Is a Total Hip Arthroplasty Stem in Varus a Risk Factor of Long-Term Mechanical Complication?

Abstract

Background: The impact of implanting cementless femoral stems in varus alignment on long-term mechanical complications remains poorly defined in the literature. The aim of our study was to compare survivorship and functional and radiographic outcomes of stems in varus alignment to those in neutral alignment with and average follow-up of 10 years.

Methods: This single-center, multisurgeon, retrospective case-control study compared a group of 105 total hip arthroplasty (THA) patients who had varus stem alignment (Varus Stem) to a matching group of 105 THA patients who had neutral stem alignment, operated on between January 2007 and December 2012. The primary outcome measure was implant survival. Secondary outcomes included functional (Harris Hip Score, Postel Merle d'Aubigné Score, thigh pain, dislocation and hip range of motion) and radiographic outcomes (radiolucency, osseointegration, heterotopic ossification, subsidence, and stress shielding).

Results: There was no significant difference in implant survival between the 2 groups with 95.7% (±2.46) in the Varus Stem group versus 97.7% (±1.64) in the Neutral Stem group (P = .41) after an average follow-up of 10 years. There was no significant difference in clinical and radiographic outcomes between groups.

Conclusion: Cementless femoral stems in varus alignment were not the cause of mechanical complications with an average follow-up of 10 years. The comparison between groups in terms of implant survival, functional, and radiographic outcomes does not show any significant differences. Positioning a femoral stem in varus alignment may be an alternative for surgeons wishing to restore preoperative offset and to ensure satisfactory hip stability.

Keywords: THA; comparative study; failure; mechanical complication; survival rate; varus stem.