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Background: Osteochondral allograft transplantation (OCAT) and meniscus allograft transplantation (MAT) have each become more commonly implemented for the treatment of young to middle-aged patients with complex knee pathology. Evidence regarding tibiofemoral OCAT in the setting of concurrent MAT is limited. Purpose/Hypothesis: The purpose of this study was to characterize outcomes for femoral condyle OCAT with concurrent MAT (OCAT+MAT) in the ipsilateral compartment of patients after evidence-based shifts in practice. It was hypothesized that OCAT+MAT would be associated with successful outcomes characterized by statistically significant and clinically meaningful improvements in patient-reported outcome measures (PROMs) of knee pain and function in >80% of patients for at least 2 years after transplantation. Study Design: Case series; Level of evidence, 4. Methods: With institutional review board approval and documented informed consent, patients who underwent primary OCAT+MAT between 2016 and 2020 and enrolled in a lifelong registry for prospective collection of outcomes after OCAT were included. Patients with minimum 2-year follow-up data regarding complications, failures, adherence, and PROMs were analyzed. Patients who required OCAT and/or MAT revision or conversion to arthroplasty were defined as experiencing treatment failures. Results: A total of 23 consecutive patients (mean age, 37.1 years; mean body mass index, 28 kg/m2; 14 men) met the inclusion criteria, with a mean follow-up of 51 months (range, 24-86 months). The initial treatment success rate was 78% based on 5 initial treatment failures, and the overall success rate was 83% based on a successful revision OCAT. All failures occurred in the medial compartment. Older patient age (42.2 vs 32.1 years; P =.046) and nonadherence to postoperative restriction and rehabilitation protocols (P =.033; odds ratio, 14) were significant risk factors for treatment failure. All measured PROMs achieved significant improvements (P <.001) and minimum clinically important differences at a minimum of 2 years postoperatively. Conclusion: OCAT+MAT was associated with successful short- to mid-term outcomes in 83% of cases. Evidence-based shifts in practice were implemented before the enrollment of this patient cohort. Older patients and those who were not adherent to postoperative restriction and rehabilitation protocols had a significantly higher risk for treatment failure and subsequent conversion to arthroplasty. [ABSTRACT FROM AUTHOR]

Purpose of Review: Management of meniscal injuries in the elite athlete is a difficult problem secondary to the high demands of athletic competition, the need for a timely return to sport, and the desire to maximize performance over time. The purpose of this review is to provide an up-to-date summary on the current literature and trends regarding the management of meniscus injuries with a special consideration for elite athletes. Recent Findings: Historically, partial meniscectomy has been the primary treatment option for meniscus injuries. However, in recent years there has been an increased emphasis on meniscus preservation due to the increased risk of cartilage degeneration over time. Moreover, while partial meniscectomy still provides a quicker return to sport (RTS), recent literature has demonstrated similar rates of RTS and return to pre-injury levels between partial meniscectomy and meniscus repair. In the setting of symptomatic meniscal deficiency, meniscus allograft transplantation has become an increasingly utilized salvage procedure with promising yet variable outcomes on the ability to withstand elite competition. Summary: Currently, there is no uniform approach to treating meniscal injuries in elite athletes. Therefore, an individualized approach is required with consideration of the meniscus tear type, location, concomitant injuries, athlete expectations, rehabilitation timeline, and desire to prevent or delay knee osteoarthritis. In athletes with anatomically repairable tears, meniscus repair should be performed given the ability to restore native anatomy, provide high rates of RTS, and mitigate long-term chondral damage. However, partial meniscectomy can be indicated for unrepairable tears. [ABSTRACT FROM AUTHOR]

Purpose: To conduct a systematic review evaluating potential correlations between preoperative articular cartilage integrity on outcomes and survivorship in patients undergoing meniscal allograft transplantation (MAT). Methods: A literature search was performed by querying SCOPUS, PubMed, Medline, and the Cochrane Central Register for Controlled Trials from database inception through May 2023 according to the 2020 PRISMA statement. Inclusion criteria were limited to studies reporting on outcomes and survivorship following MAT based on preoperative cartilage status. Results: Sixteen studies, consisting of 1723 patients (n = 1758 total menisci), were identified in six level III and 10 level IV evidence studies. There was high heterogeneity in cartilage grading scales, reporting of concomitant cartilage procedures, and indications for MAT based on osteoarthritis. Patients with lower limb malalignment were either excluded or corrected with an osteotomy. MAT failure rate was reported in nine studies, with four studies reporting a greater rate of failure in knees with higher degrees of cartilage damage. Eight studies reported on clinical outcomes based on cartilage grade, with two studies reporting significant differences in clinical outcomes based on cartilage grade. Of the five studies reporting management of full‐thickness chondral defects with cartilage surgery, three studies reported no significant difference in survivorship based on preoperative cartilage grade, while one study reported lower survivorship and one study reported unclear results. No studies found significant differences in survivorship and outcomes between medial and lateral MAT. Conclusions: Conflicting results and high variability in reporting of concomitant cartilage repair and indications for MAT exist in studies evaluating the efficacy of MAT based on articular cartilage status. The degree of preoperative chondral damage did not have a strong relationship with clinical outcomes following MAT. Higher degrees of cartilage damage were associated with higher MAT failure rates, with possible improvement in survivorship when treated with an appropriate cartilage procedure. Level of Evidence: Level IV. [ABSTRACT FROM AUTHOR]

Abstract Background Single-stage medial meniscus allograft transplantation (MAT) with concomitant anterior cruciate ligament reconstruction (ACLR) is a technically challenging procedure for management of knee pain and instability in younger patients, but clinical and functional outcomes data are sparse. The purpose of this study was to assess surgical and patient-reported outcomes following concomitant ACLR and medial MAT. Methods We conducted a retrospective case series of patients who underwent medial MAT with concomitant primary or revision ACLR at our institution from 2010 to 2021 and had minimum 12-month follow-up. Complications, reoperations, visual analog scale (VAS) pain, satisfaction, Lysholm score, return to sport, and return to work outcomes were assessed. Patient-Reported Outcomes Measurement Information System (PROMIS) Pain Interference, Pain Intensity, and Physical Function Scores were used to measure patients’ functional status relative to the US population. P-values

Background Single-stage medial meniscus allograft transplantation (MAT) with concomitant anterior cruciate liga‑ ment reconstruction (ACLR) is a technically challenging procedure for management of knee pain and instability in younger patients, but clinical and functional outcomes data are sparse. The purpose of this study was to assess surgi‑ cal and patient-reported outcomes following concomitant ACLR and medial MAT. Methods We conducted a retrospective case series of patients who underwent medial MAT with concomitant primary or revision ACLR at our institution from 2010 to 2021 and had minimum 12-month follow-up. Complications, reoperations, visual analog scale (VAS) pain, satisfaction, Lysholm score, return to sport, and return to work outcomes were assessed. Patient-Reported Outcomes Measurement Information System (PROMIS) Pain Interference, Pain Intensity, and Physical Function Scores were used to measure patients’ functional status relative to the US population. P-values<0.05 were considered signifcant. Results The cohort consisted of 17 knees of 16 individual patients. The cohort was majority male (82.4%) with mean age of 31.9 years (range 19–49 years) and mean body mass index (BMI) of 27.9 kg/m² (range 22.5–53.3 kg/m2 ). Mean follow-up time was 56.8 months (range 13–106 months). Most patients underwent revision ACLR (64.7%). The 1-year reoperation rate was high (23.5%), with two patients (11.8%) tearing their meniscus graft. Patient-reported outcomes indicated low VAS pain (mean 2.2), high satisfaction (mean 77.9%), and fair Lysholm score (mean 81.1). Return to work rate was high (92.9%), while return to sport rate was low (42.9%). Postoperative PROMIS scores were comparable or superior to the national average and correlated signifcantly with patient satisfaction (p<0.05). Conclusions The concomitant ACLR and MAT procedure is associated with excellent knee pain and functional out‑ comes and high rate of return to work after surgery, though the 1-year reoperation rate is high and rate of return to sport is low. Level of evidence: IV. [ABSTRACT FROM AUTHOR]

Preservation of the injured meniscus tissue is the ideal goal of surgical treatment. However, many meniscal tears are not repairable with the result a loss of varying degrees of meniscal tissue. Various techniques are available to replace either portions of lost meniscal tissue or the entire meniscus. These techniques include the use of scaffolds, meniscal allografts, and synthetic meniscal implants. This article reviews the techniques utilized to restore the deficient meniscus.

Purpose: To assess the return to sport rate of young professional athletes, to analyze their careers in terms of matches played and league participation over a minimum period of 6 years after Meniscal Allograft Transplantation (MAT), as well as to assess the long-term clinical subjective outcomes and satisfaction. Methods: Thirteen professional athletes (ten soccer and one basketball players, one fencer and one wrestler) with a mean age at surgery of 23.4 ± 4.0 underwent MAT (six medial, seven lateral). The time required to return to sport, post-operative performance level and the number of reoperations were evaluated. At an average follow-up of 9.0 ± 2.8 years, Lysholm, KOOS and Cincinnati scores were administered and collected. Results: Thirteen patients (100%) returned to sports practice after an average period of 11.8 ± 3.8 months. Nine athletes (69%) returned to sports at the same pre-injury level. Overall, 93%, 85%, 62% and 55% were active until the 3rd, the 5th, the 7th and the 9th season after MAT, respectively. Seven patients (54%) underwent a reoperation after MAT, where only two of them (15%) were related to graft problems (one meniscectomy and one graft suture). Of the ten athletes that completed subjective evaluation, the mean Lysholm score was 72 ± 15 (0% "Excellent", 10% "Good", 60% "Fair", 30% "Poor"). Of the athletes with lower scores, one suffered from patellar tendon rupture, one from post-operative infection and one from a previous femoral fracture. The mean Cincinnati knee score was 77 ± 18, while the average KOOS values were 60 ± 34 for sports. Conclusion: Meniscal Allograft Transplantation (MAT) in young professional athletes involved in strenuous activities allowed all patients to return to pre-injury sport and in nearly 70% of cases at their pre-injury level. After five seasons following MAT, 85% of patients were still active or playing more than 20–30 matches per season. On the other hand, nearly 50% underwent at least one reoperation and only 70% of patients were rated as "Good", or "Fair" using the Lysholm score. Level of evidence: IV. [ABSTRACT FROM AUTHOR]

The meniscus is an essential component of the knee joint, acting as a shock absorber as well as assisting in the transmission of forces. Due to the meniscus importance of the knee, much of the current literature focuses on treatment techniques that can spare and repair the meniscus when it is torn. The unique vasculature of the meniscus often makes repair difficult or, in many cases, impossible. A current focus within orthopedics has been on meniscal allograft transplantation to fill this gap. The lack of a universal surgical technique for graft fixation, along with the current failure rates, demonstrates the need for further improvements. The senior author proposes a novel technique for meniscal allograft transplantation that has shown decreased blood loss and surgical time, while also reducing intra-operative trauma to the knee. This case reports a 16-year-old patient who underwent a right lateral meniscal allograft transplant following a large segmental defect tear of the lateral meniscus. The patient initially underwent arthroscopy and meniscectomy with screw fixation of the lateral femoral condyle lesion. After physical therapy, the patient experienced increased pain and swelling, with magnetic resonance imaging (MRI) demonstrating a meniscal defect unamenable to repair. The patient met indications for meniscal allograft transplantation given the failed meniscectomy, absence of cartilage loss and significant osteoarthritis, and the patient's age of less than 50 years old., Competing Interests: Human subjects: Consent was obtained or waived by all participants in this study. Conflicts of interest: In compliance with the ICMJE uniform disclosure form, all authors declare the following: Payment/services info: All authors have declared that no financial support was received from any organization for the submitted work. Financial relationships: All authors have declared that they have no financial relationships at present or within the previous three years with any organizations that might have an interest in the submitted work. Other relationships: All authors have declared that there are no other relationships or activities that could appear to have influenced the submitted work., (Copyright © 2024, Yatsonsky et al.)

Purpose: Meniscus allograft transplantation (MAT) can be performed to treat symptomatic patients with meniscus-deficient knees. However, the current epidemiologic status of MAT is unknown in many countries, including Korea. This study aimed to investigate the national trends of MAT in Korea which covers MAT procedures by the Korean national health insurance system. Methods: Information from the national database was acquired through the Korean Health Insurance Review and Assessment Service (HIRA) from 2010 to 2017. All patients encoded as MAT were included. The total number of MATs and their incidence per 100,000 persons were determined, and the results were stratified by age and sex. Results: The total number of MATs and their incidence per 100,000 persons per year were 369 and 0.77, respectively, in 2010, which increased to 826 and 1.72, respectively, in 2017. The number of MATs increased by 124% over 8 years. The peaks for the total number of MATs and their incidence were seen in patients in their 20 s in 2010, but in 2017, the peaks were observed in patients who were in their 40 s. MAT was performed more frequently in males (61%) than in females (39%) over the study period. Conclusion: The total number of MATs and their incidence had increased by 124% between 2010 and 2017. The peak treatment age range for MAT changed from 20 years of age in 2010 to 40 years of age in 2017, and MAT was performed more frequently in males than in females. Level of evidence: IV [ABSTRACT FROM AUTHOR]

Abstract Background Meniscus allograft transplantation (MAT) is a surgical procedure performed in patients complaining post-meniscectomy syndrome. Although the effectiveness of MAT on knee stability has been already demonstrated in cadaveric studies, its biomechanical role has been poorly evaluated in-vivo. Methods A narrative review of the biomechanical effect of meniscectomy and MAT was performed. Furthermore, two cases were presented, of one patient who underwent Medial MAT and Anterior Cruciate Ligament (ACL) reconstruction, and one who underwent Lateral MAT. During the surgery, knee laxity was evaluated using a surgical navigation system. Results AP laxity and IE rotation were reduced of 25% to 50% at both 30° and 90° of knee flexion after MAT transplantation. Discussion In both cases, almost all the tests performed showed a reduction of knee laxity after meniscus transplant, when compared with pre-operative knee laxity. This assessment confirms the insights of previous in-vitro studies and underline a crucial role of MAT in knee biomechanics.

Abstract Background Graft shrinkage or radial extrusion is a reported complication after meniscus allograft transplantation (MAT). Whether shrinkage or extrusion progress after surgery and whether they are associated with the clinical outcome of MAT remain debatable. In this study, graft shrinkage and extrusion were measured in the coronal and sagittal planes using serial postoperative magnetic resonance imaging (MRI). The purpose of this study was to evaluate if graft shrinkage or extrusion is correlated to the clinical outcome of MAT. Methods MRIs acquired at 3 and 12 months postoperatively in 30 patients (21 men and 9 women) who underwent MAT (6 medial and 24 lateral menisci) from 2010 to 2016 were analyzed. Two orthopedic surgeons and two musculoskeletal specialized radiologists each performed the MRI measurements. Allograft shrinkage was measured by the width and thickness of the graft at the coronal and sagittal planes. To determine the graft extrusion, distances between the proximal tibia cartilage margin and the extruded graft margin were measured in both coronal (either lateral or medial) and sagittal (both anterior and posterior) plane and relative percentage of extrusion (RPE) were calculated. Subjective International Knee Documentation Committee (IKDC) scores at 12 months were evaluated as a clinical outcome measurement, and correlations between shrinkage or extrusion of allograft and IKDC score were analyzed. Results In the coronal plane, radial RPE averaged 43.6% at postoperative 3 months, but there was no significant progression of extrusion at 12 months (average 42.0%) (P = 0.728). In the sagittal plane, there were no significant progressions of anterior and posterior RPE (P = 0.487 and 0.166, respectively) between postoperative 3 and 12 months. Shrinkage was calculated by multiplying the width and height of the three sections and summing these values. There was no significant progression of shrinkage between postoperative 3 and 12 months (P = 0.150). RPE in the radial (R = 0.147, P = 0.525), anterior (R = 0.249, P = 0.264), and posterior (R = 0.230, P = 0.315) directions and shrinkage (R = 0.176, P = 0.435) were not correlated to IKDC score at postoperative 12 months. Conclusions In the coronal and sagittal planes, extrusion and shrinkage did not progress from 3 months to 1 year. Extrusion and shrinkage had no correlation with early clinical outcomes. This finding suggests that graft extrusion or shrinkage may be not a great concern especially in early postoperative period of MAT, and multiple, serial MRI may be not necessary.

Purpose: The purpose of this study was to compare the clinical outcomes and survival rate of autologous chondrocyte implantation (ACI) with or without concomitant meniscus allograft transplantation (MAT).Methods: Patients who underwent ACI of the medial or lateral femoral condyle with or without concomitant MAT were retrospectively reviewed. There were 14 patients (mean age, 31.2 ± 9.9 years) who underwent isolated ACI and 19 patients who underwent ACI with concomitant MAT (mean age, 34.8 ± 8.4 years). The International Knee Documentation Committee (IKDC) subjective score, Lysholm score, Tegner activity score, and 10- to 15-year survival rate were compared between groups.Results: All clinical scores showed significant improvement postoperatively in both groups. At final follow-up, the IKDC subjective score was superior in isolated ACI (75.8 ± 18.4) compared to ACI with MAT (61.0 ± 16.6, p = 0.024). The Lysholm score was also higher in isolated ACI (77.5 ± 19.1) than ACI with MAT (62.5 ± 18.1, p = 0.029). The Tegner activity score did not differ between treatments (isolated ACI, 5.3 ± 1.1; ACI with MAT, 4.5 ± 1.3; p = 0.072). The 15-year survival rate for isolated ACI was higher than that of ACI with concomitant MAT (69.6% vs 50.2%), but this difference was not statistically significant (p = 0.19).Conclusions: ACI with concomitant MAT did not restore clinical outcomes as much as isolated ACI. There was a trend for the long-term survival rate to be greater in isolated ACI than ACI with MAT. These results should be considered in planning for the treatment of focal chondral defect with meniscus deficiency.Level Of Study: Retrospective comparative trial; level of evidence, 3. [ABSTRACT FROM AUTHOR]

Purpose: Meniscal graft extrusion is a concern following meniscal allograft transplantation (MAT). MAT surgical techniques continue to evolve in an effort to reduce extrusion; however, improvements remain difficult to measure in vivo. A novel MRI-compatible in vitro loading device capable of applying physiologically relevant loads has been developed, allowing for the measurement of extrusion under a variety of controllable conditions. The objective of this study was to compare maximal medial MAT extrusion (1) with and (2) without an additional peripheral third point of fixation on the tibial plateau.Methods: Twelve human cadaveric knees underwent medial MAT, utilizing soft tissue anterior and posterior root fixation via transosseous suture, with a third transosseous suture tied over a button providing peripheral fixation on the tibial plateau. The joint was positioned at 5 degrees of flexion and loaded to 1 × body weight (647.7 ± 159.0 N) during MR image acquisition, with and without peripheral fixation. The joint was then positioned at 30 degrees of flexion and the process was repeated. Maximal coronal extrusion was measured.Results: An increase in maximal coronal meniscal extrusion was noted between the unloaded and loaded states. At 30 degrees of flexion, with the addition of a peripheral fixation point, a statistically significant difference in absolute extrusion (p = 0.02) and relative percent extrusion (p = 0.04) between the unloaded and loaded state was found. The addition of a peripheral fixation suture resulted in an overall mean percent difference of - 2.49% (SD 14.1; 95% CI - 11.95, 6.97; n.s.) in extrusion at 5 degrees of flexion and a mean percent difference of - 0.95% (SD 7.3; 95% CI - 5.62, 3.71; n.s.) in extrusion at 30 degrees of flexion. These differences were not statistically significant.Conclusion: These results suggest that the addition of a peripheral anchor in medial MAT does not reduce the amount of maximal coronal extrusion and, therefore, may not confer any clinical benefit. Surgical techniques utilized to reduce MAT extrusion need further investigation to understand if the added technical difficulty and potential expense is warranted. [ABSTRACT FROM AUTHOR]

Purpose: Injury or degeneration of the meniscus has been associated with the development of osteoarthritis of the knee joint. Meniscal allograft transplant (MAT) has been shown to reduce pain and restore function in patients who remain symptomatic following meniscectomy. The purpose of this study is to evaluate and compare the three-dimensional (3D) strain in native medial menisci compared to allograft-transplanted medial menisci in both the loaded and unloaded states.Methods: Ten human cadaveric knees underwent medial MAT, utilizing soft-tissue anterior and posterior root fixation via transosseous sutures tied over an anterolateral proximal tibial cortical bone bridge. The joint was imaged first in the non-loaded state, then was positioned at 5° of flexion and loaded to 1× body weight (650 ± 160 N) during MR image acquisition. Anatomical landmarks were chosen from each image to create a tibial coordinate system, which were then input into a custom-written program (Matlab R2014a) to calculate the 3D strain from the unloaded and loaded marker positions. Six independent strains were obtained: three principal strains and three shearing strains.Results: No statistically significant difference was found between the middle and posterior strains in the native knee compared to the meniscus allograft. This would suggest that soft-tissue fixation of meniscal allografts results in similar time zero principal and shear strains in comparison to the native meniscus.Conclusion: These results suggest that time zero MAT performs in a similar manner to the native meniscus. Optimizing MAT strain behavior may lead to potential improvements in its chondroprotective effect. [ABSTRACT FROM AUTHOR]

Objectives: Although meniscal allograft transplantation (MAT) is a well-established procedure with satisfactory clinical results, limited in vivo kinematic information exists on the effect of medial and lateral MAT performed in the clinical setting. The purpose of the present study was to evaluate the biomechanical effect of arthroscopic isolated medial and lateral MAT with a soft-tissue fixation on pre- and post-operative knee laxity using a surgical navigation system., Methods: 18 consecutive patients undergoing MAT (8 medial, 10 lateral) were enrolled. A surgical navigation system was used to quantify the anterior-posterior displacement at 30 and 90 degrees of knee flexion (AP30 and AP90), the varus-valgus rotation at 0 and 30 degrees of knee flexion (VV0 and VV30) and the dynamic laxity on the pivot-shift test (PS), which was determined through the anterior displacement of the lateral tibial compartment (APlat) and posterior acceleration of the lateral tibial compartment during tibial reduction (ACC). Data from laxity before and after MAT were compared through paired t-test (p ​< ​0.05)., Results: After medial MAT, there was a significant decrease in tibial translation of 3.1 ​mm (31%; p ​= ​0.001) for AP30 and 2.3 ​mm (27%; p ​= ​0.020) for AP90, a significant difference of 2.5° (50%; p ​= ​0.002) for VV0 and 1.7° (27%; p ​= ​0.012) for VV30. However, medial MAT did not determine any reduction in the PS kinematic data. Lateral MAT determined a significant decrease in the tibial translation of 2.5 ​mm (38%; p ​< ​0.001) for AP30 and 1.9 ​mm (34%; p ​= ​0.004) for AP90 as well as a significant difference of 3.4° (59%; p ​< ​0.001) for VV0 and of 1.7° (23%; p ​= ​0.011) for VV30. There was also a significant reduction of the PS of 4.4 ​mm (22%; p ​= ​0.028) for APlat and 384.8 ​mm/s 2 (51%; p ​= ​0.005) for ACC., Conclusion: MAT with soft-tissue fixation results in a significant laxity reduction in an in-vivo setting. Medial MAT improved knee kinematics by determining a significant reduction with particular emphasis on AP translation and VV manoeuvre. Conversely, Lateral MAT determined a massive reduction of the PS and a mild decrease of the AP translation and VV manoeuvre., Study Design: Controlled laboratory study., Competing Interests: Declaration of competing interest The authors declare the following financial interests/personal relationships which may be considered as potential competing interests: S.Z. reports a relationship with DePuy Mitek Inc that includes: consulting or advisory. S.Z. reports a relationship with Smith and Nephew Inc that includes: consulting or advisory., (Copyright © 2023 The Author(s). Published by Elsevier Inc. All rights reserved.)

Introduction: It is unclear whether the incidence and amount of graft extrusion differ between knees undergoing medial and lateral meniscus allograft transplantation (MAT). This meta-analysis, therefore, compared the incidence and amount of transplanted meniscus allograft extrusion following medial and lateral MAT.Materials and Methods: All studies comparing absolute or relative extrusions, or proportion of major extrusions (> 3 mm), on magnetic resonance imaging between medial and lateral MATs were included.Results: Eight studies were included in the meta-analysis. Using the arthroscopic-assisted technique, medial MAT had significantly greater absolute (0.99 mm, p = 0.002) and relative (19.4%, p = 0.001) extrusions than lateral MAT. Using the complete arthroscopic technique, lateral MAT had 1.45 mm greater absolute extrusion than medial MAT (p < 0.001), but there was no difference in relative extrusion. Using the arthroscopic-assisted technique, the proportion of knees with major extrusion was greater for medial than lateral MAT (OR 5.32, p < 0.001), but, using the complete arthroscopic procedure, there was no difference in proportions of major extrusions between medial and lateral MAT (OR 0.28, p = 0.08).Conclusion: Graft extrusions after medial and lateral MAT differed according to surgical technique. Graft extrusion was greater after medial than lateral MAT using the arthroscopic-assisted technique, but was greater after lateral than medial MAT using the complete arthroscopic procedure.Level Of Evidence: Meta-analysis (Level II). [ABSTRACT FROM AUTHOR]

Background: The association between preoperative tibial subchondral bone marrow lesion (BML) patterns and outcomes after isolated meniscus allograft transplantation (MAT) are unknown. Purpose: To determine (1) if a superior classification means exists (ie, high interrater reliability [IRR]) for grading tibial subchondral BML before isolated MAT and (2) whether quality and/or severity of preoperative tibial subchondral BML patterns was associated with clinical outcomes and/or failure rates after isolated MAT. Study Design: Cohort study; Level of evidence, 3. Methods: All patients who underwent isolated MAT with a single surgeon between October 2006 and February 2017 were identified. Three means were evaluated to quantify the degree of subchondral BML in the affected tibial-sided compartment: Welsch et al, based on maximum diameter of the lesion; Costa-Paz et al, based on appearance and location of the lesion; and Filardo et al, based on severity of findings. IRR was generated and compared among the 3 classifications. The preoperative magnetic resonance imaging (MRI) subchondral BML grading scheme with the highest IRR was then used to assess for associations with postoperative outcomes for those patients with >2-year follow-up, per a Spearman correlation matrix with each reviewer’s grades. Results: In total, 60 MRI scans were available for subchondral BML grading. Grader 1 identified the presence of subchondral BML in the tibia of the affected compartment in 40 (66.7%) of the available MRI scans, as compared with 38 (63.3%) for grader 2. The calculated IRRs with the Welsch et al and Costa-Paz et al classifications were rated “strong/almost perfect” agreement. A significant correlation was demonstrated between grader 1 with the Welsch et al grading scheme and outcome measures of KOOS pain (Knee injury and Osteoarthritis Outcome Score; negative correlation, P = .05), WOMAC pain (Western Ontario and McMaster Universities Osteoarthritis Index; positive correlation, P = .026), and Marx Activity Rating Scale (negative correlation, P = .019). A significant correlation was demonstrated between grader 2 with the Costa-Paz et al grading scheme and postoperative satisfaction (positive correlation, P = .018). There were no significant differences in survivorship based on gradings. Conclusion: Nearly two-thirds of patients who undergo isolated MAT have subchondral BML on preoperative MRI. Our findings suggest that increasing BML size (Welsch et al) is correlated with worse postoperative pain measures (KOOS pain, WOMAC pain) and worse activity ratings (Marx Activity Rating Scale). Additionally, increasing disruption or depression of the normal contour of the cortical surface, with or without lesion contiguity with the subjacent articular surface (Costa-Paz et al), is correlated with greater postoperative satisfaction. [ABSTRACT FROM AUTHOR]

Objectives: To evaluate the changes in the mean T2 values of articular cartilage on serial follow-up images up to 1 year in patients who underwent lateral meniscus allograft transplantation (MAT).Methods: Fifty-two patients who underwent lateral MAT surgery at our hospital were evaluated preoperatively and at 2 days, 6 weeks, 3 months, 6 months, and 1 year after MAT using 3.0-T magnetic resonance imaging (MRI) that included T2 mapping. T2 value changes according to the arthroscopic grading of chondromalacia were evaluated in the lateral and medial compartment. Lysholm scores were obtained pre- and postoperatively.Results: The T2 values of cartilage were significantly increased 2 days after operation, and then gradually reduced to the baseline level after 1 year in both compartments. In morphologic assessment performed after 1 year, most areas (92.9 %) showed no interval change of chondromalacia grade. Lyshom knee scores increased significantly from the mean preoperative value of 62.5 (range, 23-95) to 89.7 (range, 64-100) at 1 year (p < 0.001).Conclusion: Mean T2 values of cartilage following MAT exhibited a return to baseline level after 1 year. T2 measurement can be a useful tool for quantitative evaluation of postoperative cartilage changes compared to conventional MRI.Key Points: • T2 mapping provides objective data for longitudinal monitoring following surgery. • Increased cartilage T2 values post-MAT returned to baseline in one year. • Further studies are required to predict the chondroprotective effect of MAT. [ABSTRACT FROM AUTHOR]

Purpose: Lateral meniscus allograft transplantation (LMAT) is a feasible surgical option for young meniscus-deficient patients. Although several studies have explored the factors that contribute to graft extrusion, they have not been fully elucidated. The aim of this study was to determine the various factors that contribute to graft extrusion.Methods: Patients with knees that had received LMAT using a keyhole technique (n = 87 knees in 82 patients) were reviewed. The median age of these patients was 22 years (range 19-54 years), and the median postprocedural follow-up interval was 5 days (range 1-136 days). Twelve magnetic resonance imaging (MRI) measurement parameters (axial and coronal location of the bone block) that could potentially influence graft extrusion were evaluated, along with absolute graft extrusion and relative percentage of extrusion (RPE).Results: A significant correlation was found between 8 of the 12 MRI measurement parameters and both the absolute extrusion and RPE (r = 0.241-0.438, p < 0.05). The absolute middle distance and depth of the bone block were independent predictors of the absolute extrusion (β = 0.30 and 0.15, respectively; p < 0.05), and the relative middle distance and relative bone-block elevation were found to be predictors of RPE (β = 2.29 and 1.44, respectively; p < 0.05).Conclusion: The rate of graft extrusions after LMAT was high in this study. Both the coronal and axial locations of the bone block were found to influence graft extrusion in LMAT. Therefore, correct positioning of the bone block, including in both the axial and coronal planes, is essential to minimize graft extrusion. Future studies need to investigate the long-term clinical outcome and longevity of extruded menisci after transplantation.Level Of Evidence: Therapeutic case series, Level IV. [ABSTRACT FROM AUTHOR]

Meniscus allograft transplantation has been performed over the past 25 years to relieve knee pain and improve knee function in patients with an irreparable meniscus injury. The efficacy and safety of meniscus allograft transplantation have been established in numerous experimental and clinical researches. However, there is a lack of reviews to aid radiologists who are routinely interpreting images and evaluating the outcome of the procedures, and also meniscus allograft transplantation is not widely performed in most hospitals. This review focuses on the indications of the procedure, the different surgical techniques used for meniscus allograft transplantation according to the involvement of the lateral and medial meniscus, and the associated procedures. The postoperative radiological findings and surgical complications of the meniscus allograft transplantation are also described in detail. [ABSTRACT FROM AUTHOR]

Background: Little is known about the degree of articular cartilage degeneration after subtotal/total lateral meniscectomy in patients who later undergo isolated lateral meniscal allograft transplantation (LMAT). It has not yet been studied whether arthritic changes as shown on radiographs were lower during the posttransplantation period than during the meniscus-deficient period. Hypothesis: Articular cartilage will significantly degenerate during the meniscus-deficient period, but the progression in radiographic arthrosis is reduced after LMAT. Study Design: Case series; Level of evidence, 4. Methods: This study retrospectively reviewed 49 patients who underwent subtotal/total lateral meniscectomy before isolated LMAT performed over 1 year later by the same surgeon. International Cartilage Repair Society (ICRS) grades of the femorotibial joint at the time of subtotal/total meniscectomy and at LMAT were compared. Radiographic evaluation was performed at the time of initial meniscectomy, LMAT, and the latest follow-up in 38 patients (after 11 patients whose radiographs showed incomplete ossification at the time of meniscectomy were excluded). Arthrosis, based on Kellgren-Lawrence (K-L) grades, was determined on standing anteroposterior views. Joint space width (JSW) was measured on weightbearing flexion posteroanterior views. Results: Over a mean meniscus-deficient period of 4.5 years (range, 1-13 years), articular cartilage significantly degenerated on the femoral and tibial sides (P < .001). Grade ≥3 degeneration on the lateral tibial plateau was observed in 13 patients (27%) at the time of initial meniscectomy; this incidence doubled to 28 patients (57%) by the time of LMAT. The K-L grades worsened (P < .001) and JSWs narrowed significantly (–0.65 ± 1.09 mm; P = .001) during the mean meniscus-deficient period of 3.1 years. At radiographic assessment, however, the K-L grades (P = .097) and JSWs (4.06 ± 1.19 vs 3.92 ± 1.21 mm; mean difference, –0.14 ± 0.68 mm; P = .213) did not significantly change during the mean posttransplantation period of 3.8 years. The changes in ICRS grade and JSW during the meniscus-deficient period were not associated with age, body mass index, mechanical axis deviation, or Tegner activity level (P > .05 for all relationships). Conclusion: Patients who underwent isolated LMAT showed substantial articular cartilage degeneration at the time of initial subtotal/total lateral meniscectomy, and this degeneration progressed thereafter. Further progression of radiographic arthrosis was delayed after LMAT. [ABSTRACT FROM AUTHOR]

Understanding the structure and function of the meniscus is critical to understanding its role in overall knee joint function. Injury to, or removal of, meniscal tissue may be associated with articular cartilage wear, knee instability, and, ultimately, the progression of osteoarthritis. While every effort is made for preserving and/or repairing damaged meniscal tissue, in some cases, the meniscus is not amenable to repair after injury. For appropriately indicated patients with symptomatic meniscal deficiency, meniscus allograft transplantation is an excellent surgical solution aimed at reducing pain and improving function. Indications for meniscus allograft transplantation are limited, and concomitant procedures such as osteotomy for malalignment, ligamentous, and/or articular cartilage restoration may be necessary in order to ensure an optimal result following meniscus allograft transplantation. Surgical techniques for meniscus allograft transplantation are variable and include soft-tissue fixation versus bone plug fixation versus bone bridge fixation. Outcomes following meniscus allograft transplantation are generally good to excellent, though reoperation rates are relatively high. The purpose of this article is to provide a concise review of recently published data on meniscus allograft transplantation, with a focus on recent outcomes studies. [ABSTRACT FROM AUTHOR]

Background: Osteophytes can be observed on the tibial plateau during meniscus allograft transplantation (MAT). However, no studies to date have evaluated the effect of these osteophytes on meniscus allograft extrusion. Hypothesis: Osteophyte excision in the tibial plateau could reduce extrusion of the transplanted meniscus and improve short-term clinical outcomes with meniscus allograft transplantation. Study Design: Cohort study; Level of evidence, 3. Methods: Between October 2004 and July 2012, a total of 323 patients underwent MAT at a single institution. Of these, 88 patients had a peripheral osteophyte in their tibial plateau, and they were enrolled in the study retrospectively. The mean age of the patients was 35.3 years (range, 15-56 years); there were 57 male and 31 female patients. Forty-four patients underwent osteophyte excision concomitantly with MAT and 44 patients underwent MAT only. The 2 groups showed no difference in terms of age, body mass index, time after meniscectomy, and preoperative knee scores. A medial meniscus allograft was transplanted in 13 cases (15%) and a lateral meniscus in 75 (85%). The absolute extrusion and relative percentage of extrusion were measured to evaluate allograft extrusion 12 months after MAT. The modified Lysholm scoring system and the Hospital for Special Surgery score at 2 years after MAT were used to evaluate clinical outcomes. Results: The mean absolute extrusions at 1 year postoperatively in the excision and nonexcision groups were 3.5 ± 1.5 and 5.5 ± 1.6 mm, respectively. The mean relative percentages of extrusion were 34.1% 6 15.9% and 54.7% 6 20.7%, respectively. The rates of allograft extrusion (.3 mm) were 28 of 44 (63.6%) and 41 of 44 (93.2%) in the excision and nonexcision groups, respectively. The intergroup differences in absolute extrusion, relative percentage of extrusion, and rate of allograft extrusion were statistically significant (P \ .001 for all 3 parameters). There were no significant differences in the clinical outcomes (modified Lysholm or Hospital of Special Surgery scores) at 2-year follow-up (P \ .762 and \ .298, respectively). Conclusion: The excision of a peripheral osteophyte larger than 2 mm in the proximal tibial plateau was associated with less allograft extrusion after MAT. [ABSTRACT FROM AUTHOR]

Introduction: The efficacy of meniscal allograft transplantation (MAT) and osteochondral allografting (OCA) as individual treatment modalities for select applications is well established. MAT and OCA are considered symbiotic procedures due to a complementary spectrum of indications and reciprocal contraindications. However, few outcomes of concomitant MAT and OCA have been reported. This study is a retrospective review of patients who received simultaneous MAT and OCA between 1983 and 2011. Methods: Forty-eight (twenty-nine male: nineteen female) patients with a median age of 35.8 years (15-66) received combined MAT and OCA procedures between 1983 and 2011. Forty-three patients had received previous surgery with a median of 3 procedures (1-11 procedures). The underlying diagnosis was trauma (tibial plateau fracture) in 33 % with osteoarthritis predominating in 54.2 % of cases. Thirty-one patients received a lateral meniscus, 16 received a medial meniscus and one patient received bilateral MAT. The median number of OCAs was two per patient (1-5 grafts), with a median graft area of 15 cm (0.7-41 cm). There were 21 unipolar, 24 bipolar (tibiofemoral) and three multifocal lesions. Thirty-six MATs constituted a compound tibial plateau OCA with native meniscus attached. At follow-up, failure was defined as any procedure resulting in removal or revision of one or more of the grafts. Patients completed the modified Merle d'Aubigné and Postel (18-point) scale, Knee Society Function (KS-F) score, and subjective International Knee Documentation Committee (IKDC) scores. Patient satisfaction was also captured. Results: Twenty-six of 48 patients (54.2 %) required reoperation, but only 11 patients (22.9 %) were noted to have failed (10 MAT and 11 OCA). The mean time to failure was 3.2 years (95 % CI 1.5-4.9 years) and 2.7 years (95 % CI 1.3-4.2 years) for MAT and OCA, respectively. The 5-year survivorship was 78 and 73 % for MAT and OCA respectively, and 69 and 68 % at 10 years. Six of the failures were in the OA cases and one was an OCD lesion where bipolar grafts were utilized. The OCD case underwent a revision OCA and remains intact. The others were converted to knee arthroplasty. One case failed due to early deep infection, ultimately requiring arthrodesis. Of those with grafts still intact, the mean clinical follow-up was 6.8 years (1.7-17.1 years). Statistically significant improvements in all outcome scores were noted between baseline and the latest follow-up. In total, 90 % of those responding would have the surgery again and 78 % were either extremely satisfied or satisfied with the outcome. Conclusion: The overall success rate of concomitant MAT and OCA was comparable with reported results for either procedure in isolation. A trend towards a worse outcome was observed with bipolar tibiofemoral grafts in the setting of OA. Comparatively better results in less advanced, unipolar disease could suggest a benefit to early intervention that might merit a lower treatment threshold for combined MAT and OCA. Level of evidence: IV. [ABSTRACT FROM AUTHOR]

The article presents a study on graft extrusion in sagittal and coronal planes after medial and lateral meniscus allograft transplantation (MAT). Topics covered include anterior cartilage meniscus distance (ACMD), posterior cartilage meniscus distance (PCMD) horns, and magnetic resonance imaging (MRI) after MAT.

Purpose: The aim of this work is to introduce and evaluate a novel arthroscopically assisted meniscus allograft transplantation (MAT) technique that requires only one small anterior incision for an arthrotomy. Methods: In the novel technique, the posterior horn of the allograft meniscus was repaired using the modified all-inside suture technique instead of the conventional inside-out technique. By doing this, an additional posterior incision could be avoided. Thirteen consecutive patients with total or subtotal meniscectomy of the lateral meniscus underwent lateral MAT using the novel technique from August 2010 to October 2011. The clinical outcomes were evaluated according to Lysholm scores, International Knee Documentation Committee (IKDC) subjective scores, and Tegner activity level scales. Results: The median follow-up period was 21.0 months (range 13-28 months). The post-operative median Lysholm score improved to 85.0 (range 77-95, P < 0.05). The median IKDC subjective score was 80.0 (range 63-99, P < 0.05) at last follow-up. The median Tegner activity level of 6.0 (range 4-7) was improved compared with the median preoperative level ( P < 0.05). None of the patients presented with symptoms requiring a secondary surgical procedure at the time of final follow-up. Conclusion: The novel method requires only one small arthrotomy incision except for arthroscopic portals. In addition to the minimal number of incisions, this technique has several advantages over previous techniques. This single-incision technique could be effective and satisfactory option for lateral MAT. Level of evidence: Case series with no comparison group, Level IV. [ABSTRACT FROM AUTHOR]

Purpose: The purpose of this study was to evaluate the efficacy of meniscus allograft transplantation in an active patient population with moderate to severe cartilage damage and the procedure's ability to allow sports participation postoperatively. Methods: Forty-nine patients with moderate to severe cartilage damage who underwent meniscus allograft transplantation were included in this study; those with symptoms related to articular cartilage damage also underwent articular cartilage repair. Kaplan-Meier (KM) survival estimate, potential hazards to survival, and subjective clinical outcomes were analyzed. For KM survival, failure was defined as progression to knee arthroplasty, surgical removal of the meniscus transplant without revision, a self-reported follow-up pain level that was more than preoperative level, or constant moderate pain with no relief from non-operative treatment. Results: The mean follow-up time was 8.6 ± 4.2 years. The mean age at surgery was 45.3 ± 12.9 years. Meniscus transplantation was performed in 37 medial cases and 12 lateral cases. There were 41 patients with Outerbridge Grade IV and 8 with Grade III. Thirty-six (73.5 %) patients were able to participate in sporting activities postoperatively. Eleven (22.4 %) meniscus transplants failed at an average of 5.2 ± 4.4 years. The KM mean estimated survival time was 12.6 ± 0.7 years. No tested risks were found to affect sports participation or procedure success. Conclusions: Meniscus transplantation is a viable surgical option for patients with severe cartilage damage and missing or irreparable menisci to provide significant improvements in pain and function levels in the medium to long term with the majority of patients achieving their goal of participation in sporting activities. These results indicate that symptomatic patients may be able to participate in sports activities for an average of 12.6 years following meniscus transplantation. Level of evidence: Case series, Level IV. [ABSTRACT FROM AUTHOR]

The article discusses a study which evaluated 12 male professional soccer players who undergone meniscus allograft transplantation (MAT) at 12- and 36-month follow-up. The degree of knee pain was assessed using visual analog scale (VAS) and functional follow-up included Lysholm and subjective International Knee Documentation Committee (IKDC). The results showed that arthroscopic MAT in male soccer players allowed a return to play at the same level in 75 % of the cases at 36-month follow-up.

The article evaluates meniscus allograft transplantation (MAT) as a treatment method for symptomatic patients after meniscectomy. It is said the aim of MAT is to reconstruct the load transmission system and to restore the normal kinematics of the knee joints. It notes that the surgery can be performed in both the medial and lateral menisci. The use of magnetic resonance imaging or arthroscopic surgery to evaluate objective results of MAT is also discussed.

Background: In lateral meniscus allograft transplantation (MAT) using the keyhole method, precise trough drilling is critical for ensuring the graft is placed at the correct anatomic position to minimize the risk of extrusion. However, no study has focused on the effect of bony trough axial obliquity on graft extrusion. Our purpose was to investigate whether bony trough axial obliquity and bony trough position correlate with graft extrusion in lateral MAT using the keyhole method. Hypothesis: We hypothesized that drilling the tibial bony trough at a greater axial angle would increase the risk of graft extrusion. Study Design: Case series; Level of evidence, 4. Methods: The study involved 49 patients who underwent lateral MAT between 2009 and 2010 following total or subtotal meniscectomy. The mean patient age at the time of surgery was 34 years (range, 19-52 years). Graft extrusion and bony trough parameters (absolute and relative distance at the anterior, center, and posterior cuttings of the bony trough, and axial trough angle [ATA]) were assessed using conventional magnetic resonance imaging (MRI) performed on postoperative day 2. The correlation between graft extrusion and MRI trough parameters was analyzed, and multiple linear regression analysis was performed to identify predictors of graft extrusion. Results: Of the 7 MRI measurement parameters, the ATA (r = .355, P = .012), absolute anterior distance (r = .301, P = .031), and relative anterior distance (r = .307, P = .032) were found to positively correlate with absolute extrusion. The ATA (r = .296, P = .037) and relative anterior distance (r = .296, P = .039) were also found to correlate with relative extrusion. The ATA was found to be a predictor of absolute extrusion (β = .36, P = .012) and relative extrusion (β = .33, P = .019). Conclusion: The risk of graft extrusion increases as the axial plane trough angle increases. The angle can be reduced by ensuring that the bony trough starting point is not created in too lateral a position. [ABSTRACT FROM AUTHOR]

Purpose: The purpose of this study was to evaluate change in meniscal allograft extrusion during the first year after meniscus allograft transplantation (MAT) by use of serial magnetic resonance imaging (MRI). Methods: Twenty-three consecutive patients who underwent MAT between June 2002 and March 2006 with total or subtotal meniscectomy of the knee were enrolled in the study. The medial meniscus was affected in 3 cases (15%) and the lateral meniscus in 18 cases (85%). Conventional MRI of the affected knee was performed in all 21 patients at 6 weeks and at 3, 6, and 12 months after MAT. We recorded subluxation at the 4 different time points by measuring the absolute value and relative percentage of extrusion (RPE), defined as the percentage of the width of extruded menisci compared with the width of the whole meniscus, using coronal images. We considered subluxation of greater than 3 mm to indicate extrusion. Results: The mean amount of graft subluxation on serial MRI was 2.87, 2.95, 3.03, and 2.96 mm at 6 weeks, 3 months, 6 months, and 12 months after MAT, respectively. The mean RPEs were 29.2%, 29.4%, 32.4%, and 31.9%, respectively. These values were not considered statistically significant among the 4 different time periods (P > .05). Seven extruded cases (33.3%) at 6 weeks postoperatively remained extruded until the final follow-up at 1 year postoperatively. With 1 exception, the other 14 cases without extrusion at 6 weeks postoperatively did not undergo extrusion until 1 year postoperatively. Conclusions: A meniscus that extrudes early remains extruded and does not progressively worsen, whereas one that does not extrude early is unlikely to extrude within the first postoperative year. Level of Evidence: Level IV, therapeutic case series. [Copyright &y& Elsevier]

Lateral meniscus plays a crucial role in the knee stability and function. Although complex settings are required for lateral meniscus biomechanical assessment, such characteristics have been investigated over time to optimize the daily clinical practice surgical procedure. The aim of the present study was to provide an overview of literature knowledge regarding the biomechanics of lateral meniscus and give further insights about novel experimental analyses. Studies regarding lateral meniscus mobility, effect on knee laxity, and contact mechanics were included in the review. The effect of meniscal lesion, meniscal repair, partial meniscectomy, and meniscus allograft transplantation were retrieved for either in vivo , cadaveric, or in-silico computational settings. Knee laxity was evaluated both in presence of isolated meniscal tears and in anterior cruciate ligament (ACL) deficient knees. Surgical navigation systems and robots were mainly used for the investigations in vivo and in cadaveric studies, while accelerometers emerged as an alternative for ambulatory assessments. Contact mechanics was only assessed in cadaveric and computational studies. Great effort has been put into exploring lateral meniscus biomechanics from multiple perspectives. Strong evidence emerged regarding the importance of lateral meniscus repair: increased knee stability at high degrees of knee flexion and reduction of peak contact pressures on tibial cartilage were the most reported benefits. The meniscus allograft transplantation also emerged as a concrete solution for irreparable tears and further studies are needed to investigate its long-term influence on knee stability., Competing Interests: Conflicts of Interest: All authors have completed the ICMJE uniform disclosure form (available at https://aoj.amegroups.com/article/view/10.21037/aoj-20-123/coif). The series “The Lateral Meniscus” was commissioned by the editorial office without any funding or sponsorship. SZ served as the unpaid Guest Editor of the series and serves as an unpaid editorial board member of Annals of Joint from March 2021 to February 2023. AG served as the unpaid Guest Editor of the series. The authors have no other conflicts of interest to declare., (2022 Annals of Joint. All rights reserved.)

In symptomatic discoid medial meniscus, partial meniscectomy is the principal treatment method and can yield promising short-term results. However, unlike the nondiscoid meniscus, discoid medial meniscus is frequently associated with horizontal cleavage tears, attributable to the presence of myxoid degeneration in the intrameniscal substance, in that it may potentially occur deteriorating long-term results because of re-tearing of remaining meniscus or secondary degeneration of cartilage of the medial compartment after meniscectomy. We experienced three rare cases of retear or secondary degeneration of cartilage of the medial compartment after meniscectomy for two patients with torn bilateral meniscus. Both patients were highly active young males. Meniscal allograft transplantation in complicated discoid medial meniscus was performed. At 2 years after meniscal allograft transplantation, clinical outcomes were improved with a normal range of motion. Orthopedic surgeons should recommend activity modification to prevent possible complicated injury of the discoid medial meniscus. Meniscal allograft transplantation may be an alternative option in highly active young patients undergoing complicated discoid medial meniscus to diminish pain, improve knee function, and prevent or delay degeneration., (Copyright © 2016 Turkish Association of Orthopaedics and Traumatology. Production and hosting by Elsevier B.V. All rights reserved.)