Hybrid total knee arthroplasty: 10- to 16-year follow-up

A cementless femoral component may allow for a smaller surgical incision when a minimally invasive approach is used during primary total knee arthroplasty. Fixation by cement is the gold standard for total knee arthroplasty. The results of cementless total knee arthroplasty are mixed. Cementless femoral components have done well. Although some tibial components have performed well at long-term follow-up, others have been plagued by high rates of loosening and revision. The question remains whether the results of hybrid total knee arthroplasty, consisting of an uncemented femoral component and a cemented tibial component, will equal those of total knee replacement fixed with cement at long-term follow-up. The authors reviewed 148 hybrid total knee arthroplasties performed by a single surgeon between 1993 and 1995. At a mean follow-up of 14 years (range, 10-16) 5 knees (4%) had undergone revision of both the femoral and tibial components. Only 1 knee required revision for aseptic loosening. Two knees were revised for sepsis; 1 knee had been revised for fracture and 1 for instability. No additional femoral or tibial components were loose by radiographic criteria. Mild focal femoral osteolysis was identified in 3 knees (2%), and minor tibial osteolysis was present in 2 knees (1%). The rate of survivorship with revision for aseptic loosening as the end point was 99% (95% confidence interval, 0.97-100) at 16 years for both the femoral and tibial components. In this series, hybrid total knee arthroplasty showed excellent fixation at 16 years.