(i) Head size, does it matter?

Femoral head size remains one of the most controversial and oft debated aspects of hip replacement surgery. Sir John Charnley set the debate in motion in his paper on Low Friction Arthroplasty with the emphasis on finding the ideal head size to reduce friction and therefore, it was thought, wear. As our understanding of tribology improved and with the development of more wear-resistant materials, the emphasis has shifted towards finding the ideal size to improve joint stability. The ability to use large diameter heads has provided an opportunity to expand the indications for total hip arthroplasty to include trauma and younger patients.