PATHOLOGY
Isolated patellofemoral arthritis
TREATMENT
Bipolar patellofemoral fresh osteochondral allograft with distal realignment (At this juncture, the author, as do other surgeons who perform osteochon- dral allograft transplantation, assigns a significantly guarded prognosis to bipolar biologic resurfacing operations. These surgeons obtain full patient informed consent regarding the guarded prognosis and proceed with surgery only under the auspice that revision to arthroplasty is not knowingly com- promised should the allograft fail.)
SUBMITTED BY
Jack Farr, MD, Cartilage Restoration Center of Indiana, Ortholndy, Indi- anapolis, Indiana, USA
CHIEF COMPLAINT AND
HISTORY OF PRESENT ILLNESS
This patient is a 37-year-old female nurse who presented with progressive patellofemoral pain of her right knee. She had intermittent pain since a medial arthrotomy was performed 22 years previously to treat a "crushed" patella she sustained from direct impact. Her pain increases with any increase in activity.
She experiences marked pain at the end of an 8-hour nursing shift. She is unable to perform squats or climb stairs. Repeated attempts at rehabilitation failed to reduce her symptoms.
hension. Her ligament examination is normal.
Meniscal findings are absent. Quadriceps bulk is near normal.
RADIOGRAPHIC EVALUATION
Posteroanterior 45-degree flexion weight- bearing radiographs demonstrate neutral align- ment with no joint space narrowing. Merchant views demonstrate patellofemoral arthritis in the right knee with no significant subluxation or tilt (Figure C36.1), but there is joint space narrowing at the medial aspect of the patellofemoral articulation.
PHYSICAL EXAMINATION SURGICAL INTERVENTION
Height, 5 ft, 5 in.; weight, 1351b; body mass index of 23. She ambulates with an antalgic gait.
Limb alignment is neutral. She is unable to step up on a 6-in. step secondary to pain. Range of motion is from 5 to 130 degrees of flexion.
Pain and crepitus are limited to the patellofemoral joint. She has no patellar appre-
At the staging arthroscopy, the entire trochlea had grade III and IV change and the medial 60% of the patella had grade III-IV change.
Both the lesions were diffuse and incompletely contained (Figure C36.2). The tibiofemoral joint was normal. The patient then underwent pateUofemoral resurfacing with fresh osteo-
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Case 36 129
FIGURE C36.1. Preoperative posteroanterior 45-degree flexion weight-bearing (A) and Merchant (B) radi- ographs demonstrate isolated patellofemoral arthritis with significant joint space narrowing of the right knee.
chondral shell allografts (Figure C36.3). Milled cortical allograft bone pins were used for fixa- tion. The exposure was through a steep antero- medialization of the tibial tubercle, which
allowed the patella to remain central while the tubercle was elevated in an attempt to potentially decrease the load on the allograft shells.
FIGURE C36.2. Staging arthroscopy demonstrates the extensive loss of patellofemoral articular cartilage.
FIGURE C36.3. Clinical photographs obtained at the time of fresh osteochondral allograft transplanta- tion. (A) Extensive grade III and IV involvement of both the trochlea and patella. (B) Fresh osteochon- dral allograft specimen before graft preparation.
(C) Trochlear cut made so as to excise the entire trochlea. (D) Assessing patellar thickness to deter- mine osteotomy site. (E) Matching osteochondral allografts fashioned and secured to host.
Postoperatively, the patient was made weight bearing as tolerated with two crutches using a hinged brace set at 0 to 30 degrees for pro- tection. Continuous passive motion was used for 3 weeks, with early full range of motion allowed immediately as tolerated. Return to unrestricted activities was permitted after 6 months.
FOLLOW-UP
The patient is nearly symptom free with main- tenance of transplant position and joint space (Figure C36.4). She has minimal patellofemoral crepitus, and range of motion is comparable to her preoperative evaluation.
Case 36 131
FIGURE C36.4. Postoperative radiographs obtained within the first 3 months after surgery. Lateral (A), anteroposterior weight-bearing (B), and Merchant
(C) views demonstrate anatomic placement of the graft with cortical bone dowels in place without evi- dence of graft collapse or dislodgement.
DECISION-MAKING FACTORS
1.
2.
Relatively young, active individual with spe- cific symptoms related to isolated posttrau- matic patellofemoral osteoarthritis.
Young age as a relative contraindication to arthroplasty (i.e., patellofemoral or total knee arthroplasty).
3. Bipolar defects that are large, diffuse, and incompletely contained, virtually eliminat- ing other cartilage restoration procedures as viable options.
4. Unloading considerations as a part of patellofemoral cartilage restoration include a steep oblique anteromedialization to protect and unload the healing grafts.
