Journal of Bone & Joint Surgery - American Volume:
Question: In patients undergoing primary total knee arthroplasty (TKA), are better clinical, functional, and satisfaction results achieved with resurfacing or nonresurfacing of the patella?
Design: Randomized (allocation concealed)*, blinded (patients, data collectors, outcome assessors, data analysts, and data safety and monitoring committee)*, controlled trial with 10-year follow-up.
Information provided by author.
Setting: A tertiary-care university center in London, Ontario, Canada.
Patients: 90 patients (mean age, 70 y; 57% women) (100 knees) having TKA. Exclusion criteria included previous patellectomy, inflammatory arthritis, patellar fracture or instability, previous extensor mechanism procedures, high tibial osteotomy, severe valgus or varus deformity, previous unicondylar knee replacement, and history of septic arthritis or osteomyelitis. 83 patients (92%) (90 knees) were available for follow-up.
Intervention: TKA featured an anatomically designed cruciate retaining femoral trochlear groove and intercondylar notch acceptable for both resurfaced and nonresurfaced patellofemoral articulation. After the femoral and tibial cuts were done, patients were allocated to patellar resurfacing, in which an attempt was made to restore the baseline composite height of the patella (n = 42), or for the patella to remain unresurfaced, in which case a patelloplasty was done (n = 48).
Main outcome measures: Reoperation rate, Knee Society clinical rating score, functional outcomes, patient satisfaction, anterior knee pain, and radiographic assessment.
Main results: 45 patients (50 knees) were alive at 10-year follow-up. The resurfaced and nonresurfaced groups did not differ for reoperation rate (5% vs 15%; p = 0.166). Both the resurfaced and nonresurfaced groups improved in Knee Society clinical rating scores (Table). Total function scores decreased in both groups compared with assessment at 2 years (p < 0.045). Pain and total knee scores did not decrease from 2 years. The mean range of motion at the most recent follow-up was 109° in both groups. 85% of the resurfaced group and 93% of the nonresurfaced group responded as “extremely satisfied” or “very satisfied” on the patient questionnaire. The resurfaced and nonresurfaced groups did not differ for the number of stairs climbed in 30 seconds (mean, 31 vs 21; p = 0.072). The groups did not differ for flexion (29.79 vs 36.92 nm; p = 0.62) or extension (55.67 vs 63.68 nm; p = 0.36) torque. Patient-reported functional outcomes such as getting in and out of a car or chair or going up and down stairs did not differ between groups. Radiographic assessment for all patients who did not have knee revision showed similar results between resurfaced and nonresurfaced groups. There was no relation between grade of patellar cartilage loss and anterior knee pain in the nonresurfaced group at 10 years.
Conclusion: In patients undergoing primary total knee arthroplasty, long-term clinical, functional, and satisfaction outcomes were not different if the patella was resurfaced or not resurfaced.
Source of funding: No external funding.
For correspondence: R.S. Burnett, Department of Orthopedic Surgery, Washington University School of Medicine, Campus Box 8233, 660 South Euclid Avenue, St. Louis, MO 63110, USA