POROUS-COATED FEMORAL COMPONENTS WITH OR WITHOUT HYDROXYAPATITE IN PRIMARY UNCEMENTED TOTAL HIP ARTHROPLASTY: A SYSTEMATIC REVIEW OF RANDOMIZED CONTROLLED TRIALS

Abstract

Background: The purpose of this systematic review was to determine the clinical and radiologic benefit of hydroxyapatite-coating in uncemented primary total hip arthroplasty.

Methods: A database of Medline articles published up to september 2007 was compiled and relevant references screened. Studies that satisfied the following selection criteria were included:

1. a proper randomized controlled trial;

2. based on a total hip prosthesis with or without hydroxyapatite-coating with one identical geometry;

3. primary uncemented total hip arthroplasty; and

4. used objective, validated clinical and radiographic outcome measurements.

Results: Eight studies, involving 857 patients, were included in the review. Observer agreement was 94%, while the interobserver reliability was K =.799 (.611 −.987); P < 0.001. Pooled analysis for Harris Hip Score as a clinical outcome measure demonstated no advantage of the hydroxyapatite coating (WMD: 1.49, CI: −2.32 to 5.31, P = 0.44). Radiologically, both groups showed equal presence of endosteal bone ingrowth (RR: 1.04, CI: 0.88 to 1.23, P = 0.66) and radio-active lines (RR: 1.02, CI: 0.90 to 1.16, P = 0.74) in the surface area of the prosthesis. Pooling on stem subsidence was not feasible, because three different measurement techniques were used.

Conclusion: Based on eight randomized controlled trials, this meta-analysis demonstrates no clinical nor radiological benefits to the application of a hydroxy-apatite coating on a femoral component in uncemented primary total hip arthroplasty.