title: The effect of osseous ankle configuration on chronic ankle instability.
abstract: BACKGROUND
  Chronic ankle instability (CAI) is a common orthopaedic entity in sport. Although other risk factors have been studied extensively, little is known about how it is influenced by the osseous joint configuration.
  
  
  OBJECTIVE
  To study the effect of osseous ankle configuration on CAI.
  
  
  METHODS
  Case-control study, level III.
  
  
  METHODS
  Radiological examination with measurement of lateral x rays by an independent radiologist using a digital DICOM/PACS system.
  
  
  METHODS
  A group of 52 patients who had had at least three recurrent sprains was compared with an age-matched and sex-matched control group of 52 healthy subjects.
  
  
  METHODS
  The radius of the talar surface, the tibial coverage of the talus (tibiotalar sector) and the height of the talar body were measured.
  
  
  RESULTS
  The talar radius was found to be larger in patients with CAI (21.2 (2.4) mm) than in controls (17.7 (1.9) mm; p<0.001, power >95%). The tibiotalar sector, representing the tibial coverage of the talus, was smaller in patients with CAI (80 degrees (5.1 degrees )) than in controls (88.4 degrees (7.2 degrees ); p<0.001, power >95%). No significant difference was observed in the height of the talar body between patients with CAI (28.8 (2.6) mm) and controls (27.5 (4.0) mm; p = 0.055).
  
  
  CONCLUSIONS
  CAI is associated with an unstable osseous joint configuration characterised by a larger radius of the talus and a smaller tibiotalar sector. There is evidence that a higher talus might also play some part, particularly in women.
authors.affiliation: Orthopaedic Department, Musculoskeletal Care Centre, University Hospital of Basel, Basel, Switzerland. mail@arnofrigg.com
authors.forename: Arno
authors.initials: A
authors.lastname: Frigg
authors.forename: Olaf
authors.initials: O
authors.lastname: Magerkurth
authors.forename: Victor
authors.initials: V
authors.lastname: Valderrabano
authors.forename: Hans-Peter
authors.initials: HP
authors.lastname: Ledermann
authors.forename: Beat
authors.initials: B
authors.lastname: Hintermann
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000843:Ankle Joint / Q000033:anatomy & histology* / Q000000981:diagnostic imaging; D016022:Case-Control Studies; D002908:Chronic Disease; D005260:Female; D006801:Humans; D007593:Joint Instability / Q000000981:diagnostic imaging / Q000209:etiology*; D008297:Male; D008875:Middle Aged; D011859:Radiography; D012307:Risk Factors; D013180:Sprains and Strains / Q000000981:diagnostic imaging / Q000209:etiology*; D013628:Talus / Q000033:anatomy & histology* / Q000000981:diagnostic imaging