Does low body mass index constitute a risk of damage to the soft tissues during reaming for proximal femoral nailing? a cadaveric study.

BACKGROUND: The purpose of this cadaveric study was to evaluate the damage to the gluteus medius muscle, tendon and superior gluteal nerve in low BMI patients during the reaming of the greater trochanter tip for proximal femoral nailing.

MATERIALS AND METHODS: The study used 19 femurs of 10 fresh femur intact cadavers [mean BMI: 22.79 (17.60-28.70)]. A guidewire was placed in the tip of greater trochanter under C-arm fluoroscopy, and a 17-mm reamer was advanced over the wire. After the reaming was completed, the hips were dissected and the gluteus medius muscle, tendon and superior gluteal nerve were inspected to evaluate the amount of injury.

RESULTS: BMI was < 18.50 in 3 cadavers. The gluteus medius muscle was injured in all hips. The superior gluteal nerve was intact in all hips, but the thickness of gluteus medius muscle mass that remained intact was thicker in the cadavers with a higher BMI (3.86 mm for low BMI, 9.08 mm for high BMI group). The percentage of the tendon insertion disrupted by the reamer was an average of 36.20% in the low BMI group and an average of 26.93% in the high BMI group. The percentage of the tendon insertion disrupted by the reamer showed a statistically significant difference between low and high BMI cadavers.

CONCLUSION: The injury to the gluteus medius muscle and tendon after proximal femoral nailing through the greater trochanter tip may be higher in patients with low BMI. It must be kept in mind that gluteal muscle could be damaged during proximal femoral nailing and this could result in limping.