Tibial tunnel compaction-drilling technique reduces tibial tunnel enlargement and improves knee stability in ACL reconstruction with hamstring autografts: a retrospective cohort study

Tibial tunnel compaction-drilling technique reduces tibial tunnel enlargement and improves knee stability in ACL reconstruction with hamstring autografts: a retrospective cohort study | 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 Article Tibial tunnel compaction-drilling technique reduces tibial tunnel enlargement and improves knee stability in ACL reconstruction with hamstring autografts: a retrospective cohort study Gang Yang, Lian Du, Man Qiu, Aiguo Zhou, Chengjie Lian, Hua Zhang This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-8095016/v1 This work is licensed under a CC BY 4.0 License Status: Under Review Version 1 posted 20 You are reading this latest preprint version Abstract Background The application of tibial tunnel compaction-drilling technique in anterior cruciate ligament reconstruction (ACL-R) is controversy. The purpose of this study was to evaluate the impact of tibial tunnel compaction-drilling technique and extraction-drilling technique used in single‑bundle ACL reconstruction on bone tunnel enlargement value, ACL graft maturation and clinical outcomes. Methods In this retrospective cohort study, 62 patients receiving ACL-R were screened and divided into two groups based on the technique of tibial tunnel drilling: compaction-drilling group (CD group, n = 31) and extraction-drilling group (ED group, n = 31). The bone tunnel enlargement was analysed based on the multislice computerised tomography at 12 months postoperatively. The ACL graft maturation was evaluated by the signal/noise quotient (SNQ) value on magnetic resonance imaging at 12 months postoperatively. Subjectively clinical outcomes were assessed by Lysholm score and International Knee Documentation Committee (IKDC) subjective score at 12 months postoperatively. Pivot-shift test was performed at 12 months postoperatively. The instrumental laxity measurement using the KT-1000 arthrometer was performed at 12 and 24 months postoperatively. Results The tibial bone tunnel diameters were enlarged by 9–15% in CD group ( p < 0.001) and enlarged by 15–22% in ED group ( p < 0.001). The CD group showed significantly smaller bone tunnel enlargement value than the ED group at 12 months follow up ( P < 0.05). In addition, significantly decreased KT-1000 measurement was found in CD group at 12 months (3.7 ± 1.8 vs. 5.0 ± 1.8 mm) ( P = 0.003) and 24 months follow up (3.4 ± 1.6 vs. 5.4 ± 2.0 mm) ( P < 0.001) compared to the ED group. No statistically significant differences of the SNQ value ( p = 0.255), IKDC subjective score ( p = 0.599) and Lysholm score ( p = 0.378) were found between two groups at 12 months postoperatively. Conclusion This study demonstrated that bone tunnel compaction-drilling technique could reduce the tibial bone tunnel enlargement and improve knee stability compared with extraction-drilling technique in ACL-R objectively. Health sciences/Anatomy Health sciences/Diseases Health sciences/Health care Health sciences/Medical research Anterior cruciate ligament reconstruction Tunnel enlargement Serial dilation Extraction drilling Clinical outcomes Figures Figure 1 Figure 2 Figure 3 Figure 4 Figure 5 Introduction Functional knee disability is often caused by a complete rupture of the anterior cruciate ligament (ACL) [ 1 ]. Reconstructing a torn ACL involves numerous technique variations. Bone tunnel enlargement (BTE) is a common problem in primary ACL reconstruction [ 2 ]. A complex interaction among biological and mechanical factors related to graft healing are thought to be involved in the occurrence of BTE [ 3 ]. Biological factors include cell death due to heat necrosis from the tunnel drilling, or host-derived immune responses reacting to foreign bodies such as allograft [ 4 ]. Mechanical factors may be related to graft selection, graft motion, fixation method, tunnel position, or the initial tension of graft during fixation [ 5 ]. This has rendered BTE a convoluted and elusive process within ACL-R. It may pose challenges in revision surgery, as a two-stage revision procedure with bone grafting and subsequent ligament reconstruction may be required [ 6 ]. BTE is positively correlated with the Knee laxity after surgery [ 7 ]. Therefore reliably and effectively surgical techniques are required to reduce bone tunnel enlargement in ACL reconstruction. To our knowledge, numerous researches on the surgical techniques for reducing the bone tunnel enlargement had been published [ 8 – 17 ]. Reduced tibial tunnel widening was related to graft selection (autografts vs. allografts, bone-patellar tendon-bone vs. hamstring tendon) [ 8 – 10 ], tunnel position [ 11 ], fixation method (bioabsorbable screw fixation vs. cortical button-post fixation, autologous bone plugs fixation vs. interference screw fixation, button fixation vs. interference screw fixation) [ 12 – 14 ], ACL reconstruction method (double-bundle vs. single-bundle, triple-bundle vs. double-bundle, remnant-preserving vs. remnant-resection) [ 15 – 17 ]. In general, all current literature reports concerning the surgical techniques for reducing the BTE are focused on the selection of grafts and the improvement of fixation methods. Innovation of bone tunnel preparation method to reduce BTE has been rarely reported [ 5 ]. Tibial tunnel preparation plays a significant role in graft fixation and eventual success in primary ACL-R. Extraction-drilling (ED) and compaction-drilling (CD) represent the two predominant techniques for tibial tunnel preparation [ 18 ]. The purpose of CD is compressing the cancellous bone to enhance the stability of the graft-fixation-device complex in the tibial tunnel. While speeding up the surgical procedure time with a one-step approach, ED offers an intraoperative benefit [ 19 ]. A unified surgical approach for the best technique to prepare the tibial tunnel has not been established. The purpose of this study was to compare the effects of compaction-drilling technique on reducing bone tunnel enlargement, improving ACL graft maturation and knee joint function at 12 months post-surgery to the extraction-drilling technique. We hypothesized that at 12 months follow-up, the bone tunnel compaction technique would reduce the tibial tunnel enlargement and improve knee stability after ACL reconstruction. Methods Patient selection From January 2022 to August 2022, patients receiving arthroscopic ACL-R with autologous hamstring graft were enrolled in this prospective cohort study. Patients met the following criteria were included: (1) aged 18–50 years; (2) total rupture of ACL diagnosed by clinical finding and MRI; (3) The time from injury to ACL reconstruction is less than one year; (4) a normal contralateral knee. The exclusion criteria were as follows: (1) combined multiple-ligament injury; (2) combined bone metabolism-related disease; (3) revision ACL-R; (4) refusal to participate in this study. The same post-operative care, instructions and physiotherapy regimens were performed for all patients. A written informed consent was obtained from all study participants. Approval was granted by the Ethics Committee of Hospital. A cohort of 68 patients out of a total of 101 patients were included into this study. 33 patients were excluded due to the following reasons: combined bone metabolism-related disease (n = 1), combined multiple-ligament injury (n = 11); partial rupture of ACL (n = 8), revision ACL-R (n = 7), refusal to participate in this study (n = 6). Sixty-two (31 ED and 31 SD) of the 68 patients were available for the final analysis. The remaining patients were withdrawn either due to rupture of the reconstructed ACL again (n = 2) or lost for follow up (n = 4) (Fig. 1 ). Figure 1 Flowchart of participants recruitment enrollment. Surgical Technique All surgeries were conducted by a single senior orthopaedic surgeon (HZ). All patients underwent primary arthroscopic ACL reconstruction with autologous hamstring tendon graft. The autologous semitendinosus and gracilis tendons were obtained and prepared according to the method designed by Chiang et al [ 20 ]. Using a transtibial technique, the femoral tunnel was drilled with being taken care to center the tunnel in the anatomic footprint. To achieve reproducible placement of the femoral tunnel, an 'over-the-top' guide was employed. A tibial guide was used to drill the tibial tunnel, with the guide positioned at a 55° angle from the horizontal and the aimer aligned with the ACL tibial footprint. In ED group, the tibial tunnel was drilled accordingly to the same diameter as the measured graft diameter by a trephine. In CD group, the tibial tunnel was initially reamed over the guide wire with a cannulated drill that was 1 mm narrower than the graft, and then, expanded gradually in steps of 0.5 mm each to the desired diameter using the bone tunnel compaction method with dilators (Fig. 2 ). The fixation of the femoral graft was achieved with an EndoButton (Smith & Nephew). The graft of tibial side was fixed with a bio-absorbable interference screw (Smith & Nephew) and a cortical screw post. All grafts were fixed at 30° of knee flexion. Figure 2 The procedure of tibial tunnel compaction-drilling technique. (A) Different types of tibial tunnel dilators and trephines. (B) The tibial tunnel was compacted by one millimeter using the dilators. (C) Arthroscopic view of the tibial tunnel before compaction. (D) Arthroscopic view of the tibial tunnel after compaction. Rehabilitation A standardized postoperative rehabilitation protocol was performed for all patients. Immobilization with a splint in 15° of knee flexion was required within 1 week after surgery. Full range of motion exercises with a functional knee brace was allowed at 2 weeks after surgery. Partial to full weight bearing was required from 3 to 4 weeks after surgery. Jogging was allowed at 3 months postoperatively. Return to their original sports activities was allowed after 6 months postoperatively. All the postoperative functional rehabilitation exercises were completed under the guidance of rehabilitation therapists. Imaging Evaluations Computed Tomography (CT) (Phillips Brilliance CT 128-slice, Eindhoven, Netherlands) scan with 1 mm slice thickness was performed for all patients at 12 months postoperatively. All CT scan images were imported and stored in ANKE PACS image system (ASG-340). Analysis software (GE AW4.7) was used to generate three-dimensional (3D) images for the tibial tunnel measurement. Paracoronal and parasagittal multiplanar reformations (MPRs) perpendicular to the coronal and sagittal axis of tibial bone tunnel were generated. The diameter of the tibial bone tunnel was measured digitally following the method described by Ralph et al [ 18 ]. Six measurements were conducted, beginning at the level of tibial cortex (TC0; TS0) as well as 1 cm (TC1; TS1) and 2 cm (TC2; TS2) distal from the cortex (Fig. 3 -A, Fig. 3 -B). TS0 refer to CT measurement of tunnel size on sagittal view of the tibial cortex level. TS1 refer to CT measurement of tunnel size on sagittal view of 1 cm distal from the tibial cortex level. TS2 refer to CT measurement of tunnel size on sagittal view of 2 cm distal from the tibial cortex level. TC0 refer to CT measurement of tunnel size on coronal view of the tibial cortex level. TC1 refer to CT measurement of tunnel size on coronal view of 1 cm distal from the tibial cortex level. TC2 refer to CT measurement of tunnel size on coronal view of 2 cm distal from the tibial cortex level. The tunnel enlargement values were obtained by subtracting the tibial tunnel measurements to drilled diameters at 12 months postoperatively. The arithmetical mean and standard deviation of tunnel enlargement values was summarized. 3.0-T magnetic resonance imaging (MRI) (MAGNETOM Skyra MRI 3.0-T unit, Siemens, Germany) was performed to evaluate the ACL graft maturation at 12 months after surgery. The region of interest (ROI) was used to quantify the MRI signal based on the ITK-SNAP medical imaging software. Based on the ROI technique, the signal/ noise quotient (SNQ) was calculated to quantify the normalized signal intensity of the ACL graft. SNQ = (ACL graft signal- quadriceps tendon signal) / the background signal [ 21 ]. Lower signal intensity of ACL represented higher ACL graft maturation. The ROI of the ACL graft was measured at the intra-articular zones of the tibial site. The ROI of background was measured at approximately 2 cm anterior to the patellar tendon. These parameters were obtained on the sagittal MRI image (Fig. 3 -C). Figure 3 CT measurement of the tibial bone tunnel diameters on sagittal view (A) and coronal view (B). Six measurements were performed, starting at the level of the tibial cortex (TS0, TC0) as well as 1 cm (TS1, TC1) and 2 cm (TS2, TC2) distal from the cortex. MRI measurement of the ACL signal intensity (C). Signal intensity of ACL graft was determined by the SNQ. SNQ = (ACL graft signal- quadriceps tendon signal) / the background signal. Clinical Evaluations All clinical evaluations were conducted by a single orthopaedic surgeon (Cj-L). Pivot-shift test was conducted to assess the rotational knee stability at preoperatively and 12 months postoperatively. The side-to-side difference using the KT-1000 arthrometer was performed to assess the anterior laxity preoperatively, 12 months postoperatively and 24 months postoperatively. Functional scores, including the Lysholm score and subjective IKDC score were assessed preoperatively and 12 months postoperatively. Statistical Analysis All data were presented as mean ± standard deviation. The χ-square test was used for categorical data (Pivot-shift test, Sex). Within the matched pair groups, the bone tunnel diameters measured after surgery were compared to the trephine size used intraoperatively (paired t -test). BTE rates, SNQ values, instrumental laxity measurements and functional scores between two groups were compared by the independent t test. A power analysis indicated that a sample size of at least 54 total patients was necessary to detect an intergroup difference between CD group and ED Group in each parameter with an alpha of 0.05, and a power of 80%. Statistical analysis was conducted by SPSS software (version 21.0, IBM, Armonk, NY). Statistically significant difference was considered at P < 0.05. Results Patient Characteristics 62 patients with total rupture of ACL were included for analysis. 31 patients receiving tibial tunnel compaction-drilling technique were allocated into CD group. 31 patients receiving tibial tunnel extraction-drilling technique were allocated into ED group. There were 39 males and 23 females enrolled into this study. At the time of surgery, their ages varied from 18 to 46 years, with an average age of 27.8 years. The patients’ body mass index (BMI) was 24.0 ± 2.9. None of the characteristics of patients were found to be a risk factor for tibial tunnel enlargement. Demographic data are shown in Table 1 . No statistically significant difference was found between two groups (P < 0.05). Table 1 Patient demographic characteristics CD group ED group P value Patients, n 31 31 Age, yr 28.0 ± 6.8 29.7 ± 7.4 0.369 Sex, male/female 21/10 18/13 0.439 Height, cm 172.1 ± 9.2 170.4 ± 9.1 0.463 Weight, kg 71.8 ± 12.6 69.5 ± 11.1 0.449 BMI 24.1 ± 3.0 23.9 ± 2.8 0.758 KT-1000 measurement, mm 7.1 ± 4.0 8.6 ± 4.2 0.077 IKDC score 58.1 ± 6.2 61.2 ± 6.8 0.068 Lysholm score 68.7 ± 4.8 69.3 ± 6.2 0.599 NOTE. Data are presented as mean ± standard deviation unless Sex and Patients. CD group, compaction-drilling group; ED group, extraction-drilling group; BMI, body mass index Imaging Evaluation Results The results of the bone tunnel enlargement rates and the CT measurements from the time of surgery to follow up are summarized in Table 2 . The tibial bone tunnel was significantly enlarged in both groups after ACL reconstruction. In CD group, the tibial bone tunnel diameters were enlarged by 9–15% ( p < 0.001). In ED group, the tibial bone tunnel diameters were enlarged by 15–22% ( p < 0.001). At 12 months follow up after ACL reconstruction, the CD group showed smaller bone tunnel enlargement value than the ED group (Fig. 4 ). Statistically significant difference was found between two groups ( p < 0.05). Table 2 Postoperative characteristics of tibial tunnel enlargement Tunnel diameter, mm Tunnel widening, % p value CD group Drilled tunnel diameter 8.9 ± 0.8 TS0 9.7 ± 0.7 + 10 < 0.001 TS1 10.2 ± 0.9 + 15 < 0.001 TS2 10.0 ± 0.8 + 13 < 0.001 TC0 9.7 ± 0.6 + 9 < 0.001 TC1 10.1 ± 0.9 + 14 < 0.001 TC2 10.1 ± 0.6 + 14 < 0.001 ED group Drilled tunnel diameter 8.6 ± 0.8 TS0 10.0 ± 0.6 + 16 < 0.001 TS1 10.5 ± 1.1 + 22 < 0.001 TS2 10.2 ± 0.7 + 19 < 0.001 TC0 9.9 ± 0.6 + 15 < 0.001 TC1 10.4 ± 1.0 + 21 < 0.001 TC2 10.2 ± 0.8 + 19 < 0.001 NOTE. Data are presented as mean ± standard deviation. CD group, compaction-drilling group; ED group, extraction-drilling group. T, tibial; S, sagittal; C, coronal; Six measurements were conducted, beginning at the level of tibial cortex (TC0; TS0) as well as 1 cm (TC1; TS1) and 2 cm (TC2; TS2) distal from the cortex In CD group, the mean SNQ value of ACL grafts was 3.07 ± 0.52. In ED group, the mean SNQ value of ACL grafts was 2.91 ± 0.58. No statistically significant difference of the SNQ value was found between two groups ( p = 0.255). Figure 4 The tibial bone tunnel enlargement value of two groups. Tunnel widening difference = Postoperative CT measurement of tunnel diameters - Drilled diameters. * p < 0.05, ** p < 0.01, *** P < 0.001 Clinical Outcomes The clinical results are demonstrated in Table 3 . All patients showed significantly improved functional scores after ACL reconstruction surgery. The objectively functional assessments indicated that significantly decreased KT-1000 measurements and Pivot-shift test in both groups at 12 months follow up ( p < 0.001). The CD group showed significantly decreased anterior laxity assessed by KT-1000 arthrometer than the ED group at 12 months (3.7 ± 1.8 vs. 5.0 ± 1.8 mm) ( p = 0.003) and 24 months (3.4 ± 1.6 vs. 5.4 ± 2.0 mm) ( p < 0.001) follow up (Fig. 5 ). There were no statistically significant differences for Pivot-shift test ( p = 0.647), subjective IKDC score ( p = 0.378) and Lysholm score ( p = 0.599) between two groups at 12 months postoperatively. Table 3 Clinical outcomes at twelve months follow up CD group ED group P value for CD group vs ED group post-op pre-op post-op P value pre-op post-op P value Lysholm score 68.7 ± 4.8 91.2 ± 5.3 < .001 69.3 ± 6.2 90.4 ± 7.1 < .001 0.599 IKDC score 58.1 ± 6.2 86.1 ± 5.3 < .001 61.2 ± 6.8 84.8 ± 6.1 < .001 0.378 KT-1000, mm 7.1 ± 4.0 3.7 ± 1.8 < .001 8.6 ± 4.2 5.0 ± 1.8 < .001 0.003 Pivot shift, n < .001 < .001 0.647 Grade 0 0 29 0 28 Grade I 26 2 25 3 Grade II 3 0 5 0 Grade III 2 0 1 0 NOTE. Data are presented as mean ± standard deviation unless Pivot-shift. CD group, compaction-drilling group; ED group, extraction-drilling group; pre-op, preoperative; post-op, postoperative; IKDC, International Knee Documentation Committee. Figure 5 The knee stability assessed by KT-1000 arthrometer preoperatively and postoperatively. 15ib, 15 pound. 20ib, 20 pound. max-F, max force. ns, no significance. * p < 0.05, ** p < 0.01, *** P < 0.001 Discussion In this study, the CD group showed smaller bone tunnel enlargement value than the ED group at 12 months follow up. In addition, the CD group showed significantly decreased anterior laxity assessed by KT-1000 arthrometer than the ED group at 12 months and 24 months postoperatively. The rotational knee stability assessed by Pivot-shift test and the ACL graft maturation measured by SNQ value showed no statistically differences between two groups at 12 months postoperatively. No statistically differences for the subjective IKDC score and Lysholm score were found in two groups at 12 months follow up. This study demonstrates that bone tunnel compaction technique could reduce the tibial tunnel enlargement and decrease anterior laxity of knee joint in primary arthroscopic ACL reconstruction objectively. Despite the generally favorable results of ACL reconstruction, bone tunnel enlargement commonly is a problem after ACL reconstruction, and its mechanisms remain unclear. BTE has been reported to occur predominantly within the first three months after surgery, and it remains relatively constant until two years [ 22 ]. The prevalence of bone tunnel enlargement was reported to be more commonly recognized with autologous hamstring tendon graft, with incidence rate ranging in variability from 20% to 48% in tibial tunnel [ 23 , 24 ]. Extraction-drilling and compaction-drilling represent the two predominant techniques for tibial tunnel preparation in ACL-R. To increase the fixation strength with the screw, the bone tunnel compaction technique, compacting the tibial bone tunnel wall for dilation of the tunnel, has been developed and performed in clinical settings [ 19 ]. To date, there are a few reports published on the different bone tunnel enlargement of compaction-drilling technique compared with the extraction-drilling technique [ 25 – 28 ]. Mixed results have been reported in these studies. The most important finding of this study is that bone tunnel enlargement in ACL reconstruction was reduced by the tunnel compaction-drilling technique compared to the extraction-drilling technique. It retains more bone tissue and reduces the difficulty of revision surgery for ACL reconstruction. Biomechanical result suggests compaction-drilling technique to be a preferred technique to extraction-drilling technique. Compared to extraction-drilling technique, compaction-drilling technique has as following advantages, including stimulation of osteoid formation in bone tunnel, enhanced graft pullout strength and better support for interference screws [ 29 , 30 ]. These findings further confirm that mechanical circumstances are key contributors to the tunnel widening in ACL reconstruction. In our study, no statistically difference of the SNQ value was found between two groups at 12 months postoperatively. The SNQ value of ACL graft was calculated to quantify the ACL graft maturation [ 21 ]. Previous studies proved that the lower SNQ value of ACL graft is correlated with patient’s good surgical outcome [ 31 ]. In our study, no significant difference in surgical outcomes was found between two groups. Thus, two different tibial tunnel drilling techniques could not determine the ACL graft maturity. In this study, all patients showed significantly improved clinically functional assessments after ACL reconstruction surgery. No statistically significant differences in subjectively functional assessments (subjective IKDC score, Lysholm score) and objectively functional assessments (Pivot-shift test) were found between the two groups. However, the CD group showed statistically significant decreased KT-1000 measurements than the ED group at 12 months and 24 months follow up. Timothy et al. demonstrates a poor correlation between subjective IKDC score and objective knee laxity for normal and nearly normal joint as measured by the KT-1000 arthrometer [ 32 ]. It has been demonstrated that tunnel enlarge anteriorly and distally rather than concentrically after ACL reconstruction. This finding suggests that the wall supporting the graft moves closer to the direction of the pull, leading to increased anterior laxity of the knee joint due to tunnel enlargement [ 7 ]. Therefore, this study demonstrated that compaction-drilling technique could significantly decrease anterior laxity than extraction-drilling technique after primary ACL reconstruction. The rotational stability of knee joint subjectively measured by Pivot-shift test showed no significant difference between two drilling techniques. It is possible that the rotational stability objectively measured by arthrometer are different between two groups. Further research is needed to confirm this hypothesis. The exact biomechanical reasons need to be further verified. The bone tunnel compaction technique should be further revisited and reevaluated. Limitations Several limitations were present in this study. First, the sample size of this study was relatively small, and the follow-up period was not long enough. Second, since no CT scan was done immediately after surgery, the initial bone tunnel diameter was assumed equal to the drilled diameter which may cause inaccuracies. Third, the tibial tunnel placement and the orientation of the ACL graft should be measured to exclude the risk factors for tibial tunnel enlargement. Conclusions The CD group showed smaller bone tunnel enlargement value with significantly decreased KT-1000 measurements than the ED group postoperatively, though no statistically significant differences were found in ACL graft maturation, Pivot-shift test, subjective IKDC score and Lysholm score. Abbreviations ACL-R: anterior cruciate ligament reconstruction BTE: Bone tunnel enlargement BMI: Body mass index CD group: Compaction-drilling group CT: Computed Tomography ED group: extraction-drilling group IKDC: International Knee Documentation Committee MRI: magnetic resonance imaging ROI: region of interest SNQ: signal/noise quotient Declarations Author contributions Gang Yang: Article writing and Data analysis. Lian Du: Data measurement. Man Qiu: Data collection. Ai-guo Zhou: Data collection. Cheng-jie Lian: Article revision. Hua Zhang: Article conception and design Funding None Data availability Data is available from the corresponding author upon reasonable request. Ethics approval and consent to participate The study was approved by the ethics committee of Chongqing Medical University. All procedures performed in studies involving human participants were in accordance with the ethical standards of the institutional and/or national research committee and with the 1964 Helsinki declaration and its later amendments or comparable ethical standards. Conflict of interest disclosure The authors declare no conflict of interest. References Rebecca, S. et al. A comparison between physical therapy clinics with high and low rehabilitation volumes of patients with ACL reconstruction. J. Orthop. Surg. Res. 18 (1), 842 (2023). Mateusz, S., Krzysztof, F., Marcin, B. & Zygmunt, W. Bone tunnel enlargement following hamstring anterior cruciate ligament reconstruction: a comprehensive review. Phys. 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B., Charlebois, S. J. & Azar, F. M. Effect of tibial tunnel dilation on pullout strength of semitendinosus-gracilis graft in anterior cruciate ligament reconstruction. Orthopedics 28 , 779–783 (2005). Biercevicz, A. M. et al. MRI volume and signal intensity of ACL graft predict clinical, functional, and patient-oriented outcome measures after ACL reconstruction. Am. J. Sports Med. 43 , 693–699 (2015). Timothy, S. W. & Donald, H. J. Is There a Correlation Between Subjective IKDC Scores and Both Pivot Shift and KT-1000 Measurements Following Anterior Cruciate Ligament Reconstruction? Arthroscopy 28 (8), 245–246 (2012). Additional Declarations No competing interests reported. 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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-8095016","acceptedTermsAndConditions":true,"allowDirectSubmit":false,"archivedVersions":[],"articleType":"Article","associatedPublications":[],"authors":[{"id":566703689,"identity":"582d147c-2177-4942-a6d5-96c0b3269e3a","order_by":0,"name":"Gang Yang","email":"","orcid":"","institution":"Chongqing University FuLing Hospital","correspondingAuthor":false,"prefix":"","firstName":"Gang","middleName":"","lastName":"Yang","suffix":""},{"id":566703690,"identity":"8a277003-03b4-493c-b29e-a6863d60efa5","order_by":1,"name":"Lian Du","email":"","orcid":"","institution":"Chongqing University FuLing 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10:39:24","extension":"xml","order_by":15,"title":"","display":"","copyAsset":false,"role":"acdc-reference","size":97398,"visible":true,"origin":"","legend":"","description":"","filename":"ec3e5fd4cea2407596e03e4833bd76081structuring.xml","url":"https://assets-eu.researchsquare.com/files/rs-8095016/v1/4a8f28f92ca96403c130570d.xml"},{"id":99291931,"identity":"bb2f07d4-f647-419c-8d87-e311395caf0c","added_by":"auto","created_at":"2025-12-31 10:39:22","extension":"html","order_by":16,"title":"","display":"","copyAsset":false,"role":"acdc-reference","size":109705,"visible":true,"origin":"","legend":"","description":"","filename":"earlyproof.html","url":"https://assets-eu.researchsquare.com/files/rs-8095016/v1/943462693eac4b3e946d137a.html"},{"id":99291908,"identity":"0416c131-eb9b-4a18-a8d1-c732ce8ecb88","added_by":"auto","created_at":"2025-12-31 10:39:21","extension":"png","order_by":1,"title":"Figure 1","display":"","copyAsset":false,"role":"figure","size":522745,"visible":true,"origin":"","legend":"\u003cp\u003eFlowchart of participants recruitment enrollment.\u003c/p\u003e","description":"","filename":"floatimage1.png","url":"https://assets-eu.researchsquare.com/files/rs-8095016/v1/9fc87ea22562850b39cfc59b.png"},{"id":99291932,"identity":"ed04fb9a-79ab-4f40-8f6d-eab42c4cc459","added_by":"auto","created_at":"2025-12-31 10:39:22","extension":"png","order_by":2,"title":"Figure 2","display":"","copyAsset":false,"role":"figure","size":1133359,"visible":true,"origin":"","legend":"\u003cp\u003eThe procedure of tibial tunnel compaction-drilling technique. (A) Different types of tibial tunnel dilators and trephines. (B)\u003cstrong\u003e \u003c/strong\u003eThe tibial tunnel was compacted by one millimeter using the dilators. (C) Arthroscopic view of the tibial tunnel before compaction. (D) Arthroscopic view of the tibial tunnel after compaction.\u003c/p\u003e","description":"","filename":"floatimage2.png","url":"https://assets-eu.researchsquare.com/files/rs-8095016/v1/33d502765f3193769b45ed5f.png"},{"id":99291847,"identity":"22955920-ae2d-4fe8-af1e-20b585d1632f","added_by":"auto","created_at":"2025-12-31 10:39:15","extension":"png","order_by":3,"title":"Figure 3","display":"","copyAsset":false,"role":"figure","size":483423,"visible":true,"origin":"","legend":"\u003cp\u003eCT\u003cstrong\u003e \u003c/strong\u003emeasurement of the tibial bone tunnel diameters on sagittal view (A) and coronal view (B). Six measurements were performed, starting at the level of the tibial cortex (TS0, TC0) as well as 1 cm (TS1, TC1) and 2 cm (TS2, TC2) distal from the cortex. MRI measurement of the ACL signal intensity (C). Signal intensity of ACL graft was determined by the SNQ. SNQ = (ACL graft signal- quadriceps tendon signal) / the background signal.\u003c/p\u003e","description":"","filename":"floatimage3.png","url":"https://assets-eu.researchsquare.com/files/rs-8095016/v1/b6b36ed73566c86c25a3d708.png"},{"id":99291907,"identity":"83212010-87b8-44c9-b164-36c74f7bd72e","added_by":"auto","created_at":"2025-12-31 10:39:20","extension":"png","order_by":4,"title":"Figure 4","display":"","copyAsset":false,"role":"figure","size":435183,"visible":true,"origin":"","legend":"\u003cp\u003eThe tibial bone tunnel enlargement value of two groups. Tunnel widening difference = Postoperative CT measurement of tunnel diameters - Drilled diameters. * p \u0026lt; 0.05, ** p \u0026lt; 0.01, *** P\u0026lt; 0.001\u003c/p\u003e","description":"","filename":"floatimage4.png","url":"https://assets-eu.researchsquare.com/files/rs-8095016/v1/2d72384f4744c863c5f49bb9.png"},{"id":99291940,"identity":"efe7d56a-3be9-488a-9b7d-de74c4aa061e","added_by":"auto","created_at":"2025-12-31 10:39:23","extension":"png","order_by":5,"title":"Figure 5","display":"","copyAsset":false,"role":"figure","size":384016,"visible":true,"origin":"","legend":"\u003cp\u003eThe knee stability assessed by KT-1000 arthrometer preoperatively and postoperatively. 15ib, 15 pound. 20ib, 20 pound. max-F, max force. ns, no significance. * p \u0026lt; 0.05, ** p \u0026lt; 0.01, *** P\u0026lt; 0.001\u003c/p\u003e","description":"","filename":"floatimage5.png","url":"https://assets-eu.researchsquare.com/files/rs-8095016/v1/40a563629eaf373ccd80213b.png"},{"id":99320984,"identity":"180a7be2-04ec-4507-be70-05f75fc6075e","added_by":"auto","created_at":"2025-12-31 16:39:00","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":3951549,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-8095016/v1/b7ef0088-dad6-4760-926a-88d338016147.pdf"}],"financialInterests":"No competing interests reported.","formattedTitle":"\u003cp\u003eTibial tunnel compaction-drilling technique reduces tibial tunnel enlargement and improves knee stability in ACL reconstruction with hamstring autografts: a retrospective cohort study\u003c/p\u003e","fulltext":[{"header":"Introduction","content":"\u003cp\u003eFunctional knee disability is often caused by a complete rupture of the anterior cruciate ligament (ACL) [\u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e]. Reconstructing a torn ACL involves numerous technique variations. Bone tunnel enlargement (BTE) is a common problem in primary ACL reconstruction [\u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e]. A complex interaction among biological and mechanical factors related to graft healing are thought to be involved in the occurrence of BTE [\u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e3\u003c/span\u003e]. Biological factors include cell death due to heat necrosis from the tunnel drilling, or host-derived immune responses reacting to foreign bodies such as allograft [\u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e4\u003c/span\u003e]. Mechanical factors may be related to graft selection, graft motion, fixation method, tunnel position, or the initial tension of graft during fixation [\u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e5\u003c/span\u003e]. This has rendered BTE a convoluted and elusive process within ACL-R. It may pose challenges in revision surgery, as a two-stage revision procedure with bone grafting and subsequent ligament reconstruction may be required [\u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e6\u003c/span\u003e]. BTE is positively correlated with the Knee laxity after surgery [\u003cspan citationid=\"CR7\" class=\"CitationRef\"\u003e7\u003c/span\u003e]. Therefore reliably and effectively surgical techniques are required to reduce bone tunnel enlargement in ACL reconstruction.\u003c/p\u003e \u003cp\u003eTo our knowledge, numerous researches on the surgical techniques for reducing the bone tunnel enlargement had been published [\u003cspan additionalcitationids=\"CR9 CR10 CR11 CR12 CR13 CR14 CR15 CR16\" citationid=\"CR8\" class=\"CitationRef\"\u003e8\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR17\" class=\"CitationRef\"\u003e17\u003c/span\u003e]. Reduced tibial tunnel widening was related to graft selection (autografts vs. allografts, bone-patellar tendon-bone vs. hamstring tendon) [\u003cspan additionalcitationids=\"CR9\" citationid=\"CR8\" class=\"CitationRef\"\u003e8\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e10\u003c/span\u003e], tunnel position [\u003cspan citationid=\"CR11\" class=\"CitationRef\"\u003e11\u003c/span\u003e], fixation method (bioabsorbable screw fixation vs. cortical button-post fixation, autologous bone plugs fixation vs. interference screw fixation, button fixation vs. interference screw fixation) [\u003cspan additionalcitationids=\"CR13\" citationid=\"CR12\" class=\"CitationRef\"\u003e12\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR14\" class=\"CitationRef\"\u003e14\u003c/span\u003e], ACL reconstruction method (double-bundle vs. single-bundle, triple-bundle vs. double-bundle, remnant-preserving vs. remnant-resection) [\u003cspan additionalcitationids=\"CR16\" citationid=\"CR15\" class=\"CitationRef\"\u003e15\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR17\" class=\"CitationRef\"\u003e17\u003c/span\u003e]. In general, all current literature reports concerning the surgical techniques for reducing the BTE are focused on the selection of grafts and the improvement of fixation methods. Innovation of bone tunnel preparation method to reduce BTE has been rarely reported [\u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e5\u003c/span\u003e].\u003c/p\u003e \u003cp\u003eTibial tunnel preparation plays a significant role in graft fixation and eventual success in primary ACL-R. Extraction-drilling (ED) and compaction-drilling (CD) represent the two predominant techniques for tibial tunnel preparation [\u003cspan citationid=\"CR18\" class=\"CitationRef\"\u003e18\u003c/span\u003e]. The purpose of CD is compressing the cancellous bone to enhance the stability of the graft-fixation-device complex in the tibial tunnel. While speeding up the surgical procedure time with a one-step approach, ED offers an intraoperative benefit [\u003cspan citationid=\"CR19\" class=\"CitationRef\"\u003e19\u003c/span\u003e]. A unified surgical approach for the best technique to prepare the tibial tunnel has not been established.\u003c/p\u003e \u003cp\u003eThe purpose of this study was to compare the effects of compaction-drilling technique on reducing bone tunnel enlargement, improving ACL graft maturation and knee joint function at 12 months post-surgery to the extraction-drilling technique. We hypothesized that at 12 months follow-up, the bone tunnel compaction technique would reduce the tibial tunnel enlargement and improve knee stability after ACL reconstruction.\u003c/p\u003e"},{"header":"Methods","content":"\u003cdiv id=\"Sec3\" class=\"Section2\"\u003e \u003ch2\u003ePatient selection\u003c/h2\u003e \u003cp\u003eFrom January 2022 to August 2022, patients receiving arthroscopic ACL-R with autologous hamstring graft were enrolled in this prospective cohort study. Patients met the following criteria were included: (1) aged 18\u0026ndash;50 years; (2) total rupture of ACL diagnosed by clinical finding and MRI; (3) The time from injury to ACL reconstruction is less than one year; (4) a normal contralateral knee. The exclusion criteria were as follows: (1) combined multiple-ligament injury; (2) combined bone metabolism-related disease; (3) revision ACL-R; (4) refusal to participate in this study. The same post-operative care, instructions and physiotherapy regimens were performed for all patients. A written informed consent was obtained from all study participants. Approval was granted by the Ethics Committee of Hospital.\u003c/p\u003e \u003cp\u003eA cohort of 68 patients out of a total of 101 patients were included into this study. 33 patients were excluded due to the following reasons: combined bone metabolism-related disease (n\u0026thinsp;=\u0026thinsp;1), combined multiple-ligament injury (n\u0026thinsp;=\u0026thinsp;11); partial rupture of ACL (n\u0026thinsp;=\u0026thinsp;8), revision ACL-R (n\u0026thinsp;=\u0026thinsp;7), refusal to participate in this study (n\u0026thinsp;=\u0026thinsp;6). Sixty-two (31 ED and 31 SD) of the 68 patients were available for the final analysis. The remaining patients were withdrawn either due to rupture of the reconstructed ACL again (n\u0026thinsp;=\u0026thinsp;2) or lost for follow up (n\u0026thinsp;=\u0026thinsp;4) (Fig.\u0026nbsp;\u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003e).\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003cp\u003eFigure\u0026nbsp;\u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003e Flowchart of participants recruitment enrollment.\u003c/p\u003e \u003c/div\u003e\n\u003ch3\u003eSurgical Technique\u003c/h3\u003e\n\u003cp\u003eAll surgeries were conducted by a single senior orthopaedic surgeon (HZ). All patients underwent primary arthroscopic ACL reconstruction with autologous hamstring tendon graft. The autologous semitendinosus and gracilis tendons were obtained and prepared according to the method designed by Chiang et al [\u003cspan citationid=\"CR20\" class=\"CitationRef\"\u003e20\u003c/span\u003e]. Using a transtibial technique, the femoral tunnel was drilled with being taken care to center the tunnel in the anatomic footprint. To achieve reproducible placement of the femoral tunnel, an 'over-the-top' guide was employed. A tibial guide was used to drill the tibial tunnel, with the guide positioned at a 55\u0026deg; angle from the horizontal and the aimer aligned with the ACL tibial footprint. In ED group, the tibial tunnel was drilled accordingly to the same diameter as the measured graft diameter by a trephine. In CD group, the tibial tunnel was initially reamed over the guide wire with a cannulated drill that was 1 mm narrower than the graft, and then, expanded gradually in steps of 0.5 mm each to the desired diameter using the bone tunnel compaction method with dilators (Fig.\u0026nbsp;\u003cspan refid=\"Fig2\" class=\"InternalRef\"\u003e2\u003c/span\u003e). The fixation of the femoral graft was achieved with an EndoButton (Smith \u0026amp; Nephew). The graft of tibial side was fixed with a bio-absorbable interference screw (Smith \u0026amp; Nephew) and a cortical screw post. All grafts were fixed at 30\u0026deg; of knee flexion.\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003cp\u003eFigure\u0026nbsp;\u003cspan refid=\"Fig2\" class=\"InternalRef\"\u003e2\u003c/span\u003e The procedure of tibial tunnel compaction-drilling technique. (A) Different types of tibial tunnel dilators and trephines. (B) The tibial tunnel was compacted by one millimeter using the dilators. (C) Arthroscopic view of the tibial tunnel before compaction. (D) Arthroscopic view of the tibial tunnel after compaction.\u003c/p\u003e\n\u003ch3\u003eRehabilitation\u003c/h3\u003e\n\u003cp\u003eA standardized postoperative rehabilitation protocol was performed for all patients. Immobilization with a splint in 15\u0026deg; of knee flexion was required within 1 week after surgery. Full range of motion exercises with a functional knee brace was allowed at 2 weeks after surgery. Partial to full weight bearing was required from 3 to 4 weeks after surgery. Jogging was allowed at 3 months postoperatively. Return to their original sports activities was allowed after 6 months postoperatively. All the postoperative functional rehabilitation exercises were completed under the guidance of rehabilitation therapists.\u003c/p\u003e\n\u003ch3\u003eImaging Evaluations\u003c/h3\u003e\n\u003cp\u003eComputed Tomography (CT) (Phillips Brilliance CT 128-slice, Eindhoven, Netherlands) scan with 1 mm slice thickness was performed for all patients at 12 months postoperatively. All CT scan images were imported and stored in ANKE PACS image system (ASG-340). Analysis software (GE AW4.7) was used to generate three-dimensional (3D) images for the tibial tunnel measurement. Paracoronal and parasagittal multiplanar reformations (MPRs) perpendicular to the coronal and sagittal axis of tibial bone tunnel were generated. The diameter of the tibial bone tunnel was measured digitally following the method described by Ralph et al [\u003cspan citationid=\"CR18\" class=\"CitationRef\"\u003e18\u003c/span\u003e]. Six measurements were conducted, beginning at the level of tibial cortex (TC0; TS0) as well as 1 cm (TC1; TS1) and 2 cm (TC2; TS2) distal from the cortex (Fig.\u0026nbsp;\u003cspan refid=\"Fig3\" class=\"InternalRef\"\u003e3\u003c/span\u003e-A, Fig.\u0026nbsp;\u003cspan refid=\"Fig3\" class=\"InternalRef\"\u003e3\u003c/span\u003e-B). TS0 refer to CT measurement of tunnel size on sagittal view of the tibial cortex level. TS1 refer to CT measurement of tunnel size on sagittal view of 1 cm distal from the tibial cortex level. TS2 refer to CT measurement of tunnel size on sagittal view of 2 cm distal from the tibial cortex level. TC0 refer to CT measurement of tunnel size on coronal view of the tibial cortex level. TC1 refer to CT measurement of tunnel size on coronal view of 1 cm distal from the tibial cortex level. TC2 refer to CT measurement of tunnel size on coronal view of 2 cm distal from the tibial cortex level. The tunnel enlargement values were obtained by subtracting the tibial tunnel measurements to drilled diameters at 12 months postoperatively. The arithmetical mean and standard deviation of tunnel enlargement values was summarized.\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003cp\u003e3.0-T magnetic resonance imaging (MRI) (MAGNETOM Skyra MRI 3.0-T unit, Siemens, Germany) was performed to evaluate the ACL graft maturation at 12 months after surgery. The region of interest (ROI) was used to quantify the MRI signal based on the ITK-SNAP medical imaging software. Based on the ROI technique, the signal/ noise quotient (SNQ) was calculated to quantify the normalized signal intensity of the ACL graft. SNQ = (ACL graft signal- quadriceps tendon signal) / the background signal [\u003cspan citationid=\"CR21\" class=\"CitationRef\"\u003e21\u003c/span\u003e]. Lower signal intensity of ACL represented higher ACL graft maturation. The ROI of the ACL graft was measured at the intra-articular zones of the tibial site. The ROI of background was measured at approximately 2 cm anterior to the patellar tendon. These parameters were obtained on the sagittal MRI image (Fig.\u0026nbsp;\u003cspan refid=\"Fig3\" class=\"InternalRef\"\u003e3\u003c/span\u003e-C).\u003c/p\u003e \u003cp\u003eFigure\u0026nbsp;\u003cspan refid=\"Fig3\" class=\"InternalRef\"\u003e3\u003c/span\u003e CT measurement of the tibial bone tunnel diameters on sagittal view (A) and coronal view (B). Six measurements were performed, starting at the level of the tibial cortex (TS0, TC0) as well as 1 cm (TS1, TC1) and 2 cm (TS2, TC2) distal from the cortex. MRI measurement of the ACL signal intensity (C). Signal intensity of ACL graft was determined by the SNQ. SNQ = (ACL graft signal- quadriceps tendon signal) / the background signal.\u003c/p\u003e\n\u003ch3\u003eClinical Evaluations\u003c/h3\u003e\n\u003cp\u003eAll clinical evaluations were conducted by a single orthopaedic surgeon (Cj-L). Pivot-shift test was conducted to assess the rotational knee stability at preoperatively and 12 months postoperatively. The side-to-side difference using the KT-1000 arthrometer was performed to assess the anterior laxity preoperatively, 12 months postoperatively and 24 months postoperatively. Functional scores, including the Lysholm score and subjective IKDC score were assessed preoperatively and 12 months postoperatively.\u003c/p\u003e \u003cdiv id=\"Sec8\" class=\"Section2\"\u003e \u003ch2\u003eStatistical Analysis\u003c/h2\u003e \u003cp\u003eAll data were presented as mean\u0026thinsp;\u0026plusmn;\u0026thinsp;standard deviation. The χ-square test was used for categorical data (Pivot-shift test, Sex). Within the matched pair groups, the bone tunnel diameters measured after surgery were compared to the trephine size used intraoperatively (paired \u003cem\u003et\u003c/em\u003e-test). BTE rates, SNQ values, instrumental laxity measurements and functional scores between two groups were compared by the independent \u003cem\u003et\u003c/em\u003e test. A power analysis indicated that a sample size of at least 54 total patients was necessary to detect an intergroup difference between CD group and ED Group in each parameter with an alpha of 0.05, and a power of 80%. Statistical analysis was conducted by SPSS software (version 21.0, IBM, Armonk, NY). Statistically significant difference was considered at \u003cem\u003eP\u003c/em\u003e\u0026thinsp;\u0026lt;\u0026thinsp;0.05.\u003c/p\u003e \u003c/div\u003e"},{"header":"Results","content":"\u003cp\u003ePatient Characteristics\u003c/p\u003e \u003cp\u003e62 patients with total rupture of ACL were included for analysis. 31 patients receiving tibial tunnel compaction-drilling technique were allocated into CD group. 31 patients receiving tibial tunnel extraction-drilling technique were allocated into ED group. There were 39 males and 23 females enrolled into this study. At the time of surgery, their ages varied from 18 to 46 years, with an average age of 27.8 years. The patients\u0026rsquo; body mass index (BMI) was 24.0\u0026thinsp;\u0026plusmn;\u0026thinsp;2.9. None of the characteristics of patients were found to be a risk factor for tibial tunnel enlargement. Demographic data are shown in Table\u0026nbsp;\u003cspan refid=\"Tab1\" class=\"InternalRef\"\u003e1\u003c/span\u003e. No statistically significant difference was found between two groups (P\u0026thinsp;\u0026lt;\u0026thinsp;0.05).\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\u003ePatient demographic characteristics\u003c/p\u003e \u003c/div\u003e \u003c/caption\u003e \u003ccolgroup cols=\"4\"\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=\"char\" char=\".\" class=\"colspec\" colname=\"c4\" colnum=\"4\"\u003e\u003c/div\u003e \u003cthead\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c1\"\u003e\u0026nbsp;\u003c/th\u003e \u003cth align=\"left\" colname=\"c2\"\u003e \u003cp\u003eCD group\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c3\"\u003e \u003cp\u003eED group\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c4\"\u003e \u003cp\u003e\u003cem\u003eP\u003c/em\u003e value\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003ePatients, n\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e31\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e31\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eAge, yr\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e28.0\u0026thinsp;\u0026plusmn;\u0026thinsp;6.8\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e29.7\u0026thinsp;\u0026plusmn;\u0026thinsp;7.4\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e0.369\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eSex, male/female\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e21/10\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e18/13\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e0.439\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eHeight, cm\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e172.1\u0026thinsp;\u0026plusmn;\u0026thinsp;9.2\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e170.4\u0026thinsp;\u0026plusmn;\u0026thinsp;9.1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e0.463\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eWeight, kg\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e71.8\u0026thinsp;\u0026plusmn;\u0026thinsp;12.6\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e69.5\u0026thinsp;\u0026plusmn;\u0026thinsp;11.1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e0.449\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eBMI\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e24.1\u0026thinsp;\u0026plusmn;\u0026thinsp;3.0\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e23.9\u0026thinsp;\u0026plusmn;\u0026thinsp;2.8\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e0.758\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eKT-1000 measurement, mm\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e7.1\u0026thinsp;\u0026plusmn;\u0026thinsp;4.0\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e8.6\u0026thinsp;\u0026plusmn;\u0026thinsp;4.2\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e0.077\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eIKDC score\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e58.1\u0026thinsp;\u0026plusmn;\u0026thinsp;6.2\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e61.2\u0026thinsp;\u0026plusmn;\u0026thinsp;6.8\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e0.068\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eLysholm score\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e68.7\u0026thinsp;\u0026plusmn;\u0026thinsp;4.8\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e69.3\u0026thinsp;\u0026plusmn;\u0026thinsp;6.2\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e0.599\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003c/tbody\u003e \u003c/colgroup\u003e \u003ctfoot\u003e \u003ctr\u003e\u003ctd colspan=\"4\"\u003eNOTE. Data are presented as mean\u0026thinsp;\u0026plusmn;\u0026thinsp;standard deviation unless Sex and Patients.\u003c/td\u003e\u003c/tr\u003e \u003ctr\u003e\u003ctd colspan=\"4\"\u003eCD group, compaction-drilling group; ED group, extraction-drilling group; BMI, body mass index\u003c/td\u003e\u003c/tr\u003e \u003c/tfoot\u003e \u003c/table\u003e\u003c/div\u003e \u003c/p\u003e \u003cp\u003eImaging Evaluation Results\u003c/p\u003e \u003cp\u003eThe results of the bone tunnel enlargement rates and the CT measurements from the time of surgery to follow up are summarized in Table\u0026nbsp;\u003cspan refid=\"Tab2\" class=\"InternalRef\"\u003e2\u003c/span\u003e. The tibial bone tunnel was significantly enlarged in both groups after ACL reconstruction. In CD group, the tibial bone tunnel diameters were enlarged by 9\u0026ndash;15% (\u003cem\u003ep\u003c/em\u003e\u0026thinsp;\u0026lt;\u0026thinsp;0.001). In ED group, the tibial bone tunnel diameters were enlarged by 15\u0026ndash;22% (\u003cem\u003ep\u003c/em\u003e\u0026thinsp;\u0026lt;\u0026thinsp;0.001). At 12 months follow up after ACL reconstruction, the CD group showed smaller bone tunnel enlargement value than the ED group (Fig.\u0026nbsp;\u003cspan refid=\"Fig4\" class=\"InternalRef\"\u003e4\u003c/span\u003e). Statistically significant difference was found between two groups (\u003cem\u003ep\u003c/em\u003e\u0026thinsp;\u0026lt;\u0026thinsp;0.05).\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\u003ePostoperative characteristics of tibial tunnel enlargement\u003c/p\u003e \u003c/div\u003e \u003c/caption\u003e \u003ccolgroup cols=\"4\"\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\"\u0026plusmn;\" 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=\"char\" char=\".\" class=\"colspec\" colname=\"c4\" colnum=\"4\"\u003e\u003c/div\u003e \u003cthead\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c1\"\u003e\u0026nbsp;\u003c/th\u003e \u003cth align=\"left\" colname=\"c2\"\u003e \u003cp\u003eTunnel diameter, mm\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c3\"\u003e \u003cp\u003eTunnel widening, %\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c4\"\u003e \u003cp\u003e\u003cem\u003ep\u003c/em\u003e value\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c1\"\u003e \u003cp\u003eCD group\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/th\u003e \u003cth align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/th\u003e \u003cth align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eDrilled tunnel diameter\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c2\"\u003e \u003cp\u003e8.9\u0026thinsp;\u0026plusmn;\u0026thinsp;0.8\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 \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eTS0\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c2\"\u003e \u003cp\u003e9.7\u0026thinsp;\u0026plusmn;\u0026thinsp;0.7\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e+\u0026thinsp;10\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e\u0026lt;\u0026thinsp;0.001\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eTS1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c2\"\u003e \u003cp\u003e10.2\u0026thinsp;\u0026plusmn;\u0026thinsp;0.9\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e+\u0026thinsp;15\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e\u0026lt;\u0026thinsp;0.001\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eTS2\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c2\"\u003e \u003cp\u003e10.0\u0026thinsp;\u0026plusmn;\u0026thinsp;0.8\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e+\u0026thinsp;13\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e\u0026lt;\u0026thinsp;0.001\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eTC0\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c2\"\u003e \u003cp\u003e9.7\u0026thinsp;\u0026plusmn;\u0026thinsp;0.6\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e+\u0026thinsp;9\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e\u0026lt;\u0026thinsp;0.001\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eTC1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c2\"\u003e \u003cp\u003e10.1\u0026thinsp;\u0026plusmn;\u0026thinsp;0.9\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e+\u0026thinsp;14\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e\u0026lt;\u0026thinsp;0.001\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eTC2\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c2\"\u003e \u003cp\u003e10.1\u0026thinsp;\u0026plusmn;\u0026thinsp;0.6\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e+\u0026thinsp;14\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e\u0026lt;\u0026thinsp;0.001\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cb\u003eED group\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eDrilled tunnel diameter\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c2\"\u003e \u003cp\u003e8.6\u0026thinsp;\u0026plusmn;\u0026thinsp;0.8\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 \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eTS0\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c2\"\u003e \u003cp\u003e10.0\u0026thinsp;\u0026plusmn;\u0026thinsp;0.6\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e+\u0026thinsp;16\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e\u0026lt;\u0026thinsp;0.001\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eTS1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c2\"\u003e \u003cp\u003e10.5\u0026thinsp;\u0026plusmn;\u0026thinsp;1.1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e+\u0026thinsp;22\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e\u0026lt;\u0026thinsp;0.001\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eTS2\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c2\"\u003e \u003cp\u003e10.2\u0026thinsp;\u0026plusmn;\u0026thinsp;0.7\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e+\u0026thinsp;19\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e\u0026lt;\u0026thinsp;0.001\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eTC0\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c2\"\u003e \u003cp\u003e9.9\u0026thinsp;\u0026plusmn;\u0026thinsp;0.6\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e+\u0026thinsp;15\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e\u0026lt;\u0026thinsp;0.001\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eTC1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c2\"\u003e \u003cp\u003e10.4\u0026thinsp;\u0026plusmn;\u0026thinsp;1.0\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e+\u0026thinsp;21\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e\u0026lt;\u0026thinsp;0.001\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eTC2\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c2\"\u003e \u003cp\u003e10.2\u0026thinsp;\u0026plusmn;\u0026thinsp;0.8\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e+\u0026thinsp;19\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e\u0026lt;\u0026thinsp;0.001\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003c/tbody\u003e \u003c/colgroup\u003e \u003ctfoot\u003e \u003ctr\u003e\u003ctd colspan=\"4\"\u003eNOTE. Data are presented as mean\u0026thinsp;\u0026plusmn;\u0026thinsp;standard deviation.\u003c/td\u003e\u003c/tr\u003e \u003ctr\u003e\u003ctd colspan=\"4\"\u003eCD group, compaction-drilling group; ED group, extraction-drilling group. T, tibial; S, sagittal; C, coronal; Six measurements were conducted, beginning at the level of tibial cortex (TC0; TS0) as well as 1 cm (TC1; TS1) and 2 cm (TC2; TS2) distal from the cortex\u003c/td\u003e\u003c/tr\u003e \u003c/tfoot\u003e \u003c/table\u003e\u003c/div\u003e \u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003cp\u003eIn CD group, the mean SNQ value of ACL grafts was 3.07\u0026thinsp;\u0026plusmn;\u0026thinsp;0.52. In ED group, the mean SNQ value of ACL grafts was 2.91\u0026thinsp;\u0026plusmn;\u0026thinsp;0.58. No statistically significant difference of the SNQ value was found between two groups (\u003cem\u003ep\u003c/em\u003e\u0026thinsp;=\u0026thinsp;0.255).\u003c/p\u003e \u003cp\u003eFigure\u0026nbsp;\u003cspan refid=\"Fig4\" class=\"InternalRef\"\u003e4\u003c/span\u003e The tibial bone tunnel enlargement value of two groups. Tunnel widening difference\u0026thinsp;=\u0026thinsp;Postoperative CT measurement of tunnel diameters - Drilled diameters. * p\u0026thinsp;\u0026lt;\u0026thinsp;0.05, ** p\u0026thinsp;\u0026lt;\u0026thinsp;0.01, *** P\u0026thinsp;\u0026lt;\u0026thinsp;0.001\u003c/p\u003e \u003cp\u003eClinical Outcomes\u003c/p\u003e \u003cp\u003eThe clinical results are demonstrated in Table\u0026nbsp;\u003cspan refid=\"Tab3\" class=\"InternalRef\"\u003e3\u003c/span\u003e. All patients showed significantly improved functional scores after ACL reconstruction surgery. The objectively functional assessments indicated that significantly decreased KT-1000 measurements and Pivot-shift test in both groups at 12 months follow up (\u003cem\u003ep\u003c/em\u003e\u0026thinsp;\u0026lt;\u0026thinsp;0.001). The CD group showed significantly decreased anterior laxity assessed by KT-1000 arthrometer than the ED group at 12 months (3.7\u0026thinsp;\u0026plusmn;\u0026thinsp;1.8 vs. 5.0\u0026thinsp;\u0026plusmn;\u0026thinsp;1.8 mm) (\u003cem\u003ep\u003c/em\u003e\u0026thinsp;=\u0026thinsp;0.003) and 24 months (3.4\u0026thinsp;\u0026plusmn;\u0026thinsp;1.6 vs. 5.4\u0026thinsp;\u0026plusmn;\u0026thinsp;2.0 mm) (\u003cem\u003ep\u003c/em\u003e\u0026thinsp;\u0026lt;\u0026thinsp;0.001) follow up (Fig.\u0026nbsp;\u003cspan refid=\"Fig5\" class=\"InternalRef\"\u003e5\u003c/span\u003e). There were no statistically significant differences for Pivot-shift test (\u003cem\u003ep\u003c/em\u003e\u0026thinsp;=\u0026thinsp;0.647), subjective IKDC score (\u003cem\u003ep\u003c/em\u003e\u0026thinsp;=\u0026thinsp;0.378) and Lysholm score (\u003cem\u003ep\u003c/em\u003e\u0026thinsp;=\u0026thinsp;0.599) between two groups at 12 months postoperatively.\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\u003eClinical outcomes at twelve months follow up\u003c/p\u003e \u003c/div\u003e \u003c/caption\u003e \u003ccolgroup cols=\"9\"\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 \u003cdiv align=\"left\" class=\"colspec\" colname=\"c7\" colnum=\"7\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c8\" colnum=\"8\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c9\" colnum=\"9\"\u003e\u003c/div\u003e \u003cthead\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c1\" morerows=\"1\" rowspan=\"2\"\u003e\u0026nbsp;\u003c/th\u003e \u003cth align=\"left\" colspan=\"3\" nameend=\"c4\" namest=\"c2\"\u003e \u003cp\u003eCD group\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c5\"\u003e\u0026nbsp;\u003c/th\u003e \u003cth align=\"left\" colspan=\"3\" nameend=\"c8\" namest=\"c6\"\u003e \u003cp\u003eED group\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c9\" morerows=\"1\" rowspan=\"2\"\u003e \u003cp\u003e\u003cem\u003eP\u003c/em\u003e value for CD group vs ED group post-op\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c2\"\u003e \u003cp\u003epre-op\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c3\"\u003e \u003cp\u003epost-op\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c4\"\u003e \u003cp\u003e\u003cem\u003eP\u003c/em\u003e value\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c5\"\u003e\u0026nbsp;\u003c/th\u003e \u003cth align=\"left\" colname=\"c6\"\u003e \u003cp\u003epre-op\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c7\"\u003e \u003cp\u003epost-op\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c8\"\u003e \u003cp\u003e\u003cem\u003eP\u003c/em\u003e value\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eLysholm score\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e68.7\u0026thinsp;\u0026plusmn;\u0026thinsp;4.8\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e91.2\u0026thinsp;\u0026plusmn;\u0026thinsp;5.3\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e\u0026lt;\u0026thinsp;.001\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e69.3\u0026thinsp;\u0026plusmn;\u0026thinsp;6.2\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e90.4\u0026thinsp;\u0026plusmn;\u0026thinsp;7.1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003e\u0026lt;\u0026thinsp;.001\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c9\"\u003e \u003cp\u003e0.599\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eIKDC score\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e58.1\u0026thinsp;\u0026plusmn;\u0026thinsp;6.2\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e86.1\u0026thinsp;\u0026plusmn;\u0026thinsp;5.3\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e\u0026lt;\u0026thinsp;.001\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e61.2\u0026thinsp;\u0026plusmn;\u0026thinsp;6.8\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e84.8\u0026thinsp;\u0026plusmn;\u0026thinsp;6.1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003e\u0026lt;\u0026thinsp;.001\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c9\"\u003e \u003cp\u003e0.378\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eKT-1000, mm\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e7.1\u0026thinsp;\u0026plusmn;\u0026thinsp;4.0\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e3.7\u0026thinsp;\u0026plusmn;\u0026thinsp;1.8\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e\u0026lt;\u0026thinsp;.001\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e8.6\u0026thinsp;\u0026plusmn;\u0026thinsp;4.2\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e5.0\u0026thinsp;\u0026plusmn;\u0026thinsp;1.8\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003e\u0026lt;\u0026thinsp;.001\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c9\"\u003e \u003cp\u003e0.003\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003ePivot shift, n\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e\u0026lt;\u0026thinsp;.001\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003e\u0026lt;\u0026thinsp;.001\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c9\"\u003e \u003cp\u003e0.647\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eGrade 0\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e0\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e29\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e0\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e28\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c9\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eGrade I\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e26\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e2\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e25\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e3\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c9\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eGrade II\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e3\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e0\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e5\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e0\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c9\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eGrade III\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e2\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e0\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e0\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c9\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003c/tbody\u003e \u003c/colgroup\u003e \u003ctfoot\u003e \u003ctr\u003e\u003ctd colspan=\"9\"\u003eNOTE. Data are presented as mean\u0026thinsp;\u0026plusmn;\u0026thinsp;standard deviation unless Pivot-shift.\u003c/td\u003e\u003c/tr\u003e \u003ctr\u003e\u003ctd colspan=\"9\"\u003eCD group, compaction-drilling group; ED group, extraction-drilling group; pre-op, preoperative; post-op, postoperative; IKDC, International Knee Documentation Committee.\u003c/td\u003e\u003c/tr\u003e \u003c/tfoot\u003e \u003c/table\u003e\u003c/div\u003e \u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003cp\u003eFigure\u0026nbsp;\u003cspan refid=\"Fig5\" class=\"InternalRef\"\u003e5\u003c/span\u003e The knee stability assessed by KT-1000 arthrometer preoperatively and postoperatively. 15ib, 15 pound. 20ib, 20 pound. max-F, max force. ns, no significance. * p\u0026thinsp;\u0026lt;\u0026thinsp;0.05, ** p\u0026thinsp;\u0026lt;\u0026thinsp;0.01, *** P\u0026thinsp;\u0026lt;\u0026thinsp;0.001\u003c/p\u003e"},{"header":"Discussion","content":"\u003cp\u003eIn this study, the CD group showed smaller bone tunnel enlargement value than the ED group at 12 months follow up. In addition, the CD group showed significantly decreased anterior laxity assessed by KT-1000 arthrometer than the ED group at 12 months and 24 months postoperatively. The rotational knee stability assessed by Pivot-shift test and the ACL graft maturation measured by SNQ value showed no statistically differences between two groups at 12 months postoperatively. No statistically differences for the subjective IKDC score and Lysholm score were found in two groups at 12 months follow up. This study demonstrates that bone tunnel compaction technique could reduce the tibial tunnel enlargement and decrease anterior laxity of knee joint in primary arthroscopic ACL reconstruction objectively.\u003c/p\u003e \u003cp\u003eDespite the generally favorable results of ACL reconstruction, bone tunnel enlargement commonly is a problem after ACL reconstruction, and its mechanisms remain unclear. BTE has been reported to occur predominantly within the first three months after surgery, and it remains relatively constant until two years [\u003cspan citationid=\"CR22\" class=\"CitationRef\"\u003e22\u003c/span\u003e]. The prevalence of bone tunnel enlargement was reported to be more commonly recognized with autologous hamstring tendon graft, with incidence rate ranging in variability from 20% to 48% in tibial tunnel [\u003cspan citationid=\"CR23\" class=\"CitationRef\"\u003e23\u003c/span\u003e, \u003cspan citationid=\"CR24\" class=\"CitationRef\"\u003e24\u003c/span\u003e]. Extraction-drilling and compaction-drilling represent the two predominant techniques for tibial tunnel preparation in ACL-R. To increase the fixation strength with the screw, the bone tunnel compaction technique, compacting the tibial bone tunnel wall for dilation of the tunnel, has been developed and performed in clinical settings [\u003cspan citationid=\"CR19\" class=\"CitationRef\"\u003e19\u003c/span\u003e]. To date, there are a few reports published on the different bone tunnel enlargement of compaction-drilling technique compared with the extraction-drilling technique [\u003cspan additionalcitationids=\"CR26 CR27\" citationid=\"CR25\" class=\"CitationRef\"\u003e25\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR28\" class=\"CitationRef\"\u003e28\u003c/span\u003e]. Mixed results have been reported in these studies.\u003c/p\u003e \u003cp\u003eThe most important finding of this study is that bone tunnel enlargement in ACL reconstruction was reduced by the tunnel compaction-drilling technique compared to the extraction-drilling technique. It retains more bone tissue and reduces the difficulty of revision surgery for ACL reconstruction. Biomechanical result suggests compaction-drilling technique to be a preferred technique to extraction-drilling technique. Compared to extraction-drilling technique, compaction-drilling technique has as following advantages, including stimulation of osteoid formation in bone tunnel, enhanced graft pullout strength and better support for interference screws [\u003cspan citationid=\"CR29\" class=\"CitationRef\"\u003e29\u003c/span\u003e, \u003cspan citationid=\"CR30\" class=\"CitationRef\"\u003e30\u003c/span\u003e]. These findings further confirm that mechanical circumstances are key contributors to the tunnel widening in ACL reconstruction.\u003c/p\u003e \u003cp\u003eIn our study, no statistically difference of the SNQ value was found between two groups at 12 months postoperatively. The SNQ value of ACL graft was calculated to quantify the ACL graft maturation [\u003cspan citationid=\"CR21\" class=\"CitationRef\"\u003e21\u003c/span\u003e]. Previous studies proved that the lower SNQ value of ACL graft is correlated with patient\u0026rsquo;s good surgical outcome [\u003cspan citationid=\"CR31\" class=\"CitationRef\"\u003e31\u003c/span\u003e]. In our study, no significant difference in surgical outcomes was found between two groups. Thus, two different tibial tunnel drilling techniques could not determine the ACL graft maturity.\u003c/p\u003e \u003cp\u003eIn this study, all patients showed significantly improved clinically functional assessments after ACL reconstruction surgery. No statistically significant differences in subjectively functional assessments (subjective IKDC score, Lysholm score) and objectively functional assessments (Pivot-shift test) were found between the two groups. However, the CD group showed statistically significant decreased KT-1000 measurements than the ED group at 12 months and 24 months follow up. Timothy et al. demonstrates a poor correlation between subjective IKDC score and objective knee laxity for normal and nearly normal joint as measured by the KT-1000 arthrometer [\u003cspan citationid=\"CR32\" class=\"CitationRef\"\u003e32\u003c/span\u003e]. It has been demonstrated that tunnel enlarge anteriorly and distally rather than concentrically after ACL reconstruction. This finding suggests that the wall supporting the graft moves closer to the direction of the pull, leading to increased anterior laxity of the knee joint due to tunnel enlargement [\u003cspan citationid=\"CR7\" class=\"CitationRef\"\u003e7\u003c/span\u003e]. Therefore, this study demonstrated that compaction-drilling technique could significantly decrease anterior laxity than extraction-drilling technique after primary ACL reconstruction. The rotational stability of knee joint subjectively measured by Pivot-shift test showed no significant difference between two drilling techniques. It is possible that the rotational stability objectively measured by arthrometer are different between two groups. Further research is needed to confirm this hypothesis. The exact biomechanical reasons need to be further verified. The bone tunnel compaction technique should be further revisited and reevaluated.\u003c/p\u003e \u003cdiv id=\"Sec11\" class=\"Section2\"\u003e \u003ch2\u003eLimitations\u003c/h2\u003e \u003cp\u003eSeveral limitations were present in this study. First, the sample size of this study was relatively small, and the follow-up period was not long enough. Second, since no CT scan was done immediately after surgery, the initial bone tunnel diameter was assumed equal to the drilled diameter which may cause inaccuracies. Third, the tibial tunnel placement and the orientation of the ACL graft should be measured to exclude the risk factors for tibial tunnel enlargement.\u003c/p\u003e \u003c/div\u003e"},{"header":"Conclusions","content":"\u003cp\u003eThe CD group showed smaller bone tunnel enlargement value with significantly decreased KT-1000 measurements than the ED group postoperatively, though no statistically significant differences were found in ACL graft maturation, Pivot-shift test, subjective IKDC score and Lysholm score.\u003c/p\u003e"},{"header":"Abbreviations","content":"\u003cp\u003eACL-R: anterior cruciate ligament reconstruction\u003c/p\u003e\n\u003cp\u003eBTE: Bone tunnel enlargement\u003c/p\u003e\n\u003cp\u003eBMI: Body mass index\u003c/p\u003e\n\u003cp\u003eCD group: Compaction-drilling group\u003c/p\u003e\n\u003cp\u003eCT: Computed Tomography\u003c/p\u003e\n\u003cp\u003eED group: extraction-drilling group\u003c/p\u003e\n\u003cp\u003eIKDC: International Knee Documentation Committee\u003c/p\u003e\n\u003cp\u003eMRI: magnetic resonance imaging\u003c/p\u003e\n\u003cp\u003eROI: region of interest\u003c/p\u003e\n\u003cp\u003eSNQ: signal/noise quotient\u003c/p\u003e"},{"header":"Declarations","content":"\u003cp\u003eAuthor contributions\u003c/p\u003e\n\u003cp\u003eGang Yang: Article writing and Data analysis. Lian Du: Data measurement. Man Qiu: Data collection. Ai-guo Zhou: Data collection. Cheng-jie Lian: Article revision. Hua Zhang: Article conception and design\u003c/p\u003e\n\u003cp\u003eFunding\u003c/p\u003e\n\u003cp\u003eNone\u003c/p\u003e\n\u003cp\u003eData availability\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eData is available from the corresponding author upon reasonable request.\u003c/p\u003e\n\u003cp\u003eEthics approval and consent to participate\u003c/p\u003e\n\u003cp\u003eThe study was approved by the ethics committee of Chongqing Medical University. All procedures performed in studies involving human participants were in accordance with the ethical standards of the institutional and/or national research committee and with the 1964 Helsinki declaration and its later amendments or comparable ethical standards.\u003c/p\u003e\n\u003cp\u003eConflict of interest disclosure\u003c/p\u003e\n\u003cp\u003eThe authors declare no conflict of interest.\u003c/p\u003e"},{"header":"References","content":"\u003col\u003e\u003cli\u003e\u003cspan\u003eRebecca, S. et al. A comparison between physical therapy clinics with high and low rehabilitation volumes of patients with ACL reconstruction. \u003cem\u003eJ. Orthop. Surg. Res.\u003c/em\u003e \u003cb\u003e18\u003c/b\u003e (1), 842 (2023).\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eMateusz, S., Krzysztof, F., Marcin, B. \u0026amp; Zygmunt, W. Bone tunnel enlargement following hamstring anterior cruciate ligament reconstruction: a comprehensive review. \u003cem\u003ePhys. Sportsmed.\u003c/em\u003e \u003cb\u003e45\u003c/b\u003e (1), 31\u0026ndash;40 (2017).\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eShuji, T. Editorial Commentary: Tunnel Widening After Anterior Cruciate Ligament Reconstruction May Increase Laxity and Complicate Revision. \u003cem\u003eArthroscopy\u003c/em\u003e \u003cb\u003e37\u003c/b\u003e (8), 2564\u0026ndash;2566 (2021).\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eWilson, T. C., Kantaras, A., Atay, A. \u0026amp; Johnson, D. L. Tunnel enlargement after anterior cruciate ligament surgery. \u003cem\u003eAm. J. Sports Med.\u003c/em\u003e \u003cb\u003e32\u003c/b\u003e (2), 543\u0026ndash;549 (2004).\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eLi, Y., Steven, F. D., Kayleigh, S., Dioscaris, G. \u0026amp; Brett, D. O. Mechanisms of Bone Tunnel Enlargement Following Anterior Cruciate Ligament Reconstruction. \u003cem\u003eJBJS Rev.\u003c/em\u003e \u003cb\u003e8\u003c/b\u003e (4), e0120 (2020).\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eTheodore, S. W., Brian, M., Brett, D. O., Brian, R. W. \u0026amp; Michael, J. A. Tunnel Management in Revision Anterior Cruciate Ligament Reconstruction: Current Concepts. \u003cem\u003eAm. J. Sports Med.\u003c/em\u003e \u003cb\u003e51\u003c/b\u003e (2), 545\u0026ndash;556 (2023).\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eTaketomi, S. Editorial Commentary: Tunnel Widening After Anterior Cruciate Ligament Reconstruction May Increase Laxity and Complicate Revision. \u003cem\u003eArthroscopy\u003c/em\u003e \u003cb\u003e37\u003c/b\u003e (8), 2564\u0026ndash;2566 (2021).\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eRobbrecht, C. et al. Reliability of a semi-automated 3D-CT measuring method for tunnel diameters after anterior cruciate ligament reconstruction: a comparison between soft-tissue single-bundle allograft vs. \u003cem\u003eAutograft Knee\u003c/em\u003e. \u003cb\u003e21\u003c/b\u003e (5), 926\u0026ndash;931 (2014).\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eDeFroda, S. F. et al. Tibial tunnel widening following anterior cruciate ligament reconstruction: a retrospective seven year study evaluating the effects of initial graft tensioning and graft selection. \u003cem\u003eKnee\u003c/em\u003e \u003cb\u003e25\u003c/b\u003e (6), 1107\u0026ndash;1114 (2018).\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eHirotaka, M., Tomonori, K., Kotaro, I. \u0026amp; Masataka, S. Anatomic single-bundle anterior cruciate ligament reconstruction using a calcium phosphate-hybridized tendon graft: a randomized controlled trial with 2 years of follow-up. \u003cem\u003eJ. Orthop. Surg. Res.\u003c/em\u003e \u003cb\u003e13\u003c/b\u003e (1), 327 (2018).\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eShinichiro, O. et al. Minimal tibial tunnel enlargement after anatomic rectangular tunnel anterior cruciate ligament reconstruction with bone-patellar tendon-bone graft. \u003cem\u003eJ. Orthop. Sci.\u003c/em\u003e \u003cb\u003e25\u003c/b\u003e (4), 635\u0026ndash;639 (2020).\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eChiang, E. R. et al. Comparison of Tunnel Enlargement and Clinical Outcome Between Bioabsorbable Interference Screws and Cortical Button-Post Fixation in Arthroscopic Double-Bundle Anterior Cruciate Ligament Reconstruction: A Prospective, Randomized Study With a Minimum Follow-Up of 2 Years. \u003cem\u003eArthroscopy\u003c/em\u003e \u003cb\u003e35\u003c/b\u003e (2), 544\u0026ndash;551 (2019).\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eRalph, A. et al. Press-fit fixation using autologous bone in the tibial canal causes less enlargement of bone tunnel diameter in ACL reconstruction-a CT scan analysis three months postoperatively. \u003cem\u003eBMC Musculoskelet. Disord\u003c/em\u003e. \u003cb\u003e16\u003c/b\u003e, 200 (2015).\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eRaul, M. et al. ACL reconstruction with adjustable-length loop cortical button fixation results in less tibial tunnel widening compared with interference screw fixation. \u003cem\u003eKnee Surg. Sports Traumatol. Arthrosc.\u003c/em\u003e \u003cb\u003e28\u003c/b\u003e (4), 1036\u0026ndash;1044 (2020).\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eKousuke, S. et al. Less tunnel enlargement in triple-bundle versus double-bundle anterior cruciate ligament reconstruction: A randomized clinical trial. \u003cem\u003eJ. Orthop. Sci.\u003c/em\u003e \u003cb\u003e28\u003c/b\u003e (5), 1074\u0026ndash;1081 (2023).\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eCathrine, A. et al. Tunnel widening in single- versus double-bundle anterior cruciate ligament reconstructed knees. \u003cem\u003eKnee Surg. Sports Traumatol. Arthrosc.\u003c/em\u003e \u003cb\u003e25\u003c/b\u003e (4), 1316\u0026ndash;1327 (2017).\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eSuguru, K. et al. A new remnant preservation technique reduces bone tunnel enlargement after anatomic double-bundle anterior cruciate ligament reconstruction. \u003cem\u003eKnee Surg. Sports Traumatol. Arthrosc.\u003c/em\u003e \u003cb\u003e30\u003c/b\u003e (6), 2020\u0026ndash;2028 (2022).\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eStrobel, M. J. et al. Manual of Arthroscopic Surgery: Springer ScienceBusiness Media. 18. O G S\u0026oslash;rensen,, Serial dilation reduces graft slippage compared to extraction drilling in anterior cruciate ligament reconstruction: a randomized controlled trial using radiostereometric analysis. Knee Surg Sports Traumatol Arthrosc.2011;19(3):347\u0026ndash;354. (2013).\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eS\u0026oslash;rensen, O. G., Jakobsen, B. W., Kold, S., Hansen, T. B. \u0026amp; S\u0026oslash;balle, K. Serial dilation versus extraction drilling in anterior cruciate ligament reconstruction: a biomechanical study. \u003cem\u003eKnee Surg. Sports Traumatol. Arthrosc.\u003c/em\u003e \u003cb\u003e18\u003c/b\u003e (6), 742\u0026ndash;746 (2010).\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eChiang, E. R. et al. Hamstring graft sizes differ between Chinese and Caucasians. \u003cem\u003eKnee Surg. Sports Traumatol. Arthrosc.\u003c/em\u003e \u003cb\u003e20\u003c/b\u003e, 916\u0026ndash;921 (2012).\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eAhn, J. H., Lee, S. H., Choi, S. H. \u0026amp; Lim, T. K. Magnetic resonance imaging evaluation of anterior cruciate ligament reconstruction using quadrupled hamstring tendon autografts: comparison of remnant bundle preservation and standard technique. \u003cem\u003eAm. J. Sports Med.\u003c/em\u003e \u003cb\u003e38\u003c/b\u003e, 1768\u0026ndash;1777 (2010).\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eDavid, C. B., Peter, T. S., Roger, V. L., James, B. \u0026amp; David, A. N. Timeline of tibial tunnel expansion after single-incision hamstring anterior cruciate ligament reconstruction. \u003cem\u003eArthroscopy\u003c/em\u003e \u003cb\u003e20\u003c/b\u003e (1), 34\u0026ndash;36 (2004).\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eSiebold, R. \u0026amp; Cafaltzis, K. Differentiation between intraoperative and postoperative bone tunnel widening and communication in double-bundle anterior cruciate ligament reconstruction: A prospective study. \u003cem\u003eArthroscopy\u003c/em\u003e \u003cb\u003e26\u003c/b\u003e, 1066\u0026ndash;1073 (2010).\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eRainer, S. Observations on bone tunnel enlargement after double-bundle anterior cruciate ligament reconstruction. \u003cem\u003eArthroscopy\u003c/em\u003e \u003cb\u003e23\u003c/b\u003e (3), 291\u0026ndash;298 (2007).\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eSiebold, R., Kiss, Z. S. \u0026amp; Morris, H. G. Effect of compaction drilling during ACL reconstruction with hamstrings on postoperative tunnel widening. \u003cem\u003eArch. Orthop. Trauma. Surg.\u003c/em\u003e \u003cb\u003e128\u003c/b\u003e, 461\u0026ndash;468 (2008).\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eRainer, S., Pforz, H. \u0026amp; Hayden, M. Bone Tunnel Enlargement Following ACL Reconstruction. Influence of Compaction Drilling versus Bulby Drilling. A Prospective Randomised Study. \u003cem\u003eArthroscopy\u003c/em\u003e \u003cb\u003e28\u003c/b\u003e (8), 74\u0026ndash;75 (2012).\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eXu, H., Zheng, R. \u0026amp; Ying, J. Bone tunnel impaction reduced the tibial tunnel enlargement. \u003cem\u003eOpen. Med.\u003c/em\u003e \u003cb\u003e12\u003c/b\u003e, 99\u0026ndash;106 (2017).\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eGokce, A., Beyzadeoglu, T., Ozyer, F., Bekler, H. \u0026amp; Erdogan, F. Does bone impaction technique reduce tunnel enlargement in ACL reconstruction? \u003cem\u003eInt. Orthop.\u003c/em\u003e \u003cb\u003e33\u003c/b\u003e, 407\u0026ndash;412 (2009).\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eRittmeister, M. E. et al. Interactive effects of tunnel dilation on the mechanical properties of hamstring grafts fixed in the tibia with interference screws. \u003cem\u003eKnee Surg. Sports Traumatol. Arthrosc.\u003c/em\u003e \u003cb\u003e9\u003c/b\u003e, 267\u0026ndash;271 (2001).\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eCain, E. L., Phillips, B. B., Charlebois, S. J. \u0026amp; Azar, F. M. Effect of tibial tunnel dilation on pullout strength of semitendinosus-gracilis graft in anterior cruciate ligament reconstruction. \u003cem\u003eOrthopedics\u003c/em\u003e \u003cb\u003e28\u003c/b\u003e, 779\u0026ndash;783 (2005).\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eBiercevicz, A. M. et al. MRI volume and signal intensity of ACL graft predict clinical, functional, and patient-oriented outcome measures after ACL reconstruction. \u003cem\u003eAm. J. Sports Med.\u003c/em\u003e \u003cb\u003e43\u003c/b\u003e, 693\u0026ndash;699 (2015).\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eTimothy, S. W. \u0026amp; Donald, H. J. Is There a Correlation Between Subjective IKDC Scores and Both Pivot Shift and KT-1000 Measurements Following Anterior Cruciate Ligament Reconstruction? \u003cem\u003eArthroscopy\u003c/em\u003e \u003cb\u003e28\u003c/b\u003e (8), 245\u0026ndash;246 (2012).\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":false,"isAuthorSuppliedPdf":false,"isDeskRejected":"","isHiddenFromSearch":false,"isInQc":false,"isInWorkflow":false,"isPdf":false,"isPdfUpToDate":true,"isWithdrawnOrRetracted":false,"journal":{"display":true,"email":"[email protected]","identity":"scientific-reports","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"scirep","sideBox":"Learn more about [Scientific Reports](http://www.nature.com/srep/)","snPcode":"","submissionUrl":"","title":"Scientific Reports","twitterHandle":"","acdcEnabled":true,"dfaEnabled":true,"editorialSystem":"stoa","reportingPortfolio":"Scientific Reports","inReviewEnabled":true,"inReviewRevisionsEnabled":true},"keywords":"Anterior cruciate ligament reconstruction, Tunnel enlargement, Serial dilation, Extraction drilling, Clinical outcomes","lastPublishedDoi":"10.21203/rs.3.rs-8095016/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-8095016/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003cp\u003e \u003cb\u003eBackground\u003c/b\u003e The application of tibial tunnel compaction-drilling technique in anterior cruciate ligament reconstruction (ACL-R) is controversy. The purpose of this study was to evaluate the impact of tibial tunnel compaction-drilling technique and extraction-drilling technique used in single‑bundle ACL reconstruction on bone tunnel enlargement value, ACL graft maturation and clinical outcomes.\u003c/p\u003e \u003cp\u003e \u003cb\u003eMethods\u003c/b\u003e In this retrospective cohort study, 62 patients receiving ACL-R were screened and divided into two groups based on the technique of tibial tunnel drilling: compaction-drilling group (CD group, n\u0026thinsp;=\u0026thinsp;31) and extraction-drilling group (ED group, n\u0026thinsp;=\u0026thinsp;31). The bone tunnel enlargement was analysed based on the multislice computerised tomography at 12 months postoperatively. The ACL graft maturation was evaluated by the signal/noise quotient (SNQ) value on magnetic resonance imaging at 12 months postoperatively. Subjectively clinical outcomes were assessed by Lysholm score and International Knee Documentation Committee (IKDC) subjective score at 12 months postoperatively. Pivot-shift test was performed at 12 months postoperatively. The instrumental laxity measurement using the KT-1000 arthrometer was performed at 12 and 24 months postoperatively.\u003c/p\u003e \u003cp\u003e \u003cb\u003eResults\u003c/b\u003e The tibial bone tunnel diameters were enlarged by 9\u0026ndash;15% in CD group (\u003cem\u003ep\u003c/em\u003e\u0026thinsp;\u0026lt;\u0026thinsp;0.001) and enlarged by 15\u0026ndash;22% in ED group (\u003cem\u003ep\u003c/em\u003e\u0026thinsp;\u0026lt;\u0026thinsp;0.001). The CD group showed significantly smaller bone tunnel enlargement value than the ED group at 12 months follow up (\u003cem\u003eP\u003c/em\u003e\u0026thinsp;\u0026lt;\u0026thinsp;0.05). In addition, significantly decreased KT-1000 measurement was found in CD group at 12 months (3.7\u0026thinsp;\u0026plusmn;\u0026thinsp;1.8 vs. 5.0\u0026thinsp;\u0026plusmn;\u0026thinsp;1.8 mm) (\u003cem\u003eP\u003c/em\u003e\u0026thinsp;=\u0026thinsp;0.003) and 24 months follow up (3.4\u0026thinsp;\u0026plusmn;\u0026thinsp;1.6 vs. 5.4\u0026thinsp;\u0026plusmn;\u0026thinsp;2.0 mm) (\u003cem\u003eP\u003c/em\u003e\u0026thinsp;\u0026lt;\u0026thinsp;0.001) compared to the ED group. No statistically significant differences of the SNQ value (\u003cem\u003ep\u003c/em\u003e\u0026thinsp;=\u0026thinsp;0.255), IKDC subjective score (\u003cem\u003ep\u003c/em\u003e\u0026thinsp;=\u0026thinsp;0.599) and Lysholm score (\u003cem\u003ep\u003c/em\u003e\u0026thinsp;=\u0026thinsp;0.378) were found between two groups at 12 months postoperatively.\u003c/p\u003e \u003cp\u003e \u003cb\u003eConclusion\u003c/b\u003e This study demonstrated that bone tunnel compaction-drilling technique could reduce the tibial bone tunnel enlargement and improve knee stability compared with extraction-drilling technique in ACL-R objectively.\u003c/p\u003e","manuscriptTitle":"Tibial tunnel compaction-drilling technique reduces tibial tunnel enlargement and improves knee stability in ACL reconstruction with hamstring autografts: a retrospective cohort study","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2025-12-31 10:38:30","doi":"10.21203/rs.3.rs-8095016/v1","editorialEvents":[{"type":"communityComments","content":0},{"type":"decision","content":"Revision requested","date":"2026-01-20T13:32:24+00:00","index":"","fulltext":""},{"type":"editorInvitedReview","content":"","date":"2026-01-20T06:59:11+00:00","index":"hide","fulltext":""},{"type":"editorInvitedReview","content":"","date":"2026-01-13T05:47:55+00:00","index":"hide","fulltext":""},{"type":"editorInvitedReview","content":"","date":"2026-01-05T06:17:25+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"281155206439210905634149042278384213806","date":"2026-01-05T06:15:20+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"16322104943411616169385353374072375316","date":"2026-01-04T14:50:09+00:00","index":"hide","fulltext":""},{"type":"editorInvitedReview","content":"","date":"2026-01-04T00:46:20+00:00","index":"hide","fulltext":""},{"type":"editorInvitedReview","content":"","date":"2026-01-02T13:18:37+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"99759106909123121044909172648782442549","date":"2025-12-31T04:08:06+00:00","index":"hide","fulltext":""},{"type":"editorInvitedReview","content":"","date":"2025-12-30T12:21:36+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"30005412891320495414552483784084636915","date":"2025-12-30T12:12:37+00:00","index":"hide","fulltext":""},{"type":"editorInvitedReview","content":"","date":"2025-12-30T12:11:41+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"59005276593111447595312714677088776671","date":"2025-12-30T08:13:24+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"233710247980168876051451831957212904190","date":"2025-12-29T08:48:41+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"201264561318986694098468363538864942549","date":"2025-12-29T06:01:28+00:00","index":"hide","fulltext":""},{"type":"reviewersInvited","content":"","date":"2025-12-29T04:54:09+00:00","index":"","fulltext":""},{"type":"editorInvited","content":"","date":"2025-11-21T08:42:06+00:00","index":"","fulltext":""},{"type":"editorAssigned","content":"","date":"2025-11-13T05:55:06+00:00","index":"","fulltext":""},{"type":"checksComplete","content":"","date":"2025-11-13T05:54:29+00:00","index":"","fulltext":""},{"type":"submitted","content":"Scientific Reports","date":"2025-11-12T10:02:16+00:00","index":"","fulltext":""}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"scientific-reports","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"scirep","sideBox":"Learn more about [Scientific Reports](http://www.nature.com/srep/)","snPcode":"","submissionUrl":"","title":"Scientific Reports","twitterHandle":"","acdcEnabled":true,"dfaEnabled":true,"editorialSystem":"stoa","reportingPortfolio":"Scientific Reports","inReviewEnabled":true,"inReviewRevisionsEnabled":true}}],"origin":"","ownerIdentity":"8d0e32da-a830-4024-ab17-99a60eae670b","owner":[],"postedDate":"December 31st, 2025","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"under-review","subjectAreas":[{"id":60367156,"name":"Health sciences/Anatomy"},{"id":60367157,"name":"Health sciences/Diseases"},{"id":60367158,"name":"Health sciences/Health care"},{"id":60367159,"name":"Health sciences/Medical research"}],"tags":[],"updatedAt":"2026-05-02T14:23:32+00:00","versionOfRecord":[],"versionCreatedAt":"2025-12-31 10:38:30","video":"","vorDoi":"","vorDoiUrl":"","workflowStages":[]},"version":"v1","identity":"rs-8095016","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-8095016","identity":"rs-8095016","version":["v1"]},"buildId":"8U1c8b4HqxoKbykW_rLl7","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}