Clinical and radiological outcomes of an uncemented metaphyseal short stem at minimum 10 years of follow-up: a prospective observational study

Purpose: There is growing interest around short stems as they provide a less invasive approach for total hip arthroplasty preserving bone stock for a possible revision surgery if required. The main purpose of this work was to assess the long-term performance of an uncemented metaphyseal short stem in terms of survival rate and in addition its clinical and radiological outcomes. Materials and methods: From January to December 2010, we prospectively enrolled all consecutive patients undergoing primary total hip arthroplasty with an uncemented metaphyseal short stem in our institution with a minimum follow-up of 10 years. The radiographic features investigated were the varus-valgus stem orientation, areas of osteolysis and radiolucencies, stress shielding, and heterotopic calcifications. The clinical outcomes were measured using the HHS. Results: A total of 163 patients (172 hips) were finally included and the measured survival rate at 10 years was 99.6%. The average HHS increased from 55.0 preoperatively to 97.8 at the last follow-up (p < 0.0001). Among them, 137 patients (164 hips) were also available for radiographic assessment. Mild varus malalignment was observed in 40% of cases and remained stable in the serial X-rays and was not associated with step loosening. Mild stress shielding was observed around 13 stems (9%) and moderate only around 3 implants. Conclusion: In conclusion, the uncemented metaphyseal short stems showed excellent survival and clinical results at 10 years and at a radiographical level very low stress shielding was observed; moreover, besides the high frequency of varus alignment the implanted stems was not associated with revision surgery or with worse clinical outcomes.