title: Alteration of the end-plane angle in press-fit cylindrical stem radial head prosthesis: an  in vitro  study.
abstract: OBJECTIVE
  Many studies comparing the morphology of native radial head with the prosthesis have been published. However, there is limited information regarding the postoperative alignment of the articular surface following the radial head replacement. The purpose of this study is to evaluate the alteration of the end-plane angle in the modular radial head prosthesis with a press-fit cementless cylindrical stem.
  
  
  METHODS
  The study used 36 cadaveric radii. The press-fit size prosthesis with cylindrical stem was inserted into each specimen. The end-plane angles of the radial head before and after prosthetic replacement, were measured in coronal and sagittal planes with a digital inclinometer. The data were analyzed by paired t-test.
  
  
  RESULTS
  From paired t-test, there were statistically symmetrical end-plane angles before and after radial head replacement in both coronal and sagittal planes (p-value < 0.01). The mean of radial head end-plane angle alteration in the coronal plane was 3.62° (SD, 2.76°) (range, 0.3°-8.9°). In the sagittal plane, the mean of alteration was 5.85° (SD, 3.56°) degrees (range, 0.3° - 14.2°).
  
  
  CONCLUSIONS
  The modular radial head prosthesis with cylindrical stem is in vitro able to restore the native end-plane angles of radial heads statistically when used in a press-fit fashion.
authors.affiliation: Department of Orthopaedics, Phramongkutklao Hospital and College of Medicine, Bangkok, Thailand. Luenam_Suriya@yahoo.com
authors.forename: Suriya
authors.initials: S
authors.lastname: Luenam
authors.forename: Piti
authors.initials: P
authors.lastname: Chalongviriyalert
authors.forename: Arkaphat
authors.initials: A
authors.lastname: Kosiyatrakul
authors.forename: Chusak
authors.initials: C
authors.lastname: Thanawattano
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D005260:Female; D006801:Humans; D007595:Joint Prosthesis; D008297:Male; D008875:Middle Aged; D011474:Prosthesis Design; D017755:Prosthesis Fitting; D011884:Radius / Q000601:surgery*