Cementless total hip arthroplasty relies on press-fit fixation and osseointegration. Which surface coating/modification most effectively promotes bone ingrowth into the acetabular cup?
- A Polished cobalt-chromium (CoCr) smooth surface
- B Highly cross-linked polyethylene (HXLPE) coating
- C Titanium plasma-sprayed or trabecular metal (tantalum) porous coating with pore size 100–400 μm ✓
- D Calcium phosphate (hydroxyapatite) coating alone without surface porosity
Explanation
Bone ingrowth (osteointegration) into cementless implants requires a porous surface with pore size of approximately 100–400 μm — matching the osteon diameter — to allow vascular invasion and bone trabeculae to grow into the pores. Titanium plasma-spray and trabecular metal (porous tantalum) achieve this architecture; trabecular metal (Zimmer Trabecular Metal) has ~80% porosity mimicking cancellous bone. Smooth polished CoCr relies on bone cement; HXLPE is a bearing surface material; HA coating is an osteoconductive supplement that enhances early fixation but requires an underlying porous substrate, not a standalone ingrowth mechanism.
Reference: Maheshwari Essential Orthopaedics, 6th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
Written and medically reviewed by the StethoPrep medical team.