Abstract
Objectives:
Osteochondral allograft transplantation (OCA) is a common restorative technique for addressing knee articular cartilage defects. There is limited literature analyzing the prevalence or risk factors for the development of new osteochondral lesions following osteochondral transplantation of the knee. The objective of this investigation was to identify these prevalence and risk factors through a single-institution retrospective chart review.
Methods:
A retrospective review of patients who underwent an osteochondral allograft procedure from August 2010 to November 2021 at a single academic medical institution was conducted. All patients that underwent a knee osteochondral allograft implantation with a minimum 2-year follow-up were included. Patients were further excluded if they did not have both a pre-operative MRI within 1 year of their surgery and post-operative MRI at least 2 years after their surgery. The number and location of new chondral lesions on post-operative MRI were recorded. The electronic medical record was queried for demographic data such as age, sex, and body mass index (BMI). Complications assessed included graft failure, infection, reoperation rates, deep vein thrombosis/pulmonary embolism (DVT/PE) and manipulation under anesthesia/lysis of adhesions (MUA/LOA). Graft failure was defined as subchondral collapse confirmed on imaging or second-look arthroscopy, removal or revision of primary OCA, or conversion to any form of arthroplasty. Each patient was contacted in order to complete surveys for Visual Analog Scale (VAS) for pain and satisfaction, the Knee Injury and Osteoarthritis Outcome Score (KOOS), and return to sport.
Results:
330 patients underwent a unilateral OCA during the study time period. Of these, 285 patients were found to have a minimum of 2 years of clinical follow-up however only 31 patients underwent both pre-operative MRI within 1 year of surgery and post-operative MRI at least 2 years after surgery. Of the 31 patients included in this study 20 (64.5%) were found to have at least one new chondral lesion on their post-operative MRI. Nine patients (32.3%) were found to have new 2 chondral lesions on post-operative MRI and only one patient was found to have three new lesions. There was no significant difference in age (p=0.242), sex (p=0.849), or BMI (p=0.814) between patients who developed a new chondral lesion and those who did not. Furthermore, in a logistic regression analysis age, sex and BMI were not found to be significantly correlated with the development of a new chondral lesion. There was a significant difference in time between surgery and post-op MRI between patients who developed a chondral lesion and those who did not (3.32 ± 1.3 years vs. 2.62 ± 0.54 years, p=0.042). There was no significant difference between patients who did and did not develop new chondral lesions with respect to VAS satisfaction (p=0.266), VAS pain (p=0.893), return to sport (p=0.350), KOOS Symptoms (p=0.681), KOOS Pain (p=0.737) or KOOS Quality of Life (p=0.257).
Conclusions:
The majority of patients who had post-operative MRI following OCA of the knee had an additional new chondral lesion at a site distinct from the defect for which they underwent surgery. Patients undergoing OCA should be appropriately counseled on the development of novel chondral lesions in the future. There was no difference in demographic variables or patient reported outcomes between patients who did develop new chondral lesions and those who did not.