Lateral ankle pain a.k.a., pain on the outside of your foot and ankle is most commonly caused by peroneal tendon injuries and/or sinus tarsi syndrome. This is true in the absence of trauma, like a lateral ankle sprain or ankle fracture.

Peroneal Tendinopathy

The most common repetitive stress or overuse injury causing lateral ankle pain is peroneal tendinopathy. The peroneus longus and peroneus brevis tendons cross the ankle joint within a fibro-osseous tunnel, posterior to the lateral malleolus (behind the bone). The peroneus brevis tendon inserts into the tuberosity on the lateral aspect of the base of the fifth metatarsal. The peroneus longus tendon passes under the plantar surface of the foot to insert into the lateral side of the base of the first metatarsal and medial cuneiform. The peroneal tendons share a common tendon sheath proximal to the distal tip of the fibula, after which they have their own tendon sheaths. The peroneal muscles serve as ankle dorsi flexors in addition to being the primary evertors of the ankle.

Peroneal Tendinopathy may either as a result of an acute ankle inversion sprain, but more commonly is secondary to an overuse injury. Soft footwear or running barefoot may predispose to the development of peroneal tendinopathy. Common causes of an overuse injury include:

  • Excessive eversion of the foot such as occurs when running on slopes or cambered surfaces.
  • Excessive pronation of the foot.
  • Secondary to tight calf muscles (most commonly soleus) resulting in excessive load on the lateral muscles.
  • Excessive action of the peroneal (e.g. dancing, gymnastics, basketball, volleyball).

Inflammatory joint edema may also result in the development of a peroneal tenosynovitis and subsequent peroneal tendinopathy. It has been suggested that peroneal tendinopathy may be due to the excessive pulley action of, and abrupt change in direction of, the peroneal tendons at the lateral malleolus.

There are three main sites of peroneal tendinopathy:

  • Posterior to the lateral malleolus
  • At the peroneal trochlea
  • At the plantar surface of the cuboids.

The athlete commonly presents with:

  • Lateral ankle or heel pain and swelling which is aggravated by activity and relieved by rest.
  • Local tenderness over the peroneal tendons on examination sometimes associated with edema and crepitus (crunching when you move the tendon)
  • Painful passive inversion and resisted eversion, although in some cases eccentric contraction may be required to reproduce the pain.
  • Possible associated calf muscle tightness.
  • Excessive subtalar pronation or stiffness of the subtalar or midtarsal joints that is demonstrated on biomechanical examination.

MRI is the recommended investigation and shows characteristic features of tendonopathy-increased signal and tendon thickening.  If MRI is unavailable, an ultrasound may be performed. If an underlying inflammatory arthropathy is suspected, obtain blood tests to assess for rheumatologic and inflammatory marker.

Treatment involves breaking the pain cycle with rest from aggravating activities, anti-inflammatory medication, possible injection therapy, soft tissue mobilization and physical therapy..

  • Stretching in conjunction with mobilization of the subtalar and Midtarsal joints may be helpful.
  • Footwear should be assessed and the use of an orthotic may be required to correct biomechanical abnormalities.
  • Strengthening exercises should include resisted eversion especially in plantar flexion as this position maximally engages the peroneal muscles.

In severe cases, surgery may be required, which may involve a synovectomy, tendon debridement or repair. In more complicated chronic cases a lateral ankle stabilization procedure may be performed.

If you are suffering from lateral ankle pain, contact us for a complate evaluation before it gets more complicated.