Decreased postoperative gluteus medius muscle cross-sectional area measured by computed tomography scan in patients with intertrochanteric fractures nailing

In patients with femoral intertrochanteric fractures treated by cephalomedullary (CM) nailing, abduction force reportedly decreased by 25-30% during the postoperative follow-up period. The purpose of the current study is to evaluate the cross-sectional area (CSA) and adipose tissue ratio (ATR) of the gluteus medius muscle on the postoperative computed tomography (CT) view, expecting this graphic study will support clinical results.A total of 27 patients with femoral intertrochanteric fractures treated by CM femoral nail implants completed the study. The mean age at osteosynthesis was 83 years (range: 72-94 years). The mean postoperative follow-up period was 23 months. The three CT axial slice views were defined as slices A, B, and C corresponding to proximal, midway, and distal part of gluteus medius, respectively. The CSA and ATR were assessed bilaterally.The mean and standard deviation of CSA values (mm2) between the nonoperated/ operated side were as follows: slice A: 2225.8 ± 621.2/1984.5 ± 425.8; slice B: 2145.1 ± 538.3/1854.9 ± 383.9; and slice C: 1711.0 ± 459.0/1434.5 ± 396.9 ( p < 0.01 in slices A, B, and C). The mean and standard deviation of ATR values (%) from the nonoperative/ operative side were as follows: slice A: 2.8 ± 1.7/5.2 ± 3.5; slice B: 2.7 ± 1.9/4.6 ± 3.2; and slice C: 3.6 ± 3.0/4.8 ± 3.2 ( p < 0.01 in slices A and B and p < 0.05 in slice C).Our image findings documented that gluteus medius is significantly changed in CSA and ATR. The damage possibly triggers decrease in muscular strength of hip abduction in the postoperative follow-up period. This measurement is objective, and needed no patient's endurance and cooperation.