SLR - July 2020 - Eric M. Swenson

Functional Outcome and General Health Status After Plate Osteosynthesis Of Posterior Malleolus Fractures - The Quest for Eligibility 

Reference: Mertens M, Wouters J, Kloos J, Nijs S, Hoekstra H. Functional Outcome and General Health Status After Plate Osteosynthesis Of Posterior Malleolus Fractures - The Quest for Eligibility. Injury. 2020;51(4):1118-1124. doi:10.1016/j.injury.2020.02.109
Scientific Literature Review

Reviewed By: Eric M. Swenson, DPM
Residency Program: Mount Auburn Hospital – Cambridge, MA

Podiatric Relevance: Posterior malleolar fractures are present in approximately 46% of all Weber type B or C ankle fractures. Over time there has been  debate regarding surgical approach and fixation of these fractures. Historically, these fractures often went ignored or were simply reduced via ligamentotaxis and fixated with an anterior to posterior screw. We now know that reduction of these fractures are essential for syndesmotic stability as well as facilitating anatomical reduction of the fibula. Depending on the fracture pattern, open reduction internal fixation (ORIF) via a posterolateral or posteromedial approach facilitates direct reduction and fixation of posterior malleolar fractures. This study prospectively evaluated functional outcome and quality of life after plate osteosynthesis of posterior malleolar fractures and compared this with a retrospective cohort that did not receive direct reduction and fixation through a posterior approach.

Methods: A prospective cohort of 60 patients who sustained ankle fractures underwent ORIF of posterior malleolar fractures using plate osteosynthesis. This cohort was then compared to a retrospective patient cohort of 85 patients who underwent operative treatment for ankle fracture without a direct posterior approach orplate fixation of the posterior malleolar fracture. The minimum follow up time was 12 months. Exclusion criteria for both groups included: non-acute ankle fractures >4weeks; severe neurologic dysfunction; ipsilateral fracture of the tibia, talus or calcaneus; history of previous ankle fracture. Fifteen variables were grouped as demographic and operative characteristics. Fractures involving less than half the distal tibia incisura were classified as posterior malleolar fractures, larger fragments were considered posterior pilon fractures and excluded. Seven patient reported outcomes were recorded: AOFAS, EQ-5D, VAS, time trade off (TTO) score, lateral foot numbness, flexion deficit of hallux, and follow up time.

Results: Nineteen of 50 (38 percent) patients of the prospective cohort reported numbness of the lateral foot as well as 15/50 (30 percent) reported a flexion deficit of the hallux. AOFAS, EQ-5D, VAS and TTO showed no difference between patients with anterior to posterior fixation and nonoperative treatment, as well as no difference between anterior to posterior fixation and plate osteosynthesis. Plate fixation showed significantly lower AOFAS and TTO scores versus nonoperative treatment. Furthermore, EQ-5D on mobility and anxiety/depression were both significantly worse after plate fixation vs nonoperative treatment of posterior malleolar fractures.

Conclusions: There is no indication for routine plate osteosynthesis of all posterior malleolar fractures, since this was found to be associated with adverse effects. That being said there were some limitations to this study that could have influenced results. No routine postoperative CT scans were performed, follow-up times of the prospective cohort was half as long as  the retrospective cohort, and heterogeneity of the study groups makes it difficult to define unambiguous guidelines for the treatment of these fractures.

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