Earlier magnetic resonance imaging-based diagnosis and prompt surgical consultation reduce medial meniscus extrusion following posterior root repair

Earlier magnetic resonance imaging-based diagnosis and prompt surgical consultation reduce medial meniscus extrusion following posterior root repair | 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 Research Article Earlier magnetic resonance imaging-based diagnosis and prompt surgical consultation reduce medial meniscus extrusion following posterior root repair Yuta Morinobu, Yuki Okazaki, Koki Kawada, Kazuhisa Sugiu, Takayuki Furumatsu This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-8433953/v1 This work is licensed under a CC BY 4.0 License Status: Posted Version 1 posted You are reading this latest preprint version Abstract Background To investigate factors influencing the change in medial meniscus extrusion (ΔMME) following pullout repair in patients with medial meniscus posterior root tears (MMPRT). Methods This study included 84 knees of patients with MMPRT who had a clearly defined date of injury and underwent pullout repair. Preoperative and 3-month postoperative magnetic resonance imaging (MRI) data were available for all patients. The association between the ΔMME (defined as the difference between the preoperative and 3-month postoperative medial meniscus extrusion [MME] values) and the following factors was analyzed: age, sex, body mass index, and the time from injury to MRI examination (Injury/MRI interval), consultation with knee surgeons (Injury/Consult interval), and surgery (Injury/Surg interval). Results The average durations were 20.5 days for the Injury/MRI interval, 33.1 days for the Injury/Consult interval, and 53.6 days for the Injury/Surg interval. The mean MME was 3.94 mm preoperatively and 4.51 mm at 3 months postoperatively. Univariate analysis showed that the Injury/MRI, Injury/Consult, and Injury/Surg intervals were significantly correlated with the ΔMME (all P < 0.001). A strong correlation was observed between the Injury/Consult and Injury/Surg intervals (correlation coefficient = 0.933). In the multivariate analysis, the Injury/MRI and Injury/Consult intervals remained significantly associated with the ΔMME (both P < 0.01). Conclusions Shortening the Injury/MRI and Injury/Consult intervals may help prevent the progression of MME following MMPRT pullout repair. Early MRI evaluation and prompt specialist consultation are recommended when MMPRT is suspected, particularly in patients presenting with posterior knee pain or a popping episode. Level of evidence Level IV. Magnetic resonance imaging Medial meniscus Medial meniscal extrusion Posterior root tear Pullout repair Figures Figure 1 Figure 2 Figure 3 Background Recently, pullout repair has been demonstrated to have favorable clinical outcomes for medial meniscus (MM) posterior root tears (PRT) [ 1 ]. Medial meniscus posterior root tears are most commonly observed in middle-aged to older women with a mean age of 50–60 years. Obesity and varus knee alignment are recognized risk factors [ 2 ]. MMPRT leads to a loss in the ability to convert axial loads into hoop stresses, resulting in a marked increase in contact pressure, a decrease in contact area, and subsequent degenerative changes in the knee joint [ 3 ]. Approximately 31% of patients with MMPRTs who were managed non-operatively progressed to total knee arthroplasty at a mean of 30 months [ 4 ]. MMPRT leads to medial meniscus extrusion (MME), which contributes to cartilage degeneration and rapid progression of osteoarthritis [ 5 , 6 ]. Previous reports have indicated that a smaller change in MME (ΔMME) is associated with better clinical outcomes [ 7 ]. The meniscotibial ligament plays a significant biomechanical role, and its biomechanical importance has been demonstrated in several studies [ 8 , 9 ]. MMPRTs have been reported to cause intrameniscal degeneration, which appears as an increased signal intensity on proton density-weighted magnetic resonance imaging (MRI). Furthermore, the expression of small leucine-rich proteoglycans, which reflect degenerative changes in the meniscus, is increased in the menisci of patients with MMPRTs [ 10 ]. Moreover, the signal intensity significantly decreases after transtibial pullout repair, suggesting recovery of meniscal integrity [ 11 ]. MME has gained increasing attention worldwide as a critical target for MMPRT treatment. Accordingly, various surgical techniques aimed at reducing MME have been developed, with promising clinical results reported [ 12 – 14 ]. For example, centralization and dual-tunnel pullout repair, procedures designed to suppress MME in MMPRT, have demonstrated favorable clinical outcomes [ 15 , 16 ]. Although animal studies conducted on pullout repair and centralization immediately after MMPRT demonstrated a sufficient reduction of MME, in clinical situations, MME has often already progressed, making achievement of a significant decrease difficult. Among the factors influencing MME, the injury-to-surgery (Injury/Surg) interval is frequently discussed, and surgery within approximately 3–4 months is recommended based on MME [ 17 , 18 ]. In clinical situations, surgery within 3 months is recommended according to the Delphi consensus on MMPRT [ 19 ]. Although several studies have explored the relationship between the Injury/Surg interval and degree of the ΔMME [ 20 ], there is currently no research focusing on the associations of the injury-to-MRI examination (Injury/MRI) interval, injury-to-consultation with knee surgeons (Injury/Consult) interval, and Injury/Surg interval with the ΔMME. Therefore, the purpose of this study was to identify factors affecting the ΔMME, including the Injury/MRI, Injury/Consult, and Injury/Surg intervals in patients undergoing MMPRT pullout repair. We hypothesized that the shorter Injury/Consult, Injury/MRI, and Injury/Surg intervals may be associated with smaller ΔMME. Methods Patients The study was conducted in accordance with the principles of the Declaration of Helsinki. This retrospective study was approved by the Institutional Review Board of the Okayama Red Cross Hospital (No. 2024-37), and written informed consent was obtained from all patients. A retrospective review was conducted on the data of 112 patients with MMPRT and a clear injury history who underwent pullout repair between March and October 2024 and in whom the tears were classified as LaPrade type 2 [ 21 ]. The inclusion criteria for pullout repair of MMPRT were as follows: apparent injury date (with posterior painful popping episode [ 6 ]), Kellgren–Lawrence grade ≤ 2, femorotibial angle (FTA) ≤ 180°, and no-mild cartilage damage (Outerbridge grade ≤ 2). Among these patients, 25 who could not undergo follow-up MRI at 3 months postoperatively and 3 with an Injury/Surg interval exceeding 6 months were excluded from the analysis. Patients were not contraindicated based on age or body mass index (BMI). Finally, 84 patients were included in the analysis (Fig. 1 ). Surgical technique and rehabilitation Transtibial pullout repairs were performed using standard anteromedial and anterolateral portals. The medial compartment was enlarged using the outside-in pie-crusting technique, followed by arthroscopic assessment of the MMPRT for the Laprade classification [ 21 ]. Subsequently, two strands of MiniTape (Smith & Nephew, London, UK) were passed through the torn site using the two simple-stitch technique with Knee Scorpion suture passer (Arthrex, Naples, FL, USA) [ 22 ]. A tibial bone tunnel was created at the anatomical attachment area of the MM posterior root using a dedicated MMPRT guide (Smith & Nephew) [ 21 ], and the sutures were pulled out. Tibial fixation of the sutures was performed using a bioabsorbable screw and a cancellous bone screw at 30° knee flexion and 20–25 N tension for the sutures. Postoperative rehabilitation followed a standardized protocol. During the first week, the range of motion (ROM) was restricted to 0°–30°, with partial weight bearing limited to 25 kg. In the second week, the ROM was increased to 0°–60°, and weight-bearing was permitted up to 50 kg. From the third week, the ROM was extended to 0°–90°, and weight-bearing was increased to 75 kg. After 3 weeks, the ROM was allowed up to 120°, and full weight-bearing was permitted [ 16 ]. Early initiation of partial weight-bearing and range-of-motion training after surgery has been reported to result in favorable clinical outcomes [ 23 ]. MRI assessment MRI examinations were performed using 3.0-T Achieva and Elition scanners (Philips, Eindhoven, Netherlands). The imaging parameters included a slice thickness of 3 mm and a field of view of 160 mm. MME was evaluated using images obtained from the coronal T2-Weighted multi-echo fast field echo sequence. MRI was performed preoperatively and 3 months postoperatively (Fig. 2 ). MME was defined as the distance from the medial edge of the tibial plateau (excluding osteophytes) to the medial edge of the MM, measured using the coronal image at the midpoint of the anteroposterior diameter of the MM. The ΔMME was calculated as the difference between the preoperative and 3-month postoperative MME values. All measurements were expressed to two decimal places. Statistical analyses Data were presented as mean ± standard deviation. Statistical analyses were performed using the EZR software (Saitama Medical Center, Jichi Medical University, Tochigi, Japan). Univariate linear regression analysis was performed with the ΔMME as the dependent variable and age, sex, preoperative MME, FTA, and the Injury/MRI, Injury/Consult, Injury/Surgery, and MRI-to-surgery (MRI/Surg) intervals as independent variables. Variables with a p-value < 0.05 in the univariate analysis were subsequently included in the multivariate linear regression analysis. Preoperative and 3-month postoperative MME values were compared using a paired t-test. The correlation between the Injury/Consult and Injury/Surg intervals was evaluated using Spearman’s correlation coefficient. MME measurements were independently performed by two evaluators who were not involved in the surgery and were blinded to the clinical information. The mean of their measurements was used for analysis. Both inter- and intra-observer reliabilities were assessed using the intraclass correlation coefficient, and all values indicated excellent reliability (> 0.9). Results The patient demographics are summarized in Table 1 . The univariate analysis revealed that the following factors were significantly associated with the ΔMME: Injury/MRI, Injury/Consult, Injury/Surg, and MRI/Surg intervals (all, P < 0.001) as well as age (P = 0.03; Table 2 ). Table 1 Patient demographics Number of patients n = 84 Sex (men/women) 14/70 Age (year) 67.8 ± 8.45 Body mass index (kg/m²) 25.2 ± 4.37 Injury-to‐MRI interval (day) 20.5 ± 25.1 Injury-to‐consultation interval (day) 33.1 ± 30.2 Injury-to‐surgery interval (day) 53.6 ± 32.5 MRI-to‐surgery interval (day) 33.1 ± 19.3 Preoperative MME (mm) 3.94 ± 0.79 3-month postoperative MME (mm) 4.51 ± 0.94 ΔMME (mm) 0.57 ± 0.44 Femorotibial angle (°) 177.5 ± 1.71 MME, Medial meniscus extrusion; MRI, magnetic resonance imaging; ΔMME, change in medial meniscus extrusion. Table 2 Univariate analysis with ΔMME as the dependent variable. Univariate analysis Regression coefficient 95% CI SD t value P value Age 0.012 0.0010–0.023 0.0056 2.2 0.03* Sex 0.062 -0.19-0.32 0.13 0.48 0.63 Body mass index 0.00049 -0.020-0.021 0.010 0.047 0.96 Femorotibial angle 0.043 -0.011-0.097 0.027 1.58 0.118 Preoperative MME -0.0079 -0.13-0.12 0.063 -0.13 0.90 Injury/MRI 0.0084 0.0051–0.012 0.0016 5.1 < 0.001* Injury/Consult 0.011 0.0082–0.013 0.0013 8.3 < 0.001* Injury/Surg 0.010 0.0071–0.012 0.0013 7.6 < 0.001* MRI/Surg 0.0095 0.0043–0.015 0.0026 3.7 < 0.001* Independent variables are as follows: age, sex, body mass index, preoperative MME, injury-to‐MRI (Injury/MRI), injury‐to‐consultation (Injury/Consult), injury‐to‐surgery (Injury/Surg), and MRI‐to‐surgery (MRI/Surg) interval. CI, confidential interval; MME, medial meniscus extrusion; MRI, magnetic resonance imaging examination; SD, standard deviation; ΔMME, change in medial meniscus extrusion. *Significant correlation was observed using univariate linear regression analysis. P value < 0.05. In the multivariate linear regression analysis, both the Injury/MRI and Injury/Consult intervals were independently and significantly associated with the ΔMME (P = 0.0046 and P < 0.001, respectively; Table 3 and Fig. 3 ). Although the Injury/Surg interval was not significant in the original multivariate analysis (P = 0.73), when the Injury/Consult interval was excluded and the analysis was repeated, the Injury/Surg interval was found to be significantly associated with the ΔMME (P < 0.001; Online Resource 1). Correlation analysis between the Injury/Consult and Injury/Surg intervals demonstrated a strong positive correlation (correlation coefficient = 0.933, P < 0.001). Table 3 Multivariate analysis with ΔMME as the dependent variable. Multivariate analysis SE t value P value Age 0.30 0.49 0.62 Injury/MRI 0.0029 -2.9 0.0046* Injury/Consult 0.0045 3.7 < 0.001* Injury/Surg 0.0033 0.34 0.73 MRI/Surg N/A N/A N/A Adjusted R-squared: 0.4906 P-value: 8.115e-12 Independent variables are as follows; age, injury-to‐MRI (Injury/MRI), injury‐to‐consultation (Injury/Consult), injury‐to‐surgery (Injury/Surg), and MRI‐to‐surgery (MRI/Surg) interval. MRI, magnetic resonance imaging examination; ΔMME, change in medial meniscus extrusion; SE, standard error. N/A, not applicable. * Significant correlation was observed using multivariate linear regression analysis. P value < 0.05. Discussion The results of this study demonstrate that all factors—the Injury/MRI, Injury/Consult, and Injury/Surg intervals—are associated with the ΔMME. Our hypothesis was confirmed, and the results were consistent with those of previous studies. Furthermore, the Injury/MRI and Injury/Consult intervals were significantly associated with the ΔMME in the multivariate analysis. This is the first report to highlight the importance of early MRI examination and prompt consultation with a knee surgeon to prevent worsening of MME. Numerous studies have investigated the relationship among MMPRT, MME, and the progression of knee osteoarthritis [ 24 – 27 ]. A smaller ΔMME has also been reported to be associated with reduced cartilage damage and improved postoperative clinical outcomes [ 7 ]. Several factors have been reported to be associated with the suppression of MME progression, including early surgical intervention following injury, younger patient age, lower BMI, and appropriate treatment of MMPRT [ 25 , 28 ]. Therefore, identifying factors that help minimize the ΔMME is clinically important, and to the best of our knowledge, the current study is the first to investigate this issue in detail. In the multivariate linear regression analysis, the Injury/MRI and Injury/Consult intervals showed a significant correlation with the ΔMME, whereas the Injury/Surg interval did not. This may be attributed to the early diagnosis and the strong correlation between the Injury/Consult and Injury/Surg intervals. In our department, we opt for surgical treatment rather than conservative treatment as promptly as possible; therefore, a very strong correlation was observed between Injury/Consult and Injury/Surg intervals. When the Injury/Consult interval was excluded from the independent factors and the multivariate analysis was conducted, the Injury/Surg interval emerged as a significant factor associated with decreased ΔMME. A longer Injury/Surg interval caused by prolonged conservative treatment may result in an increased MME. The MRI/Surg interval was not significantly associated with the ΔMME. This may be because surgery was performed during that interval, preventing the natural, rapid progression of MME. Furthermore, patients who receive an earlier diagnosis and explanation of the pathology and natural course of MMPRT may better understand the severity of their condition, which may lead to improved adherence to activity restrictions or modification, and conservative management before surgery, such as crutch gait and quad muscle exercise. Based on the results of our multivariate regression analyses, we found correlations between the ΔMME and Injury/Consult interval as well as between the ΔMME and Injury/Surg interval. Based on the equations derived from these correlations, we estimated that patients should ideally consult a meniscal treatment specialist within 75 days of injury and undergo surgery within 101 days of injury to maintain the ΔMME below 1 mm. According to the results of this study, if MMPRT is suspected, prompt MRI examination is recommended, followed by timely referral to a knee specialist. In particular, when MMPRT is suspected based on symptoms, such as posterior knee pain or the occurrence of a popping sound, as previously reported [ 6 ], an early MRI examination should be performed. Physicians should be familiar with MRI signs suggestive of MMPRT, such as truncation, giraffe neck, and ghost signs [ 29 ]. This study has some limitations. First, it was a retrospective study with a small number of patients, a short-term follow-up period, and an MRI evaluation conducted only 3 months postoperatively. Although it is undeniable that the follow-up period of 3 months is short, it has been reported that MME progresses substantially during the first 3 months after surgery, whereas little to no progression occurs between 1 and 3 years postoperatively [ 30 ]. Therefore, we believe that suppressing MME during the initial 3-month postoperative period is the key to ultimately preventing its progression. Second, the analysis was limited to MMPRT type 2 lesions (the most common tear type); other tear types were not included in the present study. Although previous studies have reported that type 1 lesions may have better postoperative outcomes than type 2 lesions do [ 31 ] and that outcomes for type 2 and type 4 lesions may be comparable [ 32 ], further research is needed to clarify the influence of tear type on clinical and radiological outcomes. Finally, although we did not evaluate postoperative clinical outcomes, no significant worsening of lower limb alignment was observed postoperatively. Conclusions Both the Injury/MRI and Injury/Consult intervals were identified as independent factors significantly associated with the ΔMME. Shortening the Injury/MRI and Injury/Consult intervals can prevent ΔMME progression. When MMPRT is suspected, early MRI is recommended, followed by prompt referral to a knee specialist. Patients should ideally consult a meniscal treatment specialist within 75 days of injury and undergo surgery within 101 days to maintain the ΔMME below 1 mm. Abbreviations BMI, body mass index FTA, femorotibial angle Injury/Consult, injury-to-consultation with knee surgeons Injury/MRI, injury-to-magnetic resonance imaging Injury/Surg, injury-to-surgery MM, medial meniscus MME, medial meniscus extrusion MMPRT, medial meniscus posterior root tears MRI, magnetic resonance imaging MRI/Surg, magnetic resonance imaging-to-surgery ROM, range of motion ΔMME, change in medial meniscus extrusion Declarations Funding statement: No funding was received in support of this study. Ethics approval and consent to participate: The study was performed in line with the principles of the Declaration of Helsinki. Approval was granted by the Institutional Review Board of the Okayama Red Cross Hospital (August 19, 2024: /No. 2024-37). Informed consent was obtained from all individual participants included in the study. Written informed consent was obtained from the patients. Consent for publication: Not applicable. Author Contribution T.F. designed the study. Y.M. and Y.O. contributed to the analysis and interpretation of the data and drafted the manuscript. All authors participated in material preparation and data collection. All authors critically reviewed the manuscript, approved the final version, and agreed to be accountable for all aspects of the work in ensuring that questions related to the accuracy or integrity of any part of the work are appropriately investigated and resolved. References Chung KS, Noh JM, Ha JK, Ra HJ, Park SB, Kim HK, Kim JG (2018) Survivorship analysis and clinical outcomes of transtibial pullout repair for medial meniscus posterior root tears: a 5- to 10-year follow-up study. Arthroscopy 34:530–535. Hwang BY, Kim SJ, Lee SW, Lee HE, Lee CK, Hunter DJ, Jung KA (2012) Risk factors for medial meniscus posterior root tear. Am J Sports Med 40:1606–1610. Allaire R, Muriuki M, Gilbertson L, Harner CD (2008) Biomechanical consequences of a tear of the posterior root of the medial meniscus. Similar to total meniscectomy. J Bone Joint Surg Am 90:1922–1931. Krych AJ, Reardon PJ, Johnson NR, Mohan R, Peter L, Levy BA, Stuart MJ (2017) Non-operative management of medial meniscus posterior horn root tears is associated with worsening arthritis and poor clinical outcome at 5-year follow-up. Knee Surg Sports Traumatol Arthrosc 25:383–389. Guermazi A, Hayashi D, Jarraya M et al (2013) Medial posterior meniscal root tears are associated with development or worsening of medial tibiofemoral cartilage damage: the multicenter osteoarthritis study. Radiology 268:814–821. Furumatsu T, Kamatsuki Y, Fujii M, Kodama Y, Okazaki Y, Masuda S, Ozaki T (2017) Medial meniscus extrusion correlates with disease duration of the sudden symptomatic medial meniscus posterior root tear. Orthop Traumatol Surg Res 103:1179–1182. Chung KS, Ha JK, Ra HJ, Nam GW, Kim JG (2017) Pullout fixation of posterior medial meniscus root tears: correlation between meniscus extrusion and midterm clinical results. Am J Sports Med 45:42–49. Anderson MJJ, Hollenbeck JFM, Drumm AH et al (2025) Medial meniscotibial ligament deficiency increases medial meniscus extrusion and posterior root forces. Am J Sports Med 53:666–672. Gilat R, Mitchnik IY, Mimouni T, Agar G, Lindner D, Beer Y (2023) The meniscotibial ligament role in meniscal extrusion: a systematic review and meta-analysis. Arch Orthop Trauma Surg 143:5777–5786. Hiranaka T, Furumatsu T, Yoshida A et al (2025) Expression of small leucine-rich proteoglycans in the medial meniscus posterior horn associated with medial meniscus posterior root tear. J Orthop Sci:S0949-2658(25)00211-8. Okazaki Y, Furumatsu T, Masuda S et al (2018) Pullout repair of the medial meniscus posterior root tear reduces proton density-weighted imaging signal intensity of the medial meniscus. Acta Med Okayama 72:493–498. Koga H, Watanabe T, Horie M et al (2017) Augmentation of the pullout repair of a medial meniscus posterior root tear by arthroscopic centralization. Arthrosc Tech 6:e1335-e1339. Okazaki Y, Furumatsu T, Yamauchi T et al (2020) Medial meniscus posterior root repair restores the intra-articular volume of the medial meniscus by decreasing posteromedial extrusion at knee flexion. Knee Surg Sports Traumatol Arthrosc 28:3435–3442. Perry AK, Lavoie-Gagne O, Knapik DM et al (2023) Examining the efficacy of medial meniscus posterior root repair: a meta-analysis and systematic review of biomechanical and clinical outcomes. Am J Sports Med 51:1914–1926. Krych AJ, Boos AM, Lamba A, Smith PA (2024) Satisfactory clinical outcome, complications, and provisional results of meniscus centralization with medial meniscus root repair for the extruded medial meniscus at mean 2-year follow-up. Arthroscopy 40:1578–1587. Hasegawa T, Okazaki Y, Furumatsu T, Yokoyama Y, Tamura M, Kawada K, Ozaki T (2025) Dual-tunnel pullout repair for the extruded medial meniscus in patients with posterior root tear. Arthrosc Tech 14:103722. Kamatsuki Y, Furumatsu T, Miyazawa S et al (2019) The early arthroscopic pullout repair of medial meniscus posterior root tear is more effective for reducing medial meniscus extrusion. Acta Med Okayama 73:503–510. Krych AJ, LaPrade MD, Hevesi M, Rhodes NG, Johnson AC, Camp CL, Stuart MJ (2020) Investigating the chronology of meniscus root tears: do medial meniscus posterior root tears cause extrusion or the other way around? Orthop J Sports Med 8:2325967120961368. Chahla J, Garcia JR, Tollefson L et al (2025) International Delphi consensus on medial meniscal root tears shows high agreement on diagnosis, treatment, and rehabilitation but lack of agreement on treatment of asymptomatic tears. Arthroscopy 41:4683–4698. S0749-8063(25)00479-7. Moon HS, Choi CH, Jung M, Lee DY, Hong SP, Kim SH (2020) Early surgical repair of medial meniscus posterior root tear minimizes the progression of meniscal extrusion: 2-year follow-up of clinical and radiographic parameters after arthroscopic transtibial pull-out repair. Am J Sports Med 48:2692–2702. LaPrade CM, James EW, Cram TR, Feagin JA, Engebretsen L, LaPrade RF (2015) Meniscal root tears: a classification system based on tear morphology. Am J Sports Med 43:363–369. Hiranaka T, Furumatsu T, Masuda S et al (2020) A repair technique using two simple stitches reduces the short-term postoperative medial meniscus extrusion after pullout repair for medial meniscus posterior root tear. Eur J Orthop Surg Traumatol 30:901–908. Tamura M, Furumatsu T, Yokoyama Y, Okazaki Y, Kawada K, Ozaki T (2024) Fast rehabilitation does not worsen clinical, radiological, and arthroscopic outcomes after medial meniscus posterior root repair: a retrospective comparative study. Asia-Pac J Sports Med Arthrosc Rehabil Technol 38:29–35. Çamur E, Duran S (2025) Relationship of medial meniscus posterior root tears with proximal tibial morphology and knee osteoarthritis. J Knee Surg 38:433–439. Okazaki Y, Furumatsu T, Shimamura Y et al (2019) Time-dependent increase in medial meniscus extrusion after medial meniscus posterior root tear analyzed by using magnetic resonance imaging. Knee Surg Relat Res 31:120–125. Floyd ER, Rodriguez AN, Falaas KL, Carlson GB, Chahla J, Geeslin AG, LaPrade RF (2021) The natural history of medial meniscal root tears: a biomechanical and clinical case perspective. Front Bioeng Biotechnol 9:744065. Lee DW, Lee SH, Kim JG (2020) Outcomes of medial meniscal posterior root repair during proximal tibial osteotomy: is root repair beneficial? Arthroscopy 36:2466–2475. Nie S, Li H, Liao X, Liu Q, Lan M (2023) Younger patients, lower BMI, complete meniscus root healing, lower HKA degree and shorter preoperative symptom duration were the independent risk factors correlated with the good correction of MME in patients with repaired MMPRTs. Knee Surg Sports Traumatol Arthrosc 31:3775–3783. Furumatsu T, Fujii M, Kodama Y, Ozaki T (2017) A giraffe neck sign of the medial meniscus: a characteristic finding of the medial meniscus posterior root tear on magnetic resonance imaging. J Orthop Sci 22:731–736. Kawada K, Furumatsu T, Yokoyama Y, Higashihara N, Tamura M, Ozaki T (2024) Longitudinal changes in medial meniscus extrusion and clinical outcomes following pullout repair for medial meniscus posterior root tears: a 3-year evaluation. Eur J Orthop Surg Traumatol 34:2021–2029. Tamura M, Furumatsu T, Yokoyama Y, Higashihara N, Kawada K, Ozaki T (2024) Superior outcomes of pullout repairs for medial meniscus posterior root tears in partial tear compared to complete radial tear. Knee Surg Relat Res 36:8. Higashihara N, Furumatsu T, Okazaki Y et al (2024) Transtibial pullout repair improved short-term clinical outcomes in patients with oblique medial meniscus posterior root tear comparable to radial root tear. Eur J Orthop Surg Traumatol 35:30. Additional Declarations No competing interests reported. Supplementary Files OnlineResource1.docx OnlineResource2.docx Cite Share Download PDF Status: Posted Version 1 posted You are reading this latest preprint version Research Square lets you share your work early, gain feedback from the community, and start making changes to your manuscript prior to peer review in a journal. As a division of Research Square Company, we’re committed to making research communication faster, fairer, and more useful. We do this by developing innovative software and high quality services for the global research community. Our growing team is made up of researchers and industry professionals working together to solve the most critical problems facing scientific publishing. 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-8433953","acceptedTermsAndConditions":true,"allowDirectSubmit":true,"archivedVersions":[],"articleType":"Research Article","associatedPublications":[],"authors":[{"id":566856563,"identity":"2f4a9e8b-c78b-4ff9-b2bf-6e3fa0a42318","order_by":0,"name":"Yuta Morinobu","email":"","orcid":"","institution":"Okayama Red Cross General Hospital","correspondingAuthor":false,"prefix":"","firstName":"Yuta","middleName":"","lastName":"Morinobu","suffix":""},{"id":566856564,"identity":"2239c867-7d23-4ce2-8e40-a42ec18f287e","order_by":1,"name":"Yuki Okazaki","email":"","orcid":"","institution":"Okayama University Hospital","correspondingAuthor":false,"prefix":"","firstName":"Yuki","middleName":"","lastName":"Okazaki","suffix":""},{"id":566856565,"identity":"ca57a363-1c77-4371-83f7-65963a903f76","order_by":2,"name":"Koki Kawada","email":"","orcid":"","institution":"Okayama University Hospital","correspondingAuthor":false,"prefix":"","firstName":"Koki","middleName":"","lastName":"Kawada","suffix":""},{"id":566856566,"identity":"5f2ab41e-596a-425d-aaaa-002d8a9dd66f","order_by":3,"name":"Kazuhisa Sugiu","email":"","orcid":"","institution":"Okayama Red Cross General Hospital","correspondingAuthor":false,"prefix":"","firstName":"Kazuhisa","middleName":"","lastName":"Sugiu","suffix":""},{"id":566856567,"identity":"02b81d18-8645-4c72-8cd1-f2b576e17409","order_by":4,"name":"Takayuki Furumatsu","email":"data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAZAAAAAyAQMAAABI0h/eAAAABlBMVEX///8AAABVwtN+AAAACXBIWXMAAA7EAAAOxAGVKw4bAAAA3UlEQVRIiWNgGAWjYFACNjDJw8DAfABIS8gQ1MAD0WIA1MKWANLCQ7QWENMAah0BYM9+LPHTjZo/MubsPZ9f3aix4GFgP3x0A15beNIOS+ccM+Cx7Dm7zTrnGNBhPGlpN/A7LL1BOofNgMfgRu424xw2oBYJHjP8WvifN//O+QfSkvPMOOcfMVok0o5J57aBtTA/zm0jRsuNZ2nWuX3GPAZnjpkx5/ZJ8LAR8gt7f5rx7ZxvcvYGx5sff875VifHz374GF4tyIBNAkwSqxwEmD+QonoUjIJRMApGDgAAgxRBtLYmGzQAAAAASUVORK5CYII=","orcid":"","institution":"Okayama Red Cross General Hospital","correspondingAuthor":true,"prefix":"","firstName":"Takayuki","middleName":"","lastName":"Furumatsu","suffix":""}],"badges":[],"createdAt":"2025-12-23 12:53:55","currentVersionCode":1,"declarations":"","doi":"10.21203/rs.3.rs-8433953/v1","doiUrl":"https://doi.org/10.21203/rs.3.rs-8433953/v1","draftVersion":[],"editorialEvents":[],"editorialNote":"","failedWorkflow":false,"files":[{"id":99321337,"identity":"cfa658eb-4621-4e50-b371-58bbebf13cae","added_by":"auto","created_at":"2025-12-31 16:39:20","extension":"docx","order_by":1,"title":"","display":"","copyAsset":false,"role":"acdc-reference","size":48666,"visible":true,"origin":"","legend":"","description":"","filename":"Blindedmanuscript.docx","url":"https://assets-eu.researchsquare.com/files/rs-8433953/v1/a868d718a705bbaaeb1177b0.docx"},{"id":99292812,"identity":"67a2329a-179b-44f6-9dfa-4710a6f3d845","added_by":"auto","created_at":"2025-12-31 10:46:26","extension":"json","order_by":4,"title":"","display":"","copyAsset":false,"role":"acdc-reference","size":6995,"visible":true,"origin":"","legend":"","description":"","filename":"b8b664f7daf54c46a36c51dd64cb034f.json","url":"https://assets-eu.researchsquare.com/files/rs-8433953/v1/ec2c6b5fe7b9b638c175ffca.json"},{"id":99292816,"identity":"acec31d6-d17c-4e95-b6ce-377200c82a72","added_by":"auto","created_at":"2025-12-31 10:46:26","extension":"docx","order_by":5,"title":"","display":"","copyAsset":false,"role":"acdc-reference","size":18186,"visible":true,"origin":"","legend":"","description":"","filename":"OnlineResource1.docx","url":"https://assets-eu.researchsquare.com/files/rs-8433953/v1/9b08c4c9121047a74f7c283d.docx"},{"id":99320385,"identity":"aefa4b5c-f78c-494b-86ec-bb711f0f761e","added_by":"auto","created_at":"2025-12-31 16:38:33","extension":"docx","order_by":6,"title":"","display":"","copyAsset":false,"role":"acdc-reference","size":17029,"visible":true,"origin":"","legend":"","description":"","filename":"OnlineResource2.docx","url":"https://assets-eu.researchsquare.com/files/rs-8433953/v1/3c50ac628a8e14098bd86a83.docx"},{"id":99320336,"identity":"16648a03-9f61-486f-a864-b8c88e5d8c5f","added_by":"auto","created_at":"2025-12-31 16:38:30","extension":"xml","order_by":7,"title":"","display":"","copyAsset":false,"role":"acdc-reference","size":83284,"visible":true,"origin":"","legend":"","description":"","filename":"b8b664f7daf54c46a36c51dd64cb034f1enriched.xml","url":"https://assets-eu.researchsquare.com/files/rs-8433953/v1/8e3621711db6389d6793e2c3.xml"},{"id":99292818,"identity":"3bec4f2e-7fb2-47bd-8cf6-04e16384e100","added_by":"auto","created_at":"2025-12-31 10:46:26","extension":"pptx","order_by":8,"title":"","display":"","copyAsset":false,"role":"acdc-reference","size":39192,"visible":true,"origin":"","legend":"","description":"","filename":"Figure1.pptx","url":"https://assets-eu.researchsquare.com/files/rs-8433953/v1/bb6f2631435348a3d0b9e950.pptx"},{"id":99292821,"identity":"9801ee15-c353-493d-b593-6c266d2c3694","added_by":"auto","created_at":"2025-12-31 10:46:26","extension":"pptx","order_by":9,"title":"","display":"","copyAsset":false,"role":"acdc-reference","size":800612,"visible":true,"origin":"","legend":"","description":"","filename":"Figure2.pptx","url":"https://assets-eu.researchsquare.com/files/rs-8433953/v1/ebe52904a81b986a43565019.pptx"},{"id":99292819,"identity":"c741171a-29c0-44e8-ac3a-4be9e096feb2","added_by":"auto","created_at":"2025-12-31 10:46:26","extension":"pptx","order_by":10,"title":"","display":"","copyAsset":false,"role":"acdc-reference","size":50916,"visible":true,"origin":"","legend":"","description":"","filename":"Figure3.pptx","url":"https://assets-eu.researchsquare.com/files/rs-8433953/v1/1d7f5ff36b4e6d5bf26183ad.pptx"},{"id":99292823,"identity":"39911e19-4820-4bf6-ab7d-f8eccc8e4a62","added_by":"auto","created_at":"2025-12-31 10:46:26","extension":"xml","order_by":11,"title":"","display":"","copyAsset":false,"role":"acdc-reference","size":82947,"visible":true,"origin":"","legend":"","description":"","filename":"b8b664f7daf54c46a36c51dd64cb034f1structuring.xml","url":"https://assets-eu.researchsquare.com/files/rs-8433953/v1/0c77fe80dbd03284216c027e.xml"},{"id":99320413,"identity":"a384a026-fe21-4856-8fc8-ef7f1ce0419f","added_by":"auto","created_at":"2025-12-31 16:38:34","extension":"html","order_by":12,"title":"","display":"","copyAsset":false,"role":"acdc-reference","size":90100,"visible":true,"origin":"","legend":"","description":"","filename":"earlyproof.html","url":"https://assets-eu.researchsquare.com/files/rs-8433953/v1/4ddab66838e449809ec36101.html"},{"id":99292810,"identity":"bebcb745-b8c4-4edd-b348-bb4e7fd1bc22","added_by":"auto","created_at":"2025-12-31 10:46:26","extension":"png","order_by":1,"title":"Figure 1","display":"","copyAsset":false,"role":"figure","size":26174,"visible":true,"origin":"","legend":"\u003cp\u003eFlowchart showing the study population and patient recruitment process. MMPRT; medial meniscus posterior root tears.\u003c/p\u003e","description":"","filename":"Figure1.png","url":"https://assets-eu.researchsquare.com/files/rs-8433953/v1/5de08e036fc6008fea34ceed.png"},{"id":99292811,"identity":"5ad060b7-c1a6-4fd8-922b-1d0dfaee5fcb","added_by":"auto","created_at":"2025-12-31 10:46:26","extension":"png","order_by":2,"title":"Figure 2","display":"","copyAsset":false,"role":"figure","size":232904,"visible":true,"origin":"","legend":"\u003cp\u003ePreoperative and 3-month postoperative T2-weighted magnetic resonance images.\u003c/p\u003e\n\u003cp\u003e(A) Measurement of the preoperative MME on the coronal view (4.96 mm). (B) Measurement of the 3-month postoperative MME on the coronal view, without any apparent progression of MME (5.00 mm). MME; medial meniscus extrusion.\u003c/p\u003e","description":"","filename":"Figure2.png","url":"https://assets-eu.researchsquare.com/files/rs-8433953/v1/d1f85216bd4c577334b910a2.png"},{"id":99321378,"identity":"48d59e12-4c58-4eff-8274-767002c47456","added_by":"auto","created_at":"2025-12-31 16:39:21","extension":"png","order_by":3,"title":"Figure 3","display":"","copyAsset":false,"role":"figure","size":57623,"visible":true,"origin":"","legend":"\u003cp\u003eLinear regression analysis of Injury-to-MRI and Injury-to-Consultation intervals for ΔMME. (A) Linear regression analysis of the Injury-to-MRI interval for ΔMME revealed a significant positive correlation (P \u0026lt; 0.001). (B) Linear regression analysis of the Injury-to-Consultation interval for ΔMME revealed a significant positive correlation (P \u0026lt; 0.001). MRI; magnetic resonance imaging, ΔMME; change in medial meniscus extrusion.\u003c/p\u003e","description":"","filename":"Figure3.png","url":"https://assets-eu.researchsquare.com/files/rs-8433953/v1/53043c89412096cfbc1a4fde.png"},{"id":102397167,"identity":"d252622b-438a-43c6-a209-77cb032fc5bc","added_by":"auto","created_at":"2026-02-11 10:05:58","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":896958,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-8433953/v1/1d06fa9d-4240-4368-b35e-8968494a7ae7.pdf"},{"id":99292808,"identity":"cc4d31fc-f9a6-48c5-a206-e3277688cc2a","added_by":"auto","created_at":"2025-12-31 10:46:26","extension":"docx","order_by":0,"title":"","display":"","copyAsset":false,"role":"supplement","size":18186,"visible":true,"origin":"","legend":"","description":"","filename":"OnlineResource1.docx","url":"https://assets-eu.researchsquare.com/files/rs-8433953/v1/ffb2d6e9d722285c04e8a3a2.docx"},{"id":99321064,"identity":"319ea046-3267-457b-8bec-a26096825f1e","added_by":"auto","created_at":"2025-12-31 16:39:08","extension":"docx","order_by":1,"title":"","display":"","copyAsset":false,"role":"supplement","size":17029,"visible":true,"origin":"","legend":"","description":"","filename":"OnlineResource2.docx","url":"https://assets-eu.researchsquare.com/files/rs-8433953/v1/dea7b8555fc046382ffa7326.docx"}],"financialInterests":"No competing interests reported.","formattedTitle":"Earlier magnetic resonance imaging-based diagnosis and prompt surgical consultation reduce medial meniscus extrusion following posterior root repair","fulltext":[{"header":"Background","content":"\u003cp\u003eRecently, pullout repair has been demonstrated to have favorable clinical outcomes for medial meniscus (MM) posterior root tears (PRT) [\u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e]. Medial meniscus posterior root tears are most commonly observed in middle-aged to older women with a mean age of 50\u0026ndash;60 years. Obesity and varus knee alignment are recognized risk factors [\u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e]. MMPRT leads to a loss in the ability to convert axial loads into hoop stresses, resulting in a marked increase in contact pressure, a decrease in contact area, and subsequent degenerative changes in the knee joint [\u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e3\u003c/span\u003e]. Approximately 31% of patients with MMPRTs who were managed non-operatively progressed to total knee arthroplasty at a mean of 30 months [\u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e4\u003c/span\u003e]. MMPRT leads to medial meniscus extrusion (MME), which contributes to cartilage degeneration and rapid progression of osteoarthritis [\u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e5\u003c/span\u003e, \u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e6\u003c/span\u003e]. Previous reports have indicated that a smaller change in MME (ΔMME) is associated with better clinical outcomes [\u003cspan citationid=\"CR7\" class=\"CitationRef\"\u003e7\u003c/span\u003e]. The meniscotibial ligament plays a significant biomechanical role, and its biomechanical importance has been demonstrated in several studies [\u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e8\u003c/span\u003e, \u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e9\u003c/span\u003e]. MMPRTs have been reported to cause intrameniscal degeneration, which appears as an increased signal intensity on proton density-weighted magnetic resonance imaging (MRI). Furthermore, the expression of small leucine-rich proteoglycans, which reflect degenerative changes in the meniscus, is increased in the menisci of patients with MMPRTs [\u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e10\u003c/span\u003e]. Moreover, the signal intensity significantly decreases after transtibial pullout repair, suggesting recovery of meniscal integrity [\u003cspan citationid=\"CR11\" class=\"CitationRef\"\u003e11\u003c/span\u003e]. MME has gained increasing attention worldwide as a critical target for MMPRT treatment. Accordingly, various surgical techniques aimed at reducing MME have been developed, with promising clinical results reported [\u003cspan additionalcitationids=\"CR13\" citationid=\"CR12\" class=\"CitationRef\"\u003e12\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR14\" class=\"CitationRef\"\u003e14\u003c/span\u003e]. For example, centralization and dual-tunnel pullout repair, procedures designed to suppress MME in MMPRT, have demonstrated favorable clinical outcomes [\u003cspan citationid=\"CR15\" class=\"CitationRef\"\u003e15\u003c/span\u003e, \u003cspan citationid=\"CR16\" class=\"CitationRef\"\u003e16\u003c/span\u003e]. Although animal studies conducted on pullout repair and centralization immediately after MMPRT demonstrated a sufficient reduction of MME, in clinical situations, MME has often already progressed, making achievement of a significant decrease difficult.\u003c/p\u003e \u003cp\u003eAmong the factors influencing MME, the injury-to-surgery (Injury/Surg) interval is frequently discussed, and surgery within approximately 3\u0026ndash;4 months is recommended based on MME [\u003cspan citationid=\"CR17\" class=\"CitationRef\"\u003e17\u003c/span\u003e, \u003cspan citationid=\"CR18\" class=\"CitationRef\"\u003e18\u003c/span\u003e]. In clinical situations, surgery within 3 months is recommended according to the Delphi consensus on MMPRT [\u003cspan citationid=\"CR19\" class=\"CitationRef\"\u003e19\u003c/span\u003e].\u003c/p\u003e \u003cp\u003eAlthough several studies have explored the relationship between the Injury/Surg interval and degree of the ΔMME [\u003cspan citationid=\"CR20\" class=\"CitationRef\"\u003e20\u003c/span\u003e], there is currently no research focusing on the associations of the injury-to-MRI examination (Injury/MRI) interval, injury-to-consultation with knee surgeons (Injury/Consult) interval, and Injury/Surg interval with the ΔMME. Therefore, the purpose of this study was to identify factors affecting the ΔMME, including the Injury/MRI, Injury/Consult, and Injury/Surg intervals in patients undergoing MMPRT pullout repair. We hypothesized that the shorter Injury/Consult, Injury/MRI, and Injury/Surg intervals may be associated with smaller ΔMME.\u003c/p\u003e"},{"header":"Methods","content":"\u003cdiv id=\"Sec3\" class=\"Section2\"\u003e \u003ch2\u003ePatients\u003c/h2\u003e \u003cp\u003eThe study was conducted in accordance with the principles of the Declaration of Helsinki. This retrospective study was approved by the Institutional Review Board of the Okayama Red Cross Hospital (No. 2024-37), and written informed consent was obtained from all patients. A retrospective review was conducted on the data of 112 patients with MMPRT and a clear injury history who underwent pullout repair between March and October 2024 and in whom the tears were classified as LaPrade type 2 [\u003cspan citationid=\"CR21\" class=\"CitationRef\"\u003e21\u003c/span\u003e]. The inclusion criteria for pullout repair of MMPRT were as follows: apparent injury date (with posterior painful popping episode [\u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e6\u003c/span\u003e]), Kellgren\u0026ndash;Lawrence grade\u0026thinsp;\u0026le;\u0026thinsp;2, femorotibial angle (FTA)\u0026thinsp;\u0026le;\u0026thinsp;180\u0026deg;, and no-mild cartilage damage (Outerbridge grade\u0026thinsp;\u0026le;\u0026thinsp;2). Among these patients, 25 who could not undergo follow-up MRI at 3 months postoperatively and 3 with an Injury/Surg interval exceeding 6 months were excluded from the analysis. Patients were not contraindicated based on age or body mass index (BMI). Finally, 84 patients were included in the analysis (Fig.\u0026nbsp;\u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003e).\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003c/div\u003e\n\u003ch3\u003eSurgical technique and rehabilitation\u003c/h3\u003e\n\u003cp\u003eTranstibial pullout repairs were performed using standard anteromedial and anterolateral portals. The medial compartment was enlarged using the outside-in pie-crusting technique, followed by arthroscopic assessment of the MMPRT for the Laprade classification [\u003cspan citationid=\"CR21\" class=\"CitationRef\"\u003e21\u003c/span\u003e]. Subsequently, two strands of MiniTape (Smith \u0026amp; Nephew, London, UK) were passed through the torn site using the two simple-stitch technique with Knee Scorpion suture passer (Arthrex, Naples, FL, USA) [\u003cspan citationid=\"CR22\" class=\"CitationRef\"\u003e22\u003c/span\u003e]. A tibial bone tunnel was created at the anatomical attachment area of the MM posterior root using a dedicated MMPRT guide (Smith \u0026amp; Nephew) [\u003cspan citationid=\"CR21\" class=\"CitationRef\"\u003e21\u003c/span\u003e], and the sutures were pulled out. Tibial fixation of the sutures was performed using a bioabsorbable screw and a cancellous bone screw at 30\u0026deg; knee flexion and 20\u0026ndash;25 N tension for the sutures.\u003c/p\u003e \u003cp\u003ePostoperative rehabilitation followed a standardized protocol. During the first week, the range of motion (ROM) was restricted to 0\u0026deg;\u0026ndash;30\u0026deg;, with partial weight bearing limited to 25 kg. In the second week, the ROM was increased to 0\u0026deg;\u0026ndash;60\u0026deg;, and weight-bearing was permitted up to 50 kg. From the third week, the ROM was extended to 0\u0026deg;\u0026ndash;90\u0026deg;, and weight-bearing was increased to 75 kg. After 3 weeks, the ROM was allowed up to 120\u0026deg;, and full weight-bearing was permitted [\u003cspan citationid=\"CR16\" class=\"CitationRef\"\u003e16\u003c/span\u003e]. Early initiation of partial weight-bearing and range-of-motion training after surgery has been reported to result in favorable clinical outcomes [\u003cspan citationid=\"CR23\" class=\"CitationRef\"\u003e23\u003c/span\u003e].\u003c/p\u003e\n\u003ch3\u003eMRI assessment\u003c/h3\u003e\n\u003cp\u003eMRI examinations were performed using 3.0-T Achieva and Elition scanners (Philips, Eindhoven, Netherlands). The imaging parameters included a slice thickness of 3 mm and a field of view of 160 mm. MME was evaluated using images obtained from the coronal T2-Weighted multi-echo fast field echo sequence. MRI was performed preoperatively and 3 months postoperatively (Fig.\u0026nbsp;\u003cspan refid=\"Fig2\" class=\"InternalRef\"\u003e2\u003c/span\u003e). MME was defined as the distance from the medial edge of the tibial plateau (excluding osteophytes) to the medial edge of the MM, measured using the coronal image at the midpoint of the anteroposterior diameter of the MM. The ΔMME was calculated as the difference between the preoperative and 3-month postoperative MME values. All measurements were expressed to two decimal places.\u003c/p\u003e \u003cp\u003e \u003c/p\u003e\n\u003ch3\u003eStatistical analyses\u003c/h3\u003e\n\u003cp\u003eData were presented as mean\u0026thinsp;\u0026plusmn;\u0026thinsp;standard deviation. Statistical analyses were performed using the EZR software (Saitama Medical Center, Jichi Medical University, Tochigi, Japan). Univariate linear regression analysis was performed with the ΔMME as the dependent variable and age, sex, preoperative MME, FTA, and the Injury/MRI, Injury/Consult, Injury/Surgery, and MRI-to-surgery (MRI/Surg) intervals as independent variables. Variables with a p-value\u0026thinsp;\u0026lt;\u0026thinsp;0.05 in the univariate analysis were subsequently included in the multivariate linear regression analysis. Preoperative and 3-month postoperative MME values were compared using a paired t-test. The correlation between the Injury/Consult and Injury/Surg intervals was evaluated using Spearman\u0026rsquo;s correlation coefficient. MME measurements were independently performed by two evaluators who were not involved in the surgery and were blinded to the clinical information. The mean of their measurements was used for analysis. Both inter- and intra-observer reliabilities were assessed using the intraclass correlation coefficient, and all values indicated excellent reliability (\u0026gt;\u0026thinsp;0.9).\u003c/p\u003e"},{"header":"Results","content":"\u003cp\u003eThe patient demographics are summarized in Table\u0026nbsp;\u003cspan refid=\"Tab1\" class=\"InternalRef\"\u003e1\u003c/span\u003e. The univariate analysis revealed that the following factors were significantly associated with the ΔMME: Injury/MRI, Injury/Consult, Injury/Surg, and MRI/Surg intervals (all, P\u0026thinsp;\u0026lt;\u0026thinsp;0.001) as well as age (P\u0026thinsp;=\u0026thinsp;0.03; Table\u0026nbsp;\u003cspan refid=\"Tab2\" class=\"InternalRef\"\u003e2\u003c/span\u003e).\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 demographics\u003c/p\u003e \u003c/div\u003e \u003c/caption\u003e \u003ccolgroup cols=\"2\"\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 \u003cthead\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c1\"\u003e \u003cp\u003eNumber of patients\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c2\"\u003e \u003cp\u003en\u0026thinsp;=\u0026thinsp;84\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eSex (men/women)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e14/70\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eAge (year)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e67.8\u0026thinsp;\u0026plusmn;\u0026thinsp;8.45\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eBody mass index (kg/m\u0026sup2;)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e25.2\u0026thinsp;\u0026plusmn;\u0026thinsp;4.37\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eInjury-to‐MRI interval (day)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e20.5\u0026thinsp;\u0026plusmn;\u0026thinsp;25.1\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eInjury-to‐consultation interval (day)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e33.1\u0026thinsp;\u0026plusmn;\u0026thinsp;30.2\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eInjury-to‐surgery interval (day)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e53.6\u0026thinsp;\u0026plusmn;\u0026thinsp;32.5\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eMRI-to‐surgery interval (day)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e33.1\u0026thinsp;\u0026plusmn;\u0026thinsp;19.3\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003ePreoperative MME (mm)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e3.94\u0026thinsp;\u0026plusmn;\u0026thinsp;0.79\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e3-month postoperative MME (mm)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e4.51\u0026thinsp;\u0026plusmn;\u0026thinsp;0.94\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eΔMME (mm)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e0.57\u0026thinsp;\u0026plusmn;\u0026thinsp;0.44\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eFemorotibial angle (\u0026deg;)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e177.5\u0026thinsp;\u0026plusmn;\u0026thinsp;1.71\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003c/tbody\u003e \u003c/colgroup\u003e \u003ctfoot\u003e \u003ctr\u003e\u003ctd colspan=\"2\"\u003eMME, Medial meniscus extrusion; MRI, magnetic resonance imaging; ΔMME, change in medial meniscus extrusion.\u003c/td\u003e\u003c/tr\u003e \u003c/tfoot\u003e \u003c/table\u003e\u003c/div\u003e \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\u003eUnivariate analysis with ΔMME as the dependent variable.\u003c/p\u003e \u003c/div\u003e \u003c/caption\u003e \u003ccolgroup cols=\"6\"\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c4\" colnum=\"4\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c5\" colnum=\"5\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c6\" colnum=\"6\"\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=\"2\" nameend=\"c3\" namest=\"c2\"\u003e \u003cp\u003eUnivariate analysis\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/th\u003e \u003cth align=\"left\" colname=\"c5\"\u003e\u0026nbsp;\u003c/th\u003e \u003cth align=\"left\" colname=\"c6\"\u003e\u0026nbsp;\u003c/th\u003e \u003c/tr\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c2\"\u003e \u003cp\u003eRegression coefficient\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c3\"\u003e \u003cp\u003e95% CI\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c4\"\u003e \u003cp\u003eSD\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c5\"\u003e \u003cp\u003et value\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c6\"\u003e \u003cp\u003eP value\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eAge\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e0.012\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e0.0010\u0026ndash;0.023\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e0.0056\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e2.2\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e \u003cp\u003e0.03*\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eSex\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e0.062\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e-0.19-0.32\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e0.13\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e0.48\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e \u003cp\u003e0.63\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eBody mass index\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e0.00049\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e-0.020-0.021\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e0.010\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e0.047\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e \u003cp\u003e0.96\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eFemorotibial angle\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e0.043\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e-0.011-0.097\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e0.027\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e1.58\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e \u003cp\u003e0.118\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003ePreoperative MME\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e-0.0079\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e-0.13-0.12\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e0.063\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e-0.13\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e \u003cp\u003e0.90\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eInjury/MRI\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e0.0084\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e0.0051\u0026ndash;0.012\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e0.0016\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e5.1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c6\"\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\u003eInjury/Consult\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e0.011\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e0.0082\u0026ndash;0.013\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e0.0013\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e8.3\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c6\"\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\u003eInjury/Surg\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e0.010\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e0.0071\u0026ndash;0.012\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e0.0013\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e7.6\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c6\"\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\u003eMRI/Surg\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e0.0095\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e0.0043\u0026ndash;0.015\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e0.0026\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e \u003cp\u003e3.7\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c6\"\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=\"6\"\u003eIndependent variables are as follows: age, sex, body mass index, preoperative MME, injury-to‐MRI (Injury/MRI), injury‐to‐consultation (Injury/Consult), injury‐to‐surgery (Injury/Surg), and MRI‐to‐surgery (MRI/Surg) interval.\u003c/td\u003e\u003c/tr\u003e \u003ctr\u003e\u003ctd colspan=\"6\"\u003eCI, confidential interval; MME, medial meniscus extrusion; MRI, magnetic resonance imaging examination; SD, standard deviation; ΔMME, change in medial meniscus extrusion.\u003c/td\u003e\u003c/tr\u003e \u003ctr\u003e\u003ctd colspan=\"6\"\u003e*Significant correlation was observed using univariate linear regression analysis. P value\u0026thinsp;\u0026lt;\u0026thinsp;0.05.\u003c/td\u003e\u003c/tr\u003e \u003c/tfoot\u003e \u003c/table\u003e\u003c/div\u003e \u003c/p\u003e \u003cp\u003eIn the multivariate linear regression analysis, both the Injury/MRI and Injury/Consult intervals were independently and significantly associated with the ΔMME (P\u0026thinsp;=\u0026thinsp;0.0046 and P\u0026thinsp;\u0026lt;\u0026thinsp;0.001, respectively; Table\u0026nbsp;\u003cspan refid=\"Tab3\" class=\"InternalRef\"\u003e3\u003c/span\u003e and Fig.\u0026nbsp;\u003cspan refid=\"Fig3\" class=\"InternalRef\"\u003e3\u003c/span\u003e). Although the Injury/Surg interval was not significant in the original multivariate analysis (P\u0026thinsp;=\u0026thinsp;0.73), when the Injury/Consult interval was excluded and the analysis was repeated, the Injury/Surg interval was found to be significantly associated with the ΔMME (P\u0026thinsp;\u0026lt;\u0026thinsp;0.001; Online Resource 1). Correlation analysis between the Injury/Consult and Injury/Surg intervals demonstrated a strong positive correlation (correlation coefficient\u0026thinsp;=\u0026thinsp;0.933, P\u0026thinsp;\u0026lt;\u0026thinsp;0.001).\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\u003eMultivariate analysis with ΔMME as the dependent variable.\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=\"left\" class=\"colspec\" colname=\"c4\" colnum=\"4\"\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\u003eMultivariate analysis\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c2\"\u003e \u003cp\u003eSE\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c3\"\u003e \u003cp\u003et value\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c4\"\u003e \u003cp\u003eP value\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eAge\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e0.30\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e0.49\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e0.62\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eInjury/MRI\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e0.0029\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e-2.9\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e0.0046*\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eInjury/Consult\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e0.0045\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e3.7\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" 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\u003eInjury/Surg\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e0.0033\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e0.34\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e0.73\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eMRI/Surg\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eN/A\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eN/A\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003eN/A\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003c/tbody\u003e \u003c/colgroup\u003e \u003ctfoot\u003e \u003ctr\u003e\u003ctd colspan=\"4\"\u003eAdjusted R-squared: 0.4906 P-value: 8.115e-12\u003c/td\u003e\u003c/tr\u003e \u003ctr\u003e\u003ctd colspan=\"4\"\u003eIndependent variables are as follows; age, injury-to‐MRI (Injury/MRI), injury‐to‐consultation (Injury/Consult), injury‐to‐surgery (Injury/Surg), and MRI‐to‐surgery (MRI/Surg) interval.\u003c/td\u003e\u003c/tr\u003e \u003ctr\u003e\u003ctd colspan=\"4\"\u003eMRI, magnetic resonance imaging examination; ΔMME, change in medial meniscus extrusion; SE, standard error. N/A, not applicable.\u003c/td\u003e\u003c/tr\u003e \u003ctr\u003e\u003ctd colspan=\"4\"\u003e* Significant correlation was observed using multivariate linear regression analysis. P value\u0026thinsp;\u0026lt;\u0026thinsp;0.05.\u003c/td\u003e\u003c/tr\u003e \u003c/tfoot\u003e \u003c/table\u003e\u003c/div\u003e \u003c/p\u003e \u003cp\u003e \u003c/p\u003e"},{"header":"Discussion","content":"\u003cp\u003eThe results of this study demonstrate that all factors\u0026mdash;the Injury/MRI, Injury/Consult, and Injury/Surg intervals\u0026mdash;are associated with the ΔMME. Our hypothesis was confirmed, and the results were consistent with those of previous studies. Furthermore, the Injury/MRI and Injury/Consult intervals were significantly associated with the ΔMME in the multivariate analysis. This is the first report to highlight the importance of early MRI examination and prompt consultation with a knee surgeon to prevent worsening of MME.\u003c/p\u003e \u003cp\u003eNumerous studies have investigated the relationship among MMPRT, MME, and the progression of knee osteoarthritis [\u003cspan additionalcitationids=\"CR25 CR26\" citationid=\"CR24\" class=\"CitationRef\"\u003e24\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR27\" class=\"CitationRef\"\u003e27\u003c/span\u003e]. A smaller ΔMME has also been reported to be associated with reduced cartilage damage and improved postoperative clinical outcomes [\u003cspan citationid=\"CR7\" class=\"CitationRef\"\u003e7\u003c/span\u003e]. Several factors have been reported to be associated with the suppression of MME progression, including early surgical intervention following injury, younger patient age, lower BMI, and appropriate treatment of MMPRT [\u003cspan citationid=\"CR25\" class=\"CitationRef\"\u003e25\u003c/span\u003e, \u003cspan citationid=\"CR28\" class=\"CitationRef\"\u003e28\u003c/span\u003e]. Therefore, identifying factors that help minimize the ΔMME is clinically important, and to the best of our knowledge, the current study is the first to investigate this issue in detail.\u003c/p\u003e \u003cp\u003eIn the multivariate linear regression analysis, the Injury/MRI and Injury/Consult intervals showed a significant correlation with the ΔMME, whereas the Injury/Surg interval did not. This may be attributed to the early diagnosis and the strong correlation between the Injury/Consult and Injury/Surg intervals. In our department, we opt for surgical treatment rather than conservative treatment as promptly as possible; therefore, a very strong correlation was observed between Injury/Consult and Injury/Surg intervals. When the Injury/Consult interval was excluded from the independent factors and the multivariate analysis was conducted, the Injury/Surg interval emerged as a significant factor associated with decreased ΔMME. A longer Injury/Surg interval caused by prolonged conservative treatment may result in an increased MME. The MRI/Surg interval was not significantly associated with the ΔMME. This may be because surgery was performed during that interval, preventing the natural, rapid progression of MME. Furthermore, patients who receive an earlier diagnosis and explanation of the pathology and natural course of MMPRT may better understand the severity of their condition, which may lead to improved adherence to activity restrictions or modification, and conservative management before surgery, such as crutch gait and quad muscle exercise.\u003c/p\u003e \u003cp\u003eBased on the results of our multivariate regression analyses, we found correlations between the ΔMME and Injury/Consult interval as well as between the ΔMME and Injury/Surg interval. Based on the equations derived from these correlations, we estimated that patients should ideally consult a meniscal treatment specialist within 75 days of injury and undergo surgery within 101 days of injury to maintain the ΔMME below 1 mm.\u003c/p\u003e \u003cp\u003eAccording to the results of this study, if MMPRT is suspected, prompt MRI examination is recommended, followed by timely referral to a knee specialist. In particular, when MMPRT is suspected based on symptoms, such as posterior knee pain or the occurrence of a popping sound, as previously reported [\u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e6\u003c/span\u003e], an early MRI examination should be performed. Physicians should be familiar with MRI signs suggestive of MMPRT, such as truncation, giraffe neck, and ghost signs [\u003cspan citationid=\"CR29\" class=\"CitationRef\"\u003e29\u003c/span\u003e].\u003c/p\u003e \u003cp\u003eThis study has some limitations. First, it was a retrospective study with a small number of patients, a short-term follow-up period, and an MRI evaluation conducted only 3 months postoperatively. Although it is undeniable that the follow-up period of 3 months is short, it has been reported that MME progresses substantially during the first 3 months after surgery, whereas little to no progression occurs between 1 and 3 years postoperatively [\u003cspan citationid=\"CR30\" class=\"CitationRef\"\u003e30\u003c/span\u003e]. Therefore, we believe that suppressing MME during the initial 3-month postoperative period is the key to ultimately preventing its progression. Second, the analysis was limited to MMPRT type 2 lesions (the most common tear type); other tear types were not included in the present study. Although previous studies have reported that type 1 lesions may have better postoperative outcomes than type 2 lesions do [\u003cspan citationid=\"CR31\" class=\"CitationRef\"\u003e31\u003c/span\u003e] and that outcomes for type 2 and type 4 lesions may be comparable [\u003cspan citationid=\"CR32\" class=\"CitationRef\"\u003e32\u003c/span\u003e], further research is needed to clarify the influence of tear type on clinical and radiological outcomes. Finally, although we did not evaluate postoperative clinical outcomes, no significant worsening of lower limb alignment was observed postoperatively.\u003c/p\u003e"},{"header":"Conclusions","content":"\u003cp\u003eBoth the Injury/MRI and Injury/Consult intervals were identified as independent factors significantly associated with the ΔMME. Shortening the Injury/MRI and Injury/Consult intervals can prevent ΔMME progression. When MMPRT is suspected, early MRI is recommended, followed by prompt referral to a knee specialist. Patients should ideally consult a meniscal treatment specialist within 75 days of injury and undergo surgery within 101 days to maintain the ΔMME below 1 mm.\u003c/p\u003e"},{"header":"Abbreviations","content":"\u003cp\u003eBMI, body mass index\u003c/p\u003e\n\u003cp\u003eFTA, femorotibial angle\u003c/p\u003e\n\u003cp\u003eInjury/Consult, injury-to-consultation with knee surgeons\u003c/p\u003e\n\u003cp\u003eInjury/MRI, injury-to-magnetic resonance imaging\u003c/p\u003e\n\u003cp\u003eInjury/Surg, injury-to-surgery\u003c/p\u003e\n\u003cp\u003eMM, medial meniscus\u003c/p\u003e\n\u003cp\u003eMME, medial meniscus extrusion\u003c/p\u003e\n\u003cp\u003eMMPRT, medial meniscus posterior root tears\u003c/p\u003e\n\u003cp\u003eMRI, magnetic resonance imaging\u003c/p\u003e\n\u003cp\u003eMRI/Surg, magnetic resonance imaging-to-surgery\u003c/p\u003e\n\u003cp\u003eROM, range of motion\u003c/p\u003e\n\u003cp\u003eΔMME, change in medial meniscus extrusion\u003c/p\u003e"},{"header":"Declarations","content":"\u003ch2\u003eFunding statement:\u003c/h2\u003e \u003cp\u003eNo funding was received in support of this study.\u003c/p\u003e \u003cp\u003e \u003cstrong\u003eEthics approval and consent to participate:\u003c/strong\u003e \u003cp\u003eThe study was performed in line with the principles of the Declaration of Helsinki. Approval was granted by the Institutional Review Board of the Okayama Red Cross Hospital (August 19, 2024: /No. 2024-37). Informed consent was obtained from all individual participants included in the study. Written informed consent was obtained from the patients.\u003c/p\u003e \u003c/p\u003e \u003cp\u003e \u003cstrong\u003eConsent for publication:\u003c/strong\u003e \u003cp\u003eNot applicable.\u003c/p\u003e \u003c/p\u003e\u003ch2\u003eAuthor Contribution\u003c/h2\u003e\u003cp\u003eT.F. designed the study. Y.M. and Y.O. contributed to the analysis and interpretation of the data and drafted the manuscript. All authors participated in material preparation and data collection. All authors critically reviewed the manuscript, approved the final version, and agreed to be accountable for all aspects of the work in ensuring that questions related to the accuracy or integrity of any part of the work are appropriately investigated and resolved.\u003c/p\u003e"},{"header":"References","content":"\u003col\u003e\u003cli\u003e\u003cspan\u003eChung KS, Noh JM, Ha JK, Ra HJ, Park SB, Kim HK, Kim JG (2018) Survivorship analysis and clinical outcomes of transtibial pullout repair for medial meniscus posterior root tears: a 5- to 10-year follow-up study. Arthroscopy 34:530\u0026ndash;535.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eHwang BY, Kim SJ, Lee SW, Lee HE, Lee CK, Hunter DJ, Jung KA (2012) Risk factors for medial meniscus posterior root tear. Am J Sports Med 40:1606\u0026ndash;1610.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eAllaire R, Muriuki M, Gilbertson L, Harner CD (2008) Biomechanical consequences of a tear of the posterior root of the medial meniscus. Similar to total meniscectomy. J Bone Joint Surg Am 90:1922\u0026ndash;1931.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eKrych AJ, Reardon PJ, Johnson NR, Mohan R, Peter L, Levy BA, Stuart MJ (2017) Non-operative management of medial meniscus posterior horn root tears is associated with worsening arthritis and poor clinical outcome at 5-year follow-up. Knee Surg Sports Traumatol Arthrosc 25:383\u0026ndash;389.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eGuermazi A, Hayashi D, Jarraya M et al (2013) Medial posterior meniscal root tears are associated with development or worsening of medial tibiofemoral cartilage damage: the multicenter osteoarthritis study. Radiology 268:814\u0026ndash;821.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eFurumatsu T, Kamatsuki Y, Fujii M, Kodama Y, Okazaki Y, Masuda S, Ozaki T (2017) Medial meniscus extrusion correlates with disease duration of the sudden symptomatic medial meniscus posterior root tear. Orthop Traumatol Surg Res 103:1179\u0026ndash;1182.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eChung KS, Ha JK, Ra HJ, Nam GW, Kim JG (2017) Pullout fixation of posterior medial meniscus root tears: correlation between meniscus extrusion and midterm clinical results. Am J Sports Med 45:42\u0026ndash;49.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eAnderson MJJ, Hollenbeck JFM, Drumm AH et al (2025) Medial meniscotibial ligament deficiency increases medial meniscus extrusion and posterior root forces. Am J Sports Med 53:666\u0026ndash;672.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eGilat R, Mitchnik IY, Mimouni T, Agar G, Lindner D, Beer Y (2023) The meniscotibial ligament role in meniscal extrusion: a systematic review and meta-analysis. Arch Orthop Trauma Surg 143:5777\u0026ndash;5786.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eHiranaka T, Furumatsu T, Yoshida A et al (2025) Expression of small leucine-rich proteoglycans in the medial meniscus posterior horn associated with medial meniscus posterior root tear. J Orthop Sci:S0949-2658(25)00211-8.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eOkazaki Y, Furumatsu T, Masuda S et al (2018) Pullout repair of the medial meniscus posterior root tear reduces proton density-weighted imaging signal intensity of the medial meniscus. Acta Med Okayama 72:493\u0026ndash;498.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eKoga H, Watanabe T, Horie M et al (2017) Augmentation of the pullout repair of a medial meniscus posterior root tear by arthroscopic centralization. Arthrosc Tech 6:e1335-e1339.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eOkazaki Y, Furumatsu T, Yamauchi T et al (2020) Medial meniscus posterior root repair restores the intra-articular volume of the medial meniscus by decreasing posteromedial extrusion at knee flexion. Knee Surg Sports Traumatol Arthrosc 28:3435\u0026ndash;3442.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003ePerry AK, Lavoie-Gagne O, Knapik DM et al (2023) Examining the efficacy of medial meniscus posterior root repair: a meta-analysis and systematic review of biomechanical and clinical outcomes. Am J Sports Med 51:1914\u0026ndash;1926.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eKrych AJ, Boos AM, Lamba A, Smith PA (2024) Satisfactory clinical outcome, complications, and provisional results of meniscus centralization with medial meniscus root repair for the extruded medial meniscus at mean 2-year follow-up. Arthroscopy 40:1578\u0026ndash;1587.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eHasegawa T, Okazaki Y, Furumatsu T, Yokoyama Y, Tamura M, Kawada K, Ozaki T (2025) Dual-tunnel pullout repair for the extruded medial meniscus in patients with posterior root tear. Arthrosc Tech 14:103722.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eKamatsuki Y, Furumatsu T, Miyazawa S et al (2019) The early arthroscopic pullout repair of medial meniscus posterior root tear is more effective for reducing medial meniscus extrusion. Acta Med Okayama 73:503\u0026ndash;510.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eKrych AJ, LaPrade MD, Hevesi M, Rhodes NG, Johnson AC, Camp CL, Stuart MJ (2020) Investigating the chronology of meniscus root tears: do medial meniscus posterior root tears cause extrusion or the other way around? Orthop J Sports Med 8:2325967120961368.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eChahla J, Garcia JR, Tollefson L et al (2025) International Delphi consensus on medial meniscal root tears shows high agreement on diagnosis, treatment, and rehabilitation but lack of agreement on treatment of asymptomatic tears. Arthroscopy 41:4683\u0026ndash;4698. S0749-8063(25)00479-7.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eMoon HS, Choi CH, Jung M, Lee DY, Hong SP, Kim SH (2020) Early surgical repair of medial meniscus posterior root tear minimizes the progression of meniscal extrusion: 2-year follow-up of clinical and radiographic parameters after arthroscopic transtibial pull-out repair. Am J Sports Med 48:2692\u0026ndash;2702.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eLaPrade CM, James EW, Cram TR, Feagin JA, Engebretsen L, LaPrade RF (2015) Meniscal root tears: a classification system based on tear morphology. Am J Sports Med 43:363\u0026ndash;369.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eHiranaka T, Furumatsu T, Masuda S et al (2020) A repair technique using two simple stitches reduces the short-term postoperative medial meniscus extrusion after pullout repair for medial meniscus posterior root tear. Eur J Orthop Surg Traumatol 30:901\u0026ndash;908.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eTamura M, Furumatsu T, Yokoyama Y, Okazaki Y, Kawada K, Ozaki T (2024) Fast rehabilitation does not worsen clinical, radiological, and arthroscopic outcomes after medial meniscus posterior root repair: a retrospective comparative study. Asia-Pac J Sports Med Arthrosc Rehabil Technol 38:29\u0026ndash;35.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003e\u0026Ccedil;amur E, Duran S (2025) Relationship of medial meniscus posterior root tears with proximal tibial morphology and knee osteoarthritis. J Knee Surg 38:433\u0026ndash;439.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eOkazaki Y, Furumatsu T, Shimamura Y et al (2019) Time-dependent increase in medial meniscus extrusion after medial meniscus posterior root tear analyzed by using magnetic resonance imaging. Knee Surg Relat Res 31:120\u0026ndash;125.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eFloyd ER, Rodriguez AN, Falaas KL, Carlson GB, Chahla J, Geeslin AG, LaPrade RF (2021) The natural history of medial meniscal root tears: a biomechanical and clinical case perspective. Front Bioeng Biotechnol 9:744065.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eLee DW, Lee SH, Kim JG (2020) Outcomes of medial meniscal posterior root repair during proximal tibial osteotomy: is root repair beneficial? Arthroscopy 36:2466\u0026ndash;2475.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eNie S, Li H, Liao X, Liu Q, Lan M (2023) Younger patients, lower BMI, complete meniscus root healing, lower HKA degree and shorter preoperative symptom duration were the independent risk factors correlated with the good correction of MME in patients with repaired MMPRTs. Knee Surg Sports Traumatol Arthrosc 31:3775\u0026ndash;3783.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eFurumatsu T, Fujii M, Kodama Y, Ozaki T (2017) A giraffe neck sign of the medial meniscus: a characteristic finding of the medial meniscus posterior root tear on magnetic resonance imaging. J Orthop Sci 22:731\u0026ndash;736.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eKawada K, Furumatsu T, Yokoyama Y, Higashihara N, Tamura M, Ozaki T (2024) Longitudinal changes in medial meniscus extrusion and clinical outcomes following pullout repair for medial meniscus posterior root tears: a 3-year evaluation. Eur J Orthop Surg Traumatol 34:2021\u0026ndash;2029.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eTamura M, Furumatsu T, Yokoyama Y, Higashihara N, Kawada K, Ozaki T (2024) Superior outcomes of pullout repairs for medial meniscus posterior root tears in partial tear compared to complete radial tear. Knee Surg Relat Res 36:8.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eHigashihara N, Furumatsu T, Okazaki Y et al (2024) Transtibial pullout repair improved short-term clinical outcomes in patients with oblique medial meniscus posterior root tear comparable to radial root tear. Eur J Orthop Surg Traumatol 35:30.\u003c/span\u003e\u003c/li\u003e\u003c/ol\u003e"}],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":true,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":false,"hideJournal":true,"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":"researchsquare","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":true,"externalIdentity":"","sideBox":"","snPcode":"","submissionUrl":"/submission","title":"Research Square","twitterHandle":"researchsquare","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"","reportingPortfolio":"","inReviewEnabled":false,"inReviewRevisionsEnabled":true},"keywords":"Magnetic resonance imaging, Medial meniscus, Medial meniscal extrusion, Posterior root tear, Pullout repair","lastPublishedDoi":"10.21203/rs.3.rs-8433953/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-8433953/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003ch2\u003eBackground\u003c/h2\u003e \u003cp\u003eTo investigate factors influencing the change in medial meniscus extrusion (ΔMME) following pullout repair in patients with medial meniscus posterior root tears (MMPRT).\u003c/p\u003e\u003ch2\u003eMethods\u003c/h2\u003e \u003cp\u003eThis study included 84 knees of patients with MMPRT who had a clearly defined date of injury and underwent pullout repair. Preoperative and 3-month postoperative magnetic resonance imaging (MRI) data were available for all patients. The association between the ΔMME (defined as the difference between the preoperative and 3-month postoperative medial meniscus extrusion [MME] values) and the following factors was analyzed: age, sex, body mass index, and the time from injury to MRI examination (Injury/MRI interval), consultation with knee surgeons (Injury/Consult interval), and surgery (Injury/Surg interval).\u003c/p\u003e\u003ch2\u003eResults\u003c/h2\u003e \u003cp\u003eThe average durations were 20.5 days for the Injury/MRI interval, 33.1 days for the Injury/Consult interval, and 53.6 days for the Injury/Surg interval. The mean MME was 3.94 mm preoperatively and 4.51 mm at 3 months postoperatively. Univariate analysis showed that the Injury/MRI, Injury/Consult, and Injury/Surg intervals were significantly correlated with the ΔMME (all P\u0026thinsp;\u0026lt;\u0026thinsp;0.001). A strong correlation was observed between the Injury/Consult and Injury/Surg intervals (correlation coefficient\u0026thinsp;=\u0026thinsp;0.933). In the multivariate analysis, the Injury/MRI and Injury/Consult intervals remained significantly associated with the ΔMME (both P\u0026thinsp;\u0026lt;\u0026thinsp;0.01).\u003c/p\u003e\u003ch2\u003eConclusions\u003c/h2\u003e \u003cp\u003eShortening the Injury/MRI and Injury/Consult intervals may help prevent the progression of MME following MMPRT pullout repair. Early MRI evaluation and prompt specialist consultation are recommended when MMPRT is suspected, particularly in patients presenting with posterior knee pain or a popping episode.\u003c/p\u003e\u003ch2\u003eLevel of evidence\u003c/h2\u003e \u003cp\u003eLevel IV.\u003c/p\u003e","manuscriptTitle":"Earlier magnetic resonance imaging-based diagnosis and prompt surgical consultation reduce medial meniscus extrusion following posterior root repair","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2025-12-31 10:46:21","doi":"10.21203/rs.3.rs-8433953/v1","editorialEvents":[{"type":"communityComments","content":0}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"researchsquare","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":true,"externalIdentity":"","sideBox":"","snPcode":"","submissionUrl":"/submission","title":"Research Square","twitterHandle":"researchsquare","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"","reportingPortfolio":"","inReviewEnabled":false,"inReviewRevisionsEnabled":true}}],"origin":"","ownerIdentity":"85867efc-c8b2-4d47-92fe-17eee423bbf0","owner":[],"postedDate":"December 31st, 2025","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"posted","subjectAreas":[],"tags":[],"updatedAt":"2026-01-31T01:24:05+00:00","versionOfRecord":[],"versionCreatedAt":"2025-12-31 10:46:21","video":"","vorDoi":"","vorDoiUrl":"","workflowStages":[]},"version":"v1","identity":"rs-8433953","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-8433953","identity":"rs-8433953","version":["v1"]},"buildId":"8U1c8b4HqxoKbykW_rLl7","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}