Case: We describe 2 patients with no historical, examination, or imaging evidence of ischiofemoral impingement; they both developed hip abductor insufficiency and subsequent ischiofemoral impingement with progression that was confirmed by examination and advanced imaging.
Conclusion: Hip abductor insufficiency may lead to dynamic progressive ischiofemoral impingement. Hemipelvic instability from hip abductor weakness results in a Trendelenburg gait, narrowing the ischiofemoral space and impinging the quadratus femoris muscle. Treatment options for dynamic ischiofemoral impingement potentially can focus on treatment of the underlying cause of the hemipelvic instability, preventing additional ischiofemoral-space narrowing and quadratus femoris damage by minimizing the Trendelenburg gait.