Syndesmosis fixation in bimalleolar weber C ankle fractures; comparison of 3.5 and 4.5-mm screws

ABSTRACT

To study the influence of size of screws for syndesmosis fixation in bimalleolar Weber C ankle fracture. A prospective randomised controlled clinical trial. Orthopaedic Department at Combined Military Hospital Malir. From October 2002 to September 2005. 17 consecutive young active patients with Weber type C bimalleolar ankle fractures having syndesmotic injuries treated with open reduction and internal fixation were randomly allocated to two groups. In group I [n[1] = 9] 3.5mm small fragment and in group II [n[2]=8] 4.5mm large fragment AO cortical screws were used for syndesmotic fixation. All patients were followed up for 12 months. Fracture healing or loss of reduction of syndesmosis was taken as the study end point. Hardware loosening or breakage and need for hardware removal were the outcome measures. Subjective and objective assessment with Olerud-Molander Ankle [OMA] scores1, range of motion and radiographic criteria was done. Loss of reduction was not seen in any patient in both groups. Comparing two groups using paired sample t-test, there was no difference in screw loosening and breakage [p values > 0.05]. We did not find a statistically significant difference between range of motion [p = 1.08] and OMA score [p-value = 0.805]. Size of the syndesmotic screw does not appear to influence healing of syndesmotic injury. Screw loosening, which can result in reduced range of ankle motion postoperatively was more common in smaller screw group though the difference was not significant