Are Two-Part Intertrochanteric Femur Fractures Stable and Does Stability Depend on Fixation Method?

Abstract

Objectives: To determine stability of 2-part intertrochanteric femur fractures and to determine whether secondary collapse is related to fixation method.

Design: A retrospective cohort series.

Setting: Single Level I Trauma Center.

Patients: One hundred fourteen patients (82 female) older than 50 years (average age 75 years, range 50-100 years) with an acute low-energy standard obliquity 2-part intertrochanteric femur fracture (OTA/AO 31A) identified from an orthopaedic trauma database were studied.

Intervention: Twenty-three patients were treated with a sliding hip screw (dynamic hip screw [DHS]), 53 with a dual screw trochanteric entry nail (INTERTAN), and 38 with a single-blade or screw trochanteric entry intramedullary nail (trochanteric fixation nail [TFN]) based on surgeon choice by 4 fellowship-trained orthopaedic trauma surgeons.

Main outcome measures: Fracture collapse was measured by comparing immediate postoperative radiographs to those at final follow-up while controlling for magnification and rotation.

Results: Collapse averaged 6.8 mm in the DHS group, 3.7 mm in the INTERTAN group, and 7.3 mm in the TFN group. When comparing groups, there was significantly more collapse in the DHS group compared with the INTERTAN group (P = 0.021), and significantly more collapse in the TFN group compared with the INTERTAN group (P < 0.001). Six patients (26%) in the DHS group had >10-mm collapse including 4 (17%) with greater than 20-mm collapse (max = 34.2 mm). Four patients (8%) in the INTERTAN group had >10-mm collapse and none had greater than 12.9 mm. Ten patients (26%) in the TFN group had >10-mm collapse and 3 (5%) had greater than 20-mm collapse (max = 30.7 mm).

Conclusion: Stability of 2-part intertrochanteric femur fractures is dependent on the fixation device. These fractures are not necessarily stable when treated with a sliding hip screw as 26% treated with this method collapsed greater than 10 mm and 17% more than 20 mm. Dual screw intramedullary nail fixation seems to be most effective to maintain stability for patients with this fracture pattern.

Level of evidence: Prognostic Level III. See Instructions for Authors for a complete description of levels of evidence.