Variability of the Ischiofemoral Space Relative to Femur Position: An Ultrasound Study

Abstract

Femoral position affects ischiofemoral space dimensions. The ischiofemoral space widens with abduction and internal rotation and narrows with adduction and external rotation, and thus femoral position should be considered when imaging and measuring the ischiofemoral space.

Can Ultrasound Accurately Assess Ischiofemoral Space Dimensions? A Validation Study

“…In a recent study, Finnoff et al [19] used ultrasound to assess changes in IFS dimensions with femoral internal and external rotation and with adduction and abduction. Femoral position significantly changed the IFS dimensions.…”

“…Hip impingement presents as one of 2 primary types: 1) ischiofemoral impingement (IFI) and 2) femoroacetabular impingement [1]. Although a majority of the medical literature is devoted to femoroacetabular impingement [2], there is a growing number of studies that investigate IFI [1‐30]. IFI is characterized by narrowing of the space between the lesser trochanter of the femur and ischial tuberosity, resulting in compression of the quadratus femoris muscle.…”

“…Although MRI traditionally has been used to evaluate the ischiofemoral space (IFS) dimensions, a recent study used diagnostic ultrasound to measure the dimensions of the IFS during varying degrees of femoral abduction‐adduction and internal‐external rotation [19]. The results of that study suggested that femoral positions significantly affect IFS dimensions, with the narrowest dimension occurring during femoral adduction and external rotation and the widest occurring with femoral abduction and internal rotation.…”

Extra-Articular Impingement: Ischiofemoral Impingement and Trochanteric-Pelvic

“…The difference between these 2 positions has been shown to average over 20 mm in asymptomatic volunteers. 15 Static evaluations on MRI and CT scans are therefore highly dependent on the position of the limb, which may not be standardized between patients and institutions.…”

“…Physical therapy should be directed toward strengthening the abductors and internal rotators of the hip, while stretching adductors and external rotators. 15 Strengthening of the quadratus femoris and core musculature should also be achieved. In addition to physical therapy, a course of nonsteroidal antiinflammatory medication (NSAIDs) should be started to ameliorate inflammation and potentially increase the relative volume of the IFS.…”