Comparison of partially threaded and fully threaded 4mm cancellous screws in fixation of medial malleolar fractures. A randomized clinical trial

BackhroundsDisplaced medial malleolar fractures typically require open reduction and internal fixation.Purchase of two partially threaded screws may be poor in the sparse cancellous bone ofdistal tibial metaphysis especially in osteoporotic bones. An increased number of threadsin fully threaded screws can improve purchase of screws and enhance the pullout strengththereby leading to better outcomes.MethodsIn a randomized clinical trial study 44 patients with displaced closed medial malleolarfracture randomly divided into two groups. In the first group two fully threaded 4 millimeter cancellous screws were used for fracture stabilization (FT group) and the second group wasoperated by use of two partially threaded 4 millimeter cancellous screws (PT group). Clinicalresults and complications were compared in two groups at one year follow up.Results19 patients in the FT group and 21 in the PT group were present at final follow up. Nonunionwas not developed in either group however two cases (%9) of delayed union occurredin the PT group. The rate of postoperative infection and symptomatic hardware were notstatistically different. (p= 0.6 ,0.33) Functional assessment using AOFAS, MOXFQ and VASscores showed no significant difference between the two groups. (p= 0.12 ,0.84 ,0.11)ConclusionsBoth fully and partially threaded 4mm cancellous screws can be considered as acceptablefixation devices for the fixation of medial malleolar fractures with good and comparableclinical results.