Arthroscopic Delivery of Particulated Juvenile Articular Cartilage Allografts Provides Durable Outcomes for Full-Thickness Chondral Lesions of the Knee.

PURPOSE: To evaluate patient outcomes after arthroscopic particulated juvenile articular cartilage implantation for full-thickness cartilage lesions in the knee with a minimum 24-month follow-up.

METHODS: This was a retrospective case series of patients aged ≥15 years with International Cartilage Repair Society grade IV chondral lesions with exposed subchondral bone treated with primary arthroscopic particulated juvenile articular cartilage implantation between 2016 and 2023. All included patients had a minimum of 24 month follow-up. Knee Injury and Osteoarthritis Outcome Score and Western Ontario and McMaster Universities Osteoarthritis Index subscales were compared between baseline and a minimum of 24 months postoperatively using Wilcoxon signed-rank tests. Linear mixed-effects models with random intercepts for patients were constructed a priori to evaluate longitudinal associations between outcomes and prespecified covariates (age, sex, body mass index [BMI], smoking exposure, lesion area and compartment, and common concomitant procedures).

RESULTS: Thirty-four patients (16 women, 18 men; mean age 43.5 ± 10.2 years; mean BMI 27.9 ± 5.2) with mean lesion area of 2.98 ± 1.50 cm2 were included. Mean follow-up was 3.9 years (range: 2.1-9.5). All outcome subscales improved significantly from baseline to 24 months (all P < .003), with 71% to 82% of patients achieving clinically meaningful improvements (54% for Western Ontario and McMaster Universities Osteoarthritis Index Stiffness). In mixed-effects models, higher BMI was the only covariate associated with worse outcomes, with approximately 1.2-point lower Knee Injury and Osteoarthritis Outcome Score scores for each 1 increase in BMI. No acute graft displacements occurred, and 1 patient (2.9% of the cohort) experienced late graft delamination requiring revision 2.3 years postoperatively.

CONCLUSIONS: Arthroscopic particulated juvenile articular cartilage transplantation provided significant 24-month improvements across all outcome domains for high-grade knee lesions. Outcomes were not associated with lesion size, location, or demographics, though higher BMI was associated with worse results. No acute graft complications occurred.

LEVEL OF EVIDENCE: Level IV, retrospective case series.