Incidence of Rotational Malalignment after Intertrochanteric Fracture Intramedullary Nailing: A CT-Based Prospective Study.

ABSTRACT

Background and Objectives: Rotational malformation after intramedullary nailing of intertrochanteric fractures is a relatively common, possibly severe, and difficult-to-detect complication, since intraoperative radiographic imaging allows for the assessment of the quality of reduction in the frontal and sagittal planes, but not in the transverse plane. The purpose of this study is to evaluate the rotational malalignment after intramedullary nailing of intertrochanteric fractures and to investigate a possible connection with specific patients' or fractures' characteristics. Materials and Methods: 74 patients treated with intramedullary nailing due to an intertrochanteric fracture underwent a postoperative CT of the pelvis-hips and knees. The value of the anteversion was measured both in the operated-on (angle 1) and in the healthy hip (angle 2) based on the technique described by Jeanmart et al. and the difference in anteversion (D angle = angle 1 minus angle 2) was calculated. A positive D angle indicated the presence of excessive internal overcorrection of the distal fragment during fracture reduction, while a negative D angle indicated the presence of excessive external overcorrection. The absolute value of the D angle represents the postoperative difference in anteversion between the two hips. The patients were divided into three groups according to this value group A, with D < 5° (physiological difference); group B, with 5° < D < 15° (acceptable rotational alignment); and group C, with D ≥ 15° (rotational deformity). Results: Group A constitutes 56.8%, group B 12.2%, and group C 31.1% of the study population. Overall, 79.7% of the patients presented a positive angle D, while, for group C, the percentage was even higher at 91.3%. According to the AO/OTA classification system, 37.8% of the cases were stable fractures, 47.3% were unstable fractures, and 14.9% were reverse oblique fractures. Based on our analysis, the type of fracture has a serious impact on the rotational alignment, since the statistical significance of the mean angle D for the three types of fracture is reliable (p = 0.029). Stable fractures present the lowest anteversion difference values, while reverse oblique fractures present the highest difference. Conclusions: Our study reveals that the percentage of rotational malalignment after the intramedullary nailing of intertrochanteric fractures remains high (31.1%), despite the proper use of radiographic imaging during the intraoperative fracture reduction. In most cases (91.3%), this malalignment appears to be a matter of internal overcorrection. A clear correlation between hip's rotational deformity and patients' functional outcome has yet to be proven, and constitutes our objective in the near future.