Which of the following bearing combinations in total hip arthroplasty has the LOWEST volumetric wear rate?

• A Metal-on-conventional polyethylene (CoP)
• B Metal-on-metal (MoM) large head
• C Ceramic-on-ceramic (CoC) bearing couple ✓
• D Metal-on-highly cross-linked polyethylene (MoHXLPE)

Explanation

Ceramic-on-ceramic (CoC) bearings have the lowest volumetric wear rate of all bearing combinations, producing minimal and biologically inert ceramic debris (alumina/zirconia-toughened alumina), with wear rates <0.01 mm³/million cycles compared to 40-80 mm³/million cycles for conventional metal-on-polyethylene. Their limitations include squeaking (1-15% incidence), chipping/catastrophic fracture risk, higher cost, and limited head sizes. MoHXLPE has reduced wear compared to conventional polyethylene but higher than CoC. MoM fell out of favor due to ALVAL/pseudotumors from cobalt-chromium debris.

Reference: Maheshwari Essential Orthopaedics, 6th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.