title: A comparison of normal and osteoarthritic humeral head size and morphology.
abstract: BACKGROUND
  The purpose of this study was to evaluate and to compare the size and morphologic patterns among normal and osteoarthritic (OA) humeral heads.
  
  
  METHODS
  This comparative anatomic imaging study evaluated 150 humeral heads that were separated into 3 cohorts: normal, OA with symmetric glenoid erosion, and OA with asymmetric (type B2) glenoid erosion. Three-dimensional models were created of the humeral head from computed tomography data, and point coordinates were extracted for evaluation. Parameters measured were diameter (sphere fit and circle fit), chord distance (superoinferior and anteroposterior), and humeral head height.
  
  
  RESULTS
  The sphere-fit diameter of the humeral head for the entire OA cohort (100 patients; mean diameter, 59 ± 9 mm) was significantly greater (P < .001) than that of the normal cohort (50 patients; mean diameter, 49 ± 5 mm). Similarly, the humeral head circle-fit diameters in the superoinferior and anteroposterior planes were significantly greater (P < .001) in the combined OA cohorts (59 ± 9 mm and 56 ± 10 mm, respectively) compared with the normal cohort (51 ± 5 mm and 47 ± 5 mm, respectively). However, there were no significant differences (P ≥ .099) between the symmetric and asymmetric OA cohorts in sphere-fit or circle-fit diameters. The mean values of humeral head heights were not significantly different (P = .382) between cohorts, 19 ± 2 mm, 18 ± 2 mm, and 18 ± 2 mm for the normal, symmetric, and asymmetric cohorts, respectively.
  
  
  CONCLUSIONS
  Although OA humeral head morphology varies significantly from normal, it does not vary as a function of the Walch classification between symmetric and asymmetric glenoids. Understanding of the morphologic variability of the pathologic humeral head may provide insight into the pathoanatomy of osteoarthritis and the development of various erosion patterns.
authors.affiliation: University of Western Ontario, London, ON, Canada; Roth|McFarlane Hand and Upper Limb Centre, London, ON, Canada.
authors.forename: Nikolas K
authors.initials: NK
authors.lastname: Knowles
authors.affiliation: Roth|McFarlane Hand and Upper Limb Centre, London, ON, Canada.
authors.forename: Michael J
authors.initials: MJ
authors.lastname: Carroll
authors.affiliation: Washington University/Barnes-Jewish Hospital, St. Louis, MO, USA.
authors.forename: Jay D
authors.initials: JD
authors.lastname: Keener
authors.affiliation: University of Western Ontario, London, ON, Canada; Roth|McFarlane Hand and Upper Limb Centre, London, ON, Canada. Electronic address: Louis.Ferreira@sjhc.london.on.ca.
authors.forename: Louis M
authors.initials: LM
authors.lastname: Ferreira
authors.affiliation: University of Western Ontario, London, ON, Canada; Roth|McFarlane Hand and Upper Limb Centre, London, ON, Canada.
authors.forename: George S
authors.initials: GS
authors.lastname: Athwal
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D005260:Female; D006801:Humans; D058430:Humeral Head / Q000033:anatomy & histology* / Q000000981:diagnostic imaging* / Q000473:pathology; D021621:Imaging, Three-Dimensional; D008297:Male; D008875:Middle Aged; D008953:Models, Anatomic; D010003:Osteoarthritis / Q000000981:diagnostic imaging* / Q000473:pathology*; D012540:Scapula / Q000000981:diagnostic imaging / Q000473:pathology; D012785:Shoulder Joint / Q000033:anatomy & histology* / Q000000981:diagnostic imaging* / Q000473:pathology; D014057:Tomography, X-Ray Computed
keywords: Humeral head; biconcave; morphology; osteoarthritis; shoulder arthroplasty; type B2