PATHOLOGY
Focal chondral defect patella
TREATMENT
Autologous chondrocyte implantation with distal realignment (Note: The use of ACI for the patella is considered off-label usage. This procedure was per- formed with explicit patient informed consent.)
SUBMITTED BY
Tom Minas, MD, and Tim Bryant, RN, Cartilage Repair Center, Brigham and Women's Hospital, Chestnut Hill, Massachusetts, USA
CHIEF COMPLAINT AND
HISTORY OF PRESENT ILLNESS
The patient is a 24-year-old man with a history of bilateral recurrent patellar dislocations. He has failed physical therapy measures including taping and bracing to maintain patellofemoral tracking. He has had two prior arthroscopic debridements on both knees, which have been ineffective. He has severe right greater than left anterior knee pain which prevents him from participating in any sporting activities. Stair climbing is painful and requires him to use the handrail to ambulate one step at a time.
PHYSICAL EXAMINATION
Height, 6 ft; weight, 1751b. Clinical examination reveals a physically fit male with symmetric neutral aUgnment. He is unable to perform a squat. He has a moderate-sized effusion. Range of motion is symmetric. His quadriceps angle measures 25 degrees with the patella in a reduced position. There is lateral subluxation with quadriceps contraction, and he has pro- found patellar apprehension. He has moderate patellofemoral crepitus. Meniscal compression testing was unremarkable. His ligament exami- nation is normal.
RADIOGRAPHIC EVALUATION
Plain films were within normal limits, demonstrating normal patellofemoral joint space without subluxation or tilt (Figure C28.1).
SURGICAL INTERVENTION
Arthroscopic evaluation demonstrated grade IV chondrosis involving the central and medial patella. There was obvious subluxation and tilt laterally of the patella with the knee in exten- sion. The trochlea articular surface was normal.
A cartilage biopsy for future autologous chon- drocyte implantation (ACI) was obtained. Six weeks later, the patient underwent ACI combined with a lateral release, antero- medialization osteotomy (AMZ), and proximal quadriceps advancement. The defect mea- sured 25 mm by 15 mm (Figure C28.2). Posto- peratively, the patient was made weight bearing in extension with crutches and began continu- ous passive motion for 4 to 6 weeks. Activities were gradually advanced as tolerated with impact activities delayed for the first 12 months postoperatively. Radiographs demon- strated heahng of his AMZ osteotomy (Figure C28.3).
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FIGURE C28.1. Preoperative skyline radiograph of the patellofemoral joint demonstrating well-
maintained cartilage space. FIGURE C28.2. Appearance of grade IV patellar chondral defect at the time of autologous chondro- cyte implantation (ACI).
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FIGURE C28.3. Postoperative (A) skyline, (B) anteroposte- rior, and (C) lateral radiographs demonstrate centralized patella and healed anteromedialization osteotomy.
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FOLLOW-UP
One year later, a second-look arthroscopy was performed (Figure C28.4) to remove hardware and to perform a debridement of periosteal overgrowth presenting as retropatellar crepita- tions with mild discomfort. The patient was painfree afterward, had full range of motion,
FIGURE
