title: Proximal migration of fibular malleolus during tibial lengthening despite syndesmotic screw fixation: a series of 22 cases.
abstract: BACKGROUND
  During tibial lengthening procedures, it is recommended to prevent fibular malleolus proximal migration using a distal tibiofibular syndesmotic screw, which is removed at 6 months. We have observed proximal migrations of the fibular malleolus despite placement of this syndesmotic screw.
  
  
  OBJECTIVE
  The objective of this study was to demonstrate this migration and to study the influence of two factors that may favor its occurrence: positioning of the syndesmotic screw and union of the fibula at the time of removal.
  
  
  OBJECTIVE
  An unhealed fibula at the time the distal tibiofibular syndesmotic screw is removed and its tricortical position promote the proximal migration of the fibular malleolus.
  
  
  METHODS
  This was a retrospective, single-center, analytical study that included 22 lengthening procedures in 18 patients from 5 to 17 years of age who had undergone tibial lengthening and presented a preoperative continuous fibula. The position of the fibular malleolus, union of the fibula, and the tri- or quadricortical position of the screw were assessed based on four successive x-rays.
  
  
  RESULTS
  Tricortical positioning of the syndesmotic screw was significantly associated with proximal migration of the fibular malleolus during lengthening (P=0.0248<0.05). However, there was no significant relation between an unhealed fibula and proximal migration of the fibular malleolus when the screw was removed (P=0.164>0.05).
  
  
  CONCLUSIONS
  Proximal migration of the fibular malleolus during lengthening is promoted by placing a non-quadricortical syndesmotic screw. Quadricortical positioning of the screw should be recommended. Migration of the fibular malleolus after ablation of the syndesmotic screw seems to be related to absence of fibular union but this series was too small to demonstrate this clearly.
  
  
  METHODS
  Level IV: Retrospective study.
authors.affiliation: Hôpital Timone-Enfant, 6, rue Jean-de-Bernardy, 13000 Marseille, France. Electronic address: camus.dimitri@hotmail.fr.
authors.forename: D
authors.initials: D
authors.lastname: Camus
authors.affiliation: Hôpital Timone-Enfant, 6, rue Jean-de-Bernardy, 13000 Marseille, France.
authors.forename: F
authors.initials: F
authors.lastname: Launay
authors.affiliation: Hôpital Timone-Enfant, 6, rue Jean-de-Bernardy, 13000 Marseille, France.
authors.forename: J-M
authors.initials: JM
authors.lastname: Guillaume
authors.affiliation: Hôpital Timone-Enfant, 6, rue Jean-de-Bernardy, 13000 Marseille, France.
authors.forename: E
authors.initials: E
authors.lastname: Viehweger
authors.affiliation: Hôpital Timone-Enfant, 6, rue Jean-de-Bernardy, 13000 Marseille, France.
authors.forename: G
authors.initials: G
authors.lastname: Bollini
authors.affiliation: Hôpital Timone-Enfant, 6, rue Jean-de-Bernardy, 13000 Marseille, France.
authors.forename: J-L
authors.initials: JL
authors.lastname: Jouve
mesh_terms: D000293:Adolescent; D000843:Ankle Joint / Q000000981:diagnostic imaging / Q000503:physiopathology; D001863:Bone Screws; D002648:Child; D002675:Child, Preschool; D005260:Female; D005360:Fibula / Q000000981:diagnostic imaging / Q000503:physiopathology* / Q000601:surgery; D005500:Follow-Up Studies; D006801:Humans; D018889:Ilizarov Technique; D007870:Leg Length Inequality / Q000601:surgery*; D008297:Male; D009068:Movement / Q000502:physiology*; D010027:Osteotomy / Q000009:adverse effects; D011859:Radiography; D012189:Retrospective Studies; D013977:Tibia / Q000601:surgery*
keywords: Fibular malleoli; Proximal migration; Syndesmotic screw; Tibial lengthening