SLR - April 2019 - Colin Mizuo

Single-Screw Fixation Compared with Double-Screw Fixation for Treatment of Medial Malleolar Fractures: A Prospective Randomized Control Trial

Reference: Buckley R, Kwek E, Duffy P, Korley R, Puloski S, Buckley A, Martin R, Rydberg Moller E, Schneider P. Single-screw fixation compared with double-screw fixation for treatment of medial malleolar fractures: a prospective randomized control trial. J Orthop Trauma. 2018 Nov; 32(11): 548–553.

Scientific Literature Review

Reviewed By: Colin Mizuo, DPM
Residency Program: Medstar Washington Hospital Center, Washington, DC 

Podiatric Relevance: Ankle fractures are a very common injury treated among foot and ankle surgeons. Isolated medial malleolar injuries are less common, but several techniques have been described to fixate these injuries, including lag screws, buttress plating, tension band wiring and k-wires. Double-screw fixation is the most common fixation technique used for medial malleolar fractures to control rotation. However, recent studies have suggested that double screw fixation increases the possibility of patient dissatisfaction relating to posterior tibial tendon irritation or other soft-tissue irritation. This study compares the functional outcomes between two randomized groups who underwent single- or double-screw fixation for a medial malleolus fracture.

Methods: A prospective randomized study was performed on 127 patients undergoing open reduction internal fixation for an ankle fracture with a medial malleolar fracture component at a single level 1 trauma center. Of the 127 patients included in the study, 61 were randomized to receive a single 4.0 mm partially threaded cancellous screw and 66 to receive double screw fixation. Functional outcomes were assessed using the Short Form 36 (SF-36) and the visual analog scale (VAS) for pain. The Ankle and Hindfoot Scale (AHS) was used to assess joint-specific outcomes related to pain, function and ankle alignment. Secondary outcomes include reoperation rates between groups, rates of malunion and nonunion, and time to union and complications, such as implant-related pain and loss of fixation.

Results: All patients in this study were surgically treated within 14 days of their initial injury. There was no difference in operating room time or hospital length of stay postsurgery. The need for syndesmotic fixation did not play a role in functional outcomes between the two groups. There was no difference in the AHS scores between the single- and double-screw groups at the three- and 24-month follow-up. Similar results were found between the two groups in the SF-36 scores. There was no significant difference between the two groups when it came to implant pain or need for removal. There were zero nonunions in this study.

Conclusion: The authors found no difference in soft-tissue pain or incidence of nonunions between single- and double-screw fixation of a medial malleolar fracture. It has been postulated that medial malleolar fractures require two-screw fixation to prevent nonunion, malrotation and failure of fixation. This concept is further applied to calcaneal osteotomies (MCDO, Dwyer) and STJ fusions where rotational forces might affect the surgical outcome. Previous studies regarding medial malleolar fracture fixation show no advantage to using two screws over one in good bone. The limitations to this study include, but are not limited to, the short-term follow-up of two years where the late implant removal pattern is unclear between one and two screws. A CT scan was not used to evaluate malrotation. In conclusion, single-screw fixation seems to provide similar results as double-screw fixation for medial malleolar fractures in the short to medium follow-up.

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