Long-term performance of oxidized zirconium on conventional and highly cross-linked polyethylene in total hip arthroplasty

Abstract

Introduction: Polyethylene wear and subsequent osteolysis remain obstacles to the long-term survivorship of total hip arthroplasty (THA). Highly cross-linked polyethylene (XLPE) with radical quenching represents a massive leap forward with dramatically improved wear rates compared to ultra-high molecular weight polyethylene (UHMWPE). In this study we evaluate the wear of UHMWPE and XLPE coupled with oxidized zirconium (OxZr) femoral heads. Methods: A longitudinal, retrospective analysis was performed identifying consecutive patients who received a 28-mm OxZr-on-polyethylene primary THA from 2003 to 2004 by a single, high-volume arthroplasty surgeon. Patients were divided into two groups: those that received (1) UHMWPE liner and (2) a highly XLPE liner. Patients were included if clinical follow-up was complete to 2014 or later. Radiographic analysis was performed by two blinded observers. Measures included cup position, annual linear wear rate, and presence of osteolysis. Pairwise comparisons, correlations, and inter-rater reliability were calculated. Results: Eighty patients were in the UHMWPE group with an average follow-up of 10 ± 1.23 years and 88 patients in the XLPE group with an average of 10 ± 1.03-year follow-up. Average age (68) was similar between groups (p = 0.288). Observer reliability was excellent for cup abduction (ICC = 0.940), anteversion (ICC = 0.942), and detection of osteolysis (ICC = 0.811). Annual linear wear rates were significantly higher (p = 1 × 10−19) with UHMWPE (0.21 ± 0.12 mm/year) compared to XLPE (0.05 ± 0.03 mm/year). Linear wear rate was significantly correlated to decreasing acetabular abduction (p = 0.035). Osteolysis was noted only in the UHMWPE group, with 17 patients (21.2%) exhibiting acetabular osteolysis and 37 (46.3%) patients exhibiting femoral osteolysis. Conclusions: OxZr coupled with XLPE showed minimal wear and no osteolysis at 10-year follow up. The yearly linear penetration rate is similar to that seen in other studies of XLPE THA. A careful longitudinal follow-up will be required to determine if advanced bearings such as OxZr or ceramic can show improved performance in the second decade of implantation.

Hip Instability Leading to Metallosis, Polyethylene Wear, and Failure of an Oxinium Femoral Head: A Case Report and Review of Literature

“…Despite the fact that many studies have proven in vivo mid-and long-term efficacy of OFH in total hip arthroplasty in reducing linear and volumetric wear and osteolysis, [3][4][5]17 with even reduced polyethylene wear 8 in vitro; this may be not the case if any surface damage occurs to OFH, especially after dislocation/reduction when contact with the metal cup may occur. During the primary surgery, if an OFH is planned for use, careful component alignment and insertion procedure should be utilized, and vigilant reduction technique should be used to avoid any surface damage to the femoral head.…”

Oxidized zirconium versus cobalt-chrome femoral heads in total hip arthroplasty: a multicentre prospective randomized controlled trial with ten years’ follow-up

“…The current study found mean wear rates for XLPE were towards the more favourable end of the range of 0.02 mm/year to 0.07 mm/year wear rates in previous studies. 4,7,10,13,22-24–31-35 This may be attributable to our study using first-year radiographs as reference films to allow for creep deformation, excluding patients undergoing revision surgery from the final wear analysis, and using a standardized surgical technique in all patients to limit confounders such as acetabular component design, polyethylene geometry, femoral head diameter, femoral head geometry, and stem design. Roedel et al 4 reviewed outcomes in 87 patients aged under 50 years undergoing THA with XLPE, and reported that the mean polyethylene liner wear rate was 0.04 mm/year at 15 years’ follow-up.…”

“…Since then, several other laboratory-based studies and clinical trials have reported on the wear characteristics of these bearing surfaces, but there remains a paucity of prospective RCTs reporting on validated clinical outcomes, polyethylene wear rates, and risk of osteolysis with long-term follow-up. 3,4,13,21-24…”

Highly Crosslinked Polyethylene Liners Have Negligible Wear at 10 Years: A Radiostereometric Analysis Study

“…We are not aware of other RSA studies that have compared the wear rate of XLPE between the initial 5-year period and the subsequent 5 years, when oxidation and mechanical change could affect wear rates. NonRSA studies demonstrated sustained low wear rates beyond 10 years and a continued absence of wear-induced lysis [2,13,23,31], but lacked the sensitivity to compare wear rates over time. Our RSA wear measurements demonstrated a stable wear pattern with no evidence of increasing wear after 5 years in situ, and we found that no individual exceeded 0.025 mm/year proximal wear in either the first or second 5-year periods.…”