Polyethylene wear before and after isolated liner exchange in anatomic modular locking Total Hip Arthroplasty

Abstract

Introduction: This study compared the linear penetration rate of conventional polyethylene (CONPE) and highly crosslinked polyethylene (HXLPE) before and after isolated liner exchange in a group of patients with anatomic modular locking (AML) total hip arthroplasty (THA). Methods: A total of 26 patients (13 men, 13 women) with 29 AML THAs received liner and hip ball exchange due to conventional PE wear. The exchanged liners were highly cross-linked in nature. All hip balls were 28 mm in diameter. Annual X-rays were measured for linear penetration and osteolysis. Results: The mean (± standard deviation) age was 44.8 ± 13.4 years at the time of primary THA and 56.9 ± 14.5 years at revision. The mean time interval between the primary and revision THA was 12.1 ± 3.2 years. The mean follow-up time after revision was 5.8 ± 1.8 years. The mean creep of CONPE and HXLPE occurred in the first year were 0.44 ± 0.37 mm and 0.38 ± 0.35 mm, respectively (p = 0.013). The mean annual linear penetration rates from second year onwards were 0.31 ± 0.40 mm and 0.09 ± 0.22 mm in the CONPE and HXLPE groups, respectively (p = 0.04). All THAs with CONPE showed osteolysis on the radiographs before the revision. No HXLPE showed osteolysis at the last follow-up. Conclusion: The CONPE had significantly higher wear rate compared with HXLPE. The HXLPE liner showed satisfactory liner penetration rate after isolated liner exchange procedures.