Rare Ankle Fracture Pattern: Bosworth Fracture can Lead to Post-Traumatic Arthritis if Unrecognized Early

A Case Series of Bosworth Fracture-Dislocations and Review of 129 Reported Cases

Introduction

Bosworth fracture dislocations of the ankle are rare injuries of the ankle caused by extreme external rotation of the supinated foot where the proximal fibula fracture fragment is posteriorly dislocated and entrapped behind the posterior-lateral ridge of the tibia. This case series aims to document three such cases treated in our institution over a nine year period. We also provide a review of 129 cases in the existing literature.

Materials and methods

Medical records and relevant radiographs for each patient were analysed and collected from the time of presentation till the point of latest follow-up. During each clinic visit, all physical exam findings as well as all complications were recorded. The American Foot and Ankle Society (AOFAS) Hindfoot score was also tabulated for each patient at the point of latest review.

Results

Closed reduction was unsuccessful in all three patients, and all required open reduction. One patient had an uncomplicated recovery whilst the remaining two suffered significant soft tissue complications. One patient suffered severe soft tissue swelling preventing primary closure at the time of surgery, whilst another suffered post-operative wound dehiscence and infection. Eventually all fractures healed, and all three patients obtained satisfactory AOFAS scores.

Conclusion

The diagnosis of Bosworth fracture dislocations of the ankle is often delayed or missed, due to its rare occurrence. Closed reduction is often unsuccessful, and early open reduction is required to avoid poor clinical outcomes due to severe soft tissue damage or even compartment syndrome.

Posterior malleolus fractures in Bosworth fracture-dislocations. A combination not to be missed

OBJECTIVES

Posterior malleolar fractures (PM) have been linked to inferior outcome in malleolar fractures. This study aims to analyze the prevalence and pathoanatomy of PM fractures in Bosworth fracture-dislocations (BF).

MATERIALS & METHODS

Radiographs and computed tomography (CT) scans of 13 patients treated at our institution and 97 cases published between 1947 and 2018, identified in a systematic literature search, were evaluated with respect to the pathoanatomy of BF. In all 13 cases from the present study and in 10 cases from the literature, axial CT scans were performed.

RESULTS

All 13 patients (100%) with BF from the present series and 61 of 97 documented cases (63%) of BF from the literature were associated with a PM fracture. In patients with a complete CT analysis, dislocation of the fibula behind the posterior tibial rim was associated with extraincisural (Bartoníček / Rammelt type 1) PM fractures. Displacement of the fibula between the displaced PM fragment and the tibia was associated with Bartoníček / Rammelt types 2 and 3 PM fractures.

CONCLUSIONS

Seventy prevent of all reported BF are associated with a PM fracture. The true prevalence may be even higher because of the historically infrequent use of CT imaging. The pathoanatomy of the PM fragment is highly variable as is the kind of fibular displacement in BF. Therefore, CT scanning should be performed routinely in BF. Displaced PM fractures in BF involving the incisura should be treated operatively via a direct posterolateral approach.

Bosworth Dislocation without Associated Fracture

One of the rarest ankle injuries is the Bosworth fracture-dislocation, whereby the distal fibula fractures and is lodged behind the tibia and is often unable to be reduced in a closed fashion. Even more rarely, a Bosworth dislocation without any accompanying fractures may occur. In this case, a 19-year-old male presented with a Bosworth dislocation, with the ipsilateral tibia having previously undergone intramedullary nailing. After closed reduction was attempted, open reduction and fixation was performed, directly reducing the fibula and fixing the unstable syndesmosis with 2 quadricortical screws. Bosworth injuries are rare, yet severe, and should be treated in a timely manner. We were able to provide good reduction and fixation without requiring removal of the intramedullary nail, and we support the use of 2 quadricortical screws as a valid treatment option for the fixation of Bosworth dislocations.