PATHOLOGY
Uncontained focal chondral defect of the lateral trochlea
TREATMENT
Autologous chondrocyte implantation of the trochlea with distal reahgnment
SUBMITTED BY
Brian J. Cole, MD, MBA, Rush Cartilage Restoration Center, Rush Univer- sity Medical Center, Chicago, Illinois, USA
CHIEF COMPLAINT AND HISTORY OF PRESENT ILLNESS
This patient is a 16-year-old girl with complaints of left knee pain and swelling of several years duration. She stated that her knee problems date back to when she was in the fourth grade at the age of 9 years. She sustained an injury that precipitated her symptoms, which have gradually worsened over the years.
Two years previously, she underwent microfrac- ture of an isolated chondral lesion of the trochlea due to her relentless symptoms of anterolateral knee pain and activity-related swelling. Initially, her symptoms were reduced.
However, because of worsening complaints of swelling and pain over the ensuing 2 years, she presented for additional treatment.
She indicates that although she thoroughly enjoys participating in sports, she has not been able to do so for the past few years as a result of severe knee pain. Furthermore, walking more than just a few blocks causes her knee pain and swelling, requiring her to rest and elevate her left leg. She is unable to per- form stair cUmbing other than with a non- reciprocal gait due to severe anterolateral knee pain. Several months of aggressive patellofemoral rehabilitation failed to alleviate her symptoms.
PHYSICAL EXAMINATION
Height, 5 ft, 5 in.; weight, 1221b. The patient ambulates with a slightly antalgic gait on the left. Her standing aUgnment appears to be neutral and symmetric. A moderate effusion is present in the left knee. Her range of motion is from 0 to 135 degrees. She has 1 cm of quadri- ceps atrophy when measured 10 cm proximal to the patella. She has a full symmetric range of motion and mild patellar apprehension. She has mild lateral joint line tenderness, no medial joint line tenderness, and her meniscal findings are grossly absent. Additionally, she has 3-i- crepitus of the patellofemoral joint with active extension. Her Hgament examination is within normal limits.
RADIOGRAPHIC EVALUATION
Extension weight-bearing radiographs reveal some lateral femoral condyle flattening of the left knee. Overall, her aUgnment is normal with no evidence of degenerative changes or joint space narrowing (Figure C20.1). Merchant views demonstrated the patella to be centered within the trochlea and no evidence of trochlear hypoplasia. Given her well-documented history and consistent symptoms, no magnetic reso- nance imaging (MRI) was obtained.
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Case 20 67
FIGURE C20.1. Anteroposterior (A), lateral (B), and merchant (C) radiographs of the left knee reveal mild flattening of the lateral femoral condyle without any other obvious abnormalities.
SURGICAL INTERVENTION
The patient underwent a left knee arthroscopy in which articular cartilage debridement was performed as well as a biopsy for autologous chondrocyte implantation (ACI). At the time of arthroscopy, a trochlear defect of approxi- mately 30 mm by 35 mm was noted to be com- pletely filled with soft fibrocartilage (Figure C20.2). The defect was laterally based with direct contact with the patella during the initial
phases of knee flexion. Approximately 2
months later, the patient underwent ACI of
her chondral lesion in addition to a distal tibial
tubercle anteromedialization procedure. Due
to the uncontained nature of this laterally
sided trochlear lesion, two mini suture-anchors
were utilized to sew the periosteal patch to the
periphery (Figures C20.3, C20.4). Additionally,
juxtaarticular synovial tissue was utilized to
help seal the periosteal patch. Postoperatively,
she was made heel-touch weight bearing for
68 Case 20
FIGURE
C20.2. Arthroscopic probing of the trochlear lesion demonstrates a laterally based lesion with soft fibrocartilaginous repair tissue.
FIGURE
