Twenty-Year Wear Progression and Long-Term Outcomes of Conventional Polyethylene Liners After Cementless Total Hip Arthroplasty

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Background Polyethylene (PE) wear debris can cause periprosthetic osteolysis and late failure after total hip arthroplasty, but long-term wear behavior of conventional non–cross-linked PE remains unclear. Methods We reviewed 85 consecutive cementless total hip arthroplasties performed between 2002 and 2005 using ArCom non–cross-linked PE liners (Biomet Inc., Warsaw, IN). After excluding 31 hips lost to follow-up and 5 revised hips, 49 hips (45 patients) with ≥20 years of follow-up were analyzed. Femoral head penetration was measured using PolyWare (Draftware Inc., Vevay, IN) by three independent observers. The first postoperative year was defined as the bedding-in phase, and subsequent penetration as the steady-state phase (SSP). Associations between wear and patient, implant, surgical, and clinical factors were assessed. Results The mean Japanese Orthopaedic Association score improved from 39.6 ± 10.6 preoperatively to 84.4 ± 12.9 at 20 years ( P < .001). Osteolysis was observed in 18 hips. Mean bedding-in phase and SSP wear rates were 0.235 ± 0.155 mm/y and 0.031 ± 0.023 mm/y, respectively. SSP wear correlated linearly with postoperative time (R 2 = 0.99). Hips with higher SSP wear (>0.025 mm/y) had higher 20-year Japanese Orthopaedic Association gait ( P = .033), activities of daily living ( P = .018), and total scores ( P = .013). Charnley category A had higher SSP wear than category B ( P = .024), whereas osteolysis did not affect wear rates. Conclusions ArCom conventional PE showed a nearly constant SSP wear rate over 20 years. Exploratory analyses suggested associations with functional status and Charnley category, but not with other patient, implant, or surgical factors.