Intramedullary Impaction of the Basicervical Component is Determinant of Fixation Failure in a Simple Two-Part Pertrochanteric Fracture

Abstract

Objectives: To evaluate initial fracture morphology influences on outcomes in simple two-part pertrochanteric fracture, with a focus on the basicervical component and its initial impaction. Methods: Design: A retrospective cohort series Setting: Single Level I Trauma Center Patients Selection Criteria: Patients over 60 years of age with intertrochanteric fractures between 2011 and 2022 were retrospectively reviewed. Inclusion criteria comprised simple two-part pertrochanteric fractures (OTA/AO 31-A1.2) with a basicervical component who underwent cephalomedullary nailing and had a minimum follow-up of 6 months. Patients were divided whether the basicervical component was impacted into the medullary canal (intramedullary impaction (II) group) or displaced beyond the medullary canal (extramedullary (E) group). Exclusion criteria encompassed pathologic fractures, nondisplaced fractures, and basicervical neck fractures (OTA/AO 31-B3). Outcome Measurements and Comparisons: Reduction status was assessed as unacceptable if the head and neck (proximal) fragment was positioned intramedullary with respect to the distal fragment in either the AP or cross-lateral X-ray, and acceptable otherwise. Also, the degree of impaction on X-ray and CT scans (coronal, sagittal, axial) at injury were analyzed as a risk factor for failure. Revision rates and lag screw sliding over 15mm were compared between the II and E groups. Results: 115 patients (95 female, average age 80 years) were included. The II group (n=58) compared to E group (n=57) showed more acceptable postoperative reductions (57% vs 81%, p=0.001), but significantly higher fixation failure (16% vs. 3.5%, p=0.048) and fracture collapse (28% vs. 7%, p=0.01). Intramedullary impaction was identified as a significant independent predictor for failure (OR 5.64, 95% CI 2.14-16.9, p<0.001) with more than 19.5mm impaction in sagittal CT scan as the threshold linked to increased failure risk. Conclusion: The current study highlights the significance of specific intertrochanteric fracture patterns, particularly intramedullary impaction of a basicervical component and impaction severity (≥19.5mm), as drivers of fixation failure.