INFLUENCE OF PROSTHESIS DESIGN AND RESURFACING ON THE OUTCOME OF CEMENTLESS TOTAL HIP ARTHOPLASTY: AN ANALYSIS OF THE ORTHOPEDIC LITERATURE FROM 1980 TO 2004

Abstract

Purpose of the study: In order to evaluate the influence of prosthesis design and resurfacing on the outcome of total hip arthroplasty (THA) implanted without cement, we reviewed the orthopedic literature from 1980 to 2004.

Material and methods: The PubMed database was screened from 1980 to 2004 for publications reporting cementless THA with a follow-up analysis. The same criteria were used to screen three registries. In all, the publications retained had studied 50,162 cementless THA (mean patient age 48.9 years, mean follow-up 6.5 years) where were studied according to rate of revision, presence of osteolysis, and presence of operative fractures. Eleven families of components grouped together the majority of prostheses: five acetabular families [screw fixation without resurfacing (n=2997), screw fixation with hydroxyapatite (HA) resurfacing (n=3618), screw fixation with corindon resurfacing (2360), press-fit mac-roporous (15691), press-fit HA (6094)]; and six families of femoral pivots [straight macroprous (n=7502), straight HA (n=3255), straight corindon (n=6136), anatomic HA (n=3468), anatomic macroporous (n=1215), anatomic corindon (n=1041)].

Results: The rates of revision and of osteolysis were higher for screw fixed cups without resurfacing. For screw fixed or press-fit cups, HA resurfacing did not reduce the rate of revision compared with corindon coated or macroporous implants. For anatomic pivots, adjunction of HA resurfacing reduced the rate of revision but at the shortest follow-up and without reducing the rate of osteolysis. Corindon-coated pivots gave comparable results for straight or anatomic implants. Conversely, HA-coated pivots gave better results with an anatomic design. The shape of the pivot had les effect than resurfacing on osteolysis and revision, but had a greater influence on operative fractures (2.9% for straight implants versus 4.6% for anatomic versions).

Conclusion: In all:

1. uncoated implants should be abandoned;

2. HA resurfacing does not reduce the rate of revision and can be associated with a higher rage of osteolysis;

3. there is no advantage between screw fixed or press-fit cups as long as the cup has a quality resurfacing;

4. there is no real difference between straight and anatomic pivots except that intraoperative fracture can be lower for the straight implants.