title: MR imaging of ulnar collateral ligament injury in baseball players: value for predicting rehabilitation outcome.
abstract: BACKGROUND
  To compare the MR findings of the ulnar collateral ligament (UCL) injury in baseball players between rehabilitation and reconstruction surgery.
  
  
  METHODS
  Thirty nine baseball players with clinical evidence of a UCL injury based on medial elbow pain and valgus instability were included. All patients received the rehabilitation treatment for more than six weeks. The elbow MR images of 27 patients not responding to rehabilitation treatment were reviewed that consequently had reconstruction surgery; in addition to 12 patients with improved symptoms with only rehabilitation treatment. The MR imaging was compared between the two treatment groups using the Pearson's chi-square test, and linear-by-linear association for the following features: the degree, signal intensity and site of the UCL injury on fat suppressed T2-weighted images.
  
  
  RESULTS
  High-grade partial tears and complete tears were more commonly seen in the group that had surgery (14 out of 27 patients, 52%; 8 out of 27 patients, 30%), and low-grade partial tears and intact continuity were more common in the group that had rehabilitation only (5 out of 12 patients, 42%; 5 out of 12 patients, 42%) (p=0.001). The injured UCL showed a fluid-like bright high or intermediate high signal intensity in the group that had surgery more frequently (14 out of 27 patients, 52%; 12 out of 27 patients, 44%), and intermediate high or low signal intensity was more frequent in the rehabilitation group (7 out of 12 patients, 58%; 3 out of 12 patients, 25%) (p=0.013). The UCL injury at the origin site was most commonly seen in both groups (23 out of 27 patients, 85%; 11 out of 12 patients, 92%, respectively) (p=0.496).
  
  
  CONCLUSIONS
  Preoperative MR imaging is useful for predicting the rehabilitation outcome of UCL injuries in baseball players.
authors.affiliation: Department of Radiology, Konkuk University School of Medicine, Republic of Korea.
authors.forename: Na Ra
authors.initials: NR
authors.lastname: Kim
authors.forename: Sung Gyu
authors.initials: SG
authors.lastname: Moon
authors.forename: Sung Min
authors.initials: SM
authors.lastname: Ko
authors.forename: Won-Jin
authors.initials: WJ
authors.lastname: Moon
authors.forename: Jin Woo
authors.initials: JW
authors.lastname: Choi
authors.forename: Jin-Young
authors.initials: JY
authors.lastname: Park
mesh_terms: D000293:Adolescent; D000328:Adult; D001265:Athletic Injuries / Q000534:rehabilitation*; D001484:Baseball / Q000293:injuries*; D017885:Collateral Ligaments / Q000293:injuries* / Q000473:pathology*; D004551:Elbow Joint / Q000473:pathology*; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000379:methods; D011379:Prognosis; D016896:Treatment Outcome; D014457:Ulna / Q000293:injuries* / Q000473:pathology; D055815:Young Adult; D000092464:Elbow Injuries