AJSM - 2026-03-19 - Journal Article
Arthroscopic Findings After Osteochondral Allografts of the Knee: Proposed Classification Scheme and Associations With Graft Failure.
Oppenheim ZR, Moran TE, Phillips A, Richter C, Singh H, Bi AS, Cole BJ, Yanke AB
Topics
Key Takeaway
At second-look arthroscopy after knee OCA transplantation, 32.6% of grafts met structural failure criteria (Outerbridge grade 3–4 or >2 mm peripheral delamination) at a mean of 3.17 years, and structural failure was strongly correlated with clinical failure (P < .00001).
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Summary
This retrospective case series characterized macroscopic OCA appearance at second-look arthroscopy and proposed a classification distinguishing nonfailing from failing grafts using Outerbridge grade 3–4 degeneration or >2 mm peripheral delamination as structural failure criteria. Of 129 grafts reviewed, 42 (32.6%) met structural failure criteria; concomitant procedures at index surgery predicted structural success (P = .0044), while greater number of prior procedures predicted failure (P = .0319). Structural failure strongly correlated with clinical failure (P < .00001), and 42.9% of structurally failed grafts required revision reconstruction versus 9.2% of nonfailing grafts.
Key Limitation
The second-look cohort represents only symptomatic patients requiring reoperation (11.2% of all OCAs), making it impossible to determine whether the 32.6% structural failure rate reflects the true incidence or is a substantial overestimate driven by indication bias.
Original Abstract
BACKGROUND
Limited studies exist on the gross appearance of osteochondral allografts (OCAs) at the time of second-look arthroscopy to determine whether the graft and adjacent cartilage have signs of degeneration contributing to failure.
PURPOSE
To describe the gross appearance of OCAs and the adjacent cartilage at the time of a second-look knee operation to help propose an accurate definition of structural and clinical OCA failure and to standardize and classify the intraoperative findings associated with structural graft failure.
STUDY DESIGN
Case series; Level of evidence, 4.
METHODS
A retrospective review was conducted on all patients who underwent knee OCA transplantation and a subsequent procedure with graft visualization. At second look, grafts were classified using intraoperative imaging and operative reports as nonfailing or failing , with structural failure defined as grade 3 or 4 OCA degeneration (Outerbridge classification system) or moderate-to-severe (>2 mm) peripheral chondral delamination. The status of cartilage adjacent to the graft, including degeneration and delamination, was recorded. Patient characteristics, surgical factors, and graft and cartilage characteristics were evaluated for associations with functional outcomes and subsequent reconstruction (revision OCA, unicompartmental knee arthroplasty, or total knee arthroplasty). Functional outcomes were assessed using the International Knee Documentation Committee, the Osteoarthritis Outcome Score for Joint Replacement, and the Veterans RAND 12-Item Health Survey from index transplantation to the second-look procedure.
RESULTS
Of 1152 OCAs performed, 129 grafts (11.2%) from 127 patients underwent a subsequent procedure for symptomatic patellofemoral pathology that included a second-look evaluation at a mean of 2.20 ± 2.06 years. A total of 42 grafts (32.6%) were classified as demonstrating structural graft failure at a mean of 3.17 ± 2.17 years. Structural failure was attributed to graft degeneration (81%) and chondral delamination (21%). Significant cartilage damage adjacent to the OCA border was present in 13 nonfailing grafts (14.9%) and 17 failing grafts (40.5%). Concomitant procedures at index surgery were predictive of structural success ( P = .0044), whereas patients with more previous procedures were more likely to experience structural failure ( P = .0319). At a mean of 3.14 years from the index OCA, revision reconstruction was performed in 42.9% of patients with structural failure, compared with 9.2% without structural failure. Structural failure classification at second look was strongly correlated with clinical failure ( P < .00001).
CONCLUSION
Clinical failure after OCA transplantation appears to be multifactorial. Characterization of macroscopic graft morphology may help surgeons better define clinical and structural failure of OCA transplantation. Future study is required to evaluate the influence of adjacent cartilage and the factors associated with this finding.