Comparative Analysis of Preoperative and Postoperative Muscle Around Hip Joint by Computed Tomography Between Intertrochanteric Fracture and Femur Neck Fracture

Abstract Background:This study assessed the changes in hip muscles by comparing the preoperative and postoperative CT scan results between patients with intertrochanteric versus femoral neck fractures. Methods:48 patients who received surgical treatment for intertrochanteric or femoral neck fractures from February 2013 to February 2019 and underwent pelvic computed tomography(CT) preoperative and postoperatively aged 65 and older with a minimum follow-up of 1 year were included. The subjects were divided into two groups: 26 patients with intertrochanteric fracture and 22 patients with femoral neck fracture. We measured the cross-sectional area(CSA) and attenuation of the gluteus medius(G.med), gluteus minimus(G.min), iliopsoas(IP), and rectus femoris(RF) on the contralateral side. Patient basic data were collected from medial records including sex, age, height, weight, BMI, BMD, Harris hip score (HHS), and length of follow-up until the final visit. Results: There was no significant difference in sex, age, height, weight, BMI, BMD, HHS, and length of follow-up until the final visit between two groups. The femoral neck fracture group had significantly larger CSA and cross-sectional area per weight(CSA/Wt) of the G.med and G.min(G.med CSA, CSA/wt preoperative 1995.29 vs 1713.64, 38.87 vs 32.74; postoperative 2144.98 vs 1815.56, 37.48 vs 32.78/G.min preoperative 745.22 vs 566.59, 14.32 vs 10.96; postoperative 764.39 vs 619.17, 14.78 vs 11.25). On the contrary, the intertrochanteric fracture group had significantly greater CSA and CSA/Wt of the IP and RF(IP preoperative 810.86 vs 661.88, 17.73 vs 9.42; postoperative 681.98 vs 571.32, 12.68 vs 9.88/RF preoperative 503.66 vs 386.72, 9.42 vs 7.23; postoperative 426.24 vs 349.31, 7.17 vs 5.23). HHS related with function had no significant correlation with postoperative CSA and CSA/Wt. There was no significant difference in attenuation between two groups. All subjects had a significant decrease of muscle attenuation postoperatively.Conclusions: The CSA of the hip abductor(G.med and G.min) was significantly larger in the femoral neck fracture group, while the CSA of the hip flexor(IP and RF) was significantly higher in the intertrochanteric fracture group. Based on these findings, choosing the rehabilitation program suitable for the fracture site is expected to be beneficial in hip fracture rehabilitation.