Patellofemoral Cartilage Lesions Treated With Particulated Juvenile Allograft Cartilage: A Prospective Study With Minimum 2-Year Clinical and Magnetic Resonance Imaging Outcomes

To analyze the functional outcomes of patients treated with particulated juvenile articular cartilage (PJAC) for symptomatic articular cartilage lesions in the patellofemoral joint, correlates clinical outcomes with magnetic resonance imaging (MRI) appearance of the repair tissue using cartilage-sensitive quantitative T2-mapping.

All patients treated with PJAC for patellofemoral lesions were identified and prospectively followed with clinical outcome scores (International Knee Documentation Committee , Knee Outcome Survey–Activities of Daily Living , and Marx Activity Scale ). Postoperative MRI scans using quantitative T2 mapping were obtained and interpreted by an independent musculoskeletal radiologist.

Twenty-seven patients treated with PJAC for 30 full-thickness patellofemoral cartilage lesions were identified; mean postoperative follow-up was 3.84 years. Improvements from pre- to postoperative mean IKDC (45.9 vs 71.2, P < .001) and KOS-ADL (60.7 vs 78.8, P < .001) scores were observed; no significant change in MAS was seen (7.04 vs 7.17, P = .97). Advanced age, history of previous surgery, lesion location (patella vs trochlea), or concomitant tibial tubercle osteotomy did not affect outcome scores. Greater body mass index was associated with less improvement in KOS-ADL score. No patients required reoperation for graft-related issues.

Lesion fill exceeding 67% by MRI assessment was noted in 69.2% of lesions; depth of lesion fill did not correlate with clinical outcomes. Quantitative T2-mapping revealed prolonged relaxation time at the graft site compared with adjacent normal cartilage at both deep and superficial zones.

This study found significantly improved pain and function in patients treated with PJAC for symptomatic patellofemoral articular cartilage defects. No patients required reoperation for graft-related issues. Postoperative MRI revealed majority lesion fill in more than 69% of patients, but persistent morphologic differences between graft site and normal adjacent cartilage remain. Though we support PJAC use in this setting to improve patient subjective outcomes, improved appearance on postoperative imaging was not found to provide additional clinical benefit.

Level IV, case series.

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