The interfacial strength in sputtering-hydroxyapatite-coating implants with arc-deposited surface.

Orthopedic implants require strong integration with bone tissue to ensure long-term stability. Prior research has shown that surface roughness improves osseointegration. However, the role of hydroxyapatite (HA) coatings on roughened surfaces remains unclear. No prior work had resolved how HA coatings interact with arc-deposited surfaces to influence interfacial strength. This gap motivated the current study. The push-out test is a standard method for measuring implant-bone fixation. Histological analysis complements mechanical testing by revealing bone-ingrowth patterns. The sputtering technique is known for its precision in coating implants. This paper's contribution lies in comparing HA-coated and non-coated arc-deposited implants.

The study aimed to evaluate whether HA coatings on arc-deposited titanium implants improve interfacial strength compared to non-coated surfaces. Bone fixation was measured using push-out tests and histological analysis. The motivation was to determine if HA coatings enhance osseointegration on roughened surfaces. The push-out test quantifies mechanical fixation. Histology reveals qualitative bone-ingrowth patterns. The control group used non-coated arc-deposited implants. The experimental group used HA-coated arc-deposited implants. The goal was to assess HA's role in reinforcing implant-bone interfaces.

Titanium columns (Ti-6Al-4V) were first arc-deposited to create a rough surface. Hydroxyapatite (HA) was then sputtered onto the roughened surfaces to a thickness of 5 micrometers. The push-out test measured interfacial strength by applying axial force until the implant dislodged. Histological analysis evaluated bone-ingrowth patterns around the implants. Two dogs received HA-coated implants in their right femurs. The left femurs of the same dogs received non-coated arc-deposited implants as controls. The push-out force was recorded for each implant. Histological sections were stained to visualize bone-implant contact. Data were compared between HA-coated and non-coated groups.

HA-coated implants showed higher interfacial strength than non-coated implants in push-out tests. The push-out force for HA-coated implants averaged 120 N, while non-coated implants averaged 80 N. Histology revealed greater bone-ingrowth around HA-coated surfaces. The HA layer thickness was consistently 5 micrometers across all samples. No significant differences in implant positioning or surgical technique were observed. The HA coating did not flake or delaminate during testing. Bone-implant contact was denser in HA-coated regions. The study suggests HA coatings enhance mechanical fixation and osseointegration.

The authors propose that HA coatings on arc-deposited titanium implants increase interfacial strength. The push-out test results suggest HA improves mechanical fixation. Histological findings support the idea that HA promotes bone-ingrowth. The HA layer thickness of 5 micrometers was sufficient to reinforce the interface. No evidence of coating failure was observed during testing. The study supports the use of sputtering for HA deposition. HA coatings may enhance osseointegration on roughened surfaces. These findings suggest HA coatings are beneficial for orthopedic implants.