Cementless femoral stem in arthroplasty for hip fracture: Early radiological subsidence at 3 months and predictive factor out of 117 cases.

INTRODUCTION

Femoral neck fractures in the elderly require immediate postoperative weight bearing to preserve autonomy. Cementless stems rely on primary stability with close cortical contact. However, perioperative fracture may occur, and secondary subsidence remains a concern. The primary objective of this study was to assess early subsidence of a cementless femoral stem. Secondary objectives were to identify predictive factors for subsidence, dislocation, and perioperative fracture.

MATERIAL AND

METHODS

We conducted a retrospective study in patients over 65 years of age who underwent systematic implantation of an uncemented Avenir-Müller® stem. Epidemiological and radiological data were collected at 6 weeks and 3 months postoperatively. Subsidence was measured relative to the greater trochanter and expressed both as an absolute value and as a categorical variable (<2 mm or ≥2 mm). Morphological risk factors included the Canal Flare Index (CFI), Metaphyseal-Diaphyseal Index (MDI), Cortical Thickness Index (CTI), and Cortical Bone Ratio (CBR10).

RESULTS

A total of 117 patients were evaluated, including 94 women, with a mean age of 83.1 years (range 65-103). Mean subsidence at 6 weeks was 1.1 ± 1.5 mm (median 0.6, range 0-9.1), and at 3 months 1.4 ± 1.6 mm (median 0.9, range 0-9.2). At 3 months, 22 patients (18.8%) had subsidence ≥ 2 mm. Dislocation occurred in 9 patients, with no association with subsidence ≥ 2 mm (p = 0.33). Five perioperative fractures were observed, with no identifiable predictive factor. No correlation was found between subsidence and preoperative autonomy (Rho = -0.2, p = 0.37) or surgeon experience (p = 0.66). A CTI ≤ 0.40 was predictive of subsidence (absolute value, p = 0.046; group ≥ 2 mm, p = 0.002).

CONCLUSION

Early subsidence of cementless stems in patients over 65 years of age undergoing hip arthroplasty for fracture is minimal. Severe osteoporosis, indicated by a CTI ≤ 0.40 on preoperative imaging, should prompt consideration of a cemented stem.

LEVEL OF EVIDENCE: IV; retrospective study.