title: Outcome of resection of a symptomatic os trigonum.
abstract: BACKGROUND
  While an os trigonum at the posterolateral aspect of the talus is usually asymptomatic, this inconsistently present accessory bone has been associated with persistent posterior ankle pain, which has been described as the os trigonum syndrome. We present the clinical results of excision of the os trigonum through a posterolateral approach and report several factors affecting the clinical outcome.
  
  
  METHODS
  During a five-year period from 1994 through 1999, forty-one patients had a failure of nonoperative treatment of os trigonum syndrome and underwent excision of a symptomatic os trigonum. In all cases, the os trigonum syndrome was diagnosed on the basis of the history, physical examination, and radiographs. Postoperatively, the patients were evaluated according to the American Orthopaedic Foot and Ankle Society (AOFAS) Ankle-Hindfoot Scale. A questionnaire was used to evaluate the effect of several factors on the clinical outcome.
  
  
  RESULTS
  The average duration of follow-up was forty-four months. The postoperative AOFAS score averaged 87.6 points. The thirty-three patients who had had symptoms for two years or less prior to the surgery had an average postoperative score of 90 points compared with 78 points for the eight patients who had had preoperative symptoms for more than two years (p = 0.011). Eight patients had sural nerve sensory loss, which was temporary in four and permanent in four. A superficial wound infection developed in one patient, and reflex sympathetic dystrophy developed in another.
  
  
  CONCLUSIONS
  An os trigonum that is persistently symptomatic after a minimum three-month trial of nonoperative treatment can be excised through a posterolateral approach with highly satisfactory results. The main complication of this procedure is sural nerve injury.
authors.affiliation: Department of Orthopaedic Surgery, Hadassah Medical Center, Ein-Kerem, Jerusalem 91120, Israel.
authors.forename: Yigal
authors.initials: Y
authors.lastname: Abramowitz
authors.forename: Ronit
authors.initials: R
authors.lastname: Wollstein
authors.forename: Yair
authors.initials: Y
authors.lastname: Barzilay
authors.forename: Eli
authors.initials: E
authors.lastname: London
authors.forename: Yoav
authors.initials: Y
authors.lastname: Matan
authors.forename: Shay
authors.initials: S
authors.lastname: Shabat
authors.forename: Meir
authors.initials: M
authors.lastname: Nyska
mesh_terms: D000293:Adolescent; D000328:Adult; D005260:Female; D005534:Foot Diseases / Q000601:surgery*; D006801:Humans; D008297:Male; D008875:Middle Aged; D019637:Orthopedic Procedures / Q000379:methods*; D013628:Talus / Q000503:physiopathology* / Q000601:surgery*; D016896:Treatment Outcome