title: Three-dimensional morphology of the knee reveals ethnic differences.
abstract: BACKGROUND
  Studies have demonstrated sex differences in femoral shape and quadriceps angle raising a question of whether implant design should be sex-specific. Much of this research has addressed shape differences within the Caucasian population and little is known about differences among ethnic groups.
  
  
  OBJECTIVE
  We therefore asked: Do shape differences in the distal femur and proximal tibia exist among different ethnic groups and between the sexes in each ethnic population? And if ethnic differences exist, do they have a clinical impact on current TKA design?
  
  
  METHODS
  We analyzed 1000 normal adult knees (80 African American, 80 East Asian, and 860 Caucasian). Three-dimensional surface models were created for each bone and added to three-dimensional statistical bone atlases. Statistical shape analysis was conducted with a process combining principal components and multiple discriminate analyses. Eleven femoral and nine tibial measurements were calculated.
  
  
  RESULTS
  We found differences in mean measurements between the sexes and ethnicities. Males had larger knees, with a mean 5-mm-larger anteroposterior dimension than females in all ethnicities. African American females had a 7.4-mm-deeper patellar groove, 2.3-mm-smaller tibial mediolateral dimension, and 2.5-mm-larger tibial anteroposterior dimension than Caucasian females. African American males had a 4.3-mm-larger femoral anteroposterior dimension, 10.1-mm-larger tibial mediolateral dimension, and 6-mm-larger tibial anteroposterior dimension than Asian males.
  
  
  CONCLUSIONS
  We identified differences in three-dimensional knee morphology among Caucasian, African American, and East Asian populations. Clinical studies will be required to determine whether these differences are important for implant design.
authors.affiliation: Mechanical, Aerospace, and Biomedical Engineering, University of Tennessee, 307 Perkins Hall, Knoxville, TN 37996, USA. mmahfouz@cmr.utk.edu
authors.forename: Mohamed
authors.initials: M
authors.lastname: Mahfouz
authors.forename: Emam Elhak
authors.initials: EE
authors.lastname: Abdel Fatah
authors.forename: Lyndsay Smith
authors.initials: LS
authors.lastname: Bowers
authors.forename: Giles
authors.initials: G
authors.lastname: Scuderi
mesh_terms: D000328:Adult; D001741:Black or African American / Q000235:genetics*; D044466:Asian People / Q000235:genetics*; D005202:Asia, Eastern / Q000208:ethnology; D005260:Female; D006801:Humans; D007090:Image Interpretation, Computer-Assisted; D021621:Imaging, Three-Dimensional; D007719:Knee Joint / Q000033:anatomy & histology*; D008297:Male; D008953:Models, Anatomic; D012016:Reference Values; D012494:Sampling Studies; D012680:Sensitivity and Specificity; D012737:Sex Factors; D044465:White People