The role of ultrasonography in the diagnosis of gluteal muscle contracture

Abstract

To evaluate the use of ultrasonography (US) in the diagnosis of gluteal muscle contracture (GMC) by analysis of its imaging characteristics. Thirty-nine patients suspected of having GMC due to abnormal gait underwent pre-operative US. The diagnosis of GMC was confirmed by surgery in 27 patients. Six patients were diagnosed with congenital hip dysplasia, and the remaining six patients were diagnosed with sciatic nerve damage, post-poliomyelitis sequelae, and myasthenia gravis. For the patients with GMC, US showed muscle thinning and hyperechoic strips (specific for muscular contracture) in the muscles involved. In three patients with GMC, the strips were integrated into muscle bundles, demonstrating both strong and weak sonographic echoes. The sensitivity and specificity of the diagnosis of GMC using the presence of strips were 88.9% and 83.3%, respectively, and using muscle thinning, the sensitivity and specificity were 92.6% and 50%, respectively. The contracture strips, as measured by US, were significantly smaller than the actual measurements at the time of surgery, but there was a significant correlation between the two measurements (r = 0.814, P < 0.01). The highest detection rate of GMC by US was found in the gluteus maximus muscle (91.8%), and the lowest rate was found in the piriformis muscle (52.9%). Ultrasonography is a valuable tool for the diagnosis of GMC, especially for the detection of specific contracture strips in involved muscles. Its role in the pre-operative diagnosis of GMC also provides surgical planning that can guide subsequent treatment.