Autologous chondrocyte implantation and anteromedialization for isolated patellar articular cartilage lesions: 5- to 11-year follow-up.

BACKGROUND Isolated chondral lesions of the patella are particularly challenging to treat, and long-term studies of treated isolated patellar lesions are limited. Previous short-term studies have reported favorable outcomes of autologous chondrocyte implantation (ACI) of the patella and/or trochlea, with a trend toward improvement when anteromedialization (AMZ) of the tibial tubercle was performed with the procedure. HYPOTHESIS Autologous chondrocyte implantation with concomitant AMZ for symptomatic isolated patellar lesions provides functional and symptomatic improvement in patients at a minimum 5-year follow-up. STUDY DESIGN Case series; Level of evidence, 4. METHODS Patients with failed primary treatment of isolated patellar full-thickness articular cartilage defects and patellofemoral malalignment who were treated with ACI and AMZ of the tibial tubercle at least 5 years prior were contacted for final postoperative outcome scores. Outcome scales including the International Knee Documentation Committee (IKDC), Lysholm, modified Cincinnati Knee Rating System, and 12-item Short Form Health Survey (SF-12) scores were assessed at baseline and final follow-up. RESULTS Of 27 eligible patients, 23 (25 knees) were available for assessment at a mean follow-up of 7.6 years (range, 5.1-11.4 years). Significant improvements from baseline to final follow-up were observed in the IKDC score (from 42.5 to 75.7; P < .0001), modified Cincinnati Knee Rating System score (from 3.0 to 7.0; P < .0001), Lysholm score (from 40.2 to 79.3; P < .0001), and SF-12 score (physical component score: from 41.2 to 47.6; P = .002; mental component score: from 48.1 to 60.7; P = .0001). Most patients (83%; 19/23) rated their surgery as good or excellent. The overall reoperation rate was 40% (10/25) largely because of periosteal hypertrophy (33%). One patient failed at 5.9 years postoperatively and underwent patellofemoral arthroplasty. CONCLUSION Combined ACI and AMZ resulted in significant improvements in symptoms and function with a low incidence of adverse events in patients with isolated symptomatic patellar chondral defects after a mean follow-up of more than 7 years.