A PROSPECTIVE-STUDY OF A TITANIUM FEMORAL COMPONENT FOR CEMENTED TOTAL HIP-ARTHROPLASTY

The authors studied the clinical and radiographic results of a modern titanium-alloy femoral stem with a cobalt-chrome-alloy head for use in cemented total hip arthroplasty. One hundred sixteen hips (102 patien ts) were operated on using modern cement techniques and prospectively followed using the Hospital for Special Surgery hip rating system and standard radiographic criteria. At a mean follow-up period of 4.8 year s (range, 2-8 years), 69 hips were rated excellent, 38 good, 4 fair, a nd 5 poor. A total of 13 femoral components (11%) were radiographicall y loose according to the criteria of Harris. In 11 of these loose femo ral components, debonding or separation at the cement-prosthesis inter face, was the initial cause of failure, with bone-cement interface ero sions occurring later in five hips. Revision of a loose femoral compon ent has been performed in three hips and is pending in two other hips (4.3%). Significant calcar resorption was seen in only 17 hips (14.6%) , and serial measurements of distal femoral cortical widths showed no distal cortical hypertrophy except in one femur. The incidence of loos ening with this cemented titanium-alloy femoral component (with a coba lt-chrome-alloy head) is much higher than published reports of similar cobalt-chrome-alloy stems. The authors have abandoned the use of tita nium alloy femoral components for cemented total hip arthroplasty.