Endoscopic Lesser Trochanter Excision for Ischiofemoral Impingement

Ischiofemoral impingement (IFI) is a rare yet underrecognized cause of posterior hip, low back/sacroiliac region, and deep gluteal pain. Patient anatomy, including femoral anteversion, coxa valga, posterior pelvic tilt, and lumbar stiffness, contributes to symptomatic IFI.

Indications for surgical intervention include exclusion of alternative causes of posterior gluteal pain, failed nonoperative intervention including physical therapy and injection targeting the ischiofemoral space, and narrow ischiofemoral distance with quadratus femoris edema with or without sciatic nerve entrapment and protection of hamstring repair.

Our preferred technique includes endoscopic lesser trochanter (LT) excision through a posterior approach in the prone position. The patient is positioned with the hips in slight flexion and the knees at 60° of flexion to take tension off the sciatic nerve. Fluoroscopy is used to localize the LT for 4 planned portal sites, creating a diamond around the LT: 2 for sciatic nerve retraction, 1 for endoscopic visualization, and 1 for working. The sciatic nerve is identified, bluntly mobilized, and protected. Radiofrequency ablation is used to dissect through the quadratus femoris from the posterior-central LT and expose the posterior LT. A 5.5-mm diamond-tip bur is then used to fully excise the LT flush with the femoral cortex. The patient is kept touch-down weightbearing for 6 weeks to reduce the risk of proximal femur stress fracture.

Endoscopic LT excision has been widely reported as a reliable method to increase ischiofemoral distance and relieve mechanical bone impingement and sciatic nerve entrapment. In our experience, the posterior approach in the prone position allows for maximum visualization to identify and protect the neurovascular structures, completely excise the LT, and treat concomitant pathology.

Our preferred technique for surgical treatment of IFI with posterior endoscopic LT excision in the prone position is safe based on sciatic nerve visualization and effective with complete LT excision.

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