Total hip arthroplasty using highly cross-linked polyethylene in patients aged 50 years and younger

Abstract

Aims Highly cross-linked polyethylene (HXLPE) has greatly improved the durability of total hip arthroplasty (THA) in young patients because of its improved wear characteristics. Few studies have followed this population into the second decade, and therefore the purpose of this investigation was to evaluate the clinical outcome for THA patients 50 years of age and younger at a minimum of 15 years postoperatively. The second purpose was to evaluate the radiological findings secondary to wear or mechanical failure of the implant. Methods Between October 1999 and December 2005, 105 THAs were performed in 95 patients (53 female, 42 male) aged 50 years and younger (mean 42 years (20 to 50)). There were 87 patients (96 hips) that were followed for a minimum of 15 years (mean 17.3 years (15 to 21)) for analysis. Posterior approach was used with cementless fixation with a median head size of 28 mm. HXLPE was the acetabular bearing for all hips. Radiographs were evaluated for polyethylene wear, radiolucent lines, and osteolysis. Results Clinical outcomes showed significant improvement of mean Harris Hip Scores from 52.8 (SD 13.5) preoperatively to 94.8 (SD 7.6) postoperatively. One hip was revised for recurrent instability, and there were no infections. No hips were revised for mechanical loosening or osteolysis. Mean polyethylene linear wear was 0.04 mm/year and volumetric wear was 6.22 mm3/year, with no significant differences between head size or material. Osteolysis was not present in any of the hips. Conclusion The use of HXLPE in THA for patients aged 50 years and younger has performed exceptionally well without evidence of significant wear causing mechanical loosening or necessitating revision. The radiolucent lines of the acetabular component must be followed to determine the prognostic significance. This investigation represents the longest clinical follow-up of a large, consecutive cohort of patients aged 50 years or younger with THA using HXLPE. This long-term analysis found negligible polyethylene wear, no incidence of aseptic loosening, and excellent clinical outcomes at and beyond 15 years of follow-up. Cite this article: Bone Joint J 2021;103-B(7 Supple B):78–83.

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.…”

“…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. The higher wear rates may be attributable to the study having a younger and more active cohort of patients, implantation of different femoral head sizes, and longer follow-up times compared to our study.…”

“…This study supports the growing body of evidence for the low long-term wear rates and safe use of XLPE in THA. 3,4,7,9,13,23,24,31,33-35 Previous concerns with OxZr relating to surface scratching, changes in wear properties with in vitro loading, or the bioactivity of particulate debris, were not observed (either because they were not present or remained subclinical), with no additional risk of complications compared with CoCr. 39,40 Hip articulations combining both OxZr and CoCr femoral heads with XLPE produced comparable wear rates, which were within the reported threshold of 0.1 mm/year for osteolysis, at all time intervals at ten years after THA.…”

“…3 This promotes a localized inflammatory response, leading to periprosthetic osteolysis, and subsequent implant loosening. 4 The effects of polyethylene liner wear are worse in younger patients, presumably due to their higher activity levels and longer life expectancy. 1,4 In patients aged under 50 years undergoing THA with conventional polyethylene, osteolysis occurs in 50% to 60% of cases, and implant survival is approximately 83% at ten 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…”