Poster 365: Initial outcomes after unicompartmental tibiofemoral bipolar osteochondral and meniscus allograft transplantation in the knee using high-viability tissues

Abstract

Objectives: To report initial outcomes for unicompartmental tibiofemoral bipolar osteochondral allograft transplantation (OCAT) with meniscus allograft transplantation (MAT) using fresh high-cell- viability tissues for treatment of knee articular cartilage defects with meniscus deficiency. The study was designed to test the hypothesis that primary OCAT and MAT using high-viability tissues will be associated with successful short-term (2 to 6 years) outcomes based on statistically significant and clinically meaningful improvements in pain and function in the majority of patients. Methods: With IRB approval and documented informed consent, patients who underwent primary OCAT and MAT for large articular cartilage defects with meniscus deficiency involving at least one femoral condyle, tibial plateau, and meniscus, all of which were opposing (bipolar). Surgeries were defined as Uni when patients underwent OCAT and MAT involving one femoral condyle, tibial plateau, and meniscus in the same compartment or Uni-Plus when patients underwent Uni OCAT and MAT with at least one other OCA transplant to treat a large (>2.5cm2) grade III or IV focal articular cartilage defect of the patella, trochlea, femoral condyle, or tibial plateau. Patients who had at least 2-year follow up data regarding complications, failures, adherence, and patient reported outcome measures (PROMs) were analyzed. Patients who required OCA and/or MAT revision or artificial arthroplasty were defined as treatment failures. Patient reported outcome measures (PROMs) including VAS pain, IKDC, SANE, PROMIS Global Health and Physical Function, were collected at 3 and 6 months and then yearly after transplantation. Outcomes were compared based on patient sex, age, and BMI, tobacco use, previous and concurrent procedures, differences in number of surfaces transplanted (Uni vs Uni-Plus), and adherence. Significance was set at P < 0.05. Differences in PROMs were also assessed for minimum clinically important differences. Results: Seventy-six patients (n=52 males; 68%) met inclusion criteria (mean followup = 52 months; median = 56 months; range, 24-70 months). Mean age was 41.1 years (range, 15-69 years) and mean body mass index (BMI) was 28.9 kg/m2 (range, 17-46). Forty-eight patients underwent OCAT(s) in addition to Uni (Uni-Plus). Eight patients (10.5%) underwent concurrent ACL reconstruction, and 28 patients (36.8%) underwent ipsilateral lower extremity osteotomy in order to address co-morbidities. Twenty-three patients (30.3%) were documented to be non-adherent during the first year after transplantation. Initial (>2-year) success rate was 77.6% with 8 patients (10.5%) undergoing OCA and/or MAT revision and 9 patients (11.8%) converted to arthroplasty. Variables associated with increased risk for treatment failure (revision or arthroplasty) included ipsilateral osteotomy (p = .046; OR = 3.3), ipsilateral concurrent procedure (p = .0057; OR = 5.5), and non-adherence (p = .0009; OR = 7.2). None of the patients undergoing OCA and/or MAT revision surgery in the present study required arthroplasty at the time of data analysis such that overall success rate for primary and revision unicompartmental bipolar OCA plus MAT was 88.2%. There were statistically significant (p < .0001) and clinically important improvements from preoperative levels for all patient reported outcomes at each annual follow-up time point. Conclusions: Unicompartmental tibiofemoral bipolar osteochondral and meniscus allograft transplantation can result in successful short-term (2 to 6 years) outcomes and satisfaction in the majority (78%) of patients. Primary MOPS-preserved OCAT and MAT for treatment of femoral condyle and tibial plateau articular cartilage defects with concurrent meniscus deficiency was associated with statistically significant and clinically meaningful improvements in patient-reported measures of pain and function.