What is an Unstable Ankle Fracture?

---

What Is an Unstable Ankle Fracture?

Ankle fractures are among the most common orthopedic injuries, especially in active individuals and older adults. But not all ankle fractures are the same. One important distinction orthopedic specialists make is whether the fracture is stable or unstable. This classification significantly impacts how the injury is treated and how quickly a patient can return to normal activity.

Understanding the Anatomy

The ankle joint is made up of three bones:

    •    Tibia (shinbone)

    •    Fibula (the thinner bone on the outside of the leg)

    •    Talus (a small bone that sits between the heel and the tibia/fibula)

These bones are held together by strong ligaments and form a hinge joint that allows for movement and weight-bearing. When one or more of these bones break, the stability of the entire joint can be compromised.

What Makes an Ankle Fracture Unstable?

An unstable ankle fracture typically involves:

    •    Multiple broken bones (often both the tibia and fibula)

Unstable Ankle Fracture

    •    Disruption of the ankle mortise, the socket where the tibia and fibula meet the talus

    •    Ligament damage, especially the syndesmosis (the ligament that holds the tibia and fibula together at the ankle)

In these cases, the bones are misaligned or the joint is no longer able to support weight, making it unstable. This type of fracture usually requires surgical intervention to restore joint alignment and stability.

Common Causes

Unstable ankle fractures are often the result of:

    •    High-impact trauma (e.g., car accidents or sports injuries)

    •    Twisting injuries from falls

    •    Missteps on uneven ground

    •    Ankle sprains severe enough to break the bone and tear ligaments simultaneously

Symptoms

Patients with an unstable ankle fracture may experience:

    •    Immediate and severe pain

    •    Swelling and bruising

    •    Inability to bear weight

    •    Visible deformity or misalignment of the ankle

    •    Numbness or tingling if nerves are affected

Diagnosis

Diagnosis is confirmed through:

    •    Physical examination to assess swelling, deformity, and joint instability

    •    X-rays to evaluate the extent and pattern of the fracture

    •    CT or MRI scans in complex cases or when soft tissue injury is suspected

Treatment Options

Unlike stable fractures, which may be treated with casting or a walking boot, unstable fractures usually require surgery. The goal of surgery is to realign the bones (reduction) and secure them with hardware such as plates and screws (internal fixation).

Post-operative care typically includes:

    •    A period of non-weight-bearing to allow for healing

    •    Physical therapy to restore motion and strength

    •    Gradual return to activity over several months

Recovery and Prognosis

Recovery depends on the severity of the injury and the patient’s overall health. While most people can expect to return to normal activities, high-energy injuries or delayed treatment may lead to complications such as:

    •    Chronic pain

    •    Post-traumatic arthritis

    •    Decreased range of motion

When to See a Specialist

If you suspect an ankle fracture — especially if there is visible deformity or you can’t put weight on the leg — seek immediate medical attention. Prompt diagnosis and proper management are key to a successful outcome.

---

Nicholas Wessling, M.D.

Board-Certified Orthopedic Surgeon

Specializing in Foot & Ankle Surgery and Sports Medicine

If you’re dealing with an ankle injury and want expert care tailored to your lifestyle and recovery goals, schedule a consultation with Dr. Wessling today. Call 212-737-3301 or click the "Book Online" button above.