Fresh Osteochondral Resurfacing of the Patellofemoral Joint

Abstract

Large osteochondral lesions of the knee in young patients continue to be a challenge for orthopaedic surgeons and the focus of continual research. This is particularly true if the injury is a consequence of a dysplastic trochlea and involves both articular surfaces of the biomechanically complex patellofemoral joint. To obtain a healthy and congruent patellofemoral joint, the use of a bipolar fresh osteochondral allograft transplantation of the patella and trochlea is one of the few options to biologically treat these injuries. This would achieve a replacement of the entire articular surface of the patellofemoral joint with a high number of viable chondrocytes and respect the unique structural characteristics of the cartilage. The aim of this study was to obtain symptomatic and functional improvements while delaying the timing of prosthetic surgery. We present a reproducible although demanding surgical technique to perform a bipolar fresh osteochondral allograft transplantation of the patella and trochlea.

Fig 1

Right patellar graft preparation. The articular side of the patella is resected using a standard patellar guide such as that used in total knee arthroplasty.

Fig 2

Right trochlear graft preparation. The articular side of the trochlea is outlined with a sterile skin marker. The osteotomy will be performed guided by 3 K-wires placed on each side of the joint surface and oriented to 45° toward the center of the trochlea from anterior to posterior.

Fig 3

Medial view of right knee. The patellar osteotomy is performed using a standard cutting guide. Care is also taken to position the cutting guide to eliminate only 6 to 8 mm of the subchondral bone tissue.

Fig 4

Frontal view of right knee. The knee is flexed at 45° and the patella is everted, exposing the trochlea. The shape and size of the allograft's trochlea are reproduced in the patient's trochlea using a sterile skin marker.

Fig 5

Frontal view of right knee. Trochlear allograft fixation is accomplished with two 3.5-mm headless titanium compression screws.

Fig 6

Temporary fixation of the patellar graft is accomplished with two 1.8-mm K-wires positioned on the dorsal aspect of the patella (anterior to posterior) while care is taken to avoid cartilage tissue piercing.

Fig 7

Frontal view of right knee. Final disposition of patellar and trochlear grafts.