A Comparison of Two Type of Stems in Revision Hip Arthroplasty

Overview

This study compares two different hip stem components. Both hip stems used in this study allow the femur bone to attach and grow into them for stability. The main difference between the two stems is that one of the stems, the Solution® Stem, is made from Cobalt Chrome, a type of metal, and does not have a hydroxylapatite (HA) coating, while the second stem included in the study, the Restoration hip stem, is made from titanium alloy, a different type of metal that has a roughened surface and allows for a hydroxylapatite (HA) coating to be applied to the entire length of the stem. The HA coating is a thin calcium phosphate layer on the stem to encourage the bone to grow into it. We are trying to see if there is any difference in the initial bony ingrowth between the two stems and to compare the results in patients over the first two years after the surgery and then again at the five-year period.

Revision total hip arthroplasty is becoming increasingly common due to the large number of primary total hip arthroplasties being performed annually. Failure of these arthroplasties has led to an increasing number of patients requiring revision arthroplasty. Various methods have been used to reconstruct the hip during a revision procedure. These have generally consisted of a cemented or uncemented femoral stem. It is now generally accepted that uncemented femoral stems have improved results over cemented stems, especially in those cases with compromised bone stock. There are two main alloys used for the femoral revision component, that is cobalt chrome and titanium. There may be certain advantages to the use of titanium, in particular, a reduction in future bone loss caused by stress shielding. Stress shielding is commonly seen with cobalt chrome implants. In order to assess this and the overall survival of these two different implants a randomized clinical trial is proposed.