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
Abstract BackgroundThe newest generation of cementless titanium coated, isoelastic monoblock cup with vitamin E-blended highly cross-linked polyethylene (HXLPE) has been introduced to the market in 2009. Aim of the present study was to obtain mid-term data including the analyses of migration and wear.MethodsThe present prospective study investigated 101 primary total hip arthroplasty (THA) cases in 96 patients at a single institution. Patients were allowed full weight-bearing on the first day postoperatively. Harris hip score (HHS) as well as pain and satisfication on visual analogue scale (VAS) were assessed during a mean follow-up of 79.0 months. Migration and wear were assessed using Einzel-Bild-Roentgen-Analyse (EBRA) software. Additionally, radiological alterations in the acetabular bone and complications were documented.ResultsAt mid-term follow-up (mean 79.0 months (range: 51.8 – 101.7)), 81 cases with complete clinical and radiological data were analyzed. In 42 hips utilisable EBRA measurements were obtained. HHS was 91.1 (range 38.0 – 100.0), satisfaction on VAS was 9.6 (range 6.0 – 10.0), rest pain on VAS was 0.2 (range 0.0 – 4.0), and load pain on VAS was 0.6 (range 0.0 – 9.0). Mean migration was 0.86 mm (range: 0.0 – 2.56) at 24 months and 1.34 mm (range: 0.09 – 3.14) at 5 years. Mean annual migration rate was 0.22 (range: -0.24 – 1.34). Mean total wear was 0.4 mm (range: 0.03 – 1.0). The mean annual wear rate was 0.06 mm per year (range: 0.0 – 0.17). Radiographic analysis showed osteolysis in none of the cases and no revision surgeries had to be performed.ConclusionUsing vitamin-E blended HXLPE in cementless isoelastic monoblock cups, no signs of osteolysis were obvious and no cases of aseptic loosening occurred. There was no need of revision surgery at mid-term. Values for cup migration and wear stay well below the benchmarks which are considered predictive for potential future failure.Trial registrationThe trial registration number on ClinicalTrial.gov: NCT04322916 (retrospectively registered at 26.03.2020).