title: Incidence of associated injuries with acute acromioclavicular joint dislocations types III through V.
abstract: BACKGROUND
  Traumatic acromioclavicular (AC) joint dislocations are common injuries among the active population. The injury mechanism requires excessive force delivered by a fall or blow to the shoulder. Associated injuries may occur and remain undetected if they are masked by the painful and prominent AC joint injury.
  
  
  OBJECTIVE
  Intra-articular injuries associated with high-grade AC joint dislocations are common.
  
  
  METHODS
  Case series; Level of evidence, 4.
  
  
  METHODS
  Between 2002 and 2007, 77 patients (68 male, 9 female; average age, 35.5 years; range, 17-62 years) were surgically treated for acute AC joint dislocations (Rockwood type III, 5; type IV, 30; and type V, 42). All patients underwent diagnostic glenohumeral joint arthroscopy. Concomitant intra-articular injuries were identified and treated.
  
  
  RESULTS
  Intra-articular injuries were found in 14 of 77 patients (18.2%). Superior labral anterior posterior (SLAP) lesions were observed in 11 of 77 patients 14.3% (SLAP I, 3; II, 2; III, 3; and IV, 3). Nineteen percent of Rockwood V lesions had associated SLAP lesions (SLAP I excluded), whereas only 3.4% of Rockwood IV lesions showed SLAP lesions. A complete supraspinatus tear was detected in 1 case, and partial articular-sided supraspinatus tears were detected in 2 cases. Four patients sustained an accompanying fracture.
  
  
  CONCLUSIONS
  Concomitant injuries to the shoulder girdle obtained during traumatic AC joint separation may be more frequent than previously thought. Clinical diagnosis may be difficult in the setting of an acute and painful dislocated AC joint. Shoulder arthroscopy during arthroscopic AC joint stabilization may aid in detecting associated injuries.
authors: Department of Orthopaedic Sports Medicine, Klinikum Rechts der Isar, University of Munich, Munich, Germany.
authors: Thomas
authors: T
authors: Tischer
authors: Gian Max
authors: GM
authors: Salzmann
authors: Hosam
authors: H
authors: El-Azab
authors: Stephan
authors: S
authors: Vogt
authors: Andreas B
authors: AB
authors: Imhoff
mesh_terms: D000173:Acromioclavicular Joint / Q000293:injuries*; D000293:Adolescent; D000328:Adult; D005260:Female; D005858:Germany / Q000453:epidemiology; D006801:Humans; D015994:Incidence; D008297:Male; D008875:Middle Aged; D009104:Multiple Trauma / Q000175:diagnosis / Q000453:epidemiology*; D012783:Shoulder Dislocation / Q000145:classification* / Q000503:physiopathology; D055815:Young Adult