Bosworth fracture explained

Specialty:	orthopedic

The Bosworth fracture is a rare fracture of the distal fibula with an associated fixed posterior dislocation of the proximal fibular fragment which becomes trapped behind the posterior tibial tubercle. The injury is caused by severe external rotation of the ankle.^[1] The ankle remains externally rotated after the injury, making interpretation of X-rays difficult which can lead to misdiagnosis and incorrect treatment.^[2] The injury is most commonly treated by open reduction internal fixation as closed reduction is made difficult by the entrapment of the fibula behind the tibia.

The entrapment of an intact fibula behind the tibia was described by Ashhurst and Bromer in 1922, who attributed the description of the mechanism of injury to Huguier's 1848 publication.^[3] The injury involving fibular fracture with posterior dislocation was described by David M. Bosworth in 1947.^[4]

Treatment

Because of a fixed dislocation within the proximal fibular fragment posterior of the lateral ridge of the tibia, Bosworth fracture is typically irreducible using closed techniques. As a result, an early open reduction is required to avoid further complications.^[5]

Outlook

Complications such as cutaneous necrosis, superficial infection, compartmental syndrome, astragalus avascular necrosis, joint stiffness, superficial fibular nerve lesion, and secondary arthrosis are more common in the Bosworth injury compared to any other type of ankle fracture-dislocation. Delays in surgical reduction or repeated close reduction efforts are risk factors for poor results and an increased risk of complications.^[6]

Notes and References

1. Perry . CR . Rice S . Rao A . Burdge R. . Oct 1983 . Posterior fracture-dislocation of the distal part of the fibula. Mechanism and staging of injury. . J Bone Joint Surg Am . 65 . 8 . 1149–57 . 6630259 . 2009-10-10 . 10.2106/00004623-198365080-00016 . https://web.archive.org/web/20101101185423/http://www.ejbjs.org/cgi/reprint/65/8/1149 . 2010-11-01 . dead .
2. Hoblitzell . RM . Ebraheim NA . Merritt T . Jackson WT. . 1990 . Bosworth fracture-dislocation of the ankle. A case report and review of the literature. . Clin Orthop Relat Res. 255. 257–62 . 2112075.
3. Ashhurst . APC . Bromer RS . 1922 . Classification and Mechanism of Fractures of the Leg Bones Involving the Ankle. Based on a Study of Three Hundred Cases from the Episcopal Hospital. . Arch. Surg.. 4 . 51–129 . 10.1001/archsurg.1922.01110100060003.
4. Bosworth . DM . Jan 1947 . Fracture-Dislocation of the Ankle with Fixed Displacement of the Fibula behind the Tibia. . J Bone Joint Surg. 29 . 130–135. 20284692 .
5. Martin-Somoza . Francisco Jose . Picazo . David Ruiz . Cabezuelo . Jesús Amador Martinez . González . Ana Verdejo . Bosworth fracture. An atypical case of irreducible ankle fracture-dislocation . Trauma Case Reports . Elsevier BV . 28 . 2020 . 2352-6440 . 10.1016/j.tcr.2020.100322 . 100322. free . 32637534 . 7330149 .
6. Cho . Byung-Ki . Choi . Seung-Myung . Shin . Young-Duck . Prognostic factors for intermediate-term clinical outcomes following Bosworth fractures of the ankle joint . Foot and Ankle Surgery . Elsevier BV . 25 . 5 . 2019 . 1268-7731 . 10.1016/j.fas.2018.05.005 . 601–607. 30321945 .