Locking in trochanteric fractures: a comparison of static versus dynamic locking using the Gamma3 nail.

Abstract

The Gamma3 nail (Stryker®) is an intramedullary device consisting of a proximal lag screw and distal interlocking screw. It is still unknown whether the screw locking mode could influence clinical outcomes. The aim of this study is to compare static and dynamic screw locking regarding their influence on surgical revisions and lag screw displacement. A retrospective single-centre study was performed on patients ≥ 60 years admitted for a trochanteric fracture between September 2016 and January 2020. Surgical revisions and lag screw displacement were evaluated at 6 weeks and 1-year follow-up, respectively. A total of 142 patients were included for analysis. Surgical revisions were needed in 13 cases (9.2%). Indications included implant breakage (n = 3), lag screw cut-out (n = 3), lateral hip pain (n = 6) and non-union (n = 1). The number of surgical revisions was not different between static and dynamic locking (OR 2.55; 95%CI 0.73-8.56; p 0.142). The median lag screw displacement was 2.5 mm, which was similar for static and dynamic locking (2.3 mm versus 2.7 mm; p 0.785). The screw locking mode of the Gamma3 nail is not associated with a higher risk of surgical revisions. However, the design of the Gamma3 nail may not be suitable for static locking.