Inverse relationship between femoral lateralization and neck-shaft angle is a joint event after intramedullary nailing of per trochanteric fractures

Abstract

This study explored the relationship between femoral lateralization and femoral neck-shaft angle after intramedullary nail (IM) fixation for per trochanteric fractures. 70 patients (AO/OTA 31A1-2) were investigated. Anteroposterior (AP) and lateral X-ray views pre- and post-operation were recorded. Patients were classified into three groups according to the position of the medial cortex of the head-neck fragment to that of the femoral shaft: being slightly superomedial (positive medial cortex support, PMCS), being smoothly contacted (neutral position, NP) or being displaced laterally (negative medial cortex support, NMCS). Patient demographics, femoral lateralization, and neck-shaft angle were measured and statistically analyzed pre- and post-operation. Functional recovery was evaluated by Harris score 3- and 6- months post-operation. All cases ultimately demonstrated radiographic fracture union. There was a tendency to have an increased neck-shaft angle (valgus alignment) in the PMCS group and increased femoral lateralization in the NP group (p < 0.05). Among those three groups, the change in femoral lateralization and neck-shaft angle was statistically different (p < 0.05). An inverse relationship between femoral lateralization and femoral neck-shaft angle was observed. Femoral lateralization increased correspondingly when the neck-shaft angle continuously decreased from the PMCS group to the NP group and then to the NMCS group, and patients in the PMCS group had better functional recovery than the other two groups (p < 0.05). Femoral lateralization was commonly produced after IM fixation for per trochanteric fractures. The fracture fixed in PMCS mode possesses the slightest change in femoral lateralization while maintaining valgus alignment of the femoral neck-shaft angle and good functional outcome, which is superior to NP or NMCS mode.

Anteromedial Cortical Support in Reduction of Trochanteric Hip Fractures

“…However, when compared with more critical outcomes such as screw cut-out, morbidity, and mortality, the clinical importance of these differences was relatively modest. Cho et al 35 and Fang et al 18 reported similar results. Furthermore, in a retrospective review of 92 patients, Kristan et al 19 and Li et al 20 found that 16 (35%) of 46 patients with intraoperative neutral MCS transitioned to negative MCS at the 6-month postoperative follow-up, whereas this occurrence was found in only 2 (9%) of 23 patients with intraoperative positive MCS (p = 0.022).…”

“…However, on a global scale, there exists some ambiguity with regard to the precise definition and application of the AMCS types, such as the misidentification of negative reduction as neutral reduction 17 . Moreover, increasing evidence has raised uncertainty with regard to the effectiveness of neutral medial cortical support (MCS), an aspect that has been previously overlooked 18-20 . Therefore, this article aims to distill the AMCS concept from definition to application.…”