[What effect does the hydroxyapatite coating have in cementless knee arthroplasty?].

Area of Science:

• Orthopedic surgery
• Biomaterials science
• Medical imaging

Background:

• Tibial component migration is a key factor in aseptic loosening of knee replacements.
• Titanium fibermesh coatings aim to improve bone integration and implant stability.
• Hydroxyapatite (HA) is a bioactive ceramic known to promote bone healing.

Purpose of the Study:

• To compare the in vivo migration of noncemented, diffusion sintered titanium fibermesh-coated tibial components with and without additional hydroxyapatite (HA) coating.
• To evaluate the long-term stability and revision rates of HA-coated versus non-HA coated tibial components.

Main Methods:

• Digital radiostereometry (DIRSA) was employed to track the migration of tibial components.
• Migration was assessed at two and nine years post-implantation.
• Two groups were compared: HA-coated and non-HA coated titanium fibermesh tibial components.

Main Results:

• After two years, HA-coated components showed approximately half the mean maximum subsidence (0.24 mm) compared to non-HA coated components (0.55 mm).
• At nine years, HA-coated components exhibited reduced subsidence and maximum total point motion (MTPM) (0.54 mm) compared to non-HA coated components (0.74 mm).
• Only one non-HA coated component required revision for aseptic loosening, while no HA-coated components were revised for this reason.

Conclusions:

• Hydroxyapatite coating significantly enhances the stability of titanium fibermesh-coated tibial components.
• HA coating reduces tibial component migration and the risk of aseptic loosening in knee arthroplasty.
• The use of HA coating is a promising strategy for improving the long-term outcomes of cementless knee replacement surgery.