title: Multiple hereditary exostoses and ischiofemoral impingement: a case-control study.
abstract: OBJECTIVE
  To assess whether there is a significant difference in the ischiofemoral space in patients with multiple hereditary exostoses affecting the proximal femora compared to normal patients.
  
  
  BACKGROUND
  Ischiofemoral impingement is an increasingly recognized cause of hip and buttock pain. This causes narrowing of the ischiofemoral space resulting in an abnormal quadratus femoris muscle.
  
  
  METHODS
  We performed a retrospective search for individuals with MHE with proximal femoral involvement on pelvic MRI over a 7-year period (2006-2013). Suitable patients were age- and sex-matched with a control group. The minimum ischiofemoral space (MIFS) was recorded in each hip, as was the presence of edema and atrophy of quadratus femoris and concomitant hip osteoarthrosis. MRI features suggestive of ischiofemoral impingement were defined as MIFS less than 10 mm or an abnormal quadratus femoris muscle.
  
  
  RESULTS
  Twenty-one hips in 11 individuals with MHE were included in the study. A total of 42 hips were analyzed. The mean age was 37 years (range, 13-72 years) and 55% were male. There was a significant difference (p < 0.05) in the MIHS in individuals with MHE (mean, 10.7 mm, range, 0-21 mm) compared to a control group (mean, 18.1 mm, range, 10.5-26.5 mm). MRI features suggestive of ischiofemoral impingement were seen in 13/21 (62%) hips in the MHE group and 0/21 (0%) in the control group.
  
  
  CONCLUSIONS
  The reduced ischiofemoral space and associated quadratus femoris abnormalities in patients with MHE involving the proximal femora may account for hip/buttock symptoms in the absence of significant degenerative change.
authors.affiliation: Department of Radiology, Nuffield Orthopaedic Centre, Windmill Road, Headington, Oxford, OX3 7LD, UK, philipyoong@gmail.com.
authors.forename: Philip
authors.initials: P
authors.lastname: Yoong
authors.forename: Ramy
authors.initials: R
authors.lastname: Mansour
authors.forename: James L
authors.initials: JL
authors.lastname: Teh
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D016022:Case-Control Studies; D005097:Exostoses, Multiple Hereditary / Q000150:complications* / Q000473:pathology*; D005260:Female; D057925:Femoracetabular Impingement / Q000209:etiology* / Q000473:pathology*; D005269:Femur / Q000473:pathology*; D006801:Humans; D007512:Ischium / Q000473:pathology*; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D008875:Middle Aged; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D055815:Young Adult