[Hip resurfacing: current state of knowledge].

The tribologic quality of metal-on-metal bearings has enabled a second generation of hip resurfacing techniques. Compared with a conventional hip prosthesis, this type of arthroplasty has many advantages: sparing femoral (and acetabular) bone stock, preservation of hip joint biomechanics (femoral offset, leg length), better recovery for high-level sports activities, easier revision, less risk of dislocation, less risk of extension to the shaft in the event of osteolysis. Hip resurfacing can thus be considered as true "minimally invasive bone surgery". There are however specific complications of resurfacing, including femoral neck fracture and collapse of the femoral head. All of the conventional approaches can be used for hip resurfacing procedures, but a precise operative technique is mandatory. The key to success is a proper position of the femoral piece. Certain biomechanical rules for implantation are required in order to limit the cam effect, spare femoral bone, and maintain harmonious loading. Hip resurfacing can be indicated for young and/or active subjects for whom restoration of hip biomechanics offers a real advantage over conventional hip arthroplasty. The mid-term results have been encouraging, both clinically and radiographically.