Posterior Malleolus Fracture Displacement is Associated with Rotational Ankle Fracture Stability in Patients without Medial Malleolar Fractures. Issue 2 (December 2020)

• Record Type: Journal Article
• Authors: Levack, Ashley E.; Gausden, Elizabeth B.; Dvorzhinskiy, Aleksey; Wellman, David S.; Lorich, Dean G.
• Is Part Of: HSS journal. Volume 16:Issue 2(2020)Supplement
• Page Start: 238
• Page End: 244
• Publication Date: 2020-12
• Subjects: supination-external rotation -- posterior malleolus -- deltoid ligament -- ankle stability -- external rotation stress test -- medial clear space; Musculoskeletal system -- Surgery -- Periodicals; Orthopedic surgery -- Periodicals; Musculoskeletal System -- surgery -- Periodicals; Orthopedic Procedures -- Periodicals; Orthopédie -- Périodiques; Appareil locomoteur -- Maladies -- Périodiques; Appareil locomoteur -- Maladies -- Patients -- Réadaptation -- Périodiques; 617.47005
• DOI: 10.1007/s11420-019-09697-9
• Languages: English
• ISSNs: 1556-3316

Abstract

Background: The optimal method for the determination of ankle stability remains controversial in rotational ankle fractures without medial bony injury. Questions/Purposes: The purposes of this study were to (1) evaluate whether posterior malleolar (PM) fracture displacement is associated with deltoid ligament injury in supination-external rotation (SER) ankle fractures and (2) compare the diagnostic accuracy of PM displacement and magnetic resonance imaging (MRI) evaluation of the deep deltoid ligament in identifying fractures with deltoid ligament incompetence. Methods: Patients with rotational bimalleolar injuries containing lateral malleolar and PM fractures without bony medial injury were included. After operative lateral and PM fixation, an external rotation stress test was performed to evaluate deltoid ligament stability. Operative dictations were reviewed to confirm injury pattern, stability on stress test, and visual inspection of the deltoid ligament. Maximum PM displacement was assessed on lateral X-ray. Pre-operative MRI of the ankle was performed following closed reduction and splinting. Results: The final cohort consisted of 13 trimalleolar equivalent fractures (torn deltoid ligament) and 20 bimalleolar fractures (medial malleolus and deltoid ligament intact). Average PM displacement was significantly higher for SER trimalleolar equivalent patterns when measured on lateral X-ray. The sensitivity of detecting trimalleolar equivalent fracture was higher on all reported X-ray findings than the sensitivity obtained by the reported MRI findings of deltoid ligament injury. Conclusion: PM displacement on X-ray is a useful adjuvant along with external rotation stress radiography and MRI evaluation of deep deltoid integrity to distinguish between stable and unstable fracture patterns and thus helps facilitate treatment decisions.