At a paper presented at the American Association of Hip and Knee Surgeons, which I co-authored with Dr. Dowd, Dr. Kindsfater, and Dr. Dalury, we reviewed 1181 consecutive total hips that were performed between July 2000 and April 2006. The incidence of dislocation of the hip was 3.7% for 28mm heads, 1.2% for 32mm heads, and 0.2% for 36mm heads. This underscores what has been previously reviewed that larger femoral heads provide greater stability for hip replacement and decrease the risk of dislocation, postoperatively. The use of larger heads can be safely done in patients with a larger hip socket, but should not be used if they sacrifice appropriate thickness of the polyethelene liner used in the hip socket. There are several factors that determine what size head is used in hip replacement and you should discuss these with your orthopedic surgeon.
William P. Barrett, M.D.
Dictated but not reviewed.