Extract
In the 1950s, Sir John Charnley introduced the first hip resurfacing implant as a Teflon-on-Teflon (polytetrafluoroethylene [PTFE]) articulation. He chose Teflon-on-Teflon because he was convinced that the natural lubrication with synovial fluid would not be sufficient to reduce the high frictional torque of metal-on-metal articulations, which leads to early implant failure1. Unfortunately, the Teflon-on-Teflon articulation was associated with a high failure rate and poor wear characteristics2. Later designs of hip resurfacing implants made use of metal-on-polyurethane, metal-on-polyethylene, ceramic-on-ceramic, and early metal-on-metal articulations3-7. The results of these early hip resurfacing designs were disappointing and were mostly related to catastrophic wear, which led to abandonment of the procedure in the middle part of the 1980s8.