Dual-lock total hip arthroplasty: A preliminary experience

The long-term experience with total hip arthroplasty (THA) has shown an increasing failure rate associated with aseptic loosening of components. A Dual-Lock system incorporates features designed to reduce the incidence of loosening. The Dual-Lock THA has a low-profile acetabular component that permits preservation of subchondral bone. The design features a large, collarless, straight-stem femoral component with an interlocking metal-to-bone press fit as the primary form of fixation. In a series of 210 THAs in 180 patients, with follow-up examinations over a period of one to four years, the results were 92% good or excellent. A problem with the press fit is femoral cracking. Subsidence, early loosening, and calcar changes have not been found to a significant degree. Preliminary results with this new design have been encouraging and support the concept of the press fit.