Is Mid-head Resection a Durable Conservative Option in the Presence of Poor Femoral Bone Quality and Distorted Anatomy?

Abstract

High medium-term survivorship of hip resurfacing arthroplasty in young patients has led to its increased usage. To achieve high survival rates, selecting patients with appropriate proximal femoral morphology and bone quality is important. For patients with poor bone quality or abnormal morphology, the mid-head resection technique is an alternative, bone-conserving procedure but whether this technique results in acceptable complications and survival is unknown. We therefore assessed (1) implant survivorship of a mid-head resection device during short- and medium-term followup, (2) hip function, (3) adverse radiographic features emphasizing proximal stress shielding, and (4) complications. We retrospectively reviewed 164 patients (171 hips) who underwent reconstruction with the Birmingham Mid-Head Resection device (Smith and Nephew Orthopaedics Ltd, Warwick, UK) between 2003 and 2008. Patients were reviewed with hip outcome questionnaires, clinical examination, and radiographs. We report findings in 156 of these 171 hips with a minimum followup of 2 years (mean, 3.5 years, range, 2-7.5 years). They include three successive iterations based on the same design rationale. There were four revisions during this period, including two femoral failures, giving 3.5-year survivorships of 97.4% and 98.7% with revision or reoperation for any reason and femoral failure as the end points, respectively. No patient is currently awaiting revision. Average hip function was 98%, as assessed by Oxford hip score. Five of the 87 intermediate-iteration (V1) stems showed proximal femoral stress shielding, a phenomenon not observed in the other two iterations. Four patients had asymptomatic below-knee deep venous thrombosis and one had nonfatal pulmonary embolism, all of which resolved uneventfully. The mid-head resection technique can circumvent the need for a more invasive procedure such as standard THA in patients who would benefit from a conservative arthroplasty but do not possess good femoral head bone quality or morphology.