title: Internal impingement: findings on magnetic resonance imaging and arthroscopic evaluation.
abstract: OBJECTIVE
  The purpose of this study was to examine preoperative shoulder magnetic resonance imaging (MRI) and intraoperative arthroscopic findings in throwing athletes with a clinical diagnosis of internal impingement.
  
  
  METHODS
  Retrospective review.
  
  
  METHODS
  A retrospective review of the surgical indications for 769 shoulder arthroscopic procedures performed from 1997 to 2000 revealed 9 throwing athletes with a diagnosis of severe internal impingement. Each had failed treatment that included a minimum of 3 months of rehabilitation. Preoperative MRIs in all 9 were read by a fellowship-trained musculoskeletal radiologist blinded to the operative findings. Findings at arthroscopy were culled from the operative reports.
  
  
  RESULTS
  On both MRI and at arthroscopy, all 9 athletes had posterosuperior labral lesions, 1 had a humeral head articular cartilage lesion, and 1 had a SLAP lesion. Additional findings on MRI included humeral head edema, subchondral cystic changes, posterosuperior glenoid sclerosis, and rotator cuff tendonopathy predominantly in the infraspinatus. At arthroscopy, there were additional findings of articular-sided partial rotator cuff tears not shown on MRI.
  
  
  CONCLUSIONS
  Both MRI and arthroscopic findings described labral and humeral head articular cartilage lesions. These findings may be indicative of internal impingement in throwing athletes.
  
  
  METHODS
  Level III, diagnostic.
authors.affiliation: Department of Orthopedics and Rehabilitation, University of Wisconsin-Madison, Madison, Wisconsin, USA. Kaplan@surgery.wisc.edu
authors.forename: Lee D
authors.initials: LD
authors.lastname: Kaplan
authors.forename: Patrick J
authors.initials: PJ
authors.lastname: McMahon
authors.forename: Jeffrey
authors.initials: J
authors.lastname: Towers
authors.forename: Jay J
authors.initials: JJ
authors.lastname: Irrgang
authors.forename: Mark W
authors.initials: MW
authors.lastname: Rodosky
mesh_terms: D000328:Adult; D001182:Arthroscopy; D001265:Athletic Injuries / Q000175:diagnosis* / Q000473:pathology / Q000601:surgery; D002358:Cartilage, Articular / Q000293:injuries / Q000473:pathology; D015331:Cohort Studies; D003131:Combined Modality Therapy; D006801:Humans; D026741:Physical Therapy Modalities; D012189:Retrospective Studies; D017006:Rotator Cuff / Q000473:pathology; D000070636:Rotator Cuff Injuries; D019534:Shoulder Impingement Syndrome / Q000175:diagnosis* / Q000473:pathology / Q000601:surgery