1951 saw the first hip resurfacing (HR) procedure performed by Sir John Charnley using teflon-on-teflon bearings [1]. Approximately 20 years later, a polyethylene acetabular component and metal femoral component had become popular but osteolysis was prevalent due to tissue response to wear particles [2,3]. By the early 1980s, HR had almost been phased out due to high failure rates, but work continued in some centres, leading to the development of metal-on-metal (MOM) HR prostheses. The advantages of using MOM components in HR include less wear and bone re-absorption, and a low rate of dislocation [4]. Indeed, various reports in the literature have documented excellent short and mid-term results and low complication rates associated with MOM HR [5][6][7]. The results of our series of over 1000 patients treated with MOM HR are in agreement with such reports. The mean patient age at the time of surgery was 53.8 years (range 16 to 82). The mean Harris hip score (HHS) was 98 points at a mean follow-up of 2 years. The following major complications were recorded: 9 femoral neck fractures (FNFs), 2 acetabular component loosenings, 1 pseudotumour and 1 sciatic peroneal nerve deficit. Although we believe that MOM HR is a successful technique, long-term studies have not yet been published and there is always room for improvement. MOM implants do in fact have several drawbacks, including osteolysis, implant loosening, the development of hypersensitivity and pseudotumours [8-10], and serum metal ion elevation [11], the latter being particularly important with regards to fertile females. A novel type of bearing for use in HR consists of an uncemented 2.7 mm-thick acetabular polycarbonate-urethane (PCU) component, which can be coupled to large diameter metal heads. Commercially known as the Tribofit ® Acetabular Buffer™ (Active Implants Corporation, Memphis Tennessee, USA), this innovative bearing allows fluid film lubrication and as a result, wear is minimized. PCU is a hydrophilic, biocompatible, endotoxin-resistant material and acts as a stress-absorber, transmitting loads to the subchondral bone in a physiological manner. As of January 2010, 3 patients with avascular necrosis (AVN) and 5 with osteoarthritis (OA) were treated with HR using the Buffer™. Large diameter cobalt-chromium (CoCr) resurfacing heads were used in all patients (Tribofit ® , Active Implants Corporation, Memphis, Tennessee, USA). The mean patient age at the time of surgery was 53.1 years (range 30 to 68). In pristine sockets, no acetabular bone reaming was performed and the Buffer™ alone was used. In 3 of the OA patients who had deformed sockets, standard reaming was performed and the Buffer™ was placed into an acetabular metal shell, the former acting as a liner. The mean follow-up in this patient series was 12 months (range 0 to 25). No osteolysis or loosening were observed on X-rays. However, in 1 patient who did not have the acetabular metal shell, the acetabular bone had been mistakenly reamed. The patient became symptomatic 2 years after surgery and periacetabular bone rarefaction was visible. The mean HHS of the remaining cases at the latest follow-up was 99. In conclusion, HR has gone a long way since its development over 50 years ago. MOM HR is a successful technique performed worldwide, but implant longevity and the long-term effects of wear debris remain unclear. However, with the continuous evolution of hip bearings and the recent developments in technology, HR is set to be taken to the next level.