EP3.31 Ischiofemoral Impingement is Common, Incidence in a Comprehensive Hip Only Practice

Background: Ischiofemoral impingement (IFI) is a cause of posterior hip pain defined by a narrowing of the space between the lateral aspect of the ischium and the posterior aspect of the femur. The lesser trochanter is the most common cause, but the entire trochanteric region can impinge on the ischium. Several underlying anatomic, functional and iatrogenic pathologies have been identified for symptomatic IFI in native hip joints and after THA. Clinical symptoms vary, but most commonly consist of LBP, posterior hip, groin including the inner thigh. A snapping or clunking phenomenon is often reported. Symptoms may be provoked by combined extension, adduction and external rotation. IFI has been described as rare and few articles have been published on its incidence.

Purpose: The purpose of this study is to report on the incidence of IFI in patients undergoing surgery in a comprehensive hip only practice. The incidence and treatment of both symptomatic and asymptomatic IFI will be analyzed

Methods: A retrospect chart review of all patients undergoing surgery over a 10 month period were analyzed. Patients were identified with both physical exam and MRI evidence of IFI. Age, sex, and treatment method was analyzed.

Results: A total of 820 patients underwent 836 primary surgeries and 858 surgeries in total. A total of 87 hips (10.4%) in 81 patients were found to have IFI prior to surgery and 83 (9.92%) of those were symptomatic and treated. The incidence in females undergoing surgery was 17.1% (81/473) and only 1.35% (5/369) of the symptomatic hips were in male patients. The average age was 58 ± 14. Four patients had a prior THA and 4 patients did not have symptomatic IFI despite MRI and mild exam findings. Six patients had IFI surgery on both hips. Surgical treatments were THA with abductor repair (24 pts), THA alone (23 pts) partial resection of the ischium with hamstring repair (17 pts), endoscopic partial lesser trochanter excision (7 pts), proximal derotational femoral osteotomy (7 pts.), open abductor repair (3 pts) heterotopic ossification excision (1 pt).

Conclusion: Once considered to be a rare cause of posterior hip pain, IFI is relatively common with a symptomatic incidence of 17.1% in women undergoing surgery for hip pain in a busy hip only practice. Ischiofemoral impingement should be considered in all women with posterior hip pain. The treatment varies depending on coexistent pathologies in the patient and should be individualized.