Mid-term failure rates, timing, and mechanisms for osteochondral allograft transplantation in the knee: Characterizing risk factors and identifying modifiable variables.

Abstract

Knee osteochondral allograft transplantation (OCAT) is consistently successful, however, higher failure rates for multisurface and bipolar OCATs persist. Failure mechanisms have involved OCA erosion, delamination, degeneration, fracture, and/or fragmentation, and progression of joint disease, associated with older patient age, higher BMI, male sex, nicotine use, comorbidities, low chondrocyte viability, larger OCA volume, and bipolar OCAT. Patient outcomes were prospectively followed after primary knee OCAT and analyzed for failure mechanisms categorized as OCA Cartilage, OCA Bone, Meniscus Allograft, Joint Disease Progression, or Unknown. Cases were included when OCAT was performed >5 years prior; all failure cases were included regardless of final follow-up (FFU) time. Failure and non-failure cohorts, and failure mechanism subcohorts, were compared based on patient sex, age, BMI, nicotine use, concurrent procedures, OCAT surgery type, and adherence. There were 186 cases in 184 patients (n = 112 males; mean age = 37.1 years; mean BMI = 28.5 kg/m²; mean FFU = 79 months). Initial failure rate was 23.1% (n = 43) with mechanisms attributed to OCA Bone (n = 15; 34.9%), Meniscus (n = 13; 30.2%), Joint Disease Progress (n = 11; 25.6%), OCA Cartilage (n = 2; 4.7%), or Unknown (n = 2; 4.7%). Risk factors included concurrent ligament reconstruction, ipsilateral osteotomy, and tibiofemoral bipolar + OCAT. However, older age and higher BMI, as well as potential barriers for post-operative adherence should be considered during patient selection. Recent advances have mitigated key risk factors, such that reductions in knee OCAT failure rates with improvements in function, mental health, and quality of life have been more consistently realized. 2, prospective cohort study.