imprint:
[Erscheinungsort nicht ermittelbar]: Oulun yliopisto, 2018
Language:
English
Origination:
University thesis:
Dissertation, Oulun yliopisto, 2018
Footnote:
Description:
Abstract Isolated lateral malleolar supination-external rotation (SER) -type ankle fractures without incongruity on the standard radiographs can be either stable or unstable depending on the status of the deep deltoid ligament. Neither clinical signs of injury on the medial aspect of the ankle nor the displacement of fibular fracture on mortise radiographs seem to predict stability. Therefore, stress testing has been adopted in clinical use. No gold standard" method exists but the manual external rotation (ER) stress test is the most extensively studied. The ER stress test has some disadvantages, and other methods—such as gravity stress radiography and magnetic resonance imaging—have been suggested instead. However, the evidence to support the use of these methods is still insufficient. The aims of this dissertation were to assess the roles of (1) morphological factors from standard radiographs of 286 patients, (2) clinical findings on the medial side of the ankle and gravity stress radiography of 79 patients, and (3) MRI of 61 patients in evaluating the stability of the ankle mortise in patients with unimalleolar SER-type fractures with no talar shift on standard radiographs. The ER stress test result was considered to be the reference for stability throughout these studies. We found that a fracture line width < 2 mm in lateral radiographs, only two fracture fragments, and female sex are independent factors predicting a stable ankle mortise. Neither clinical signs on the medial side of the ankle nor gravity stress radiography alone predict the stability of the ankle mortise accurately. According to our MRI findings, total tears of the deep deltoid ligaments are rare, and partial tears are common in this this patient group. The reliability of the MRI assessment is only moderate. In conclusion, patients with non-comminuted fractures and < 2 mm displacement on lateral radiographs have stable ankle mortises and need no further stress testing. The gravity stress radiography is an accurate test for the evaluation of the ankle mortise stability only if the clinical signs indicate a similar result with the gravity stress radiographs. The use of MRI provides no additional benefit compared to ER stress testing for stability evaluation of an SER-type ankle fracture.