SLR - July 2011 - Bryce Jolley
Reference: Stuart, K., Panchbhavi, V. The Fate of Syndesmotic Screws. Foot & Ankle International, (May 2011) Vol. 32, No. 5: 519-525
Scientific Literature Review
Reviewed by: Bryce Jolley, DPM, MHA
Residency Program: North Colorado Medical Center
Podiatric Relevance:
Syndesmotic injuries are commonly seen in the podiatric community, however, a standard protocol for their management has yet to be established. Debate persists regarding number of screws, screw diameter, number of cortices purchased, and the need for and timing of screw removal. The purpose of this study was to identify factors related to screw fixation that may lead to the ultimate failure of syndesmosis fixation.
Methods:
A retrospective assessment of 137 consecutive patients who underwent open reduction and internal fixation of the distal tibiofibular joint from 2004 to 2008 was performed. The mean patient age was 46 (range, 14 to 91) years. Mean follow-up was 5.3 months. The assessment consisted of ankle radiographs, fracture type (according to the Danis-Weber classification system), number of syndesmotic screws, number of cortices, screw diameter, screw location, adequacy of reduction, broken screws, screw loosening, and widening of the syndesmosis. Screw loosening was defined by radiographic evidence of screw back-out, the presence of sufficient osteolysis around a screw to allow a change in its coronal position within the tibia, or the documentation of screw loosening in the operative report at the time of removal. Quality of reduction was also noted. A fair reduction was defined by asymmetry of the ankle mortise less than 1 mm or increased medial clear space up to 4 mm. A good reduction was defined by 1 cm tibiofibular overlap and a symmetric ankle mortise. Loss of syndesmotic reduction was defined as medial clear space widening of 4 mm or greater, lateral talar shift of 1 mm or greater, or loss of normal tibiofibular overlap.
Results:
Broken or failed hardware was found in 30 patients (22%). Broken hardware consisted of 14 patients among whom two had single screw fixation, one had three screws, and eleven had two screws. In 57 patients 4.0-mm screws were utilized among whom six had screw breakage compared to eight out of 54 that had 3.5-mm screws (p= 0.0489). None of the 12 patients with 4.5-mm screws had screw breakage. Mean distance from the tibial plafond for broken syndesmotic screws did not differ from the mean distance for non-broken screws (1.3 cm and 2.7 cm for the distal and proximal screws, respectively).
Eight patients were found to have an unsatisfactory syndesmotic reduction at last follow-up. Of these eight, five patients were felt to have a good initial reduction of the syndesmosis while three patients were considered to have a fair reduction. Three patients experienced screw loosening and one patient sustained broken hardware. Transyndesmotic fixation was performed in seven of the eight patients. Five patients had tricortical fixation. Among patients with 3.5-mm screws, three lost reduction of the syndesmosis (5% of all patients with 3.5-mm screws) whereas five patients with 4.0-mm screws lost reduction (8% of all patients with 4.0-mm screws). No patients with 4.5-mm screws and no patients who underwent screw removal were noted to have a loss of reduction.
Conclusions:
Screw breakage or loosening in itself may be not be clinically significant, especially when such an occurrence is asymptomatic or happens after healing of the syndemosis. Based on findings of this retrospective study it is recommended that 4.0-mm or higher-diameter screws be used for syndesmosis stabilization. Routine screw removal should be discussed with the patient and does not appear to affect radiographic outcome.