Overview

A trimalleolar ankle fracture occurs when the ankle joint sustains three fractures:

• Lateral malleolus: The lower section of the fibula, positioned near the ankle joint^1,2
• Medial malleolus: The inner portion of the lower tibia, close to the ankle joint^1,2
• Posterior malleolus: The rear section of the tibia, aligning with the ankle joint^1,2

Roles of the ankle, fibula and tibia

The ankle, a key joint of the musculoskeletal system, plays an essential role in the movement and stability of the human body. It bears your body weight and enables movements such as jumping, running, and walking.³ Serving as a hinge joint, it facilitates dorsiflexion (lifting the foot upward) and plantar flexion (pointing the foot downward). Both of these movements are fundamental for everyday activities that we complete within our homes or outside such as going up a set of stairs, standing, or even adjusting to different surfaces. Moreover, whilst we move the ankle, it also allows for slight rotational adjustments which help maintain balance and adapt to uneven surfaces, reducing the risk of injury.^3,4

The tibia is the most significant load-bearing bone in the lower leg and is accountable for distributing body weight from the leg to the foot. It provides stability and appropriate alignment by making up the majority of the ankle joint's structure.³ Important functions in preserving the integrity of the joint are performed by the posterior malleolus and medial malleolus.^1,2 Mobility, joint stability, and weight distribution can all be greatly impacted by damage to these components, such as evident in a trimalleolar fracture.⁴ 

For ankle lateral stability, the fibula plays a significant role even though it's smaller and less weight-bearing than the tibia. Many muscles and ligaments controlling ankle movement and balance do attach to it. The lateral malleolus, which is the fibula's lower end, prevents excessive outward foot movement, giving support to the ankle joint. Although non-weight bearing, the integrity of the fibula is essential in normal joint functioning, especially that of stabilising the leg as well as inhibiting excess movement of the ankle that would bring about damage.⁵

Collectively, the ankle, fibula and tibia work in sync to effectively permit flexibility, mobility, and support, necessitating the vital functions for everyday activities and daily movement. In a trimalleolar fracture where all of these structures are compromised, substantial treatment and rehabilitation are often required to restore the function of the ankle and prevent long-term complications.

Causes of a trimalleolar fracture

• High-impact trauma: includes direct injuries to the ankle, falls from a height, and vehicular accidents^2,6
• Injuries involving twisting: extreme rotational stresses, like in dancing, jumping or skipping^2,6
• Falls: uncomfortable foot landing (particularly if from a significant height)^2,6
• Sports injuries: Sudden switches of direction, particularly in basketball, football or rugby^2,6
• Bone conditions: The risk of fractures from minor trauma is increased by present arthritis, osteoporosis or previous fractures to the ankle^2,6

Clinical signs and symptoms

Severe pain

A clear indication of a trimalleolar fracture is severe pain in the ankle. This pain is usually sharp and throbbing, particularly around the site of the fracture. It often intensifies with movement, weight-bearing on the foot, or even gentle touch. The discomfort can be so overwhelming that standing or walking on the affected foot becomes nearly impossible.

To assess the severity of pain, most healthcare professionals often use the Numerical Pain Rating Scale (NPRS-11). This 11-point scale allows patients to rate their pain on a scale from 0 (no pain) to 10 (extreme pain, worst possible). This scale helps quantify pain intensity and can aid in monitoring pain management over time.^7,8

 Pain is typically categorised as:

• 0–3: No to mild pain
• 4–6: Moderate pain
• 7–10: Severe pain

Swelling 

Swelling is among the most apparent signs of a trimalleolar fracture. As the body reacts to the trauma, this occurs shortly after the damage. The afflicted ankle may feel tight to the touch and will appear substantially larger. Swelling may be restricted to the ankle alone, or it may extend to the foot and lower leg, depending on how severe the damage is. Moving around can be challenging due to swelling, and may still feel uncomfortable while at rest.⁹

Clinically, it is assessed through visual inspection, noting skin tightness and asymmetry compared to the uninjured ankle. Palpation checks for firmness, tenderness, and pitting skin, while circumferential measurement highlights the swelling’s extent in comparison to the uninjured adjacent ankle.¹⁰ Range of motion tests help evaluate functional limitations. In severe cases, imaging like an ultrasound or Magnetic Resonance Imaging (MRI) may be used to assess soft tissue involvement.²

Bruising

Bruising usually develops within hours following a trimalleolar fracture and will be evident at the time of assessment to healthcare professionals. At the fracture site, the skin may appear red or purple at the beginning, and later alternatively change to blue, yellow, or green as the bruising heals. Furthermore, the bruising can radiate to the foot or lower leg, due to the severity of the injury. Severe bruising suggests prominent tissue damage and may be associated with other complications, such as internal bleeding.^2,10

Deformity and inability to bear weight

Deformity is frequently the outcome of a trimalleolar fracture, especially as the bone may become displaced. This results in unusual foot posture, apparent angulation, or rotational changes. Weight-bearing becomes practically impossible due to the fractured bones' inability to offer structural support, which frequently results in instability. In an attempt to reduce discomfort, patients may automatically keep their ankles up.¹⁰ 

A visual inspection is the first step in clinical assessment, where a medical professional will look for misalignment or an abnormal foot posture. Palpation confirms bone displacement and tenderness, in addition to instability tests which involve applying gentle pressure to detect abnormal joint movement.¹⁰ Clinicians may ask the patient to try standing or walking to assess their weight-bearing capacity. A serious fracture would be indicated by increased discomfort, dependence on help, and an incapacity to support weight. Verifying the fracture through imaging is crucial for medical practitioners to decide on the best course of action.

Numbness

If there is nerve damage or compression due to swelling, a numbness, tingling, or pins-and-needles sensation can occur in the toes or the foot. There may be loss of sensation in severe cases if the nerves are severely damaged. Sensory loss will be examined by clinicians with light touch, pain, and vibration sense. 

Testing and treatment of a trimalleolar fracture 

A trimalleolar fracture is generally classified as unstable because of the disruption of the structure in the ankle joint.⁹ Due to the involvement of all three malleoli, non-surgical treatment is not usually an option, as it would lead to inadequate healing and long-term effects like arthritis, instability and malunion.

Testing and diagnosis

A trimalleolar fracture is diagnosed through:

• Physical examination by a healthcare professional¹¹ 
• X-rays: to assess bone displacement and confirm the malleolar fractures¹¹ 
• Computed Tomography (CT) scan: provides detailed imaging of complex fractures¹¹ 

Treatment

Surgical approach: Open reduction and internal fixation (ORIF)

The conventional surgical management for trimalleolar fractures is Open Reduction and Internal Fixation (ORIF), consisting of two important steps:

1. Open Reduction: The bones are repositioned by the surgeon to their normal anatomical location^12,13
2. Internal Fixation: The realigned bones are secured using hardware such as plates, screws, or rods to maintain stability and promote proper healing. The choice of fixation depends on the fracture pattern and severity^12,13

Summary

In summary, a trimalleolar fracture is a serious and rare injury which significantly affects mobility, stability, and weight-bearing functions of the ankle. The main signs and symptoms associated include bruising, deformity of the joint, inability to bear weight on the foot, intense pain, numbness and swelling. Owing to the implication of all three malleoli within the joint, this fracture is fundamentally unstable, necessitating surgical intervention in nearly all cases. Open Reduction and Internal Fixation (ORIF) is the preferred treatment, as it valuably restores joint alignment, is associated with superior healing qualities, and minimises the risk of long-term complications such as post-traumatic arthritis and chronic instability. Accurate diagnosis through clinical examination by healthcare professionals and CT or MRI imaging is critical to ensuring favourable outcomes.