Hydroxyapatite-coated proximal ingrowth femoral stems. A matched pair control study

Area of Science:

• Orthopedic Surgery
• Biomaterials Science
• Medical Imaging

Background:

• Uncemented total hip replacements aim for biological fixation.
• Hydroxyapatite coating is used to enhance bone integration.
• The efficacy of hydroxyapatite in porous-coated stems requires further clinical validation.

Purpose of the Study:

• To compare the clinical and radiographic outcomes of uncemented femoral stems with and without hydroxyapatite coating.
• To evaluate the effect of hydroxyapatite coating on bone fixation and remodeling in total hip arthroplasty.

Main Methods:

• A retrospective matched pair study involving 84 uncemented total hip replacements (42 hydroxyapatite-coated, 42 porous-coated controls).
• Minimum 3-year follow-up evaluating clinical outcomes and radiographic evidence of femoral stem fixation and bone remodeling.
• Statistical analysis to compare fixation stability and bone hypertrophy between the two groups.

Main Results:

• No significant clinical differences were observed between the hydroxyapatite-coated and control groups.
• Both groups demonstrated high rates of stable bony fixation at 3-year follow-up (90% vs. 83%).
• Hydroxyapatite coating led to significantly accelerated bone remodeling, evidenced by proximal cancellous hypertrophy.

Conclusions:

• Hydroxyapatite coating on porous-coated femoral stems does not provide a demonstrable clinical advantage in total hip arthroplasty.
• While hydroxyapatite promotes bone remodeling, this radiographic change does not necessarily translate to improved implant durability.
• The study advises against the use of patched porous-coating and titanium-bearing surfaces in hip arthroplasty.