Quadratus Femoris Partial Tear Secondary to Occult Ischiofemoral Impingement.

Introduction: Hip pain in children and adolescents may become a diagnostic challenge. A wide range of causes must be considered in the deferential diagnosis. Ischiofemoral impingement (IFI) is a pathological condition defined by hip pain associated with narrowing of the ischiofemoral (IF) space. We report the case of an adolescent patient with non-traumatic quadratus femoris (QF) tear secondary to an occult IFI syndrome. To the best of our knowledge, this is the first such case reported in the literature.

Case Report: A 15-year-old girl reported persisting hip pain for a month following increased physical activity. The symptoms had started a couple of days following a weekend of increased activity due to her participating in a dancing contest. Physical examination and imaging studies (standard anterior pelvis radiograph and MRI-scan) failed to reveal any pathology apart from an area of diffused edema in the IF space. Standard hematology and biochemistry laboratory tests were all within normal range. Conservative treatment for 6 months with rest and modification of physical activities failed. A new MRI scan showed partial edema resolution and marked reduction in the IF and QF spaces (12 mm and 8 mm, respectively), thus suggesting IFI, which, in turn, led to a partial rupture of the QF. The patient underwent a local infiltration of the QF with betamethasone sodium phosphate and betamethasone acetate (6+6 mg/2 ml) under CT guidance, which led to the complete resolution of all her symptoms. She remains symptoms free for 24 months.

Conclusion: IFI is a rather uncommon condition in the developing skeleton. As in adults, in adolescents as well, MRI is the study of choice in cases of IFI, since it shows QF pathology and allows measurement of the IF and QF spaces, assisting physicians in establishing the right diagnosis. However, the coexistence of a QF hematoma and/or edema, may temper with the initial MRI measurements and render the diagnosis of the primary condition rather difficult. Conservative treatment (with local infiltration of the QF) was proven to be successful in the hereby described case.