Total Hip Arthroplasty with the Conservative Cementless MINIMA Size 1 Stem in Patients with a Small Femoral Canal: 3–6 Years of Follow-Up

TL;DR

This study shows that a small, cementless hip implant works well in patients with narrow femurs, providing excellent results over 3–6 years.

Contribution

The study provides long-term clinical and radiological evidence for using the size 1 Minima stem in patients with a narrow femoral canal.

Findings

The Harris Hip Score improved significantly from 38.3 preoperatively to 96.4 post-surgery.

Initial stem migration occurred in 11.1% of cases but did not progress or cause loosening.

Clinical and radiological implant survival was 100% at the final follow-up.

Abstract

Background: The objective of this study was to evaluate the short-term clinical and radiological outcomes of a conservative cementless stem (Minima) in total hip arthroplasty (THA) for patients presenting with a narrow femoral canal. Methods: We retrospectively analyzed 18 patients (18 THAs) who received a size 1 Minima stem between 2018 and 2022. Clinical assessment was performed using the Harris Hip Score (HHS). Radiological evaluation focused on stem migration, trabecular bone development, cortical hypertrophy, and the presence of radiolucent or reactive lines. Implant survival was determined using Kaplan–Meier analysis. Results: The mean patient age was 51.6 years, with an average follow-up of 57 months. The mean HHS improved significantly from 38.3 preoperatively to 96.4 at the final evaluation (p < 0.001). Initial stem migration occurred in two hips (11.1%) within the first 6 postoperative months, with no further progression or loosening observed thereafter. Bony trabecular development was identified in Gruen zones 3 (27.8%), 4 (5.5%), and 5 (16.7%). Reactive lines were present around four stems (zones 3–5). One intraoperative complication (5.5%) occurred (acetabular component migration during trial reduction), which required screw fixation. No revisions were performed. Both clinical and radiological implant survival at the final follow-up was 100.0%. Conclusions: At a mean follow-up of 57 months, the use of the size 1 Minima stem in patients with a narrow femoral canal demonstrated excellent clinical and radiological outcomes. These findings suggest that this conservative stem is a reliable option for this specific patient population.

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