Poster 209: Clinically Significant Outcomes and Survival of Meniscal Allograft Transplantation at Minimum 5-Year Follow-up

OBJECTIVES: In the meniscal deficient patient, meniscal allograft transplantation (MAT) has demonstrated promising early- and mid-term outcomes. Despite exhibiting improvement when compared to baseline values, outcomes at long-term follow-up have been shown to gradually decline secondary to graft failure and osteoarthritic development. However, it remains largely unknown if patient reported outcome measures (PROM) at long-term follow-up continue to meet thresholds for clinically significant outcome (CSO) measures such as minimum clinically important difference (MCID) and patient acceptable symptomatic state (PASS). The purpose of this investigation was to analyze CSOs after MAT at a minimum 5-year follow-up, while evaluating graft survival and overall patient satisfaction. METHODS: A retrospective review of a prospectively collected, single-institution database spanning from 1999-2016 was performed to identify patients who underwent MAT using the bridge-in-slot technique and completed baseline PROMs with a minimum of 5-year follow-up. Baseline patient and surgical characteristics were collected. Preoperative and final follow-up PROMs were analyzed to determine whether patients met established MCID and PASS thresholds for International Knee Documentation Committee (IKDC; 9.9 and 36.0, respectively) and Lysholm (12.3 and 66.5, respectively) scores. Knee Injury and Osteoarthritis Outcome Score (KOOS) subscales were also collected, though not analyzed for CSO attainment. Failure was defined as revision MAT, conversion to unilateral or total knee arthroplasty, and macroscopic graft failure during second-look arthroscopy. RESULTS: A total of 275 underwent MAT, of which 34% (n=95/275) completed PROMs with a minimum of 5-year follow-up (mean follow up, 8.5 ± 3.2 years [range, 5.0 – 16.8]). Mean patient age was 29.5 ± 9.9 years, with a mean symptom duration of 5.3 ± 5.5 years (Table 1). The majority of patients received concomitant procedures at the time of index MAT, including osteochondral allograft transplantation (43.1%) and anterior cruciate ligament reconstruction (20.0%) (Table 2). Mean PROMs at final follow-up significantly improved when compared to preoperative values for IKDC, Lysholm, and KOOS subscales (all P < .01; Figure 1). MCID and PASS for the IKDC survey were met by 77.8% and 38.8% of patients at final follow up, respectively. MCID for Lysholm score was achieved by 69.2% of patients, while only 2.6% met PASS (Table 3). Failure was reported in 20% (n=19/95) of patients, occurring at a mean 3.8 ± 3.0 years following surgery (Figure 2). Overall, 91% of patients with an intact meniscal allograft reported being satisfied at final follow-up. CONCLUSIONS: At a minimum of 5-year follow-up, significant improvements in PROMs were appreciated when compared to preoperative values. MCID was achieved in a total of 77.8% of patients for IKDC and 69.2% for Lysholm. PASS thresholds were met by 38.8% of patients for IKDC and 2.6% of patients for Lysholm. Failure was reported in 20% of patients. Further investigations analyzing variables associated with the success and failure to meet CSO in patients undergoing MAT with long-term follow up are warranted.