The additional value of weight-bearing radiographs in assessing stability of isolated type B fibular fractures.

Abstract

In isolated type B fibular fractures, the decision whether to operate or treat conservatively is principally based on congruency and stability of the ankle joint. The purpose of the current study is to examine the additional diagnostic value of the weight-bearing radiograph (WBR) in assessing stability of potentially unstable type B fibular fractures. In this retrospective cohort study, patients were selected based on who presented an isolated type B fracture of the fibula. Unstable fractures were directly planned for surgery. Other patients underwent additional weight-bearing imaging 4-7 days after initial trauma, on which definitive treatment was based. The medial clear space (MCS) was compared between the WBR and the conventional radiograph. A total of 70 patients were included in the period January 2018-December 2021. The average MCS on conventional mortise radiograph was 3.56 mm compared to 3.02 mm on the WBR(p<0.05). The superior clear space (SCS) was equal between both groups (respectively 3.12 mm and 3.08 mm, p = 0.44). All 70 patients were initially treated conservatively with immediate weight-bearing in a brace or soft cast. One patient had the need for open repair and internal fixation due to non-union. Different techniques for the assessment of deep deltoid ligament integrity exist, such as the MRI, the ultrasonography and different kinds of stress test radiographs. As fractured ankles don't need direct fixation and operative treatment can be postponed, a stepped approach for the assessment of deep deltoid ligament (DDL) integrity can be of assistance in assessing ankle stability. In isolated type B fibular fractures a stepped approach, using the weight-bearing radiograph can be of additional value in assessing the stability. It is a low cost, prevents unnecessary surgery and contributes to a quick weight-bearing non-operative treatment.