The Influence of Full-Thickness Chondral Defects on Outcomes Following Meniscal Allograft Transplantation: A Comparative Study.

PURPOSE: To compare a series of patients who underwent meniscus allograft transplantation (MAT) with full-thickness chondral defects (FTD) with those with no chondral defect (ND) with regard to the following: change in patient-reported outcomes (PROs) from baseline to 2-year follow-up and baseline to the final follow-up (including comparisons to minimal clinically important differences), complications and complication rates, reoperations and reoperation rates/timing, and failures and time to failure (revision MAT or conversion to total knee arthroplasty).
METHODS: Patients who underwent isolated medial or lateral MAT between September 1997 and March 2013 with a minimum of 2 years of follow-up were retrospectively identified and split into 2 groups based on the presence or absence of FTD (femoral condyle or tibial plateau) identified intraoperatively after debridement to allow for a better understanding of the lesion characteristics (when applicable): ND (Outerbridge grade 0/I) or FTD (Outerbridge grade IV). Patients with osteochondritis dissecans were eligible for inclusion, as were those with isolated single lesions, multiple lesions, or bipolar lesions. Those with a moderate Outerbridge grade (II and III)-whether treated or neglected-were excluded given the poorer reliability of grading intermediate lesions. Indications for MAT included those patients with subjective complaints (persistent joint-line pain) and objective findings (previous meniscectomy or nonviable meniscus state with pain localized to the affected compartment) of functional meniscal deficiency. All lateral MAT patients used a bridge-in-slot surgical technique, as did most medial MAT patients (few patients with earlier surgical dates received a keyhole technique). All FTD were treated concurrently at the time of index MAT with cartilage restoration procedures (microfracture, autologous chondrocyte implantation, DeNovo particulate cartilage grafting, or osteochondral auto/allografting). Reoperations, failures (revision MAT or conversion to arthroplasty), and PRO deltas were reported comparing baseline to 2-year follow-up and baseline to the final follow-up. Intergroup comparisons were made using Bonferroni-adjusted independent sample t-tests for continuous variables and χ-square for categorical variables.
RESULTS: A total of 91 patients (22 ND and 69 FTD) were identified and followed for a mean 4.48 ± 2.63 and 3.84 ± 2.47 years, respectively. There were no significant between-group differences in age, body mass index, or number of prior surgeries. The mean chondral lesion size in the FTD group was 4.43 ± 2.5 cm2. Concomitant anterior cruciate ligament reconstruction was performed significantly more in ND-group patients than FTD-group patients (8 [38.1%] vs 8 [11.8%], P = .004). There were no differences between ND-group and FTD-group patients in concomitant realignment procedures performed (2 [9.1%] vs 7 [10.1%], P = .986), or prior ligament reconstruction (9 [40.9%] vs 18 [26.1%], P = .111) or realignment procedure (0 [0%] vs 0 [0%]). FTD-group patients underwent concomitant osteochondral allograft (69.6%), autologous chondrocyte implantation (18.8%), microfracture (13.0%), osteochondral autograft (4.3%), or DeNovo juvenile particulate cartilage implantation (1.4%). A comparison of the patient groups found no statistically significant differences in PROs preoperatively (P > .003 for all). Intergroup comparisons of both the 2-year and final follow-up delta PRO scores showed no statistically (P > .003 for all) or clinically (number of PROs meeting minimal clinically important differences) significant differences. One complication occurred (fractured hardware) in the FTD-group patients (1.3%). There were no differences in the number of subsequent surgeries (revision MAT: ND, 2 (10.0%) vs FTD, 8 (12.9%); P = .845) or failures (conversion to total knee arthroplasty: ND, 1 (5.0%) vs FTD, 2 (3.3%); P = .646).
CONCLUSIONS: When comparing a patient series with FTD who underwent MAT with a patient series with ND, there were no differences in the change in individual PROs from preoperative to the final follow-up. Similarly, there were no differences in complications or failure between those with ND or FTD diagnosed intraoperatively. The results of the current study suggest that chondral damage identified and treated by cartilage restoration means at the time of MAT may not affect the clinical outcomes of MAT. LEVEL OF EVIDENCE: Level III, retrospective comparative study.