Comparison of Partially Threaded and Fully Threaded 4mm Cancellous Screws in Fixation of Medial Malleolar Fractures

Background: Several devices have been described for fixation of displaced medial malleolar fractures. Fully threaded cancellous screws engaging the bone may provide advantages compared to partially threaded screws. This study was designed to compare the clinical results of fully and partially threaded 4 millimeter cancellous screws in fixation of medial malleolar fractures. Methods: In a randomized clinical trial study 44 patients with displaced closed medial malleolar fractures were randomly divided into two groups. Two fully threaded four millimeter cancellous screws were used for fracture stabilization (FT group) in the first group, while, the second group was operated by use of two partially threaded four millimeter cancellous screws (PT group). The clinical outcomes and complications were compared in two groups at one year follow up. Results: Nineteen patients in FT group and 21 in PT group were present at final follow up. Nonunion was not developed in either group but two cases (9%) of delayed union occurred in PT group. The rate of postoperative infection and symptomatic hardware were not statistically different. Functional assessment using AOFAS, MOXFQ and VAS scores showed no significant difference between the two groups. Conclusion: Both fully and partially threaded 4 mm cancellous screws can be considered as acceptable devices for the fixation of medial malleolar fractures with good and comparable clinical results.