Focal chondral defect of the lateral femoral condyle TREATMENT

PATHOLOGY

Focal chondral defect of the lateral femoral condyle TREATMENT

Autologous chondrocyte implantation of the lateral femoral condyle 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 The patient is a 27-year-old woman with a long- standing history of right knee patellar instabil- ity. As a child, before she was skeletally mature, she underwent two lateral releases that failed to resolve her instability. Subsequently, when she had reached skeletal maturity, she under- went an anteromedialization of her tibial tubercle. Although her patellar instability was successfully treated, she developed locking and mechanical symptoms requiring arthroscopic removal of several loose bodies approximately 2 years before presentation for cartilage treat- ment. At the time of the arthroscopy, she was noted to have an approximately 3 cm by 3 cm grade IV lesion in the lateral femoral condyle.

She experienced some relief from the removal of the loose bodies; however, she still reports significant lateral-sided knee pain, sweUing, and giving-way. Repeated attempts at formal phys- ical therapy failed to alleviate her symptoms.

PHYSICAL EXAMINATION

Height, 5 ft, 3 in.; weight, 1251b. She has a nonantalgic gait. She stands in slight symmet- ric physiologic valgus. She has a large lateral incision extending down inferiorly from her anteromedialization procedure and previous

lateral releases. She has a trace effusion with mild patellofemoral crepitus. Her range of motion is from 0 to 135 degrees. She has a pos- itive J sign with active extension. She has mild patellar apprehension with lateral gUde testing in 30 degrees of flexion. She has significant ten- derness over the lateral femoral condyle. Her medial and lateral joint lines are not tender.

Her ligament exam is within normal limits.

RADIOGRAPHIC EVALUATION Plain radiographs of the right knee (Figure C15.1) reveal hardware fixation from the pre- vious anteromedialization procedure in place as well as an incongruity on the lateral femoral condyle of her left knee. Magnetic resonance imaging (MRI) examination reveals a chondral defect of the lateral femoral condyle with a full- thickness lesion extending into the subchondral bone with subchondral edema present.

SURGICAL INTERVENTION The patient underwent arthroscopy in which a lateral femoral condyle defect with soft fibro- cartilaginous tissue measuring 20 mm by 25 mm was noted (Figure C15.2).The defect was noted to be contained with a well-defined transi- tion zone and normal surrounding articular

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Case 15 47

FIGURE CI5.1. Preoperative anteroposterior (AP) (A) and lateral (B) radiographs of the right knee demonstrate fixation hardware from prior osteotomy

procedure as well as flattening and irregularity of the lateral femoral condyle.

cartilage. An articular cartilage biopsy for future autologous chondrocyte implantation (ACI) was harvested from the intercondylar notch, in the same region as a notchplasty per- formed during anterior cruciate ligament (ACL) reconstruction is typically performed.

Approximately 2 months later, the patient

underwent ACI to the lateral femoral condyle lesion, which was noted to be 32 mm by 18 mm in dimension following debridement (Figure C15.3). Postoperatively, she was made heel- touch weight bearing for approximately 8 weeks and continued to use a continuous passive motion (CPM) machine for 6 to 8h/day

FIGURE C15.2. Arthroscopic photograph of the lateral femoral condyle of the right knee demon- strates large chondral defect filled with fibrocarti- laginous tissue.

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FIGURE C15.3. (A) Intraoperative photograph demonstrates large lateral femoral condyle lesion with full-thickness cartilage loss noted, with the

B

central area filled with fibrocartilaginous tissue.

(B) Lateral femoral condyle lesion with periosteal patch sewn in place, sealed by fibrin glue.

FIGURE C15.4. Twelve-month postoperative 45- degree posteroanterior flexion weight-bearing radi- ograph (A) and lateral radiograph (B) demonstrate

slight improvement in the contour of the left lateral femoral condyle. No change in joint space is observed compared to preoperative radiographs.

Case 15 49 for that same period of time. At 8 weeks, she

was advanced to weight bearing and range of motion as tolerated. She advanced through the traditional rehabilitation protocol for ACI of the femoral condyle. She was asked to refrain from any impact or ballistic activities for 12 to 18 months.

FOLLOW-UP

The patient is now 18 months status post ACI.

She states that she is totally painfree; however, she is still unable to fully perform high-impact activities due to muscular deconditioning. Her knee physical examination is entirely within normal limits. Radiographs obtained at 12 months demonstrate slight improvement in the contour of the lateral femoral condyle.

DECISION-MAKING FACTORS 1. Persistent symptoms despite several failed

surgical attempts at patellar stabilization and loose body removal.

2. Young, high-demand patient with a large superficial chondral lesion amenable to chondrocyte transplantation or fresh osteo- chondral allograft. Lesion size precludes optimal result with microfracture or osteo- chondral autograft transplantation.

3. Patient preference for her own tissue and surgeon preference for ACI given the rela- tively young age of this patient and the desire to avoid the creation of a subchondral defect otherwise required for fresh osteo- chondral allograft transplantation.

4. Ability and willingness to be compHant with

the postoperative course.