The Value of Additional Gravity Stress Radiographs for Decision Making in the Treatment of Isolated Type B Distal Fibular Fractures.

BACKGROUND

Prior to treatment decisions concerning isolated Weber type B ankle fractures, assessment of the stability of the ankle joint is mandatory. The gravity stress (GS) radiograph is a radiographic tool to determine stability. We hypothesized that this additional GS radiograph would lead to fewer operative treatments by applying the criterion of operative treatment when medial clear space (MCS) > superior clear space (SCS) + 2 mm on the GS radiograph, compared with the nonstressed mortise view criteria of advising operative treatment in case of MCS > SCS + 1 mm.

METHODS

This retrospective comparative cohort study analyzed 343 patients aged between 18 and 70 years with an isolated Weber type B ankle fracture diagnosed at the emergency department between January 2014 and December 2019. The cohort was divided into 2 groups based on whether an additional GS radiograph was performed. Group I consisted of 151 patients in whom a regular mortise and lateral radiograph were performed. Group II comprised 192 patients, with an additional GS radiograph. Primary outcome was type of treatment (conservative vs operative). Secondary outcomes were patient-reported functional outcomes and pain.

RESULTS

Baseline characteristics of both groups did not differ. In group I, surgery was performed in 60 patients (39.7%) compared with 108 patients (56.3%) in group II (P = .002). In the operatively treated patients, the mean MCS on regular mortise view was significantly smaller in patients in whom an additional GS radiograph was performed compared to patients without an additional GS radiograph (4.1 mm vs 5.2 mm, P < .001). Mean Olerud-Molander Ankle Score and mean visual analog scale (VAS) for pain did not differ significantly between groups I and II.

CONCLUSIONS

Contrary to what was hypothesized, the introduction of an additional gravity stress radiograph, by which operative treatment was indicated if the MCS was wider than the SCS + 2 mm, did not result in reduced operative treatment of Weber type B ankle fractures when operative treatment was indicated for MCS > SCS + 1 mm on non-gravity stress radiographs.

LEVEL OF EVIDENCE: Level III: retrospective comparative study.