RM Pressfit vitamys: the 10-year follow-up

Abstract

Introduction: The RM Pressfit vitamys is an uncemented, titanium particle-coated, isoelastic monoblock cup made of vitamin E blended highly cross-linked polyethylene. We addressed the following questions: (1) What are the clinical and (2) radiographic outcomes 10 years after implantation? (3) What is the revision rate?

Methods: In this prospective observational study in a tertiary care centre we investigated all consecutive cases of total hip replacement with the RM Pressfit vitamys cup between September 2009 and November 2011. It was implanted in 162 hips, 49.4% in women. The mean age was 67.2 years (standard deviation [SD] 9.5), and the mean BMI was 27.3 kg/m² (SD 4.7). In 153 cases (94.4%), primary or secondary osteoarthritis was the diagnosis. We evaluated preoperative and follow-up data at 6 weeks, 1, 5, and 10 years. A modified Harris Hip Score (mHHS), pain and satisfaction on a visual analogue scale (VAS), radiographic evaluation, complications and revision rate were investigated.

Results: At the 10-year follow-up (mean 120.5 months, SD 1.4, range 118-126), 99 hips were available for clinical and radiographic evaluation. (1) The mean mHHS was 94.8 (SD 9.9), rest pain 0.2 (SD 0.6), load pain 0.5 (SD 1.5), and satisfaction 9.5 (SD 1.1). The mean improvement as compared to preoperatively was +33.7 (SD 16.8), -3.3 (SD 2.7), -6.0 (SD 2.4) and +5.7 (SD 2.5), respectively. (2) In the radiographic evaluation, no loose cups, no acetabular lucent lines, or acetabular osteolysis were seen. (3) 2 cups were revised, both due to malpositioning. The 10-year cumulative revision rate was 2.0% (95%CI, 0.0-4.2%). The implant survival rate with aseptic loosening as endpoint was 100%. No adverse events were reported.

Conclusions: At the 10-year follow-up, the RM Pressfit vitamys cup still had promising results with good clinical and radiographic outcomes and a low revision rate.

Keywords: 10-year follow-up; Acetabular cup; RM Pressfit vitamys; highly cross-linked polyethylene (HXLPE); isoelastic uncemented monoblock cup; radiographic/clinical outcomes; revision rate; survival; total hip arthroplasty; vitamin E.