A NOVEL TAPERED WEDGE STEM: MULTICENTRE CLINICAL OUTCOMES STUDY

Abstract

Introduction Cementless tapered wedge stems have shown excellent results over the last decade. Distal potting with inadequate proximal fit, as well as failure to achieve biologic fixation has led to thigh pain, loosening and implant failure. To support a variety of patient morphologies a novel tapered wedge stem was designed with reduced distal morphology, maximizing the proximal contact of the grit blasted surface. The objective of the study was to analyze the clinical outcomes of this stem design. Methods Three hundred and nineteen patients enrolled into prospective, post-market multicenter studies received a novel tapered wedge stem. Clinical and patient-reported outcomes including the Harris Hip Score (HHS), Lower Extremity Activity Scale (LEAS), Short Form 12 (SF12), and Euroqol 5D Score (EQ-5D) were evaluated preoperative through two years postoperative. Results Demographics of the study population include 53.3% male patients with a mean age of 62.4 ± 9.3 years and BMI of 29.8 ± 4.5. To date, there has been one incidence of thigh pain (0.3%) and a 0.63% aseptic revision rate. Kaplan-Meier survivorship analysis for the population at two years postoperative estimated 97.87% with 95% CI (93.98% – 99.25%) survivorship to all cause revision ( Figure 1 ). Statistically significant improvements in pain, function, and quality of life were seen initially at six weeks postoperative and continued through one year in all of the clinical and patient reported outcome measures ( Figure 2 ). Conclusion A novel tapered wedge stem was designed to maximize proximal fit medially and laterally across a variety of patient morphologies. Radiographic studies have shown the stem design has significantly better canal fit compared to older tapered wedge designs. The current study exhibits low incidence of thigh pain and revisions, with improvements in function, pain and quality of life after hip arthroplasty with this tapered wedge stem.