Bipolar Fresh Osteochondral Allograft Transplantation and Joint Reconstruction for Patellar and Trochlear Cartilage Defects

Abstract

Patellar instability is a debilitating condition, and trauma due to the dislocations may severely damage the articular cartilage of the patellofemoral joint. The lack of healing capacity of cartilage makes treatment of such lesions challenging. In young patients, preservation of native bone and cartilage is a priority, and therefore arthroplasty procedures should be avoided even in relatively larger lesions. Fresh osteochondral allografting has been described for these difficult and complex cases, with recent studies showing promising results. In this surgical technique, we describe the use of bipolar osteochondral allografts of the patella and trochlea and patellofemoral joint reconstruction for large bipolar full-thickness cartilage defects due to recurrent dislocation events.

Fig 1

Intraoperative photograph of a right knee with a midline skin incision and development of full-thickness skin flaps bilaterally. Retractors are being used to visualize the patella and extensor mechanism.

Fig 2

Intraoperative photograph of a right knee with a lateral parapatellar arthrotomy being performed to enter the knee joint. An incision is being made at the superolateral aspect of the patella and is continued distally to the pretibial recess.

Fig 3

Intraoperative photographs of a right knee undergoing tibial tubercle osteotomy. An Arthrex AMZ Guide System (A) is being used to determine the medial and lateral sites for release of the tibial tubercle, followed by a 45° cut osteotomy being performed with an oscillating saw, tapered distally (B). The osteotomy is completed with an osteotome within the pretibial recess and should result in complete release of the tibial tubercle (C). (TT, tibial tubercle.)

Fig 4

Intraoperative photographs of a right knee undergoing preparation for bipolar osteochondral allografting of the patellofemoral joint. With the tibial tubercle reflected superiorly, excision of the suprapatellar fat pad and soft tissue attachments is being performed (A) to reveal the native trochlear and patellar articular surfaces (B). *Arthritic lesions. (TT, tibial tubercle.)

Fig 5

Intraoperative photographs of a right knee undergoing removal of the native trochlear surface. Surgical pen markings are used to delineate boundaries of the arthritic and dysplastic native trochlea in preparation for removal and osteochondral allograft transplantation (A). Using these lines as a guide, an oscillating saw is being used to remove the native trochlea in one solid piece (B), with reaming performed to the depth at which bleeding healthy subchondral bone is encountered (C).

Fig 6

Intraoperative photograph of a right knee undergoing sizing of a trochlear osteochondral allograft. A surgical pen being used to mark areas of incongruence between the trochlear osteochondral graft and the appropriate donor trochlear shape and size (A). Using these markings, bone cutters (B) are being used to make fine adjustments to ensure the graft re-approximates an appropriate trochlea given the individual patients anatomic considerations.

Fig 7

Intraoperative photographs of a right knee undergoing fixation of a trochlear osteochondral allograft. The trochlear allograft is secured to the donor site with 4 K-wires (A), and 3.5-mm headless screws are being placed over the K-wires (B), lateral to the trochlear groove on the nonarticular surface.

Fig 8

Intraoperative photograph of a right knee with the Zimmer Arthroplasty System being used to measure the size of the arthritic native patella in preparation for excision and placement of an osteochondral allograft.

Fig 9

Intraoperative photograph of a right knee undergoing removal of an arthritic native patellar surface in preparation for osteochondral allograft transplantation. An oscillating saw is being used to remove the native patella from lateral to medial (A), with reaming performed to ensure a flat surface at the level of healthy, bleeding subchondral bone and a minimum of 13 mms of native patellar thickness (B).

Fig 10

Intraoperative photograph of a right knee undergoing fixation of a patellar osteochondral allograft. K-wires are being placed at the periphery of a patellar osteochondral allograft (A), with 2 lateral and 2 medial K-wires used for temporary fixation (B). For definitive fixation, headless screws are being placed using the K-wires as a guide for placement (C).

Fig 11

Intraoperative photograph of a right knee with bipolar osteochondral allografts appropriately sized and definitively fixed at the patellofemoral joint.

Fig 12

Intraoperative photograph of a right knee undergoing fixation of a tibial tubercle osteotomy with large frag screws being drilled in a lag fashion. (TT, tibial tubercle.)

Fig 13

Intraoperative photograph of a right knee undergoing MPFL reconstruction with a semitendinosus allograft. An anchor guide pin is being used to mark the origin of the MPFL on the femur and tagging sutures used to mark the location of its insertion on the patella. (MPFL, medial patellofemoral ligament.)

Fig 14

Intraoperative photograph of a right knee undergoing MPFL reconstruction with hemostats being used to grab the free ends of a semitendinosus allograft that has been fixed with suture tack anchors to reconstruct the native MPFL. (MPFL, medial patellofemoral ligament.)

Fig 15

Intraoperative photograph of a right knee undergoing medial patellofemoral ligament reconstruction. Imbricating stitches are being used to imbricate the graft to the tissues of the medial retinaculum and remnants of the native medial patellofemoral ligament.