title: Hill-Sachs lesion classification under arthroscopic findings.
abstract: BACKGROUND
  The Hill-Sachs lesion (HSL) plays a role in recurrent glenohumeral joint instability. Currently, there are no studies based on the form characteristics of HSL. The purposes of this study were to report the HSL form characteristics and to determine whether they are correlated with number of prior subluxations and dislocations.
  
  
  METHODS
  The study enrolled 134 consecutive patients diagnosed with anterior shoulder instability during an arthroscopic procedure. We classified the arthroscopic findings into 4 types, as follows: type 1, cyst type; type 2, gutter type; type 3, island type; and type 4, wide type. Subsequently, we investigated the correlation between each type and the number of shoulder subluxations and dislocations reported. The following data were analyzed: subluxation and dislocation history, arthroscopic findings, and maximum lesion size.
  
  
  RESULTS
  Of the patients evaluated, 18, 32, 30, and 54 were classified as types 1 to 4, respectively. The mean numbers of shoulder dislocations were 3.3, 7.3, 6.0, and 12.0 for types 1 to 4, respectively. The wide type was correlated with more subluxations and dislocations than the other types (P = .001, .046, and .007, respectively). There were significant differences in mean width among all types (P < .0001). HSL width was correlated with lesion type and angle.
  
  
  CONCLUSIONS
  We classified HSL into 4 types on the basis of visual inspection and found a correlation between lesion type and lesion size. However, HSL width was correlated with lesion type and angle; that is, the number of dislocations and subluxations does not affect HSL width.
authors.affiliation: Department of Orthopedic Sports Surgery, Kanto Rosai Hospital, Kanagawa, Japan. Electronic address: kazuhiro04132001@yahoo.co.jp.
authors.forename: Kazuhiro
authors.initials: K
authors.lastname: Shibayama
authors.affiliation: Department of Orthopedic Sports Surgery, Kanto Rosai Hospital, Kanagawa, Japan.
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Iwaso
mesh_terms: D000293:Adolescent; D000328:Adult; D001182:Arthroscopy; D005260:Female; D006801:Humans; D007593:Joint Instability / Q000209:etiology / Q000601:surgery; D008297:Male; D008875:Middle Aged; D012189:Retrospective Studies; D012783:Shoulder Dislocation / Q000145:classification* / Q000601:surgery; D012785:Shoulder Joint / Q000601:surgery; D055815:Young Adult
keywords: Hill-Sachs; classification; form characteristics; instability; shoulder dislocation; shoulder subluxation