Peroneal tenosynovitis is often caused by overuse, especially in athletes who engage in repetitive activities like running, jumping, or lateral movements. However, it can also develop from acute injuries or poor biomechanics, such as excessive inversion or eversion at the ankle. Other contributing factors include muscle imbalances, tight calf muscles, flat feet (overpronation), poor running technique and poor load management (including excessive increases in loading).

1. Patients with peroneal tenosynovitis typically present with the following symptoms:

   • Pain along the lateral aspect of the ankle, which may worsen with activity and improve with rest. Start up pain is usually reported, which is pain that is quite high when moving after a period of sleeping or sitting.
   • Tenderness on palpation of the peroneal tendons, particularly near the fibula and the groove in the ankle where the tendons pass.
   • Difficulty with activities involving running, jumping, or walking on uneven surfaces.
   • Reduced ankle mobility, especially with eversion and dorsiflexion, due to tendon stiffness and pain.
   • Weakness in the ankle, particularly with foot eversion and plantar flexion.

Diagnosis of peroneal tenosynovitis is primarily clinical, based on patient history, symptoms, and physical examination. Patients will often walk with a limp. Looking at the outside of the ankle, there may be some subtle (or not so subtle) swelling behind the lateral malleolus (the prominent bone on the outside of the ankle). Pressing on this area will often create discomfort. Many patients will have a higher and stiffer arched foot, with increased ankle inversion (inward motion) compared to eversion.

Imaging techniques such as ultrasound or MRI can be used to confirm the diagnosis, assess the degree of inflammation or tendon damage, and rule out other conditions such as tendon tears, fractures, or osteoarthritis.

Effective treatment for peroneal tenosynovitis focuses on reducing inflammation, improving tendon function, and preventing recurrence through appropriate rehabilitation. A combination of manual therapy, exercise, and modalities has shown to be highly beneficial in managing this condition.

1. Rest and activity modification

Initial management includes rest to allow the tendons to heal and reduce inflammation. This may involve activity modification, such as avoiding high-impact sports or activities that exacerbate symptoms. Ice therapy can also be applied during the acute phase to manage swelling and pain.

2. Manual therapy

Manual therapy techniques, such as soft tissue mobilisation and joint mobilisations, can be effective in reducing stiffness and improving the mobility of the ankle joint. Joint mobilisations can particularly be directed at the stiff joints of the foot in and around the arch.

3. Strengthening exercises

Once the tendon has settled down, isometric holds, heavy isotonic strengthening and eccentric strengthening exercises for the peroneal muscles are essential for rehabilitation. The goal is to gradually build the strength and capacity of the peroneal muscles to improve the resilience of the tendon. Specific exercises include:

• Proprioceptive training, such as balancing on one leg, to enhance ankle stability.
• Resisted eversion exercises using bands or weights.
• Calf raises to improve plantar flexor strength.

4. Education and advice

Further thought can be given to biomechanical abnormalities (such as overpronation or excessive inversion) are contributing factors. Footwear adjustments can also be helpful, as those with stiff high arches are thought to be better suited to a curved, less supportive shoe.