Purpose

Patellofemoral joint cartilage defects are difficult to treat due to their unique thickness and topography. Several cartilage restoration techniques are available to surgeons treating articular cartilage defects. However, patellofemoral joint restoration historically produces worse outcomes than tibiofemoral joint restoration. One cell-based option is particulated juvenile allograft cartilage (PJAC). Few studies have focused on patients who receive PJAC as an option, and among these, even fewer patients under the age of 21 have been reported. The aim of this investigation is to 1) report on clinical outcomes and complication rates of pediatric and adolescent patients who received PJAC for cartilage restoration of the patellofemoral joint for any underlying diagnoses and 2) provide objective scores of cartilage defect restoration by independent assessment of PJAC fill, integration and appearance on post-operative Magnetic Resonance Imaging (MRI) studies.

Methods

At a single tertiary care urban musculoskeletal institution, patients were identified through the surgical materials department, and cross referenced with current procedural terminology codes. Patients 21 years old or younger with minimum clinical follow-up of 1 year and postoperative MRI at a minimum of 6 months after surgery were included. Cartilage restoration was assessed by MRI using the International Cartilage Repair Society’s (ICRS) standardized system. Sport activity was collected from medical records.

Results

Thirty-six knees in 34 patients with a mean age of 16.1 ± 3.1 years old (range 10—21 years old) were analyzed. Mean follow-up was 32.1 months. Defects were located on the patella in 25 knees, and trochlea in 11 knees. There were no bipolar lesions in the cohort. Mean defect size was 2.47 cm2. By ICRS grade, twenty-four knees (66.7%) were graded either ‘normal’ or ‘nearly normal’, and 28 knees (77.8%) had greater than 50% of the defect filled on follow-up imaging. Return to sport rates among patients who participated in a sport preoperatively was 100%. Two patients necessitated a second surgery to address a failure of their cartilage allograft.

Conclusion

Restoration of patellofemoral chondral defects in young patients with particulated juvenile allograft can be performed with satisfactory short-term efficacy, excellent postoperative MRI appearance, and rates of return to sport.