Chondral defects on the patella are a difficult problem in the young active patient and there is no consensus on how to treat these injuries. Fresh osteochondral allografts are a valid option for the treatment of full-thickness osteochondral defects and can be used to restore joint function and reduce pain. The primary purpose of this study was to investigate the clinical and subjective outcomes of a series of patients following fresh osteochondral allograft transplantation for isolated chondral defects of the patella.

A series of 5 patients underwent surgery using an open approach for graft transplantation. A strict protocol for the allograft tissue was followed. Transplant recipients must be aged <60, have a full-thickness, isolated chondral lesion and have failed previous traditional treatments. The fresh allografts are hypothermically stored at 4°C in X-VIVO10 media for up to 30 days to maintain cartilage viability. Pre- and post-operative clinical measures including knee stability, range of motion, and quadriceps girth were completed. Post-operative plain radiographs were completed including weight-bearing AP, lateral and skyline views. Patient-centred outcome measures including the Knee Osteoarthritis Outcome Score (KOOS) and the Knee Society Score (KSS) were gathered a minimum of 1-year post-operative. Descriptive and demographic data were collected for all patients. A paired t-test was employed to determine the difference between the pre-operative and post-operative outcomes.

All patients were female, with a mean age of 27.4 (SD 3.65). Knee ligament stability was similar pre- and post-operatively. Knee ROM assessment of flexion and extension demonstrated a less than 10° increase from pre to post-operative. Quadriceps girth measurements demonstrated a mean change of 0.5 cm from pre- to post-operative for the surgical limb. Post-operative radiographs demonstrated incorporation of the graft in 4/5 cases within 6-months of surgery. One patient developed fragmentation of the graft after 18-months, and one patient had a subsequent trochleoplasty for persistent pain. The mean KOOS domain scores demonstrated significant improvement (p<0.05) as follows: Symptoms pre-op = 28.57, post-op = 55; Pain pre-op 28.89, post-op = 57.22; ADLs pre-op = 48.92, post-op = 66.18; Sports/Recreation pre-op = 6, post-op = 32; and QoL pre-op = 12.5, post-op = 42.5. Mean pre-op surgical versus non-surgical limb KSS scores were 107.4 and 179 respectively. The mean post-op surgical versus non-surgical limb KSS scores were 166 and 200.

Isolated chondral defects of the patella can cause substantial pain, reduced function, and can be challenging to address surgically. This series of 5 cases demonstrated improved function, KOOS and KSS for 4/5 patients. To our knowledge this is a novel biological procedural technique for this problem, which has shown promising results making it a viable treatment option for young active patients with osteochondral defects of the patella.