Factors determining ideal head size

Factors favoring large diameter head

Factors limiting head diameter

・ Lower dislocation rates

・ Improved stability

・ Increased head-neck ratio leads to greater ROM

・ Impingement-free ROM

・ Near “anatomic” head size

・ COC large heads have less stripe wear

・ COC heads have lower risk of femoral head fracture

・ Patient anatomy

・ Bearing material

・ Increased serum ions in MOM hip arthoplasty

・ Recent concerns of adverse local tissue reactions (ALTR) and aseptic lymphocytic vasculitis-associated lesions (ALVAL) with MOM hip

・ Psoas impingement (noted with MOM)