RESUMO
BACKGROUND: Many approaches to management of medial malleolar fractures are described in the literature however, their morphology is under investigated. The aim of this study was to analyse the morphology of medial malleolar fractures to identify any association with medial malleolar fracture non-union or malunion. METHODS: Patients who had undergone surgical fixation of their MMF were identified from 2012 to 2022, using electronic patient records. Retrospective analysis of their preoperative, intraoperative, and postoperative radiographs was performed to determine their morphology and prevalence of non-union and malunion. Lauge-Hansen classification was used to characterise ankle fracture morphology and Herscovici classification to characterise MMF morphology. RESULTS: A total of 650 patients were identified across a 10-year period which could be included in the study. The overall non-union rate for our cohort was 18.77% (122/650). The overall malunion rate was 6.92% (45/650). Herscovici type A fractures were significantly more frequently mal-reduced at time of surgery as compared to other fracture types (p = .003). Medial wall blowout combined with Hercovici type B fractures showed a significant increase in malunion rate. There is a higher rate of bone union in patients who had been anatomically reduced. CONCLUSION: The morphology of medial malleolar fractures does have an impact of the radiological outcome following surgical management. Medial wall blowout fractures were most prevalent in adduction-type injuries; however, it should not be ruled out in rotational injuries with medial wall blowouts combined with and Herscovici type B fractures showing a significant increase in malunions. Herscovici type A fractures had significantly higher malreductions. LEVEL OF EVIDENCE: Level 3 - Retrospective Cohort Study.
RESUMO
BACKGROUND: To date, there have been no studies describing the characteristics of posteromedial fragment in the posterior malleolus fracture. The aim was to investigate the variability of posteromedial fracture fragments to enable better surgical planning. METHODS: All Mason and Molloy type 2B fractures, defined as fracture of both the posterolateral and the posteromedial fragments of the posterior malleolus, from our database were identified to analyze the preoperative computed tomography scan. The posteromedial fragment was investigated in 47 cases (mean age, 46.6 years; 11 male, 36 female). RESULTS: Morphologically, the fracture could be divided into 2 subtypes: (1) a large pilon intra-articular fragment (mean of X axis: 33.0 mm, Y: 30.7 mm, Z: 31.7 mm) presented in 29 cases with mean interfragmentary angle of 32.1 and back of tibia angle of 32.7 degrees (this was seen in 25 of 27 cases with supination injury pattern); and (2) a small extra-articular avulsion fragment (mean of X axis: 9.6 mm, Y: 13.2 mm, Z: 11.5 mm) present in 18 cases with a mean interfragmentary angle of 11.0 and back of tibia angle of 10.1 degrees. It was seen in 80% of pronation injuries. CONCLUSION: The avulsion type of the posteromedial fragment of posterior malleolus fracture was more common in pronation injuries, likely the result of traction by the intermalleolar ligament, and the pilon type was more common in supination injuries, likely the result of the rotating talus impaction. Because of the intra-articular involvement, we believe the pilon type should undergo fixation to achieve articular congruity, unlike the avulsion type which may only function as a secondary syndesmotic stabilizer. LEVEL OF EVIDENCE: Level III, retrospective comparative series.