Hydroxyapatite-coated versus grit-blasted femoral stems. a prospective, randomised study using EBRA-FCA

Area of Science:

• Orthopedic surgery
• Biomaterials science
• Medical device engineering

Background:

• Cementless femoral implants are widely used in hip arthroplasty.
• Stem surface characteristics influence implant fixation and long-term stability.
• Differentiating between grit-blasted (GB) and hydroxyapatite (HA) coatings is crucial for understanding implant performance.

Purpose of the Study:

• To compare the long-term stability of cementless femoral implant stems with grit-blasted (GB) versus hydroxyapatite (HA) surface configurations.
• To evaluate the influence of surface treatment on femoral stem migration and subsidence.
• To determine if HA coating offers superior stability over GB surfaces in cementless hip implants.

Main Methods:

• Prospective, randomized study involving 50 hips (46 patients).
• Randomization into two groups: GB stem and HA-coated stem, with identical implant geometry.
• Assessment of stem stability using Ein Bild Roentgen Analyse femoral component analysis (EBRA-FCA) over a mean follow-up of 8.66 years.

Main Results:

• Mean stem migration was significantly lower in the HA group (1.26 mm) compared to the GB group (2.57 mm) (p = 0.04).
• Initial subsidence differed statistically between groups within the first 24 months.
• After 24 months, subsidence increased similarly in both groups, with no significant difference observed.

Conclusions:

• Hydroxyapatite (HA) coating enhances the long-term stability of cementless femoral stems compared to grit-blasted (GB) surfaces.
• The findings suggest HA coating may lead to improved implant fixation and potentially better clinical outcomes.
• Surface modification plays a critical role in the biomechanical performance of cementless femoral implants.