/p\u003e \u003c/div\u003e \u003c/caption\u003e \u003ccolgroup cols=\"3\"\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e \u003cthead\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c1\"\u003e \u003cp\u003ePhase\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c2\"\u003e \u003cp\u003eWeek\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c3\"\u003e \u003cp\u003eWeight bearing and brace\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e1\u0026ndash;3\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eUse of brace with knee immobilized at 90\u003csup\u003eο\u003c/sup\u003e.\u003c/p\u003e \u003cp\u003eNon weight bearing.\u003c/p\u003e \u003cp\u003eUse of walking aids.\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e2\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e4\u0026ndash;5\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e4th: Brace at 60\u0026ndash;90\u003csup\u003eo\u003c/sup\u003e.\u003c/p\u003e \u003cp\u003e5th: Brace at 30\u0026ndash;90\u003csup\u003eo\u003c/sup\u003e\u003c/p\u003e \u003cp\u003eNon weight bearing.\u003c/p\u003e \u003cp\u003eUse of walking aids.\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e3\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e6\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eBrace from 0\u003csup\u003eο\u003c/sup\u003e to full flexion (avoiding hyperextension).\u003c/p\u003e \u003cp\u003ePartial weight bearing.\u003c/p\u003e \u003cp\u003eUse of walking aids.\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e4\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e7\u0026ndash;10\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eFull weight bearing.\u003c/p\u003e \u003cp\u003eEnd of brace use.\u003c/p\u003e \u003cp\u003eEnd of walking aids use.\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e5\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e10\u0026ndash;12\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eFull weight bearing.\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003c/tbody\u003e \u003c/colgroup\u003e \u003c/table\u003e\u003c/div\u003e \u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec8\" class=\"Section4\"\u003e \u003ch2\u003e2.3.1.2 BFR training protocol.\u003c/h2\u003e \u003cp\u003eRegarding the exercise programme, during Phase 1, participants will perform seated isometric quadriceps and hamstring contractions guided by a visual stimulus from an electronic hand dynamometer. For each exercise, participants will complete a total of 75 repetitions divided into four sets (30, 15, 15, 15) at 30% of the maximum strength of the uninjured leg. The scheme of 75 repetitions is suggested as sufficient volume to lead to adaptations and thus repetitions to failure may not be needed [\u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e9\u003c/span\u003e]. The required cuff pressure to achieve complete vascular occlusion of the lower extremity will be measured at rest, with the participant seated at the edge of an examination bed \u0026mdash;as during exercises of Phase 1 and 2, due to dependence on body posture[\u003cspan citationid=\"CR12\" class=\"CitationRef\"\u003e12\u003c/span\u003e]. The cuff will be positioned on the most proximal part of the thigh [\u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e10\u003c/span\u003e].\u003c/p\u003e \u003cp\u003eAn automated, personalised tourniquet device (MAD-UP Pro system, Angers, France) will be used to calculate each participant\u0026rsquo;s occlusion pressure. This device has acceptable accuracy and high reliability [\u003cspan citationid=\"CR12\" class=\"CitationRef\"\u003e12\u003c/span\u003e]. Both groups will follow the same exercise protocol and parameters. The intervention group pressure will be set at 80% and for sham group at 15%. Phases 1 and 2 will be performed using the installed settings of the device labelled as \u0026ldquo;free\u0026rdquo; mode, due to the inability of the device to recognise any movement below approximately 60\u003csup\u003eo\u003c/sup\u003e. From Phase 3 onward, the installed \u0026ldquo;rehabilitation\u0026rdquo; settings will be used.[\u003cspan citationid=\"CR12\" class=\"CitationRef\"\u003e12\u003c/span\u003e], [\u003cspan citationid=\"CR13\" class=\"CitationRef\"\u003e13\u003c/span\u003e]. In Phase 2, the exercise protocol will be maintained as in Phase 1. Additionally, the \"sliding\" exercise will be introduced where the heel is dragged on the bed causing knee flexion, along with the skateboard sliding exercise in a seated position within the allowed range of motion. The exercise parameters (volume of repetitions, sets, execution speed, breaks) will remain unchanged. In Phase 3, single-leg squats of up to 60\u0026deg; will be incorporated, while exercise parameters will remain unchanged. In Phase 4, the exercise protocol will be modified. Participants will begin with 5 min on a stationary bike (without BFR), and quadriceps/hamstring isometrics will be replaced with resistance exercises for knee extension and flexion seated on the edge of a bed using KEISER device to set the ideal resistance. Sliding and single-leg squats will be performed with an increased range of motion (up to 90\u0026deg;), and a 30 cm step climb will be added. The exercise parameters will remain consistent with previous phases. In Phase 5 (final phase), gait retraining on a treadmill for 5 min and Y-balance exercises will be introduced, both without BFR. Rest intervals between sets will be 30 s, and the interval between exercises will be 1 min.\u003c/p\u003e \u003cp\u003eThe intervention group will perform the exercise programme with lower-extremity BFR. The cuff pressure will be reduced to 10% (minimum allowed by device) during the rest intervals. The execution speed of the exercises will be 2 s for contraction, followed by 2 s of release. All isometric exercises will be held for 3 s.\u003c/p\u003e \u003cp\u003eCryotherapy and anti-inflammatory medication will be prohibited to minimise impairment of the acute inflammatory response [\u003cspan citationid=\"CR11\" class=\"CitationRef\"\u003e11\u003c/span\u003e]. Participants will be encouraged to hydrate well, perform calf pump exercises (included in home exercise plan) and take Rivaroxiban 10 mg for the first 8 weeks (prescribed by their doctor) as Deep Vein Thrombosis (DVT) risk mitigation strategy. The use of paracetamol will be allowed in cases of intolerable pain but will be reported to the principal physiotherapist at each session. Table\u0026nbsp;\u003cspan refid=\"Tab2\" class=\"InternalRef\"\u003e2\u003c/span\u003e presents in detail the exercise protocol our intervention.\u003c/p\u003e \u003cp\u003e \u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab2\" border=\"1\"\u003e \u003ccaption language=\"En\"\u003e \u003cdiv class=\"CaptionNumber\"\u003eTable 2\u003c/div\u003e \u003cdiv class=\"CaptionContent\"\u003e \u003cp\u003eInjured Leg Exercise Protocol\u003c/p\u003e \u003c/div\u003e \u003c/caption\u003e \u003ccolgroup cols=\"6\"\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c4\" colnum=\"4\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c5\" colnum=\"5\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c6\" colnum=\"6\"\u003e\u003c/div\u003e \u003cthead\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c1\"\u003e \u003cp\u003ePhase\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c2\"\u003e \u003cp\u003eExercise\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c3\"\u003e \u003cp\u003ePosition\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c4\"\u003e \u003cp\u003eEquipment\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c5\"\u003e \u003cp\u003eParameters\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c6\"\u003e \u003cp\u003eRequired time (min)\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\" morerows=\"1\" rowspan=\"2\"\u003e \u003cp\u003e1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eQuadriceps isometric (with biofeedback)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eSeated, knee at 90\u003csup\u003eo\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003eHand-held dynamometer (Kinvent)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e4 sets with a total of 75 reps (30,15,15,15) at 30% of healthy leg peak force.\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e5.25\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eHamstrings isometric (with biofeedback)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eProne, knee at 90\u003csup\u003eo\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003eHand-held dynamometer (Kinvent)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e4 sets with a total of 75 reps (30,15,15,15) at 30% of healthy leg peak force.\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e5.25\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colspan=\"5\" nameend=\"c5\" namest=\"c1\"\u003e \u003cp\u003eTime required to complete phase: Exercises 10.5 min, 4 min breaks.\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e14.5\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\" morerows=\"3\" rowspan=\"4\"\u003e \u003cp\u003e2\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eQuadriceps isometric (with biofeedback)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eSeated, knee at 90\u003csup\u003eo\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003eHand-held dynamometer (Kinvent)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e4 sets with a total of 75 reps (30,15,15,15) at 30% of healthy leg peak force.\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e5.25\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eHamstrings isometric (with biofeedback)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eProne, knee at 90\u003csup\u003eo\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003eHand-held dynamometer (Kinvent)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e4 sets with a total of 75 reps (30,15,15,15) at 30% of healthy leg peak force.\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e5.25\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eHeel slide\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eLaying on a bed\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003eSock\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e4 sets with a total of 75 reps (30,15,15,15)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e5.25\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eHeel slide seated with leg on a skateboard\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eChair\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003eSkateboard\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e4 sets with a total of 75 reps (30,15,15,15)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e5.25\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colspan=\"5\" nameend=\"c5\" namest=\"c1\"\u003e \u003cp\u003eTime required to complete phase: Exercises 16 min, 6.5 min breaks.\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e27.5\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e3\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eSemi \u0026ndash; squats up to 60\u003csup\u003eο\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eStanding\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003eChair\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e4 sets with a total of 75 reps (30,15,15,15) at 30% of healthy leg peak force.\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e6.5\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colspan=\"5\" nameend=\"c5\" namest=\"c1\"\u003e \u003cp\u003eTime required to complete phase: Exercises 22.5 min, 8.5 min breaks.\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e36\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\" morerows=\"3\" rowspan=\"4\"\u003e \u003cp\u003e4\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eKnee extension\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eSeated\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003eKEISER\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e4 sets with a total of 75 reps (30,15,15,15) at 30% of healthy leg peak force.\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e6.5\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eKnee flexion\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eProne\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003eKEISER\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e4 sets with a total of 75 reps (30,15,15,15) at 30% of healthy leg peak force.\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e6.5\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eStep\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eStanding\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003eStep 30cm\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e4 sets with a total of 75 reps (30,15,15,15) at 30% of healthy leg peak force.\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e6.5\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eStationary bike *\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eSeated\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003eStationary bike\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e5 min\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e5\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colspan=\"5\" nameend=\"c5\" namest=\"c1\"\u003e \u003cp\u003eTime required to complete phase: Exercises 36.5 min, 12 min breaks.\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e53.5\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\" morerows=\"1\" rowspan=\"2\"\u003e \u003cp\u003e5\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eGait retraining *\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eStanding\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003eWalkway\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e5 min\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e5\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eBalance exercise (Υ test)*\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eStanding\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003eTape\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e5 reps at each direction\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e5\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colspan=\"5\" nameend=\"c5\" namest=\"c1\"\u003e \u003cp\u003eTime required to complete phase: Exercises 58.5 min, 14 min breaks.\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e77.5\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colspan=\"6\" nameend=\"c6\" namest=\"c1\"\u003e \u003cp\u003eGenerally: break within sets 30 sec, break between exercises 1 min. Pressure deflated during breaks. Exercise execution speed 2 sec concentric 2 sec eccentric. Hold at isometric exercises 3 sec.\u003c/p\u003e \u003cp\u003e* = Exercise without BFR\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003c/tbody\u003e \u003c/colgroup\u003e \u003c/table\u003e\u003c/div\u003e \u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec9\" class=\"Section4\"\u003e \u003ch2\u003e2.3.1.3 Home based program.\u003c/h2\u003e \u003cp\u003eParticipants of both groups (BFR and Sham-BFR) will receive the same, home-based, exercise programme, via a mobile platform that will allow monitoring of compliance. Additionally, the platform will ensure correct exercise execution through instructional videos and specific exercise parameters. Such intervention has been reported to improve participants compliance and improve clinical outcomes in ACL post-surgery patients [\u003cspan citationid=\"CR13\" class=\"CitationRef\"\u003e13\u003c/span\u003e].\u003c/p\u003e \u003cp\u003eDuring Phase 1, exercises will include seated hip flexion, hip extension, hip adduction, abduction using a red resistance band or a ball. Each exercise will be performed as three sets of 10 repetitions, twice daily. These exercises will be selected to preserve as much muscle strength as possible in the muscle groups around the knee, specifically the hip. The position in which the exercises will be performed will be chosen for convenience due to the splint. During the Phase 2, glides will be added to the programme. In the 3rd phase, single-leg sit-ups of up to 45\u0026deg; will be introduced. During the 4th and 5th phases, all hip exercises (flexion, extension, abduction, and adduction) will be performed using a higher resistance band (blue bands). Slides and sit-ups of up to 45\u0026deg; will be performed up to 90\u0026deg;. Exercise volume and frequency will remain identical. Load progression will be achieved through the increase of band resistance. Resistance will be determined by the band colour. All participants will be provided with the necessary equipment (bands). Detailed description is presented in Table\u0026nbsp;\u003cspan refid=\"Tab3\" class=\"InternalRef\"\u003e3\u003c/span\u003e.\u003c/p\u003e \u003cp\u003e \u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab3\" border=\"1\"\u003e \u003ccaption language=\"En\"\u003e \u003cdiv class=\"CaptionNumber\"\u003eTable 3\u003c/div\u003e \u003cdiv class=\"CaptionContent\"\u003e \u003cp\u003eHome Exercise Programme and Exercise Parameters.\u003c/p\u003e \u003c/div\u003e \u003c/caption\u003e \u003ccolgroup cols=\"5\"\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c4\" colnum=\"4\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c5\" colnum=\"5\"\u003e\u003c/div\u003e \u003cthead\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c1\"\u003e \u003cp\u003ePhase\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c2\"\u003e \u003cp\u003eExercise\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c3\"\u003e \u003cp\u003ePosition\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c4\"\u003e \u003cp\u003eEquipment\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c5\"\u003e \u003cp\u003eParameters\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\" morerows=\"4\" rowspan=\"5\"\u003e \u003cp\u003e1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eHip abduction\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eSeated\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003eChair\u003c/p\u003e \u003cp\u003eRed band\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e3 sets of 10 reps\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eHip extension\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eStanding (single leg)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003eChair\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e3 sets of 10 reps\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eHip flexion\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eSeated\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003eChair\u003c/p\u003e \u003cp\u003eRed band\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e3 sets of 10 reps\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eHip adduction\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eSeated\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003eChair\u003c/p\u003e \u003cp\u003eRed band\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e3 sets of 10 reps\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eHeel raises\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eSeated\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003eChair\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e3 sets of 10 reps\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\" morerows=\"1\" rowspan=\"2\"\u003e \u003cp\u003e2\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colspan=\"4\" nameend=\"c5\" namest=\"c2\"\u003e \u003cp\u003eSame as Phase 1 plus:\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eHeel slides \u0026ndash; according to pain\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eSupine\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003eBed\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e3 sets of 10 reps\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e3\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eSame as Phase 2 plus:\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003ePartial squat up to 45\u003csup\u003eo\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eStanding\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003eChair\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e3 sets of 10 reps\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\" morerows=\"6\" rowspan=\"7\"\u003e \u003cp\u003e4\u0026ndash;5\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eHip abduction with band\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eStanding\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003eChair\u003c/p\u003e \u003cp\u003eBlue band\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e3 sets of 10 reps\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eHip adduction with band\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eStanding\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003eChair\u003c/p\u003e \u003cp\u003eBlue band\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e3 sets of 10 reps\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eHip extension with band\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eStanding\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003eChair\u003c/p\u003e \u003cp\u003eBlue band\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e3 sets of 10 reps\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eHip flexion with band\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eStanding\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003eChair\u003c/p\u003e \u003cp\u003eBlue band\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e3 sets of 10 reps\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eHeel raises\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eStanding\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003eChair\u003c/p\u003e \u003cp\u003eBlue band\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e3 sets of 10 reps\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eSquats up to 90\u003csup\u003eo\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eStanding\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003eChair\u003c/p\u003e \u003cp\u003eBlue band\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e3 sets of 10 reps\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eHeel slides\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eSupine\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003eBed\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e3 sets of 10 reps\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003c/tbody\u003e \u003c/colgroup\u003e \u003c/table\u003e\u003c/div\u003e \u003c/p\u003e \u003c/div\u003e \u003c/div\u003e \u003cdiv id=\"Sec10\" class=\"Section3\"\u003e \u003ch2\u003e2.3.2 Control Group\u003c/h2\u003e \u003cp\u003eThe sham BFR protocol will mirror the intervention group\u0026rsquo;s exercise programme, except that sham pressure settings will be applied using the MAD-UP system [\u003cspan citationid=\"CR14\" class=\"CitationRef\"\u003e14\u003c/span\u003e]. Since the minimum allowable pressure on the device is 10%, the sham group\u0026rsquo;s cuff pressure will be set at 15%. This allows the therapist to deflate the cuff by 5% during breaks mimicking the procedure used in the intervention group, where the cuff is inflated during exercise and deflating during breaks.\u003c/p\u003e \u003c/div\u003e \u003c/div\u003e \u003cdiv id=\"Sec11\" class=\"Section2\"\u003e \u003ch2\u003e2.4 Outcome Measures\u003c/h2\u003e \u003cp\u003eThe outcome measures will be divided into three main categories. The first category will include measures for assessing the functionality and structure of the knee. The second category will consist of participant self-assessment questionnaires, and the third will focus on questionnaires evaluating the participant's quality of life [\u003cspan citationid=\"CR11\" class=\"CitationRef\"\u003e11\u003c/span\u003e].\u003c/p\u003e \u003cp\u003eInitial measurements will be conducted upon participant enrolment and will include magnetic resonance imaging (MRI), Lachman test, arthrometry, strength, swelling, Lysholm scale, Tegner scale, pain, balance, single-leg hop and exercise pain. At the beginning of each Phase, strength, swelling, and pain will be reassessed by the physical therapist responsible for each group. Final measurements will be taken at the conclusion of the intervention period and will include all baseline measurements.\u003c/p\u003e \u003cdiv id=\"Sec12\" class=\"Section3\"\u003e \u003ch2\u003e2.4.1 Functionality and Structure\u003c/h2\u003e \u003cdiv id=\"Sec13\" class=\"Section4\"\u003e \u003ch2\u003e2.4.1.1 Strength (Primary Outcome)\u003c/h2\u003e \u003cp\u003eStrength is the primary outcome, given its importance in long-term functional recovery following ACL injuries. Isokinetic strength assessment is the most recommended procedure for measuring strength and identifying deficits/differences in ACL injuries. This method has demonstrated satisfactory reliability and validity [\u003cspan citationid=\"CR15\" class=\"CitationRef\"\u003e15\u003c/span\u003e].\u003c/p\u003e \u003cp\u003eDue to the immediate use of a splint, strength assessment will be performed using a handheld electric dynamometer (Kinvent). This tool is considered reliable and valid instruments to assess muscle strength in clinical settings because of its ease of use, cost, compact size and portability [\u003cspan citationid=\"CR16\" class=\"CitationRef\"\u003e16\u003c/span\u003e]. The handheld dynamometer seems to be a reliable option (ICC values above 0.90) to measure knee extension muscle strength, particularly when two measurements are taken, and their average is used [\u003cspan citationid=\"CR17\" class=\"CitationRef\"\u003e17\u003c/span\u003e].\u003c/p\u003e \u003cp\u003eDuring Phase 1 and 2 \u0026ldquo;Sitting Knee Extension at 90\u003csup\u003eo\u003c/sup\u003e\u0026rdquo; and \u0026ldquo;Prone Knee Flexion at 90\u003csup\u003eo\u003c/sup\u003e\u0026rdquo; as described in Kinvent Physio mobile application will be implemented to identify the ideal exercise load. The sitting knee extension and prone knee flexion are isometric tests for the evaluation of the maximum neuromuscular capacities of the quadriceps and hamstrings at 90\u003csup\u003eo\u003c/sup\u003e of flexion, respectively. The procedures are well described and standardized within the application, ensuring consistency. These tests are widely used to quantify knee extensors strength in participants with ACL reconstruction [\u003cspan citationid=\"CR17\" class=\"CitationRef\"\u003e17\u003c/span\u003e].\u003c/p\u003e \u003cp\u003eDue to the locked position of the knee (90\u003csup\u003eo\u003c/sup\u003e) any maximal isometric effort of the injured limb could result in high anterior shear force, damaging any newly formed fibers. Thus, at Phase 1 and 2 the participant will be asked to perform isometric knee extension and flexion to failure. Then Holten diagram will be implemented to identify One Repetition maximum (1RM). At Phases 3 to 5 the Holten diagram with a submaximal weight will be used to the injured leg. To have comparability during the initial assessment strength will be evaluated with both procedures. Measurements during the intervention period will be taken by the principle physical therapists at the beginning of each phase.\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec14\" class=\"Section4\"\u003e \u003ch2\u003e2.4.1.2 Magnetic Resonance Imaging\u003c/h2\u003e \u003cp\u003eEach participant will undergo and initial and a final examination. MRI will be used to confirm ACL tears initially and reevaluate them at the end of the intervention period. The radiologist interpreting the images will be asked to grade the injury using the Anterior Cruciate Ligament Osteoarthritis Score (ACLOAS) system, a reliable tool for evaluating acute ACL ruptures and assessing tissue continuity [\u003cspan citationid=\"CR18\" class=\"CitationRef\"\u003e18\u003c/span\u003e]. The radiologist will also measure the cross-sectional area of ​​the knee muscles in anatomic position. All MRI scans will be performed at a designated radiology centre (OPSIS Medical Imaging Nicosia) that has agreed to evaluate participants as required for the study. The radiologist will be blinded to allocation to reduce assessment bias. The initial MRI will be conducted through the National Health System, as this is the standard procedure for the injury to be confirmed. The final MRI scan will be provided free of charge to our participants by the radiology centre.\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec15\" class=\"Section4\"\u003e \u003ch2\u003e2.4.1.3 Anterior Tibial Translation\u003c/h2\u003e \u003cp\u003eKnee laxity will be assessed by measuring the anterior displacement of the tibia relative to the femur using the arthrometer (Lachmeter) only at the initial and final assessments. This device provides a user-friendly and economical solution for quantifying anterior tibial displacement. Its validity and reliability have been studied in relation to the classic KT-1000 arthrometer, with satisfactory validity and reliability results [\u003cspan citationid=\"CR19\" class=\"CitationRef\"\u003e19\u003c/span\u003e].\u003c/p\u003e \u003cp\u003eThe measurement will be conducted using the Lachman test, with the participant in a supine position and the knee slightly flexed, supported on a cushion to standardize the procedure. The arthrometer will be positioned with one fixed end on the thigh and the other end on the shin. The meter will then be pressed until it touches the shin and is reset. From this initial position, three measurements will be performed for each leg by applying anterior traction to the shin. The average of the three measurements will be considered as the final result [\u003cspan citationid=\"CR19\" class=\"CitationRef\"\u003e19\u003c/span\u003e].\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec16\" class=\"Section4\"\u003e \u003ch2\u003e2.4.1.4 Balance\u003c/h2\u003e \u003cp\u003eTo evaluate this parameter, measurements will be performed using a star execution test (SET). During the test, participants will attempt to reach the maximum distance with one leg while balancing on the other. The SET is a closed kinetic chain exercise that stimulates a single-leg squat and t assesses strength, proprioception, neuromuscular control, and range of motion in the hip, knee, and ankle. This test is considered reliable [\u003cspan citationid=\"CR19\" class=\"CitationRef\"\u003e19\u003c/span\u003e], [\u003cspan citationid=\"CR20\" class=\"CitationRef\"\u003e20\u003c/span\u003e], [\u003cspan citationid=\"CR21\" class=\"CitationRef\"\u003e21\u003c/span\u003e]. Balance will be measured only post-intervention due to the participants\u0026rsquo; inability to stand on the affected leg due to the injury. Both limbs will be assessed to identify any dominance-related asymmetry.\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec17\" class=\"Section4\"\u003e \u003ch2\u003e2.4.1.5 Single-Leg Hop\u003c/h2\u003e \u003cp\u003eThe second outcome measure of dynamic stability will be the single-hop test. After familiarisation, the participants will perform three attempts to achieve the maximum distance with one leg. For a jump trial to be considered valid, participants must maintain balance upon landing. This test is considered reliable and valid [\u003cspan citationid=\"CR22\" class=\"CitationRef\"\u003e22\u003c/span\u003e], [\u003cspan citationid=\"CR23\" class=\"CitationRef\"\u003e23\u003c/span\u003e]. For both dynamic tests, three attempts will be made after familiarisation, and the average score will be recorded. Single-Leg Hop will be measured only post-intervention due to the inability of the participant to stand on the affected leg due to the injury. Both limbs will be assessed to identify any limb dominance.\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec18\" class=\"Section4\"\u003e \u003ch2\u003e2.4.1.6 Oedema\u003c/h2\u003e \u003cp\u003eKnee circumference will be measured at the middle of the patella with the participant in the supine position and the knee fully extended. Measurements will be taken in centimetres and rounded to the nearest decimal place 0.1 cm. This measurement will be assessed during the initial assessment and then again once full knee extension is allowed according to the protocol. Knee circumference is a reliable method for assessing oedema in patients with ACL injuries [\u003cspan citationid=\"CR24\" class=\"CitationRef\"\u003e24\u003c/span\u003e]\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec19\" class=\"Section4\"\u003e \u003ch2\u003e2.4.1.7 Pain intensity\u003c/h2\u003e \u003cp\u003ePain intensity will be assessed using the Visual Analogue Scale (VAS), in addition to the Lysholm pain subscale. Participants will rate their pain on a scale from 0 (no pain) to 10 (worst imaginable pain). Pain measurements will be recorded in an Excel file by the group physiotherapist at the beginning of each phase. The file will be transferred to the main investigator only after the completion of the intervention period [\u003cspan citationid=\"CR25\" class=\"CitationRef\"\u003e25\u003c/span\u003e].\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec20\" class=\"Section4\"\u003e \u003ch2\u003e2.4.1.8 Exercise Discomfort\u003c/h2\u003e \u003cp\u003eDiscomfort experienced during exercise will be recorded using the VAS methodology. The participants will report the degree of discomfort they experienced at the end of each session, describing it as a number from 0 (no discomfort) to 10 (maximum discomfort), similar to the pain measurement. Measurements will be recorded at the end of every session (Exercise discomfort). Exercise discomfort has previously been reported to be less in patients undergoing surgery with the use of BFR [\u003cspan citationid=\"CR26\" class=\"CitationRef\"\u003e26\u003c/span\u003e]. Thus, we will examine the effectiveness of BFR in inducing hypoalgesia in our study population.\u003c/p\u003e \u003c/div\u003e \u003c/div\u003e \u003cdiv id=\"Sec21\" class=\"Section3\"\u003e \u003ch2\u003e2.4.2 Self-assessment Questionnaires\u003c/h2\u003e \u003cdiv id=\"Sec22\" class=\"Section4\"\u003e \u003ch2\u003e2.4.2.1 IKDC Scale\u003c/h2\u003e \u003cp\u003eThe International Knee Documentation Committee (IKDC) scale is a subjective assessment of participant functionality. It is divided into three subcategories in which participants rate the symptoms, athletic activity, and knee functionality. The IKDC is recommended for individuals with ACL injuries for several reasons. It offers a reduced response time, sufficient internal consistency, and high levels of reliability and validity [\u003cspan citationid=\"CR27\" class=\"CitationRef\"\u003e27\u003c/span\u003e]. The scale has been standardised in the Greek population[\u003cspan citationid=\"CR28\" class=\"CitationRef\"\u003e28\u003c/span\u003e]\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec23\" class=\"Section4\"\u003e \u003ch2\u003e2.4.2.2 Lysholm Scale\u003c/h2\u003e \u003cp\u003eThe Lysholm scale is a self-assessment questionnaire comprising subscales that assess pain, knee locking, swelling, stair climbing, squatting, and support requirements. The scale ranges from 0 (greatest disability) to 100 (least possible) [\u003cspan citationid=\"CR29\" class=\"CitationRef\"\u003e29\u003c/span\u003e].\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec24\" class=\"Section4\"\u003e \u003ch2\u003e2.4.2.3 Tegner Scale\u003c/h2\u003e \u003cp\u003eThe Tegner scale is a self-assessment scale for participant activity. The score ranges from 0 (sick leave or sedentary) to 10 (participation in high-level competition). Both the Lysholm and Tegner scales were validated for use in the Greek population with good results [\u003cspan citationid=\"CR29\" class=\"CitationRef\"\u003e29\u003c/span\u003e].\u003c/p\u003e \u003c/div\u003e \u003c/div\u003e \u003cdiv id=\"Sec25\" class=\"Section3\"\u003e \u003ch2\u003e2.4.3 Quality of Life Assessment\u003c/h2\u003e \u003cp\u003eQuality of life assessment largely covers how the injury affects the participant physically, emotionally, and socially\u0026mdash;parameters that should not be underestimated or ignored in this specific injury. To assess quality of life, ​the EQ-5D questionnaire will be used [\u003cspan citationid=\"CR30\" class=\"CitationRef\"\u003e30\u003c/span\u003e]. The questionnaire consists of five categories (mobility, self-care, usual activities, pain, and anxiety/depression). The participant will rate each category with a score (level) from no problems to extreme problems. Each level will correspond to a 1-digit number. The results of each level are then combined to create a 5-digits number that describes the patient\u0026rsquo;s health state. This questionnaire is valid and reliable for use with participants with ACL injuries [\u003cspan citationid=\"CR31\" class=\"CitationRef\"\u003e31\u003c/span\u003e].\u003c/p\u003e \u003c/div\u003e \u003c/div\u003e \u003cdiv id=\"Sec26\" class=\"Section2\"\u003e \u003ch2\u003e2.5 Participant timeline\u003c/h2\u003e \u003cp\u003eThe intervention period is expected to begin with subject recruitment on July 1, 2025, and will last for nine months (until April of 2026). Then two months will be spent on statistical analysis and results followed by another two months for writing and manuscript preparation for publication submission. Our study will have two main assessment points (baseline and at the end) with four minor assessment points at the beginning of each phase.\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec27\" class=\"Section2\"\u003e \u003ch2\u003e2.6 Sample Size\u003c/h2\u003e \u003cp\u003eThe sample size was calculated based on quadriceps strength data, with (4G Power software (Version 3.1) [\u003cspan citationid=\"CR32\" class=\"CitationRef\"\u003e32\u003c/span\u003e]. Sample size was calculated based on the results of a previous relevant study [\u003cspan citationid=\"CR33\" class=\"CitationRef\"\u003e33\u003c/span\u003e]. The effect size (ES) was set at 1.16 using Cohen\u0026rsquo;s method. To achieve a power of 80% and an alpha level of 0.05, 20 participants (10 per group) are required. To account for a 10% dropout rate per group, a total of 22 participants are deemed necessary.\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec28\" class=\"Section2\"\u003e \u003ch2\u003e2.7 Recruitment\u003c/h2\u003e \u003cp\u003eParticipants will be recruited through a combination of digital and professional outreach strategies. Specifically, targeted advertisements will be disseminated via social media platforms (e.g., Facebook, Instagram) to reach a broad audience of potential candidates within the appropriate age and demographic range. In parallel, formal invitation letters and study information sheets will be distributed to healthcare professionals, including general practitioners, orthopedic surgeons, and physical therapists, encouraging them to refer eligible patients. This dual recruitment approach aims to maximize participant reach and ensure the inclusion of individuals who meet the study\u0026rsquo;s eligibility criteria.\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec29\" class=\"Section2\"\u003e \u003ch2\u003e2.8 Randomization and Blinding\u003c/h2\u003e \u003cp\u003eThis will be a double-blind study. To achieve assessor blinding, ensure allocation concealment and prevent selection bias, we will perform the sealed envelope randomization method (SNOSE). To minimize the limitations of this technique [\u003cspan citationid=\"CR34\" class=\"CitationRef\"\u003e34\u003c/span\u003e] the procedure will adhere to relevant instructions [\u003cspan citationid=\"CR35\" class=\"CitationRef\"\u003e35\u003c/span\u003e]. Thus, we will cut an aluminium foil into 44 pieces of the same width and twice the height of the envelope. Then, the carbon paper will be cut into 44 sheets at the size of the envelope and will be separated into 2 sets of 22 sheets. On each set, \u0026ldquo;BFR group\u0026rdquo; or \u0026ldquo;Control group\u0026rdquo; will be written. Then each carbon paper will be folded, covered with foil and then placed in the envelope, each envelope will be signed on its top.\u003c/p\u003e \u003cp\u003eInitially, the measurements will be performed by the principal investigator, who will thus, not know the group assignment of each participant. The radiologist evaluating the MRIs will not have access to the subject\u0026rsquo;s allocation and thus will be blinded to allocation too. Participants in the control group will be training with the same BFR device but with different parameters under sham conditions. Only the physiotherapist of the specific group will have access to the relevant details.\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec30\" class=\"Section2\"\u003e \u003ch2\u003e2.9 Data collection\u003c/h2\u003e \u003cp\u003eData collection will take place on the premises of the European University Cyprus before the randomization and beginning of any intervention (baseline) and immediately after (post-intervention). Each prospective participant will undergo an initial assessment, and baseline measurements will be recorded by the principal investigator. The MRI scans will be evaluated by a specialist both at baseline and post intervention period. During the intervention period, strength, swelling and pain will be assessed by the physical therapist of each group. Each physical therapist will maintain an excel file with all his patient\u0026rsquo;s initials, measurements and group. Those files will be given to the main assessor after the intervention period competition to achieve blinding of the assessor.\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec31\" class=\"Section2\"\u003e \u003ch2\u003e2.10 Data management\u003c/h2\u003e \u003cp\u003eParticipants details will be kept in an Excel file saved on main investigator\u0026rsquo;s computer. The place will be accessible only to him. Participant files will be maintained in storage five years after the end of the study. In any files or documents that contain any personal information the initials of each participant will be used. The only data that will be given to anyone beyond the main researcher will be the contact list, containing the name and the contact details of each participant. The investigator that will hold this contact list will be principal for the communication during the intervention period ensuring that any within study communication does not affect blinding.\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec32\" class=\"Section2\"\u003e \u003ch2\u003e2.11 Statistical Analysis\u003c/h2\u003e \u003cp\u003eStatistical analysis will be conducted on an intention-to-treat (ITT) basis, including all participants as randomized, regardless of adherence to the intervention protocol. Baseline demographic and clinical characteristics will be summarized descriptively to assess comparability between groups. The normality of continuous variables will be assessed using the Shapiro\u0026ndash;Wilk test. Descriptive statistics will be presented for all outcome variables (MRI, anterior tibial translation (ATT), balance, single-leg hop (SLH), oedema, resting pain, exercise pain, IKDC scale, Lysholm scale, Tegner scale, and ACL-QoL at baseline and post-intervention. Continuous variables will be reported as means and standard deviations, and categorical variables as frequencies and percentages, both at baseline and post-intervention. Between-group comparisons at baseline will be performed using independent t-tests for continuous variables and chi-square tests for categorical variables.\u003c/p\u003e \u003cp\u003eTo evaluate intervention effects, independent t-tests will be used to assess between-group differences at post-intervention. Additionally, two-way mixed ANOVA will be conducted for each dependent variable to examine the effects of time (baseline vs. post-intervention), group (intervention vs. control), and their interaction. A significance level of 5% (p\u0026thinsp;\u0026lt;\u0026thinsp;0.05) and 95% confidence intervals will be applied throughout. All participants will be analysed in their assigned groups, regardless of adherence or dropout, to preserve the benefits of randomization. All analyses will be performed using IBM SPSS Statistics version 21 (IBM Corp., Armonk, NY, USA).\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec33\" class=\"Section2\"\u003e \u003ch2\u003e2.12 Adverse events\u003c/h2\u003e \u003cp\u003eAny adverse events will be recorded. Once an adverse event is identified by the group physiotherapist an independent investigator will be notified. He will be responsible to inform the main assessor who will decide if the participant can continue. All adverse events will be kept in an Excel file and will be published with the rest of the results.\u003c/p\u003e \u003cp\u003eA relevant study reported 2 below knee DVT (before DVT prophylaxis was added to the protocol) [\u003cspan citationid=\"CR11\" class=\"CitationRef\"\u003e11\u003c/span\u003e]. To minimize the possibility of such an adverse event our protocol follows the same DVT risk mitigation strategies (hydration, calf pump exercises and Rivaroxiban 10 mg for the first 8 weeks).\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec34\" class=\"Section2\"\u003e \u003ch2\u003e2.13 Protocol amendments\u003c/h2\u003e \u003cp\u003eAny necessary amendments will be done through an interpointed investigator. Communication between assessor and physiotherapists or participants will only be done through him in a way that study blinding is not affected.\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec35\" class=\"Section2\"\u003e \u003ch2\u003e2.14 Confidentiality\u003c/h2\u003e \u003cp\u003eAll records that contain names or other personal identifiers will be locked in the main investigator\u0026rsquo;s office. All documents will be destroyed upon study publication.\u003c/p\u003e \u003c/div\u003e\u003ch2\u003e2.15 Declaration of interest\u003c/h2\u003e\n\u003cp\u003e\u003cem\u003eAll authors have completed the ICMJE uniform disclosure form at\u0026nbsp;\u003c/em\u003e\u003cem\u003ehttp://www.icmje.org/disclosure-of-interest/\u003c/em\u003e\u003cem\u003eand declare: no support from any organisation for the submitted work; no financial relationships with any organisations that might have an interest in the submitted work in the previous three years; no other relationships or activities that could appear to have influenced the submitted work.\u003c/em\u003e.\u003c/p\u003e"},{"header":"3. Discussion","content":"\u003cp\u003eEmerging evidence suggests that one of the primary barriers to ACL healing is the physical separation between the two ruptured ends of the ligament, which may prevent the natural restoration of fibre continuity. Based on this understanding, we propose that a conservative period of joint immobilisation in a flexed knee position—designed to minimise the gap between the torn ends—may facilitate an optimal environment for spontaneous ligament healing. However, prolonged use of a knee brace and joint immobilisation can contribute to significant muscle atrophy, particularly in the quadriceps.\u003c/p\u003e\n\u003cp\u003eTo mitigate this adverse effect, the incorporation of BFR training during the immobilisation period may offer a viable solution. BFR exercises have been shown to stimulate muscle hypertrophy, and strength gains even at low training intensities, making them particularly suitable for use in patients with limited mobility or weight-bearing capacity.\u003c/p\u003e\n\u003cp\u003eThe present study will be the first to investigate the effects of BFR exercise as part of a completely conservative rehabilitation programme. Additionally, will be the first to evaluate the potential benefits of the method in matter of healing of the ligament. In case of positive results, the suggested methodology might provide an alternative to surgical intervention as conservative management of the completely ruptured ACL. \u0026nbsp;\u003c/p\u003e\n\u003cp\u003eIn conclusion, we propose that a rehabilitation protocol combining joint immobilisation with BFR exercise presents a promising conservative approach for individuals with acute, complete ACL tears. This integrated strategy could potentially support ligament healing, preserve muscle mass, and ultimately reduce overall recovery time, offering an alternative to immediate surgical intervention in selected cases.\u003c/p\u003e"},{"header":"Abbreviations","content":"\u003cp\u003eACL, anterior cruciate ligament\u003c/p\u003e\n\u003cp\u003eACLOAS, Anterior Cruciate Ligament OsteoArthritis Score\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eBFR, blood flow restriction\u003c/p\u003e\n\u003cp\u003eES, effect size\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eIKDC,\u0026nbsp;International Knee Documentation Committee\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eMRI, magnetic resonance imaging\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eSET, star execution test\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eVAS, Visual Analogue Scale\u003c/p\u003e\n\u003cp\u003eATT, Anterior Tibial Translation\u003c/p\u003e\n\u003cp\u003eACLR, anterior cruciate ligament reconstruction\u003c/p\u003e\n\u003cp\u003eRCT, Randomised Controlled Trial\u003c/p\u003e\n\u003cp\u003eCERT, Consensus on Exercise Reporting Template\u003c/p\u003e\n\u003cp\u003eDVT, Deep Vein Thrombosis\u003c/p\u003e\n\u003cp\u003eITT, Intention To Treat\u003c/p\u003e"},{"header":"Declarations","content":"\u003cp\u003e\u003cstrong\u003eEthics approval and consent to participate\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThis protocol was approved by the Cyprus National Bioethics Committee (\u0026Epsilon;\u0026Epsilon;\u0026Beta;\u0026Kappa;/\u0026Epsilon;\u0026Pi;/2024/70) and registered on ClinicalTrials.gov (Registration number: NCT06727344).Participation will be entirely voluntary, and all potential participants will receive comprehensive verbal and written information regarding the study\u0026rsquo;s purpose, methodology, potential benefits, and possible side effects. Those who agree to participate will be required to provide written informed consent before the trial commences and will be explicitly informed of their right to withdraw at any time without providing a reason.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eConsent for publication\u0026nbsp;\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eNot applicable\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eAvailability of data materials\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eMaterials described in the manuscript, including all relevant raw data, will be available to any scientist wishing to use them for non-commercial purposes, without breaching participant confidentiality. Our results will be published as supplementary files using a code instead of participant names. The code will be relevant to only two indirect identifiers (treatment and series) ensuring anonymization [36]\u003cstrong\u003e.\u0026nbsp;\u003c/strong\u003eFor example, the first patient who joined the intervention group will receive the code \u0026ldquo;BFR-1\u0026rdquo; in published supplementary files.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eCompeting interests\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe authors declare that they have no competing interests.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eFunding\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThis research received no external funding.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eAuthors\u0026rsquo; contributions\u0026nbsp;\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eAP:\u0026nbsp;\u003c/strong\u003eConceptualisation, Writing, review and editing, Methodology, and statistical analysis\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eKG:\u0026nbsp;\u003c/strong\u003eConceptualisation, review and editing, Methodology, statistical analysis, and supervising.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eAK\u003c/strong\u003e: Conceptualisation, review and editing, Methodology and supervising.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eCK:\u0026nbsp;\u003c/strong\u003eConceptualisation and review.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eAll authors read and approved the final manuscript.\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eAcknowledgements:\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eAll MRIs will be conducted at OPSIS diagnostic center after a relevant agreement.\u003c/p\u003e\n\u003cp\u003eFor the purposes of our study E-sense ROM Knee brace \u0026ndash; Ref: RS3000 will be used. All participants will receive a discount due to a relevant agreement with local distributor (Orthohouse).\u003cstrong\u003e\u003cbr\u003e \u003c/strong\u003e\u003c/p\u003e"},{"header":"References","content":"\u003col\u003e\u003cli\u003e\u003cspan\u003eArdern CL, Taylor NF, Feller JA, Webster KE. 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Jan. 2010;11(1):1\u0026ndash;5. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003e10.1186/1745-6215-11-9/TABLES/1\u003c/span\u003e\u003cspan address=\"10.1186/1745-6215-11-9/TABLES/1\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e.\u003c/span\u003e\u003c/li\u003e\u003c/ol\u003e"}],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":true,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":false,"hideJournal":false,"highlight":"","institution":"","isAcceptedByJournal":true,"isAuthorSuppliedPdf":false,"isDeskRejected":"","isHiddenFromSearch":false,"isInQc":false,"isInWorkflow":false,"isPdf":false,"isPdfUpToDate":true,"isWithdrawnOrRetracted":false,"journal":{"display":true,"email":"[email protected]","identity":"journal-of-orthopaedic-surgery-and-research","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"josr","sideBox":"Learn more about [Journal of Orthopaedic Surgery and Research](http://josr-online.biomedcentral.com)","snPcode":"13018","submissionUrl":"https://submission.nature.com/new-submission/13018/3","title":"Journal of Orthopaedic Surgery and Research","twitterHandle":"@MSKmedBMC","acdcEnabled":true,"dfaEnabled":true,"editorialSystem":"em","reportingPortfolio":"BMC/SO AJ","inReviewEnabled":true,"inReviewRevisionsEnabled":true},"keywords":"Anterior cruciate ligament, Complete rupture, Blood flow restriction training, Ligamental healing, Bracing protocol, Clinical trial","lastPublishedDoi":"10.21203/rs.3.rs-6940729/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-6940729/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003ch2\u003eBackground\u003c/h2\u003e \u003cp\u003eInadequate long-term outcomes are common following both surgical and non-surgical management of anterior cruciate ligament (ACL) rupture. Emerging evidence suggests that a bracing protocol may facilitate ligamental healing; however, a period of immobilization can induce muscle atrophy. This study aims to investigate potential benefits of adding blood flow restriction (BFR) training to the conservative treatment of ACL rehabilitation.\u003c/p\u003e\u003ch2\u003eMethods\u003c/h2\u003e \u003cp\u003eThis is a double-blinded, two-arm randomised clinical trial. Participants in the intervention group will follow an exercise protocol using BFR training, while participants in the control group will follow the same protocol with sham BFR. Both groups will follow the same splint protocol. Individuals aged between 18 and 40 years with an acute or subacute complete ACL tear confirmed by imaging will be eligible to participate.\u003c/p\u003e\u003ch2\u003eDiscussion\u003c/h2\u003e \u003cp\u003eEmerging evidence suggests that a conservative period of joint immobilisation, positioning the knee reduces the distance between the two torn ligament ends, may promote ACL healing after a complete rupture. However, brace use can result in muscle atrophy. BFR exercises may play an important role during this period of immobilisation and restricted movement. Positive results of exercise under BFR, in combination with a brace, can serve as an alternative treatment for participants with acute or subacute complete ACL tear, potentially reducing recovery time or even avoiding surgery.\u003c/p\u003e\u003ch2\u003eTrial registration:\u003c/h2\u003e \u003cp\u003e This protocol was approved by the Cyprus National Bioethics Committee (ΕΕΒΚ/ΕΠ/2024/70) and registered on ClinicalTrials.gov (Registration number: NCT06727344).\u003c/p\u003e","manuscriptTitle":"Conservative Treatment using Blood Flow Restriction in Individuals with Complete Anterior Cruciate Ligament Rupture: Protocol for a Randomised Clinical Trial","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2025-06-30 08:04:36","doi":"10.21203/rs.3.rs-6940729/v1","editorialEvents":[{"type":"communityComments","content":0},{"type":"decision","content":"Revision requested","date":"2025-07-12T07:23:36+00:00","index":"","fulltext":""},{"type":"editorInvitedReview","content":"","date":"2025-07-12T00:44:33+00:00","index":"hide","fulltext":""},{"type":"editorInvitedReview","content":"","date":"2025-07-01T18:43:36+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"243707045134580700662326655900498275701","date":"2025-06-29T17:32:36+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"179084483139852202257470418697997311658","date":"2025-06-29T11:50:58+00:00","index":"hide","fulltext":""},{"type":"reviewersInvited","content":"","date":"2025-06-23T08:38:39+00:00","index":"","fulltext":""},{"type":"editorAssigned","content":"","date":"2025-06-23T08:23:05+00:00","index":"","fulltext":""},{"type":"checksComplete","content":"","date":"2025-06-23T04:13:02+00:00","index":"","fulltext":""},{"type":"submitted","content":"Journal of Orthopaedic Surgery and Research","date":"2025-06-20T16:53:29+00:00","index":"","fulltext":""}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"journal-of-orthopaedic-surgery-and-research","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"josr","sideBox":"Learn more about [Journal of Orthopaedic Surgery and Research](http://josr-online.biomedcentral.com)","snPcode":"13018","submissionUrl":"https://submission.nature.com/new-submission/13018/3","title":"Journal of Orthopaedic Surgery and Research","twitterHandle":"@MSKmedBMC","acdcEnabled":true,"dfaEnabled":true,"editorialSystem":"em","reportingPortfolio":"BMC/SO AJ","inReviewEnabled":true,"inReviewRevisionsEnabled":true}}],"origin":"","ownerIdentity":"e03364c0-a543-4b72-82fc-c44bd6763ed6","owner":[],"postedDate":"June 30th, 2025","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"published-in-journal","subjectAreas":[],"tags":[],"updatedAt":"2025-12-08T16:00:08+00:00","versionOfRecord":{"articleIdentity":"rs-6940729","link":"https://doi.org/10.1186/s13018-025-06285-y","journal":{"identity":"journal-of-orthopaedic-surgery-and-research","isVorOnly":false,"title":"Journal of Orthopaedic Surgery and Research"},"publishedOn":"2025-12-01 15:57:17","publishedOnDateReadable":"December 1st, 2025"},"versionCreatedAt":"2025-06-30 08:04:36","video":"","vorDoi":"10.1186/s13018-025-06285-y","vorDoiUrl":"https://doi.org/10.1186/s13018-025-06285-y","workflowStages":[]},"version":"v1","identity":"rs-6940729","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-6940729","identity":"rs-6940729","version":["v1"]},"buildId":"8U1c8b4HqxoKbykW_rLl7","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}