Ischiofemoral impingement: a recently described pathological entity responsible for chronic hip pain

Ischiofemoral impingement, or abutment, is a relatively recently described clinical entity which can cause pain in the hip and abnormalities of the quadratus femoris muscle. Although it was reported a long time ago – in 1977 by Johnson – in patients with total hip arthroplasty, only recently has it been considered responsible for chronic hip pain in patients with an otherwise normal hip. Ischiofemoral impingement is essentially caused by repeated abutment or impingement of the soft tissues of the region between the lesser trochanter of the femur and the ischial ramus, which results in pain and also in compression of the quadratus femoris muscle, which normally occupies this space.
This impingement has been observed to occur usually in patients in whom the distance between these two bony structures is reduced, to about 13 millimetres, plus or minus five millimetres, as against the normal distance, which is considered to lie at about 20 millimetres. These patients usually present with chronic pain in the proximal thigh or with posterior pain in the buttock, which may radiate distally and without there being any history of previous acute injury. In his 1977 paper Johnson described the reproduction of the symptoms by a combination of extension, adduction and external rotation of the hip. It has also been reported that problems of the iliopsoas bursa, and also injuries of the hamstrings, may coexist with this pathological entity and form part of the pathology of ischiofemoral impingement.