Bimalleolar and trimalleolar ankle fractures
Contributors: Robert Lachky MD, Eric Ingerowski MD, FAAP
Synopsis
Bimalleolar and trimalleolar
ankle fractures involve twisting or impaction injury to the ankle with pain, swelling, and often visible deformity. These injuries typically occur during high-energy activities, ie, they are usually some kind of torsional injury (sports, etc) versus being due to an automobile accident. The average age of patients in one study was 27.5 years.
The number of fractures determines whether the injury is "bimal" or "trimal." They very often occur in the setting of polytrauma. Think of lateral malleolus fractures with medial deltoid ligament disruption as "bimal-equivalents."
In most cases, patients will present immediately after an injury. Swelling can progress rapidly, and the degree of swelling has a major impact on the timing of surgery and can lead to complications.
With all suspected ankle fractures, it is important to:
- Get a basic history (eg, whether injury occurred during sports activity, a fall from a height, or a car accident).
- Perform a thorough physical examination, including assessment for neurovascular deficit.
- Reduce the fracture if necessary (particularly if there is a neurovascular deficit).
- Evaluate x-rays for stability. NOTE: By definition, these injuries are unstable, as 2 structures are "out."
This is a radiographic rather than clinical diagnosis. Surgery is necessary.
Call orthopedics.
Codes
ICD10CM:
S82.843A – Displaced bimalleolar fracture of unspecified lower leg, initial encounter for closed fracture
S82.846A – Nondisplaced bimalleolar fracture of unspecified lower leg, initial encounter for closed fracture
S82.853A – Displaced trimalleolar fracture of unspecified lower leg, initial encounter for closed fracture
S82.856A – Nondisplaced trimalleolar fracture of unspecified lower leg, initial encounter for closed fracture
SNOMEDCT:
123975002 – Trimalleolar fracture
263244000 – Bimalleolar fracture of ankle
Differential Diagnosis & Pitfalls
To perform a comparison, select diagnoses from the classic differential
Last Reviewed:06/24/2018
Last Updated:06/28/2018