Meniscal Allograft Transplantation Research Articles

Osteochondral Allograft (OCA) Transplantation with Concomitant Meniscus Allograft Transplantation (MAT) Improves Clinical Outcomes and Yields High Patient Satisfaction: A Systematic Review.

To conduct a systematic review evaluating subjective patient reported outcomes (PROs), reoperations, and graft failure after concomitant osteochondral allograft (OCA) transplantation and meniscal allograft transplantation (MAT). A literature search was performed by querying MEDLINE, Embase, and PubMed according to the 2020 PRISMA statement. Inclusion criteria were limited to peer-reviewed English level I-IV studies with at least 10 patients reporting clinical outcomes and complications following OCA transplantation with concomitant MAT for osteochondral defects and meniscal deficiency with a minimum of 2-years follow up. For a majority of the included studies, failure was defined as conversion to arthroplasty, revision OCA, or graft failure on postoperative imaging. Six studies with a total of 188 patients met inclusion/exclusion criteria. The mean patient age was 32.4 years (Range 15 to 66 years). Improvement in the following outcome scores was observed across all included studies from pre- to postoperative status: Lysholm Knee Score (+21 to +26.69), International Knee Documentation Committee (IKDC) Subjective Knee Form (+19 to +26.55), Knee Injury and Osteoarthritis Outcome Score (KOOS) Pain Score (+17.91 to +26), KOOS Symptom Score (+9 to +18.16), KOOS Activities of Daily Living (ADL) Score (+11.91 to +23.4), KOOS Sport Score (+19 to +26.04), KOOS Quality of Life Score (+22 to +35.01), 12-Item Short Form Survey (SF-12) Physical Score (+5 to +12.26), and SF-12 Mental Score (+1.8 to +4) (P < 0.05 for all). Reoperation rate was found to be between 6.7% and 54%. Failure rate was found to be between 13% and 22.9%. Although patient satisfaction data was only available in 2 studies, 82% - 90% of patients would choose to undergo OCA transplantation with MAT again. OCA transplantation with concomitant MAT for the treatment of focal chondral defects in the presence of meniscus deficiency results in improved patient-reported outcome measures with high patient satisfaction rates. Reoperation rates and failure rates at a mean follow up time of 4.7 years (Range 1.7 to 17.1 years) are 37.3% and 17.1%, respectively, which are expected and consistent with the existing literature in isolated procedures. Level IV; Systematic Review of Level III-IV Studies.

Meniscal Allograft Transplantation Survivorship and Conversion to Arthroplasty in Patients Older and Younger than 40: A Systematic Review and Meta-Analysis

Meniscal Allograft Transplantation Survivorship and Conversion to Arthroplasty in Patients Older and Younger than 40: A Systematic Review and Meta-Analysis

Concomitant Cartilage Procedures With Meniscal Allograft Transplantation Do Not Substantially Alter Failure or Survival Rates Relative to Meniscal Allograft Transplantation Without Cartilage Procedures: A Systematic Review.

Timely recognition and addressing of concomitant cartilage damage at the time of meniscal allograft transplantation (MAT) is critical to warrant future success. However, there remains a scarcity of data comparing outcomes between MAT with and without cartilage procedures. To compare patient-reported outcomes and rates of complications, failures, reoperations, and graft survivorship after MAT with concomitant cartilage procedures (MAT/Cart) and MAT without (MAT/NoCart). Systematic review; Level of evidence, 4. A literature search was performed according to the 2020 PRISMA guidelines (Preferred Reporting Items for Systematic Reviews and Meta-analyses) using the Scopus, PubMed, and Embase computerized databases from inception to January 7, 2024. Human clinical studies with levels of evidence 1 to 4 were included that evaluated patient-reported outcomes, postoperative complications, failures, reoperations, and graft survivorship with a minimum mean follow-up of 2 years. Study quality was assessed using the Methodological Index for Non-randomized Studies criteria and Modified Coleman Methodology Score. Twenty-six studies from 2006 to 2024 consisting of 1031 patients were included. Thirteen studies (n = 367) reported on MAT/Cart with a mean patient age of 37.6 years and mean follow-up of 72.9 months. Thirteen studies (n = 665) reported on MAT/NoCart procedures in patients with a mean age of 33.6 years and mean follow-up of 58.6 months. Postoperatively, both study groups had improved clinical outcomes, with International Knee Documentation Committee scores ranging from 55.3 to 74.4 in the MAT/Cart group versus 61.7 to 89.8 in the MAT/NoCart group and Lysholm scores from 62.5 to 85.9 versus 72 to 92.4, respectively. The incidence of failure ranged from 0% to 33% after MAT/Cart versus 3.8% to 43.7% after MAT/NoCart. All included patients either had well-aligned lower extremities in the coronal plane, within 3° to 5° of neutral on the affected side, or underwent correction via an osteotomy before or during the MAT procedure. Subsequent surgery not related to failure was higher in the MAT/Cart group (range, 11.8%-83.3%) as compared with the MAT/NoCart group (range, 4.3%-30.8%). The mean survival rates after MAT/Cart ranged from 86.2% to 100% at 2 years, 75% to 97.9% at 5 years, and 70% to 85% at 10 years. The mean survival rates after MAT/NoCart ranged from 83.5% to 93% at 2 years, 82.6% to 85% at 5 years, and 55% to 90% at 10 years. Decreased range of motion and arthrofibrosis were the most frequently reported complications in each group. In patients with normal lower limb coronal plane alignment, performing cartilage restoration procedures in combination with MAT does not substantially alter clinical outcomes or complication, failure, and survival rates relative to isolated MAT.

Assessment of four sterilization techniques for meniscal allograft transplantation in rabbits.

This study aimed to compare the effects of four sterilization techniques on meniscal allograft transplantation (MAT) in rabbits. In total, 85 medial or lateral meniscuses were obtained from 22 adult New Zealand white rabbits. These 85 meniscal allografts were seeded with Staphylococcus aureus (S. aureus) and randomly divided into five groups (n = 17): iodine group, Cobalt-60 group, glutaraldehyde group, ethylene oxide group and control group. Bacterial colonies of the allografts were determined before (n = 7) and after (n = 7) sterilization. Histological features were analyzed using haematoxylin and eosin (H&E) staining (n = 3). An additional 50 medial or lateral meniscuses were taken from 13 adult New Zealand white rabbits, and they were kept fresh-frozen (-40°C) for 1 month. Subsequently, these 50 meniscuses were randomly divided into five groups, which were treated with iodine, Cobalt-60, glutaraldehyde, ethylene oxide and normal saline, separately (n = 10), and stored at -20°C before MAT. MAT was given to the knee joints of the right hind legs of 50 adult Japanese white rabbits. After 6 weeks of MAT, the transplanted meniscal allografts were taken for biomechanical test (n = 7) and H&E staining (n = 3). The results of the bacterial count indicated that the number of S. aureus colonies was less than 1 colony-forming unit (CFU)/allograft in all five groups after sterilization, except for the control group (415 CFU/allograft). H&E staining revealed that allografts in the iodine group presented the complete structure; allografts in the Cobalt-60 and glutaraldehyde groups were preserved relatively well; and allografts in the control and ethylene oxide groups were severely destructed, especially in the ethylene oxide group. Using the transplanted allografts, the biomechanical test showed that the maximum load of allografts in each group was significantly different, with ethylene oxide effective sterilization agents being used for disinfecting meniscal grafts (iodine group: 270.71 ± 62.81 N, Cobalt-60 group: 182.14 ± 71.29 N, glutaraldehyde group: 254.29 ± 31.55 N, ethylene oxide group: 40.00 ± 22.73 N and control group: 183.14 ± 76.40) (p ≤ 0.001). H&E staining with transplanted allografts revealed that allografts in the iodine group had the most intact structure; allografts in the Cobalt-60 and glutaraldehyde groups presented a relatively intact structure; and allografts in the control and ethylene oxide groups were seriously damaged, especially in the ethylene oxide group. It was found that iodine, Cobalt-60, glutaraldehyde and ethylene oxide are effective sterilization agents for disinfecting meniscal grafts. Iodine exhibited superior preservation of both the biomechanics and structural integrity of the meniscal allografts, whereas ethylene oxide caused the most severe destruction to the meniscal allografts. Not applicable because this is an animal study.

Clinical and Radiological Outcomes After Lateral Meniscal Allograft Transplantation Through a Medial Arthrotomy: A Minimum 4-Year Follow-up.

Previous studies have demonstrated that lateral meniscal allograft transplantation (MAT) through medial arthrotomy showed less extrusion than that of the lateral arthrotomy. However, there is a paucity of literature reporting clinical and radiological outcomes after lateral MAT through the medial arthrotomy. Lateral MAT through a medial arthrotomy would show significantly improved clinical scores and minimal joint space narrowing compared with preoperative status. Case series; Level of evidence, 4. Between 2001 and 2019, a retrospective chart review was conducted for all patients who underwent lateral MAT using the bony bridge technique through medial arthrotomy. Inclusion criteria were patients who underwent lateral MAT after subtotal or total meniscectomy of the lateral meniscus. A total of 27 patients who were not followed up for >4 years or had follow-up magnetic resonance imaging after surgery were excluded. At final follow-up, Lysholm scores and Tegner activity scale scores were collected. Graft extrusion, trough angle, and position of the bony bridge were measured by magnetic resonance imaging at 6 months after MAT. Joint space width (JSW) of the lateral compartment on Rosenberg view was measured and compared preoperatively and at follow-up. A total of 28 patients were included in this study. Their mean age was 29.8 years (range, 15-48 years) with a mean follow-up of 11.4 years. Preoperative Lysholm scores and Tegner activity scale scores (66.5 ± 16.6 and 3.1 ± 1.9, respectively) significantly improved at follow-up (84.8 ± 11.1 [P < .001] and 4.4 ± 1.5 [P = .008], respectively). The JSW decreased from 6.2 ± 1.6 mm to 5.7 ± 1.4 mm (P = .014). Extrusion was 2.2 ± 1.5 mm, and trough angle was 1.5°± 8.9°. The bony bridge was positioned at 43.9% ± 4.3% from the lateral edge on the entire tibial plateau. Nine patients (32.1%) underwent subsequent procedures. Partial meniscectomies were performed in 2 patients, meniscal repairs in 2, manipulation under anesthesia in 1, and lateral capsular plication in 1. Three patients who underwent total meniscectomy or revision surgery were regarded as having a failure; therefore, 89.3% grafts survived. Lateral MAT through the medial arthrotomy demonstrated satisfactory clinical and radiological outcomes at long-term follow-up.

A Bedside-to-Bench-to-Bedside Journey to Advance Osteochondral Allograft Transplantation towards Biologic Joint Restoration.

More than 70 million adults in the United States are impacted by osteoarthritis (OA). Symptomatic articular cartilage loss that progresses to debilitating OA is being diagnosed more frequently and earlier in life, such that a growing number of active patients are faced with life-altering healthcare decisions at increasingly younger ages. Joint replacement surgeries, in the form of various artificial arthroplasties, are reliable operations, especially for older (>65 years), more sedentary patients with end-stage OA, but have major limitations for younger, more active patients. For younger adults and those who wish to remain highly active, artificial arthroplasties are associated with significantly higher levels of pain, complications, morbidity, dysfunction, and likelihood for revision. Unfortunately, non-surgical management strategies and surgical treatment options other than joint replacement are often not indicated and have not proven to be consistently successful for this large and growing population of patients. As such, these patients are often relegated to postpone surgery, take medications including opioids, profoundly alter their lifestyle, and live with pain and disability until artificial arthroplasty is more likely to meet their functional demands without high risk for early revision. As such, our research team set out to develop, test, and validate biologic joint restoration strategies that could provide consistently successful options for young and active patients with joint disorders who were not considered ideal candidates for artificial arthroplasty. In pursuit of this goal, we implemented a targeted bedside-to-bench-to-bedside translational approach to hypothesis-driven studies designed to address this major unmet need in orthopaedics by identifying and overcoming key clinical limitations and obstacles faced by healthcare teams and patients in realizing optimal outcomes after biologic joint restoration. The objective for this article is to condense more than two decades of rigorous patient-centered research aimed at optimizing osteochondral and meniscus allograft transplantation towards more consistently successful management of complex joint problems in young and active patients.

Knee osteotomy combined with meniscal allograft transplantation versus knee osteotomy alone in patients with unicompartmental knee osteoarthritis: a prospective double-blind randomised controlled trial protocol

IntroductionKnee osteotomy combined with meniscal allograft transplantation (MAT) showed promising results to treat unicompartmental knee osteoarthritis (OA) secondary to meniscal deficiency and knee malalignment. However, there is still no high-level...

Predictive factors for coronal and sagittal graft extrusion length after using tendon autograft for medial meniscus reconstruction.

Meniscus extrusion occurs in most elderly individuals and most patients after meniscus allograft transplantation. The risk factors and correlative factors of meniscus extrusion have been extensively studied. However, for using tendon autograft for meniscus reconstruction, both graft type and surgical method are different from those in previous studies on meniscus extrusion. To identify predictive factors for coronal and sagittal graft extrusion length after using tendon autograft for medial meniscus reconstruction. Ten patients who underwent medial meniscus reconstruction with tendon autograft were selected for this retrospective observational study. The graft extrusions and potential factors were measured and correlation and regression analyses were performed to analyze their relationships. The medial graft extrusion correlated with the preoperative bilateral hip-knee-ankle angle difference, preoperative Kellgren-Lawrence grade, preoperative relative joint space width, and preoperative bilateral medial edge incline angle difference. The anterior graft correlated with the anterior tunnel edge distance at 1 week after operation. The posterior graft extrusion correlated with the preoperative bilateral hip-knee-ankle angle difference, preoperative relative joint space width, and posterior tunnel edge distance at 1 week after operation. The mean graft extrusion correlated with the preoperative bilateral hip-knee-ankle angle difference and preoperative relative joint space width. The preoperative joint space width and anterior and posterior tunnel edge distance at 1 week can be used to predict the medial, anterior, posterior, and mean graft extrusion length. The preoperative joint space width and tunnel position can be used to predict the coronal and sagittal graft extrusion length after using tendon autograft for medial meniscus reconstruction.

Meniscal allograft transplantation in patients with substantial cartilage disease led to a sustained long-term improvement in patient-reported outcome measures.

Due to a lack of consensus regarding effective treatment options in young patients, the indications of meniscal allograft transplantation (MAT) have widened to include those with substantial cartilage disease. The aim of this study was to report the long-term patient-reported outcome measures (PROMs) and allograft survival rates for patients with substantial cartilage disease. A review of the prospectively maintained database was performed. Patients with International Cartilage Repair Society 3b or above cartilage grading in either their femur or tibia were classified as having substantial cartilage disease. Postoperative International Knee Documentation Committee, Tegner, Knee Injury and Osteoarthritis Outcome Score and Lysholm were compared between those with and without substantial cartilage disease. Kaplan-Meir analysis was used to assess the survival rates. Survival was defined as revision or removal of allograft or conversion to arthroplasty. Data from 422 patients were included in the analysis with 129 patients found to have full-thickness chondral lesions and 281 patients without full-thickness chondral lesions. The mean follow-up was 6.33 (SD 3.48) years for the cohort. The mean age for the entire cohort was 30 (SD 9.23). Patients in substantial cartilage disease group underwent meniscal transplantation at an older age (32 [standard deviation {SD} 8.47] years vs. 29 [SD 9.35] years [p < 0.001]). There was no significant difference in PROMs between the two groups up to 10 years postoperatively (p > 0.05). The substantial cartilage disease group had significantly lower survival rates compared to those without (80.62% vs. 94.32%). MAT in the context of substantial cartilage disease was associated with an improvement in PROMs up to 10 years with no difference to the group without substantial cartilage disease. The PROMs in combination with the long-term survival rates in this study can be used to counsel patients preoperatively. Level IV.

Lateral Meniscus Allograft Transplant With Capsulodesis and an Osteochondral Allograft to the Lateral Femoral Condyle

Background: Anterior cruciate ligament (ACL) injuries frequently present with lateral meniscal injuries, and when irreparable, this may lead to meniscectomy, increasing the risk for osteoarthritis. Lateral meniscal allograft transplant (LMAT) can restore knee function and proper contact pressures. When combined with osteochondral allograft (OCA) for chondral defects, results are highly positive. Indications: LMAT is indicated in relatively young patients (&lt;50 years of age) with a symptomatic, meniscus-deficient knee that has failed conservative treatment. The knee must be stable, without articular cartilage damage that cannot be repaired, and patients should be able to adhere to postoperative rehabilitation and future care. Indications for OCA include young, active patients with posttraumatic osteochondral defects, osteonecrosis, osteochondritis dissecans, large focal defects, previous cartilage repair failure, or patellofemoral joint cartilage lesions. Technique Description: After a diagnostic arthroscopy is performed and concomitant injuries are ruled out, the lateral meniscal tissue is debrided to a 1- to 2-mm rim for the recipient site preparation. Tibial sockets for root fixation are created using tibial guides and passing sutures are placed. A capsulodesis is performed to reduce meniscal extrusion by securing the lateral capsule through a transtibial tunnel to the anteromedial tibial cortex with high-strength sutures. A meniscal allograft, prepared with bone plugs, is introduced through an enlarged anterolateral portal. After it is accurately positioned, it is stabilized using Fast-Fix Flex devices and circumferential sutures. The bone plug sutures are then fixed through the tibial tunnels to the anteromedial tibial cortex with a button. The large cartilage defect is addressed with an OCA transplant, involving defect measurement, careful reaming, and press-fit insertion of a donor plug, ensuring congruent articulation. Results: Patients can expect improved clinical outcomes and high patient satisfaction with LMAT and concomitant OCA. The use of bone plugs minimizes soft tissue dissection while achieving solid osseous fixation. Discussion/Conclusions: LMAT with OCA leads to restored contact pressures to near-physiological levels, a high patient satisfaction of over 85%, and mean allograft survival of 16 years. Patient Consent Disclosure Statement: The author(s) attests that consent has been obtained from any patient(s) appearing in this publication. If the individual may be identifiable, the author(s) has included a statement of release or other written form of approval from the patient(s) with this submission for publication.

The potential of tendon autograft as meniscus substitution: Current concepts

Meniscectomy is known to alter the mechanics, stability, and kinematics of the tibiofemoral joint, leading to early knee osteoarthritis (KOA). While several meniscal substitutions exist, such as meniscus allograft transplantation, collagen meniscus implants, and artificial substitutes, they often come with technical challenges, high costs, and risks, including allograft failure, infections, and disease transmission. Tendon autografts emerge as a promising option, offering safety, availability, biocompatibility, and a reduced risk of pathophoresis. This review delves into basic, in vivo, in vitro, and biomechanical studies alongside clinical outcomes and future prospects of tendon autografts as meniscus substitutes. A thorough understanding of this option is vital for integrating these evolving techniques into clinical practice and mitigating early KOA progression.

Addressing meniscal deficiency part 1: An umbrella review of systematic reviews and meta‐analyses on meniscal allograft transplantation

AbstractPurposeMeniscal injuries are common in the young and active population. There is increasing utilization of surgical interventions like meniscal allograft transplantation (MAT) to restore the protective function of menisci following injury leading to meniscal deficiency. Extensive research and publications exist on the management of meniscal injury and the sequalae of meniscal deficiency. However, a comprehensive synthesis of the existing evidence through an umbrella review is lacking. This study aims to fill this gap by providing a current examination of the literature on MAT.MethodsA comprehensive search was conducted in the MEDLINE, Embase and Scopus databases to identify relevant systematic reviews and meta‐analyses. Studies were screened based on predefined inclusion and exclusion criteria. The quality of the included studies was assessed using the AMSTAR‐2 tool.ResultsA total of 41 studies were included in the review, with most published within the last decade. The majority of studies (56.1%) received a ‘Critically Low’ confidence rating, 26.8% were rated as ‘Low’, and only 14.6% were rated as ‘High’ confidence. From the included studies, 51.2% reported on PROMs, with the Lysholm score being the most common. Transplant failure and reoperation rate were reported in 34.1% and 19.5% of studies respectively. Studies on MAT reported favourable short‐term outcomes in terms of patient‐reported outcome measures (PROMs) but were limited by the lack of randomized control trials and consistent comparison groups.ConclusionsThis umbrella review highlights an increase in interest in MAT but underscores the need for higher‐quality reviews with standardized reporting and rigorous methodologies. Future research should focus on long‐term outcomes, optimal surgical techniques, patient selection criteria and risk factors for transplant failure. There is also a need for more studies focusing on MAT in pediatric populations. Overall, this review provides a comprehensive assessment of the current state of research in MAT and identifies areas for improvement in future studies.Level of EvidenceLevel IV.

Initial Outcomes following Fresh Meniscus Allograft Transplantation in the Knee.

Based on recent evidence-based advances in meniscus allograft transplantation (MAT), fresh (viable) meniscus allografts have a potential for mitigating key risk factors associated with MAT failure, and preclinical and clinical data have verified the safety of fresh meniscus allografts as well as possible efficacy advantages compared to fresh-frozen meniscus allografts. The objective of this study was to prospectively assess clinical outcomes for the initial cohort of patients undergoing MAT using fresh meniscus allografts at our center. Patients who were prospectively enrolled in a dedicated registry were included for analyses when they had undergone primary MAT using a fresh meniscus allograft for treatment of medial and/or lateral meniscus deficiency with at least 1-year follow-up data recorded. Forty-five patients with a mean final follow-up of 47.8 months (range = 12-90) were analyzed. Mean patient age was 30.7 years (range = 15-60), mean BMI was 29.7 kg/m2 (range = 19-48), and 14 patients (31%) were female. In total, 28 medial, 13 lateral, and 4 combined medial and lateral MATs with 23 concurrent ligament reconstructions and 2 concurrent osteotomies were included. No local or systemic adverse events or complications related to MAT were reported for any patient in the study. Treatment success rate for all patients combined was 91.1% with 3 patients requiring MAT revision and 1 patient requiring arthroplasty. Treatment failures occurred 8 to 34 months after MAT and all involved the medial meniscus. None of the variables assessed were significantly different between treatment success versus treatment failure cohorts. Taken together, the data suggest that the use of fresh (viable) meniscus allografts can be considered a safe and effective option for medial and lateral meniscus allograft transplantation. When transplanted using double bone plug suspensory fixation with meniscotibial ligament reconstruction, fresh MATs were associated with a 91% success rate, absence of local or systemic adverse events or complications, and statistically significant and clinically meaningful improvements in patient-reported measures of pain and function at a mean of 4 years postoperatively.

Low Rates of 30-Day Postoperative Complications After Meniscal Allograft Transplantation: A Retrospective Study Using the National Surgical Quality Improvement Program Database

PurposeThe purpose of this study is to determine the short-term (30-day) postoperative complication rates in patients undergoing meniscus allograft transplantation (MAT). MethodsAmerican College of Surgeons National Surgical Quality Improvement Program (ACS NSQIP) database was queried for patients who had undergone MAT from 2014 to 2021 using Current Procedural Terminology (CPT) codes. Patients were excluded if they did not have sufficient demographic data – namely those without data for age, sex, BMI, preoperative functional status, ASA classification, operative time, and length of hospital stay. Post-operative complications within 30 days were identified and rates of complications were examined as the primary outcome of this study. As a secondary outcome, multivariate logistic regression was used to identify risk factors associated with the thirty-day incidence of post-operative complications. Subgroup analysis was performed to analyze differences in postoperative outcomes following isolated MAT versus MAT with concomitant ligament reconstruction/repair, cartilage preservation, or realignment osteotomy. ResultsA total of 396 meniscal transplants were identified, with mean age of 35.2 ± 14.9, mean body mass index (BMI) of 29.6 ± 6.7, mean length of stay of 0.5 ± 1.8 days. 11 patients experienced any adverse event (AAE), Specific complications included surgical site infections (5), deep vein thrombosis (DVT) (1), urinary tract infection (UTI) (3), and return to the operating room (OR) (2). On subgroup analysis, there was no significant difference between AAE rates in patients undergoing MAT with concomitant procedures compared to patients undergoing isolated MAT (7 vs 4, p=0.5). ConclusionPatients who underwent MAT had an overall complication rate of 2.8% in the short-term postoperative period (≤30 days). Patients undergoing MAT with concomitant ligament reconstruction/repair, cartilage preservation, and realignment osteotomy had similar rates of all postoperative complications when compared to patients undergoing isolated MAT. Level of EvidenceLevel IV, therapeutic case series.

Long-Term Results of Meniscus Allograft Transplantation With Bone Fixation Show Improved Outcomes but Progression of Joint Space Narrowing, Osteoarthritis, and Cartilage Degeneration

PurposeTo investigate the clinical and objective outcomes of meniscal allograft transplantation (MAT) using bone fixation in patients after a minimum follow-up duration of 15 years, and to compare the demographic factors and allograft status between patients who experienced progression of osteoarthritis and those who did not. MethodsThe consecutive patients who underwent primary MAT between December 1996 and January 2008 were retrospectively reviewed. The inclusion criteria was primary MAT with a minimum follow-up duration of 15 years. Clinical outcomes were evaluated using the modified Lysholm score, along with an evaluation of clinical failure. In objective outcomes, the progression of joint space narrowing, osteoarthritis, and the status of the associated cartilages and allografts were evaluated with follow-up radiographs and MRI. ResultsAmong the 79 cases, 54 knees in 52 patients were included in the study and evaluated for clinical outcomes. The mean Lysholm score improved from 73.9 ± 17.5 preoperatively to 86.4 ± 15.6 over a mean follow-up period of 17.5 ± 3.8 years (P<0.001). Regarding the Minimal clinically important differences (MCID), 38 cases (70.4%) showed an improvement in the Lysholm score. The cumulative clinical survival rate was 87.0%. Objective evaluations evaluated in 32 cases with a minimum of 15 years of radiographic data revealed significant progression of joint space narrowing, osteoarthritis, and cartilage degeneration at the final follow-up, with 11 (34.4%) out of 32 cases exhibiting allograft tears involving ˃50% of the allograft. Patients with osteoarthritis progression exhibited more meniscal allograft tears and extrusion on the last follow-up MRI scan than those without progression. ConclusionNotable progression in joint space narrowing, osteoarthritis, and cartilage degeneration were observed in objective assessment. The progression of osteoarthritis might be associated with allograft tears and extrusion. In clinical evaluations, favorable long-term clinical outcomes were consistently demonstrated after MAT using the bone fixation technique. Level of EvidenceLevel Ⅳ, therapeutic case series.

Prospective Assessment of Outcomes After Femoral Condyle Osteochondral Allograft Transplantation With Concurrent Meniscus Allograft Transplantation.

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. 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. Case series; Level of evidence, 4. 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. 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. 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.

Differences in Graft Tear Configurations in Medial and Lateral Meniscal Allograft Transplantation: Objective Evaluations Using Magnetic Resonance Imaging

Background: Few studies have compared the characteristics of meniscal allograft tears between medial and lateral meniscal allograft transplantation (MAT) using bone fixation. Purpose: To investigate the prevalence, location, and patterns of allograft tears after MAT with the bone fixation technique and compare tear patterns between medial and lateral compartments according to the time elapsed after surgery. Study Design: Cohort study; Level of evidence, 3. Methods: The charts of consecutive patients who underwent primary medial or lateral MAT between December 1996 and June 2019 were retrospectively reviewed. The location, pattern, and postoperative periods during which allograft tears occurred were evaluated by reviewing all series of follow-up magnetic resonance imaging (MRI) scans, which were performed at 6 weeks, 3 months, 6 months, and 1 year postoperatively and every 2 years thereafter with the patient's agreement. Postoperative periods for allograft tears were defined as the time between surgery and the follow-up MRI scan in which the meniscal tear was first confirmed. Allograft tears were compared between the medial and lateral MAT groups. Results: A total of 327 consecutive patients who underwent MAT (55 medial, 272 lateral) with a minimum 2-year follow-up were retrospectively reviewed. The incidences of allograft tears after medial and lateral MATs were 32.7% and 30.9%, respectively. The mean times for tears were 80.1 ± 81.1 months and 48.9 ± 46.3 months in the medial and lateral MAT groups, respectively (P = .130). In both the medial and lateral MAT groups, allograft tears were observed mainly in the posterior horn, with complex tears being the most commonly identified tear type. In medial MATs, root tears were the second most common at 27.8%, with a significantly higher proportion than the lateral MATs (P = .014). On the other hand, in lateral MATs, meniscocapsular separation and radial tears were the second most common at 15.5% each, albeit not significantly more common than in medial MATs (P = .123 and P = .454, respectively). All root tears in medial MATs and meniscocapsular separations in lateral MATs were observed within 1 year postoperatively. Conclusion: Significant differences in allograft tear patterns were identified between the medial and lateral MAT groups. The proportion of root tears in medial MATs was higher than that in lateral MATs; conversely, the proportion of meniscocapsular separation was more common in lateral MATs. Such tear patterns, which may require surgical repair or graft resection, were observed only within 1 year of surgery. Therefore, close observation and regular follow-up in the earlier postoperative period are necessary after medial or lateral MATs.

Load Distribution After Serial Resection of the Posterior Horn of the Lateral Meniscus and Subsequent Meniscal Allograft Transplant: A Biomechanical Study

Background: Data are lacking as to when a meniscal allograft transplant (MAT) may be biomechanically superior to a partially resected lateral meniscus. Hypothesis: Lateral MAT using a bone bridge technique would restore load distribution and contact pressures in the tibiofemoral joint to levels superior to those of a partial lateral meniscectomy. Study Design: Controlled laboratory study. Methods: Eleven fresh-frozen human cadaveric knees were evaluated in 5 lateral meniscal testing conditions (native, one-third posterior horn meniscectomy, two-thirds posterior horn meniscectomy, total meniscectomy, MAT) at 3 flexion angles (0°, 30°, and 60°) under a 1600-N axial load. Pressure sensors were used to acquire contact pressure, contact area, and peak contact pressure within the tibiofemoral joint. Results: Limited (one-third and two-thirds) partial lateral posterior horn meniscectomy showed no significant increase in mean and peak contact pressures as well as no significant decrease in contact area compared with the intact state. Total meniscectomy significantly increased mean contact pressure at 0° and 30° (P = .008 and P < .001, respectively), increased peak contact pressure at 30° (P = .04), and decreased mean contact area in all flexion angles compared with the native condition (P < .01). Lateral MAT significantly improved mean contact pressure compared with total meniscectomy at 0° and 30° (P = .002 and P = .003, respectively) and increased contact area at 30° and 60° (P = .003 and P = .009, respectively), although contact area was still significantly smaller (24.1%) after MAT relative to the native meniscus (P = 0.015). However, allograft transplant did not result in better tibiofemoral contact biomechanics compared with limited partial meniscectomy (P > .05). Conclusion: The peripheral portion of the lateral meniscus provided the most important contribution to the distribution of contact pressure across the tibiofemoral joint in the cadaveric model. Total meniscectomy significantly increased mean and peak contact pressure in the cadaveric model and decreased contact area. Lateral MAT restored contact biomechanics close to normal but was not superior to the partially meniscectomized status. Clinical Relevance: Surgeons should attempt to preserve a peripheral rim of the posterior lateral meniscus. Meniscal allograft transplant appears to improve but not normalize mean contact pressure and contact area relative to total lateral meniscectomy.

Meniscal Allograft versus Synthetic Graft in Treatment Outcomes of Meniscus Repair: A Mini-review and Meta-analysis.

Meniscal injuries are highly correlated with osteoarthritis (OA) onset and progression. Although meniscal allograft transplantation (MAT) is a therapeutic option to restore meniscal anatomy, a shortage of donor material and the donor-derived infectious risk may be concerns in clinics. This review summarizes the literature reporting meniscus repair status in preclinical models and clinical practice using allografts or synthetic grafts. The advantages and limitations of biodegradable polymer-based meniscal scaffolds, applied in preclinical studies, are discussed. Then, the long-term treatment outcomes of patients with allografts or commercial synthetic scaffolds are compared. A total of 47 studies are included in our network meta-analysis. Compared with the meniscal allografts, the commercial synthetic products significantly improved clinical treatment outcomes in terms of the Knee Injury and Osteoarthritis Outcome Score (KOOS), Visual Analog Scale (VAS) scores, and Lysholm scores. In addition, development strategies for the next generation of novel synthetic scaffolds are proposed through optimization of structural design and fabrication, and selection of cell sources, external stimuli, and active ingredients. This review may inspire researchers and surgeons to design and fabricate clinic-orientated grafts with improved treatment outcomes.

Paper 15: Survivorship of 157 Arthroscopic Meniscal Allograft Transplants Using Bone Fixation at Mean 7 Years and Prognostic Factors Analysis

Objectives: Meniscal allograft transplantation (MAT) is an accepted and effective treatment option in the context of unsalvageable menisci, particularly in young and active patients. It has been shown to reduce pain and improve knee function in previously symptomatic patients. However, there is still limited knowledge about the long-term survival rates of allografts, the durability of clinical results, and the influence of patient-specific parameters, such as leg alignment, tibial slope, and preoperative International Cartilage Regeneration &amp; Joint Preservation Society (ICRS) grade. The purpose of this study was to determine (1) the long-term clinical success rate after MAT with bony fixation in a large, single-center cohort of consecutive patients, and (2) if patient-specific and procedural variables influence the clinical, anatomic, and subjective outcomes and risk of failure. Methods: Data on 185 consecutive knees undergoing MAT in a single institution were prospectively collected and screened for inclusion in this study. The minimum follow-up time was 2 years. Radiographic variables (International Cartilage Regeneration &amp; Joint Preservation Society [ICRS] grade and Kellgren and Lawrence grade) were assessed preoperatively and at follow-up. Subjective patient-reported outcome measures (PROMs), Lysholm score, Knee Disability and Osteoarthritis Outcome Score (KOOS) including subscores, International Knee Documentation Committee (IKDC) score, and visual analog score (VAS) were collected preoperatively and at follow-up. Clinical failure was defined as revision surgery due to graft failure or conversion to total knee arthroplasty (TKA). Anatomic failure was considered a tear covering &gt;20% of the allograft, any peripheral tear, and unstable peripheral fixation leading to dislocation of the graft. Subjective failure was defined as Lysholm score ≤65. Preoperative tibial slope and leg alignment were assessed. Survival analyses were performed utilizing the Kaplan-Meier estimate. Univariate and multivariate analyses were performed to determine risk factors for clinical and anatomic failure. Results: A total of 157 knees met inclusion criteria (Table 1). After a mean follow-up time of 7 ± 3.5 years, 127 (80.9%) knees were free of clinical, anatomic, and subjective failure. Fourteen (8.9%) knees experienced clinical failure, 26 (16.6%) knees were identified as anatomic failure, and 13 patients (8.3%) suffered from subjective failure with a reported Lysholm score of ≤65 at a mean follow-up of 7 years. Concurrent osteochondral allograft transplantation was identified as a predictor of both clinical (HR 4.55; 95% CI 1.46-14.17; p=0.009) and anatomic failure (HR 3.05; 95% CI 1.34-6.92; p=0.008). Cartilage damage of ICRS grade 3 or 4 of the index compartment conveyed an increased risk for clinical (HR 3.41; 95% CI 1.05-11.01; p=0.04) and anatomic failure (HR 3.04; 95% CI 1.31-7.11; p=0.01) (Table 2). There were no differences in outcomes between medial and lateral MAT. High-grade cartilage damage (defined as ICRS grades 3 and 4) preoperatively (HR 10.67; 95% CI 1.037-109.768; p=0.046), patients age over 25 (HR 5.44; 95% CI 0.120-246.070; p=0.384), and a body mass index &gt;30 (HR 2.24; 95% CI 0.748-6.705; p=0.149) were associated with subjective failure. Considering the entire study population, PROMs including KOOS and IKDC were significantly improved at final follow-up compared to preoperative scores across all measurements (p&lt;0.005). Conclusions: MAT showed good-to-excellent clinical results at a mean follow-up of 7 years. Low ICRS lesion grade was associated with a higher clinical and anatomic survival rate. Patients with concurrent osteochondral allograft transplantation are at higher risk of clinical and anatomic failure, but still report significantly improved PROMs. These results suggest MAT has a lasting beneficial effect both as in isolation and in complex cases with one or more concurrent procedures.