title: Morphologic Variability of the Shoulder between the Populations of North American and East Asian.
abstract: BACKGROUND
  The aim of this study was to determine if there were significant differences in glenohumeral joint morphology between North American and East Asian populations that may influence sizing and selection of shoulder arthroplasty systems.
  
  
  METHODS
  Computed tomography reconstructions of 92 North American and 58 East Asian patients were used to perform 3-dimensional measurements. The proximal humeral position was normalized in all patients by aligning it with the scapular plane utilizing anatomic landmarks. Measurements were performed on the humerus and scapula and included coronal and axial humeral head radius, humeral neck shaft and articular arc angles, glenoid height and width, and critical shoulder angle. Glenohumeral relationships were also measured and included lateral distance to the greater tuberosity and acromion, abduction lever arm, and acromial index. Parametric and nonparametric statistical analyses were used to compare population metrics.
  
  
  RESULTS
  East Asian glenohumeral measurements were significantly smaller for all linear metrics (p < 0.05), with the exception of acromial length, which was greater than in the North American cohort (p < 0.001). The increase in acromial length affected all measurements involving the acromion including abduction lever arms. No difference was found between the neck shaft and articular angular measurements.
  
  
  CONCLUSIONS
  The East Asian population exhibited smaller shoulder morphometrics than their North American cohort, with the exception of an extended acromial overhang. The morphologic data can provide some additional factors to consider when choosing an optimal shoulder implant for the East Asian population, in addition to creating future designs that may better accommodate this population.
authors: Phillip Spiegel Orthopaedic Research Laboratory, Foundation for Orthopaedic Research and Education, Tampa, FL, USA.
authors: Andres F
authors: AF
authors: Cabezas
authors: Phillip Spiegel Orthopaedic Research Laboratory, Foundation for Orthopaedic Research and Education, Tampa, FL, USA.
authors: Kristi
authors: K
authors: Krebes
authors: Florida Orthopaedic Institute, Tampa, FL, USA.
authors: Michael M
authors: MM
authors: Hussey
authors: Phillip Spiegel Orthopaedic Research Laboratory, Foundation for Orthopaedic Research and Education, Tampa, FL, USA.
authors: Brandon G
authors: BG
authors: Santoni
authors: Department of Orthopedic Surgery, Yonsei University College of Medicine, Seoul, Korea.
authors: Hyuong Sik
authors: HS
authors: Kim
authors: Florida Orthopaedic Institute, Tampa, FL, USA.
authors: Mark A
authors: MA
authors: Frankle
authors: Department of Orthopedic Surgery, Seoul National University Bundang Hospital, Seoul National University College of Medicine, Seongnam, Korea.
authors: Joo Han
authors: JH
authors: Oh
mesh_terms: D001741:Black or African American / Q000706:statistics & numerical data*; D000368:Aged; D000886:Anthropometry; D044466:Asian People / Q000706:statistics & numerical data*; D005260:Female; D006801:Humans; D008297:Male; D011474:Prosthesis Design; D056910:Republic of Korea / Q000453:epidemiology; D012782:Shoulder / Q000033:anatomy & histology*; D012785:Shoulder Joint / Q000033:anatomy & histology*; D000072227:Shoulder Prosthesis; D014481:United States / Q000453:epidemiology; D044465:White People / Q000706:statistics & numerical data*
keywords: Acromion; Anatomy; Arthroplasty; East Asian; Shoulder