ANKLE FRACTURES INVOLVING THE FIBULA PROXIMAL TO THE DISTAL TIBIOFIBULAR SYNDESMOSIS

Thirty-two cases of ankle fractures associated with fibular fractures above the distal tibiofibular syndesmosis were studied. All were treat ed with open reduction and internal fixation. The average follow-up wa s 25 months. The results of the postoperative evaluation were rated, b ased on subjective clinical criteria, as good, fair, and poor. Accordi ng to the Lauge-Hansen classification, there were 17 (53%) cases of su pination-external rotation injury (2 stage 2 and 15 stage 4), 9 (28%) cases of stage 3 pronation-abduction injury, and 6 (19%) cases of pron ation-external rotation injury (3 stage 3 and 3 stage 4). All cases co uld be classified as Weber type 6 or as suprasyndesmotic, fibular diap hyseal fracture (44-C) according to the Orthopaedic Trauma Association classification. In 18 (56%) cases, the fracture was associated with a nkle dislocation. There were seven (22%) open fractures (two grade I, four grade II, and one grade IIIA). Syndesmotic screws were used in 23 (72%) cases (12 supination-external rotation injury, 6 pronation-exte rnal rotation injury, and 5 pronation-abduction injury). The syndesmot ic screw was removed after an average of 9 weeks. Four (13%) nonunions and two (6%) delayed unions of the fibula were treated with bone graf ting and/or hardware revision and eventually healed. Three of the nonu nions had poor clinical results because of degenerative ankle joint ar thritis in two (one of them ended in arthrodesis) and deep infection, which was eventually cured, in the third. The fourth nonunion had a fa ir result. One of the delayed unions had a fair result (an obese patie nt) and the other had a good result. Two patients developed deep infec tions; one ended in gangrene and amputation in a diabetic patient, and the other was a patient with fibular nonunion that eventually healed. Three patients had superficial infections that were treated successfu lly. Of the 32 cases, 23 (72%) showed good results, 4 (13%) showed fai r results, and 5 (16%) showed poor results. The cases with poor result s included three fibular nonunions, one deep infection, and one recurr ent superficial infection and wound dehiscence after hardware removal. A syndesmotic screw is usually needed in cases of fracture-dislocatio ns. Two patients with occult fibular nonunions developed diastasis of the syndesmosis after removal of the syndesmotic screw. It was found t hat reduction and temporary pinning of the distal tibiofibular joint h elps achieve fibular length, which is crucial to restoring the biomech anics of the ankle joint. It seems advisable not to remove the syndesm otic screw until there are signs of healing of fibular fracture to avo id diastasis of the distal tibiofibular joint. Done grafting should be considered in high energy fractures with comminution. These complex i njuries are associated with higher rates of complications. Poor result s can be attributed to fracture factors, e.g., open fractures, infecti ons; patient factors, e.g., obesity, lowered immunity as in diabetes, and noncompliance; and iatrogenic factors, e.g., early removal of synd esmotic screws.