Todd A Morrison1, Rebecca D Moore1, Jia Meng2, Clare M Rimnac3, Matthew J Kraay1. 1. 1Department of Orthopaedic Surgery, University Hospitals Case Medical Center and Case Western Reserve University, 11100 Euclid Avenue, Cleveland, OH 44106 USA. 2. 2Case Western Reserve University School of Medicine, Cleveland, OH USA. 3. 3Departments of Mechanical and Aerospace Engineering and Orthopedic Surgery, Case Western Reserve University and University Hospitals Case Medical Center, Cleveland, OH USA.
Abstract
BACKGROUND: Concerns have arisen regarding deterioration of wear properties of yttria-stabilized zirconia (YSZ) femoral head on conventional polyethylene (PE) bearings due to YSZ phase transformation. QUESTIONS/PURPOSES: The purpose of this study was to determine if there is a difference in long-term PE wear properties between YSZ and cobalt-chromium-molybdenum (Co-Cr-Mo) femoral heads. METHODS: Ten-year radiographic wear assessment was performed on a cohort of patients enrolled in a prospective randomized clinical trial comparing total hip arthroplasty with YSZ or Co-Cr-Mo femoral heads on conventional, non-cross-linked PE. RESULTS: PE linear wear, annualized wear, and steady-state wear rates remained low and similar between groups. No cases of osteolysis were observed. CONCLUSIONS: Measured conventional PE wear was similar between YSZ and Co-Cr-Mo femoral heads with the steady-state wear rates for both remaining below the generally accepted threshold at which osteolysis typically occurs. Whether clinically relevant phase transformation with YSZ femoral heads occurs is uncertain; however, the use of YSZ femoral heads in this study was not associated with increased PE wear, osteolysis, or deterioration of wear properties.
BACKGROUND: Concerns have arisen regarding deterioration of wear properties of yttria-stabilized zirconia (YSZ) femoral head on conventional polyethylene (PE) bearings due to YSZ phase transformation. QUESTIONS/PURPOSES: The purpose of this study was to determine if there is a difference in long-term PE wear properties between YSZ and cobalt-chromium-molybdenum (Co-Cr-Mo) femoral heads. METHODS: Ten-year radiographic wear assessment was performed on a cohort of patients enrolled in a prospective randomized clinical trial comparing total hip arthroplasty with YSZ or Co-Cr-Mo femoral heads on conventional, non-cross-linked PE. RESULTS: PE linear wear, annualized wear, and steady-state wear rates remained low and similar between groups. No cases of osteolysis were observed. CONCLUSIONS: Measured conventional PE wear was similar between YSZ and Co-Cr-Mo femoral heads with the steady-state wear rates for both remaining below the generally accepted threshold at which osteolysis typically occurs. Whether clinically relevant phase transformation with YSZ femoral heads occurs is uncertain; however, the use of YSZ femoral heads in this study was not associated with increased PE wear, osteolysis, or deterioration of wear properties.
Authors: John L Masonis; Robert B Bourne; Michael D Ries; Richard W McCalden; Abraham Salehi; David C Kelman Journal: J Arthroplasty Date: 2004-10 Impact factor: 4.757