THR  

There are two major types of hip replacement systems, cemented and cementless hips.  Cemented systems were the original hip replacement systems used.  In these systems, the implants(cup and stem) are held to the bone with a type of cement.  Cementless systems are temporarily held stable while the surrounding bone grows into the porous surface of the implant.  In the long-term, the bone is what holds the implants stable.

The type of hip replacement system which is best will be determined in part by the details of the individual case and also in large part by the surgeon’s preference.  Each system has advantages and disadvantages.  Cemented systems have been in use for a long time and are well proven, but can have problems with infection in the cement or loosening of the cement over time.  Cementless systems are presumably less susceptible to infection, and once bony ingrowth occurs, they are less likely to loosen.  However, cementless systems may have more problems with  movement of the implants in the early post operative period.

The most common cemented system in use is the biomedtrix CFX system.  Currently there are two cementless systems in common usage.  The Kyon, or Zurich cementless hip system, is system that is held in place by screws as the bony ingrowth occurs.  The boimedtrix BFX is a cementless system based on an earlier experimental system which is held in place by a press fit and has recently been introduced for clinical use.