Background: Reoperations after intertrochanteric fractures are often necessitated by fracture displacement following mobilization of the patient. The biomechanical complexity of the fracture, the position of the implant, and the patient's characteristics are known to influence postoperative outcome. We investigated the importance of an intact lateral femoral wall as a factor in postoperative fracture displacement after fixation with a sliding compression hip screw.
Methods: Two hundred and fourteen consecutive patients with an intertrochanteric fracture were treated with a 135° sliding compression hip screw with a four-hole side-plate between 2002 and 2004. The fractures were classified on preoperative radiographs according to the AO/OTA classification system. The status of the greater and lesser trochanters, the integrity of the lateral femoral wall, and the position of the implant were assessed postoperatively. Reoperations due to technical failure were recorded for six months postoperatively.
Results: Only 3% (five) of 168 patients with an intact lateral femoral wall postoperatively underwent a reoperation within six months, whereas 22% (ten) of forty-six patients with a fractured lateral femoral wall were operated on again (p < 0.001). Multivariate logistic regression analyses combining demographic and biomechanical parameters showed a compromised lateral femoral wall to be a significant predictor of a reoperation (p = 0.010). Seventy-four percent (thirty-four) of the forty-six fractures of the lateral femoral wall occurred during the operative procedure itself. A fracture of the lateral femoral wall occurred in only 3% (three) of the 103 patients with an AO/OTA type-31-A1.1, A1.2, A1.3, or A2.1 intertrochanteric fracture compared with 31% (thirty-one) of the ninety-nine with an AO/OTA type 31-A2.2 or A2.3 fracture (p < 0.001).
Conclusions: A postoperative fracture of the lateral femoral wall was found to be the main predictor for a reoperation after an intertrochanteric fracture. Consequently, we concluded that patients with preoperative or intraoperative fracture of the lateral femoral wall are not treated adequately with a sliding compression hip-screw device, and intertrochanteric fractures should therefore be classified according to the integrity of the lateral femoral wall, especially in randomized trials comparing fracture implants.
Level of Evidence: Prognostic Level II. See Instructions to Authors for a complete description of levels of evidence.