Patellar Shell Osteochondral Allograft Transplantation for Full-Thickness Patellar Cartilage Lesions.

Abstract

Background: Large cartilage defects of the patella in young, active patients present a significant treatment challenge, with a risk of progression to patellofemoral arthritis. Shell osteochondral allografts are a treatment option for large, irregular, or uncontained lesions, particularly in cases involving subchondral bone pathology or the failure of previous cartilage repair surgeries.

Case presentation: We present the case of a 24-year-old female with persistent anterior knee pain and mechanical symptoms after 5 previous knee surgeries. Preoperative imaging confirmed diffuse, full-thickness chondral lesions with subchondral bone involvement.

Operative technique: The patient underwent a patellar shell osteochondral allograft transplantation. The procedure involved resection of a 7-mm patellar shell, creation of a superior bony shelf with a step cut osteotomy in the native patella, and fixation of a precisely matched shell allograft. The step-cut osteotomy of the native patella and the corresponding bony shelf created on the graft creates added stability to the graft, with the shelf secured with superior bioabsorbable polylactic acid (PLA) bone fixation nails and the inferior aspect of the graft secured with antirotation bioabsorbable PLA pins.

Results: Postoperative imaging at 3 months demonstrated excellent graft incorporation while maintaining the native patellar thickness. The patient progressed through a 5-phase rehabilitation protocol designed for a 9-to-16-month recovery and return to play.

Discussion/conclusion: A review of the literature supports the efficacy of patellar osteochondral allograft transplantation, with reported graft survival rates of approximately 88% at 5 years and 77% at 10 years. Studies also show high rates of return to sport (75%-87%) and patient satisfaction. Shell osteochondral allografting is a viable and effective treatment for complex patellar chondral defects, providing durable outcomes and a reliable return to activity for young patients. In this video, we describe a novel technique for allograft fixation to enhance the stability of the shell allograft, allowing earlier postoperative weightbearing and range of motion activities.

Patient consent disclosure statement: The author(s) attests that consent has been obtained from any patient(s) appearing in this publication. If the individual may be identifiable, the author(s) has included a statement of release or other written form of approval from the patient(s) with this submission for publication.