title: Radiographic comparison of adolescent athletes with elbow osteochondritis dissecans to ulnar collateral ligament injuries and controls.
abstract: BACKGROUND
  There are excellent data supporting recommendations to prevent elbow injuries (osteochondritis dissecans [OCD] and ulnar collateral ligament [UCL] injuries), such as pitch count and pitch type in baseball, but anatomic risk factors have not been thoroughly examined. This study aimed to evaluate radiographic measurements in adolescents with elbow OCD lesions or UCL injuries and controls.
  
  
  METHODS
  We retrospectively identified adolescent patients between 2011 and 2016 with isolated capitellum OCD, UCL tear, or normal elbows based on magnetic resonance imaging. Nineteen patients (mean age, 13.5 years) had isolated OCD defects of the capitellum, 8 patients (mean age, 16.9 years) had isolated UCL complete tear, and the remaining 16 patients (mean age, 14.6 years) were normal controls. Radiographic measurements from corresponding anterior-posterior elbow radiographs were taken, including carrying angle, distal humeral articular surface angle, and radial neck-shaft angle. On the lateral radiograph, anterior angulation of the articular surface of distal humerus was measured.
  
  
  RESULTS
  Significant differences were observed in carrying angle between controls (15.7°) and OCD patients (11.6°; P = .03) as well as between controls and UCL patients (10.3°, P = .02), with the OCD and UCL patients tending to be in more varus. Significant differences were also found between controls (88.5°) and OCD patients (93.6°; P = .01) and between controls and UCL patients (93.3°; P = .03) in distal humeral articular surface angle, with OCD and UCL patients with increased valgus at the distal humerus articular surface. There were no significant differences between groups in radial neck-shaft angle or anterior angulation of articular surface of distal humerus.
  
  
  CONCLUSIONS
  Patients with OCD and UCL injuries have anatomic differences compared with normal controls that can be measured radiographically.
authors.affiliation: Department of Orthopaedic Surgery, University of California San Francisco Medical Center, San Francisco, CA, USA.
authors.forename: Brian C
authors.initials: BC
authors.lastname: Lau
authors.affiliation: Department of Orthopaedic Surgery, University of California San Francisco Medical Center, Children's Hospital of Oakland, Oakland, CA, USA. Electronic address: Nirav.Pandya@ucsf.edu.
authors.forename: Nirav K
authors.initials: NK
authors.lastname: Pandya
mesh_terms: D000293:Adolescent; D056352:Athletes; D000070637:Collateral Ligament, Ulnar / Q000000981:diagnostic imaging* / Q000293:injuries; D004551:Elbow Joint / Q000000981:diagnostic imaging*; D005260:Female; D006801:Humans; D006811:Humerus / Q000000981:diagnostic imaging*; D008279:Magnetic Resonance Imaging; D008297:Male; D010008:Osteochondritis Dissecans / Q000000981:diagnostic imaging*; D011859:Radiography; D011884:Radius / Q000000981:diagnostic imaging; D012189:Retrospective Studies; D000092464:Elbow Injuries
keywords: Elbow; OCD; UCL; adolescent; alignment; radiographic