Assessment of Coronal Plane Malalignment Following Reduction of Trochanteric Fractures-Simple Intraoperative Guideline Using Greater Trochanter Orthogonal Line

ABSTRACT

PURPOSE: There is no consensus on a clear intraoperative guideline for judging the coronal plane alignment following reduction of trochanteric fractures. Complex angular measurements using fluoroscope monitors are tedious. Therefore the relation of the horizontal line from the tip of the greater trochanter (GT orthogonal) and femur head center (HC orthogonal) was studied to define this line as a criterion for predicting varus-valgus malalignment. MATERIALS AND METHODS: We studied this relation in 200 standing orthoradiograms which included 100 males and 100 females. The images were digitally analyzed using the picture archiving and communication system. GT orthogonal line and HC orthogonal line were evaluated. The distance of these lines was measured as trochanter center distance (TCD) and its correlation with angular parameters like neck shaft angle, medial proximal femoral angle with reference to anatomical axis (aMPFA) and lateral proximal femoral angle with reference to mechanical axis (mLPFA) were analyzed. RESULTS: In all patients, the GT orthogonal line passed either at or above the center of the head. Overall mean of TCD was 7.22 mm, ranging from 0 to 17.57 mm. TCD was found to show strong correlation with angular parameters like aMPFA, mLPFA and neck shaft angle. TCD was less than one fourth of the corresponding head diameter in around 90%. Therefore following reduction of trochanteric fractures, the GT orthogonal line should pass through the superior juxta central quadrant of the femoral head. CONCLUSION: This line can be represented by a guide wire with fluoroscopy during surgery. The GT orthogonal line can be used intraoperatively as a simplified tool for prediction of varus/valgus malalignment following the reduction of trochanteric fractures.