Intrapelvic migration of a gamma nail lag screw: review of the possible mechanisms.

Abstract

This article presents a case of intrapelvic migration of a Gamma nail lag screw (Stryker, Mahwah, New Jersey) in an 82-year-old woman 7 months after fixation of an unstable pertrochanteric fracture. Two of the most common complications associated with the use of the Gamma nail and other sliding intramedullary devices, as well as lag screw and side plate devices, relate to the lag screw: cut out and medial migration in the femoral head. As compared to lag screw migration in the femoral head, intrapelvic migration of the Gamma lag screw is a rare complication. To our knowledge, intra-pelvic migration after disengagement of the lag screw from the Gamma nail has been reported in the literature only 3 times. Several risk factors can be associated with Gamma nail failure, most importantly damage to femoral head leading to lag screw migration, plate/lag or nail/lag screw interface dysfunction, technical mistakes, and additional subsequent trauma. This article reviews the literature and the theories for such device failures.