UNCEMENTED HYBRID TOTAL HIP ARTHROPLASTY: REVISION RATE, REVISION RISK FACTORS, AND REVISION CAUSE.

Total hip arthroplasty (THA) is one of the most successful surgeries. Cemented, uncemented and hybrid methods of implant fixation can be used with different chances for implant survival. There is no consensus on the best fixation method. The aim of the study was to compare the groups of uncemented and hybrid implants according to survival, revision risk and revision cause. Until October 2015, a total of 199 THA uncemented and hybrid (uncemented acetabulum, cemented femur) implants implanted during the 1995-2003 period that had revision or last x-ray taken at least seven years after the initial operation were included in the study. Revision rate, risk factors, revision cause and revised components were investigated. A significant difference was found in the revision rate, i.e., 48 (27.9%) in uncemented group 13 (48.1%) in hybrid group (p=0.032). The relative risk for revision was significantly higher (RR=1.72; 95% CI: 1.09-2.73; p=0.019) in hybrids, most often due to loosening (p=0.004). The linear wear of polyethylene was the main cause of revision in uncemented THA (p<0.001). In hybrid group, larger revision replacing the femoral component was most often performed. Uncemented THA showed a lower revision rate, lower revision risk, and required 'minor' revisions compared to the hybrid ones.