James A. Rand award paper: early failure of cementless mobile bearing TKA

A consecutive series of 82 cementless mobile bearing total knee arthroplasties (TKAs) were performed and studied. The indications for surgery in all cases was osteoarthritis with only mild or moderate deformity. Evaluation consisted of a Knee Society clinical score (KSCS) and radiographic evaluation preoperatively and at annual follow-up. A minimum two-year follow-up was obtained in 73 of 82 knees (89%). Results were compared to those of a subsequent consecutive series of 76 knees (66 with a 2-year follow-up) performed with a mobile-bearing TKA with cemented components with the same indications, implant, technique, and length of follow-up. Six of 73 cementless mobile-bearing TKA’s (8%) underwent tibial component revision for symptomatic subsidence and failure of ingrowth, compared to 0/66 revisions in the cemented group (p<.05). Patients with cementless mobile bearing TKA also had a significantly lower KSCS (161 vs. 184, p<.05), a significantly higher incidence of pain rated more than mild (23% vs. 7%, p<.01) and a trend toward less arc of motion (1060 vs. 1150, p<0.2). The results do not support the hypothesis that mobile-bearing TKA imparts the advantage of reliable tibial bone ingrowth.