2-year results of an RCT of 2 uncemented isoelastic monoblock acetabular components: lower wear rate with vitamin E blended highly cross-linked polyethylene compared to ultra-high molecular weight polyethylene

Abstract

Background and purpose — The long-term survival of arthroplasty components may be limited by polyethylene wear-related problems such as periprosthetic osteolysis and aseptic loosening. Highly cross-linked polyethylene (HXLPE) blended with vitamin E was introduced to improve oxidative stability and to avoid long-term embrittlement. This study clinically compares the tribological behavior and clinical outcome of vitamin E blended HXLPE with ultra-high molecular weight polyethylene (UHMWPE) in an isoelastic monoblock cup for uncemented total hip arthroplasty. Patients and methods — In this randomized controlled trial (RCT), 199 patients were included: 102 patients received the vitamin E blended HXLPE cup, 97 patients the UHMWPE cup. Clinical and radiographic parameters were obtained preoperatively, directly postoperative and at 3, 12, and 24 months. Wear rates were compared using the mean linear femoral head penetration (FHP) rate. Results — 188 patients (94%) completed the 2-year follow-up. Mean patient satisfaction was higher in the vitamin E blended HXLPE group (8.9 [1]) than in in the control group (8.5 [2], p = 0.03). The Harris Hip Score (HHS) was higher in the vitamin E blended HXLPE group (95 [8]) than in the control group (92 [11], p = 0.3). The FHP rate was lower in the vitamin E blended HXLPE group: 0.046 mm/year compared with 0.056 mm/year in the control group (p = 0.05). No adverse reactions associated with the clinical application of vitamin E blended HXLPE were observed during follow-up, with an excellent 2-year survival to revision rate of 98% for both cups. Interpretation — This study shows the superior performance of the HXLPE blended with vitamin E acetabular cup with lower linear femoral head penetration rates and better clinical results compared with the UHMWPE acetabular cup after 2 years.

The concept of a cementless isoelastic monoblock cup made of highly cross-linked polyethylene infused with vitamin E: Radiological analyses of migration and wear using EBRA and clinical outcomes at mid-term follow-up

“…These results were again con rmed in a recent randomized-controlled trial comparing annual wear rates of the RM Press t cup (UHMWPE) to those of the RM Press t vitamys cup (HXLPE/VitE). At 2 years [36] and 6 years [37], the wear rates were signi cantly lower for the HXLPE/VitE cup.…”

The concept of a cementless isoelastic monoblock cup made of highly cross-linked polyethylene infused with vitamin E: Radiological analyses of migration and wear using EBRA and clinical outcomes at mid-term follow-up

“…These results have been con rmed by a very recent randomized-controlled trial, again, comparing annual wear rates of the RM Press t cup (UHMWPE) to those of the RM Press t vitamys cup (HXLPE/VitE). At two years [36], as well as at 6 years [37] wear rates were signi cantly lower for the HXLPE/VitE cup than those for the UHMWPE cup.…”

Heterotopic ossification in primary total hip arthroplasty using the posterolateral compared to the direct lateral approach

“…An uncemented hydroxyapatite coated stem (Twinsys, Mathys Ltd, Bettlach, Switzerland) was implanted in all cases. All patients received an uncemented vitamin E blended HXLPE cup (RM uncemented monoblock pressfit Vitamys ® cup, Mathys Ltd, Bettlach, Switzerland) or a UHMWPE cup (RM uncemented monoblock pressfit ® , Mathys Ltd, Bettlach, Switzerland) [ 15 , 17 ]. No pulse lavage was used.…”