SLR - May 2017 - Vanessa Cardenas

Dynamic Stress Testing Is Unnecessary for Unimalleolar Supination-External Rotation Ankle Fractures with Minimal Fracture Displacement on Lateral Radiographs
 

Reference: Simo Nortunen, MD, Hannu-Ville Leskela, MD, PhD, Heidi Haapasalo, MD, PhD, Tapio Flinkkila, MD, PhD, Pasi Ohtonen, MSc, and Harri Pakarinen, MD, PhD. Dynamic Stress Testing Is Unnecessary for Unimalleolar Supination-External Rotation Ankle Fractures with Minimal Fracture Displacement on Lateral Radiographs. J Bone Joint Surg Am. 2017 99:482–7.

Reviewed By: Vanessa Cardenas, DPM 
Residency Program: Temple University Hospital, Philadelphia, PA

Podiatric Relevance: Foot and ankle surgeons encounter ankle fractures pathology in daily practice. The controversy of when it is appropriate to conservatively or surgically address lateral malleolar fractures without talar displacement is present in the literature and in practice. Dynamic/stress radiographs are tools utilized to ascertain the degree of instability of these injuries and to make operative versus conservative treatment decisions. This study aims at categorizing factors in standard ankle radiographs that contribute to the stability of the ankle mortise in patients with isolated SER fractures of the lateral malleolus. 

Methods: Level IV Prospective study of 286 patients from two trauma centers. Nonstress radiographs from skeletally mature patients (> 16 y/o) of the mortise and lateral views, without medial clear space widening or incongruity, were collected. Two senior orthopaedic trauma surgeons from the two trauma centers performed manual external rotation stress test radiographs for stability reference. They also assessed fracture morphology at which time their measurements were blinded from each other (as well as results from the stress test).

Results: Two hundred seventeen patients had a stable injury (medial clear space of < 5 mm) based on the external rotation stress radiographs. Factors predicting stable ankle injury: posterior diastasis < 2 mm on lateral radiographs and when this factor and only two fracture fragments were present, the probability of a stable ankle mortise was 0.98 in 48 females and 0.994 for 37 males.

Conclusion: Based on the results of the study, in noncomminuted lateral malleolar fractures, when the fibula is posteriorly displaced < 2 mm on the lateral view, the ankle mortise can be diagnosed as stable without the need for stress radiographs.           

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