Bosworth-type fibular entrapment fracture of the ankle without dislocation: a rare case report and a review of the literature

Bosworth ankle fracture-dislocation: current concept review

Bosworth fracture (BF) is a special type of locked ankle fracture-dislocation, characterized by displacement of a fragment of the fractured fibula from the fibular notch behind the posterior surface of the distal tibia. BF is a complex injury affecting multiple structures of the ankle joint, which is still frequently misjudged even today, potentially leading to severe complications. CT examination, including 3D reconstructions, should be the diagnostic standard in BF, as it provides a complete picture of the fracture pathoanatomy, most prominently the morphology of the frequently associated posterior malleolar fracture. BF requires early reduction of the displaced fibular fragment without repeated attempts on closed reduction. Non-operative treatment of BF almost always fails. The standard treatment procedure is early open reduction internal fixation. Due to the relative severity and paucity of the injury, BF seems to be particularly prone to soft tissue complications, including compartment syndrome. The results of operative treatment are mixed. Many studies report persistent pain even after a short time interval, with limitations of the range of motion or even stiffness of the ankle joint, and development of degenerative changes. Larger studies with long-term results are still missing.

Bosworth Fractures of the Ankle: A Systematic Literature Review

Bosworth lesions are fracture-dislocations of the ankle and are characterized by entrapment of the proximal segment of the fibula behind the posterior tubercle of the distal tibia. Treatment is challenging, mainly due to failure of a closed reduction. The aim of this study was to review the literature concerning this type of injury. A total of 103 patients with Bosworth fractures were included in the study. The analyzed studies yielded a total of 103 cases, of which 68% (n = 70) were male and 32% (n = 33) were female. Bosworth fractures are mainly due to accidental trauma (58.2%), sports-related injuries (18.4%), and traffic accidents (18.4%). More than 76% of the patients presented a Danis-Weber B fracture, 8.7% a type C fracture, and only 0.97% presented a type A fracture. In 92.2% of the patients, the attempted closed reduction was unsuccessful. A definitive treatment with open reduction and internal fixation (ORIF) was used in 96 patients (93.2%). The most frequent complication was post-traumatic arthritis (10.7%). Bosworth fractures are challenging. The available literature lacks adequate information about this fracture, and an approved standardized algorithm for treating such fractures is not available.

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.