title: The cam impinging femur has multiple morphologic abnormalities.
abstract: This study was performed to establish whether the "cam" impinging femur has a single deformity of the head-neck junction or multiple abnormalities. Average dimensions (anteversion angle, α angle of Notzli, β angle of Beaulé, normalized anterior head offset) were compared between normal and impinging femora. The results demonstrated that impinging femora had wider necks, larger heads, and decreased head-neck ratios. There was no difference in neck-shaft angle or anteversion angle. Forty-six percent of impinging femora had significant posterior head displacement (>2mm), which averaged 1.93 mm for the cam impinging group, and 0.78 mm for the normal group. In conclusion, surgical treatment limited to localized recontouring of the head-neck profile may fail to address significant components of the underlying abnormality.
authors.affiliation: Baylor College of Medicine, Houston, Texas, USA.
authors.forename: Andrew R
authors.initials: AR
authors.lastname: Ellis
authors.forename: Philip C
authors.initials: PC
authors.lastname: Noble
authors.forename: Steven J
authors.initials: SJ
authors.lastname: Schroder
authors.forename: Matthew T
authors.initials: MT
authors.lastname: Thompson
authors.forename: Gregory W
authors.initials: GW
authors.lastname: Stocks
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002102:Cadaver; D005260:Female; D005269:Femur / Q000002:abnormalities* / Q000000981:diagnostic imaging; D005270:Femur Head / Q000002:abnormalities* / Q000000981:diagnostic imaging; D005272:Femur Neck / Q000002:abnormalities* / Q000000981:diagnostic imaging; D006801:Humans; D007592:Joint Diseases / Q000209:etiology*; D007719:Knee Joint / Q000002:abnormalities; D008297:Male; D008875:Middle Aged; D016059:Range of Motion, Articular; D014057:Tomography, X-Ray Computed