Fig. 1

Histopathological examination of contracture sites in patients with GMC. Three-step arthroscopic gluteal muscle release method: A The triangle area is the artificial cavity area, the left x is the arthroscopic observation approach, the middle x is the arthroscopic operation approach, and the right x is the arthroscopic-assisted operation approach (this approach may be required for very severe gluteal muscle patients); B Arthroscopic operation; C Contracture zone in the arthroscopic field of vision; D After the release of the contracture band in 1c; E. HE staining result; F. Masson staining result; G Sirius red staining result; H Sirius red staining result under polarized light. CM is contracture muscle; NM is normal muscle. The scale for E–G is 200 um. The scale for H is 500 um