Mid-term results with a neck-preserving femoral stem for total hip arthroplasty

Abstract

Introduction: This prospective study aims to evaluate the mid-term clinical and radiological performance of a new short, neck-preserving femoral stem in total hip arthroplasty (THA). Patients and methods: 178 consecutive patients (190 hips) underwent THA from November 2008 to July 2016. Mean follow-up is 62.4 months. Women make up 41% of the cohort at a mean age of 50 ± 4 years, with primary hip osteoarthritis as the main complaint. All patients underwent radiological evaluation using the modified Gruen method, and clinical assessment via the Harris Hip Score (HHS), preoperatively and at 1, 6, 12, 24, 60, 80 and 106 months post-op. Results: A mean HHS increase (from 50 ± 12 points preoperatively to 96 ± 4 at 62 months), together with painless articular improvement, was present at 6 months postoperatively indicating early functional recovery. Effective osteointegration and primary stability were present on radiographic analysis, without evidence of stress shielding or stem mal-positioning: subsidence amounting to <1 mm was present in 40% of implants immediately after surgery, with subsequent stabilisation within 6 months in all cases. Metaphyseal trabecular re-orientation in absence of symptomatic cortical hypertrophy or progressive radiolucency indicates physiological load transfer in the proximal femur. Stem-related revision surgery was necessary for 1.05% of all implants due to fracture and infection. No loosening, dislocations or mechanical failures were reported. Conclusions: All patients show excellent functional recovery and clinical outcomes at 62 months, demonstrating the role optimal primary stability and physiological joint reconstruction play in ensuring stable secondary fixation and long-term survival of a short, neck-preserving stem.