Femoral malrotation after intramedullary nailing in obese versus non-obese patients

Abstract

Objective: Intramedullary nailing (IMN) of obese patients with femoral fractures can be difficult due to soft tissue considerations and overall body habitus. Complications including malrotation can occur and have significant impact on postoperative function. The purpose of this study was to evaluate femoral rotation after intramedullary nailing of obese and non-obese patients to see if there was a difference in rotation, complications and any risk factors for malrotation.

Materials and methods: Between 2000 and 2009, 417 consecutive patients with femur fractures treated with IM nail at Level I trauma and tertiary referral center. Of these, 335 with postoperative computed tomography (CT) scanogram of the bilateral lower extremities were included in this study. Baseline demographic, perioperative and postoperative femoral version calculations were included in the dataset. Statistical analysis included chi-squared test for categorical data, t-test for continuous data, and univariate and multivariate regression analysis. Significance was set at p<0.05.

Results: Of the 417 patients with femur fractures between 2000 and 2009, 335 met criteria for this study. There were 111 patients with a BMI <25, 129 with BMI 25-29.9, and 95 patients with a BMI >30. When BMI was categorised into 3 groups (<25, 25-29.9, or 30+), none of these groups were predictive of version in univariate or multivariate regressions. Among only obese patients (BMI 30+), BMI of 35+ was not a significant predictor of version when compared to BMI 30-34.9. There were no significant differences in femoral version based on entry point (antegrade vs. retrograde) in any BMI category. There were also no significant difference between groups of patients with a DFV of >15̊ (p=0.212).

Conclusions: Based on this study, BMI did not have an effect on postoperative difference in femoral version. In fact, in our multivariate regression analysis, BMI of over 30 was actually predictive of significantly lower difference in femoral version. While other studies have documented the intraoperative difficulties encountered with obese patients with femur fractures, the outcome of femoral rotation is not affected by an increasing BMI.

Keywords: BMI; Femoral version; Intramedullary nail; Obesity; Outcomes level of evidence: Level III prognostic.