Revision knee arthroplasty with a rotating-hinge design in elderly patients with instability following total knee arthroplasty.

BACKGROUND: Revision knee arthroplasty with a rotating-hinge design could be an option for the treatment of instability following total knee arthroplasty (TKA) in elderly patients. PURPOSE: To evaluate the clinical and radiographic results of revision arthroplasties in TKAs with instability using a rotating-hinge design in elderly patients. METHODS: We retrospectively reviewed 96 rotating-hinge arthroplasties. The average age of the patients was 79 years (range, 75-86 years); the minimum follow-up was 5 years (mean, 7.3 years; range, 5-10 years). Patients were evaluated clinically (Knee Society score) and radiographically (position of prosthetic components, signs of loosening, bone loss). RESULTS: At a minimum followup of 5 years (mean, 7.3 years; range, 5-10 years), Knee Society pain scores improved from 37 preoperatively to 79 postoperatively, and function scores improved from 34 to 53. ROM improved on average from -15° of extension and 80° of flexion before surgery to -5° of extension and 120° of flexion at the last followup (p = 0.03). No loosening of implants was observed. Nonprogressive radiolucent lines were identified around the femoral and tibial components in 2 knees. One patient required reoperation because of a periprosthetic infection. CONCLUSIONS: Revision arthroplasty with a rotating-hinge design provided substantial improvement in function and a reduction in pain in elderly patients with instability following TKA. LEVEL OF EVIDENCE: Level IV, therapeutic study.