Patient-reported outcome and survival following meniscal allograft transplantation : an international case series.

AIMS: Meniscal allograft transplantation (MAT) for patients with symptomatic meniscal loss has demonstrated good clinical results and survivorship. Factors that affect both functional outcome and survivorship have been reported in the literature. These are typically single-centre case series with relatively small numbers and conflicting results. Our aim was to describe an international, two-centre case series, and identify factors that affect both functional outcome and survival. METHODS: We report factors that affect outcome on 526 patients undergoing MAT across two sites (one in the UK and one in Italy). Outcomes of interest were the Knee injury and Osteoarthritis Outcome Score four (KOOS4) at two years and failure rates. We performed multiple regression analysis to examine for factors affecting KOOS, and Cox proportional hazards models for survivorship. RESULTS: Our results indicate that baseline KOOS4 score affects functional outcome at two years, but no other included factors were significantly related to functional outcome. The only factor that affected failure rate was the presence of cartilage lesions down to bone on both the femur and tibia, decreasing the five-year survivorship from 95% (95% confidence interval (CI) 91 to 99) to 84% (95% CI 74 to 94). CONCLUSION: To our knowledge, this is the largest international cohort reporting on MAT. Our results indicate that factors such as age, BMI, and cartilage lesions down to bone on both the femur and tibia of the affected compartment should not present barriers to offering MAT. Baseline KOOS4 score and the presence of bone-on-bone arthritis can be used to help counsel patients regarding the expected risks and rewards of surgery. Cite this article: Bone Joint J 2022;104-B(6):657-662.

Creating Crosswalks for Knee Outcomes After ACL Reconstruction Between the KOOS and the IKDC-SKF.

BACKGROUND: Anterior cruciate ligament (ACL) registries do not all use the same patient-reported outcome measures, limiting comparisons and preventing pooling of data for meta-analysis. Our objective was to create a statistical crosswalk to convert cohort and registry mean Knee Injury and Osteoarthritis Outcome Scores (KOOS) to International Knee Documentation Committee-Subjective Knee Form (IKDC-SKF) scores and vice versa to allow these comparisons. METHODS: Data from 3 ACL registries were pooled (n = 14,412) and were separated into a training data set (70% of the sample) or a validation data set (30% of the sample). The KOOS and the IKDC-SKF scores were available prior to the operation and at 1, 2, and 5 or 6 years postoperatively. We used equipercentile equating methods to create crosswalks in the training data set and examined accuracy in the validation data set as well as bootstrapping analyses to assess the impact of sample size on accuracy. RESULTS: Preliminary analyses suggested that crosswalks could be attempted: large correlations between scores on the 2 measures (r = 0.84 to 0.94), unidimensionality of scores, and subpopulation invariance were deemed sufficient. When comparing actual scores with crosswalked scores in the validation data set, negligible bias was observed at the group level; however, individual score deviations were variable. The crosswalks are successful for the group level only. CONCLUSIONS: Our crosswalks successfully convert between the KOOS and the IKDC-SKF scores to allow for a group-level comparison of registry and other cohort data. CLINICAL RELEVANCE: These crosswalks allow comparisons among different national ligament registries as well as other research cohorts and studies; they also allow data from different patient-reported outcome measures to be pooled for meta-analysis. These crosswalks have great potential to improve our understanding of recovery after ACL reconstruction and aid in our ongoing efforts to improve outcomes and patient satisfaction, as well as to allow the continued analysis of historical data.

Extrusion, meniscal signal change, loss of shape, synovitis and bone marrow oedema are reliable scoring parameters to assess MRI appearance post meniscal transplant.

PURPOSE: Meniscal allograft transplantation (MAT) has shown good promise in restoring normal knee joint biomechanics in a meniscal deficient patient. However, MRI appearance of the meniscal allograft is often questioned and raises concerns of its viability and function. This paper aims to introduce and validate a new scoring system for MAT MRI appearance at 12 months [MRI appearance in Meniscal Transplant Score (MIMS)], using key changes such as extrusion, meniscal signal change, loss of shape, synovitis and bone marrow oedema. METHODS: A retrospective analysis of 10 patients from a single surgeon series was conducted. All MAT were performed with soft tissue fixation technique. MRI was performed at 12 months post-transplant with two independent consultant musculoskeletal radiologists and one experienced meniscal transplant surgeon scoring the images obtained. Interobserver agreement and intraclass correlation were measured. RESULTS: Interobserver agreement between examiners on individual features of the MIMS was superior for tibial bone oedema, substantial for meniscal extrusion and femoral bone oedema, moderate for meniscal shape and synovitis, and fair for meniscal signal changes. Absolute agreement between raters found good reliability (ICC = 0.774; 95% 0.359, 0.960) for single measures and excellent reliability (ICC = 0.911; 95% 0.627, 0.986) for average measures. CONCLUSION: MIMS is a reliable method of evaluating the meniscal allograft transplant 12 months post-transplant. Further research with larger MAT cohort groups and patient reported outcome measures may be helpful to correlate its clinical significance and guide further management. LEVEL OF EVIDENCE: Level III.

Polyurethane Meniscal Scaffold for the Treatment of Partial Meniscal Deficiency: 5-Year Follow-up Outcomes: A European Multicentric Study.

BACKGROUND: A biodegradable polyurethane scaffold was developed to treat patients with the challenging clinical condition of painful partial meniscal defects. HYPOTHESIS: The use of an acellular polyurethane scaffold in patients with symptomatic partial meniscal defects would result in both midterm pain relief and improved function. STUDY DESIGN: Case series; Level of evidence, 4. METHODS: A total of 155 patients with symptomatic partial meniscal defects (101 medial and 54 lateral) were implanted with a polyurethane scaffold in a prospective, single-arm, multicentric study with a minimum 5-year follow-up. Clinical outcomes were measured with the visual analog scale for pain, International Knee Documentation Committee subjective knee evaluation form, Lysholm knee scale, and Knee injury and Osteoarthritis Outcome Score at baseline and at 2- and 5-year follow-ups. Magnetic resonance imaging (MRI) was used to evaluate the knee joint, meniscal implant, and meniscal extrusion. Kaplan-Meier survival analysis was also performed. Removal of the scaffold, conversion to a meniscal transplant, and unicompartmental/total knee arthroplasty were used as endpoints. RESULTS: Eighteen patients were lost to follow-up (11.6%). The patients who were included in this study showed significant clinical improvement after surgery as indicated by the different outcome measures (P = .01). However, the clinical improvement tended to stabilize between 2 and 5 years of follow-up. MRI scans of the scaffolds in 56 patients showed a smaller-sized implant in the majority of the cases when compared with the native meniscus with an irregular surface at the 5-year follow-up. During the follow-up period, 87.6% of the implants survived in this study. At 5 years of follow-up, 87.9% of the medial scaffolds were still functioning versus 86.9% of the lateral scaffolds. In total, 23 treatments had failed: 10 removed scaffolds because of breakage, 7 conversions to meniscal allograft transplantation, 4 conversions to unicompartmental knee arthroplasty, and 2 conversions to total knee arthroplasty. CONCLUSION: The polyurethane meniscal implant was able to improve knee joint function and reduce pain in patients with segmental meniscal deficiency over 5 years after implantation. The MRI appearance of this scaffold was different from the original meniscal tissue at the midterm follow-up. The treatment survival rates of 87.9% of the medial scaffolds and 86.9% of the lateral scaffolds in the present study compared favorably with those published concerning meniscal allograft transplantation after total meniscectomy.

Higher survivorship following meniscal allograft transplantation in less worn knees justifies earlier referral for symptomatic patients: experience from 240 patients.

PURPOSE: To analyse the clinical outcome and survivorship of meniscal allograft transplantation (MAT), performed in a single unit, specifically to assess the impact of concomitant operations and the influence of articular cartilage lesions on outcome. METHOD: A prospective case series analysis of 240 patients undergoing MAT with follow-up greater than 12 months (range 1-10 years) was performed. Group A represented patients with good chondral surfaces (ICRS 0-3A); Group B had good chondral surfaces with concomitant realignment osteotomy. Group C had good chondral surfaces with ACL reconstruction performed at the same time. Groups D and E had bare bone on one or both surfaces respectively. Kaplan-Meier survivorship and PROMS including Lysholm, KOOS, Tegner, and IKDC subjective scores were analysed. RESULTS: Overall survivorship was 96.7% at 1 year, 87% at 5 years and 82.2% at 7 years. Groups A-C (knees without significant chondral damage) had significantly improved survivorship (95% at 5 years) compared to Groups D, E (full-thickness chondral wear) with 77% survivorship at 5 years. Survivorship and PROMS were equivalent between Groups A-C. Groups D and E had similar PROMS to Group A, but did have a higher failure rate. Overall 27% required further operative intervention. CONCLUSIONS: Meniscal transplantation is clinically effective in treating patients with symptomatic meniscal deficiency. Where indicated, the addition of osteotomy or ACL reconstruction achieves results similar to patients undergoing simple meniscal transplantation in stable and normally aligned knees. Survivorship is lower in patients with full-thickness chondral loss and future treatments should, therefore, be directed at improving success in this at-risk group. The results support encouragement for earlier referral of symptomatic patients to a specialist meniscal reconstruction centre before a significant chondral damage is sustained. LEVEL OF EVIDENCE: III.

Factors Predicting Meniscal Allograft Transplantation Failure.

BACKGROUND: Meniscal allograft transplantation (MAT) is performed to improve symptoms and function in patients with a meniscal-deficient compartment of the knee. Numerous studies have shown a consistent improvement in patient-reported outcomes, but high failure rates have been reported by some studies. The typical patients undergoing MAT often have multiple other pathologies that require treatment at the time of surgery. The factors that predict failure of a meniscal allograft within this complex patient group are not clearly defined. PURPOSE: To determine predictors of MAT failure in a large series to refine the indications for surgery and better inform future patients. STUDY DESIGN: Cohort study; Level of evidence, 3. METHODS: All patients undergoing MAT at a single institution between May 2005 and May 2014 with a minimum of 1-year follow-up were prospectively evaluated and included in this study. Failure was defined as removal of the allograft, revision transplantation, or conversion to a joint replacement. Patients were grouped according to the articular cartilage status at the time of the index surgery: group 1, intact or partial-thickness chondral loss; group 2, full-thickness chondral loss 1 condyle; and group 3, full-thickness chondral loss both condyles. The Cox proportional hazards model was used to determine significant predictors of failure, independently of other factors. Kaplan-Meier survival curves were produced for overall survival and significant predictors of failure in the Cox proportional hazards model. RESULTS: There were 125 consecutive MATs performed, with 1 patient lost to follow-up. The median follow-up was 3 years (range, 1-10 years). The 5-year graft survival for the entire cohort was 82% (group 1, 97%; group 2, 82%; group 3, 62%). The probability of failure in group 1 was 85% lower (95% CI, 13%-97%) than in group 3 at any time. The probability of failure with lateral allografts was 76% lower (95% CI, 16%-89%) than medial allografts at any time. CONCLUSION: This study showed that the presence of severe cartilage damage at the time of MAT and medial allografts were significantly predictive of failure. Surgeons and patients should use this information when considering the risks and benefits of surgery.