Clinical, Radiographic, and Histological Outcomes After Cartilage Repair With Particulated Juvenile Articular Cartilage

Abstract

Background: Biological repair of cartilage lesions remains a significant clinical challenge because of the lack of natural regeneration and limited treatment options. Hypothesis: Treatment of articular cartilage lesions in the knee with particulated juvenile articular cartilage (PJAC) will result in an improvement in patient symptoms of pain and function and magnetic resonance imaging (MRI) findings at 2 years compared with baseline. Study Design: Case series; Level of evidence, 4. Methods: Patients with symptomatic articular cartilage lesions on the femoral condyles or trochlear groove of the knee were identified for treatment with PJAC. There were 25 patients with a mean age of 37.0 ± 11.1 years and a mean lesion size of 2.7 ± 0.8 cm2. All patients were assessed preoperatively (baseline) with a knee examination and surveys including the International Knee Documentation Committee (IKDC) subjective knee form, 100-mm visual analog scale (VAS) for pain, and Knee injury and Osteoarthritis Outcome Score (KOOS). Patients were followed at predetermined time points postoperatively through 2 years. Also, MRI was performed at baseline and at 3, 6, 12, and 24 months. At 2 years, patients were given the option of undergoing voluntary diagnostic arthroscopic surgery with cartilage biopsy to assess the histological appearance of the cartilage repair including safranin O staining for proteoglycans and immunostaining for type I and II collagen. Results: Clinical outcomes demonstrated statistically significant increases at 2 years after surgery compared with baseline, with improvements seen as early as 3 months. Over the 24-month follow-up period, the IKDC score increased from a mean of 45.7 to 73.6, KOOS-pain score from 64.1 to 83.7, KOOS-symptoms score from 64.6 to 81.4, KOOS–activities of daily living score from 73.8 to 91.5, KOOS–sports and recreation score from 44.6 to 68.3, and KOOS–quality of life score from 31.8 to 59.9. The MRI results suggested that T2-weighted scores were returning to a level approximating that of normal articular cartilage by 2 years. Histologically, the repair tissue in biopsy samples from 8 patients was composed of a mixture of hyaline and fibrocartilage; immunopositivity for type II collagen was generally higher than for type I collagen, and there appeared to be excellent integration of the transplanted tissue with the surrounding native articular cartilage. Other than elective biopsies, there were no reoperations, although 1 graft delamination was reported at 24 months. Conclusion: This study demonstrates a rapid, safe, and effective treatment for cartilage defects. For the patient population investigated, the clinical outcomes of the PJAC technique showed a significant improvement over baseline, with histologically favorable repair tissue 2 years postoperatively.