Two-year radiostereometric analysis evaluation of femoral head penetration in a challenging population of young total hip arthroplasty patients
Department of Orthopedics and Physical Rehabilitation
Medical Subject Headings
Aged; Arthroplasty, Replacement, Hip; Female; Femur Head; Femur Head Necrosis; Humans; Male; Middle Aged; Osteoarthritis, Hip; *Polyethylene; Prospective Studies; *Prosthesis Failure; Time Factors; Treatment Outcome
Orthopedics | Rehabilitation and Therapy
This prospective, randomized protocol evaluated femoral head penetration after total hip arthroplasty in a young population. Forty-five patients randomly received either a cross-linked or conventional ultrahigh-molecular-weight polyethylene (UHMWPE) liner in a noncemented hemispheric cup (Trilogy, Zimmer, Warsaw, Ind) with a 28-mm femoral head. Radiostereometric analysis film pairs, Harris hip, UCLA, SF-12, and Western Ontario and McMaster Universities scores were obtained through 2 years. Median femoral head penetration was less among cross-linked compared to conventional liners as follows: 0.06 mm (0.04-0.08 mm) vs 0.08 mm (0.02-0.19 mm) at 6 months, 0.07 mm (-0.14 to 0.16 mm) vs 0.11 mm (0.01-0.27 mm) at 1 year, and 0.065 mm (-0.04 to 0.193 mm) vs 0.169 mm (0.09-0.22 mm) at 2 years. Clinical outcomes were similar between the groups. Highly cross-linked UHMWPE demonstrated 55% less femoral head penetration compared to conventional polyethylene at 2 years. Despite improvements in the manufacturing process and sterilization of conventional UHMWPE, the femoral head penetration rate is unchanged from historical standards.
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Citation: J Arthroplasty. 2009 Sep;24(6 Suppl):9-14. Link to article on publisher's site