Orthopedics This Week—April 6, 2014
Geoffrey H. Westrich, M.D. is Research Director of the Adult Reconstruction and Joint Replacement Service at Hospital for Special Surgery (HSS). He told OTW, “Dual mobility hip replacement was introduced to the U.S. several years ago and we have been using it at HSS with great success. With traditional hip replacement we have had to worry about dislocation, instability, impingement, and long-term wear on the plastic. With a dual mobility hip replacement, instead of the plastic liner being fixed to the cup and ball moves in that, the plastic liner is press fit onto the ball in the OR. The ball inside the liner is placed on the stem; then the hip is reduced and because the ball can’t come out of the plastic liner the risk of dislocation with this prosthesis goes down to almost zero. These hips have eliminated dislocation in primary hip replacements…and in the revision setting our dislocation rates are always higher.”
“The first study involved a number of institutions, and included almost 500 dual mobility hip replacements in primary surgery. We have yet to see any dislocations with a minimum of two year follow up. The second study involved in revisions only…over 130 cases where dual mobility was used and they only had a 3% recurrent dislocation rate.”
“The major advantage to these hips is the reduction in wear characteristics. And third generation highly cross-linked plastic tested in wear simulation studies reveals little if any wear. We also have retrieval and wear studies where we see virtually no wear with this hips out to 3 million cycles. If you look at the number one reason now for revision surgery in databases is instability. It used to be wear of the plastic and loosening but because the technology is so good now fixation is not an issue.”
Read the full article on ryortho.com.