Introduction
Peroneal tendon subluxation is a condition affecting the outer part of your ankle, where the tendons responsible for stabilizing your foot may slip out of their normal position, causing discomfort or pain. The peroneal tendons, which run along the outer edge of your lower leg and behind the ankle bone (lateral malleolus), are crucial for foot movement and stability. Damage to the fibrous tunnel that holds these tendons in place can lead to them snapping in and out of their groove—a condition known as peroneal tendon subluxation.
Case Example
Imagine an active 35-year-old woman named Sarah, who loves to ski. One winter day, while skiing, she accidentally turned her foot sharply inward. She immediately felt a sharp pain on the outside of her ankle but was able to finish her day on the slopes. Over the following weeks, she noticed a strange snapping sensation on the outside of her ankle whenever she walked or moved her foot. After months of discomfort, Sarah visited her doctor and was diagnosed with peroneal tendon subluxation, which had been triggered by her ankle injury on the slopes. After trying non-surgical treatments without much success, Sarah eventually underwent surgery to repair her retinaculum and restore stability to her ankle.
This guide will help you understand:
- How peroneal tendon subluxation happens
- How doctors diagnose the condition
- What can be done to treat this problem
Anatomy: What Part of the Ankle is Involved?
The peroneal muscles and their tendons are located along the outer side of the lower leg bone (fibula), crossing behind the outside ankle bone (lateral malleolus). The tendons pass through a groove at the back of the lateral malleolus, where they are kept in place by a ligament called the retinaculum. The tendons glide in this groove like a pulley when the muscles contract, which allows the foot to point downward (plantarflexion) and outward (eversion).
Causes: Why Does Peroneal Tendon Subluxation Happen?
Peroneal tendon subluxation often results from an ankle injury, such as a sprain. During a typical ankle sprain, when the foot rolls inward (inversion), the peroneal tendons are forcibly stretched. This can tear the retinaculum, the ligament that holds the tendons in place, causing them to snap out of their normal groove. Sometimes the condition isn’t diagnosed right away because the focus is on other ligament injuries, leading to chronic issues later.
Other possible causes include:
- Repeated ankle sprains or trauma
- A shallow groove in the ankle bone
- Loose or weakened retinaculum due to congenital differences
Symptoms: What Does Peroneal Tendon Subluxation Feel Like?
If you have peroneal tendon subluxation, you may notice:
- A popping or snapping sensation on the outer edge of the ankle
- Visible movement of the tendons out of place when you move your ankle
- Pain or tenderness along the tendons
- Swelling behind the lateral malleolus (outer ankle bone)
Diagnosis: How is Peroneal Tendon Subluxation Diagnosed?
Your doctor will start by physically examining your ankle and may move it in different positions to check if the tendons snap out of place. Special tests, such as putting pressure on the ankle while you move your foot, help to confirm the diagnosis.
Imaging tests may also be used, including:
- X-rays to check for fractures or bone issues
- MRI scans to detect tears, swelling, or scar tissue around the tendons
Treatment: How Can Peroneal Tendon Subluxation Be Treated?
Nonsurgical Treatment
In early or mild cases, your doctor may recommend nonsurgical treatments like:
- Immobilization with a short-leg cast for 4–6 weeks to allow the retinaculum to heal
- Physical therapy to regain ankle strength and coordination
- Anti-inflammatory medications to reduce pain and swelling
However, nonsurgical treatments have only a 50% success rate in active patients, and long-term cases may require surgery.
Surgical Treatment
Surgery is often needed when nonsurgical treatments fail, or in chronic cases. Surgical options include:
- Retinaculum Repair: The torn retinaculum is stitched back into place to restore its function and prevent the tendons from slipping out of the groove.
- Groove Reconstruction: The groove behind the lateral malleolus is deepened to keep the tendons in place. A small bone flap is folded back, bone is removed, and the flap is replaced to deepen the groove.
- Bony Blocks: In some cases, a small piece of bone is moved to create a barrier, ensuring the tendons don’t slip out again.
Rehabilitation: What to Expect After Treatment
Nonsurgical Rehabilitation
If you avoid surgery, you will likely need a rehabilitation program with exercises to strengthen and stabilize your ankle. Physical therapy is important in regaining full function after a cast is removed.
After Surgery
Following surgery, patients are usually placed in a short-leg cast for about six weeks. A walking boot is worn for an additional four weeks, and physical therapy begins once the cast is removed. Full recovery can take up to six months, but with proper rehabilitation, most patients regain strength and mobility.