Attritional Anterior Tibialis Tendon Rupture
(Anterior Tibial Tendon Attritional Rupture)
Attritional anterior tibialis tendon rupture is an uncommon injury that typically affects individuals over the age 60. The tibialis anterior muscle and tendon are primarily responsible for lifting the foot up towards the shin (or preventing the foot from flopping downwards). Tearing the tendon results in pain, local swelling, and difficulty with walking. Patients may even develop a dropfoot. Treatment options include doing nothing, using an ankle-foot orthosis (AFO), or surgery. Selecting an option will depend on the patient’s preferences and lifestyle.
Symptoms of an Attritional Anterior Tibialis Tendon Rupture
The tibialis anterior muscle and tendon is the primary dorsiflexor of the foot –moving the foot upwards towards the shin (dorsiflexion). Attritional rupture of the tibialis anterior tendon occurs when over time the patient develops weakening and eventual failure of the anterior tibial tendon. This is an attritional tendon rupture. it is similar to how a rope can fray and eventually break over time. Patients may have symptoms of pain and swelling due to tibialis anterior tendonitis prior to the tendon actually rupturing. Although, many patients have no symptoms prior to the tendon rupturing. The injury tends to occur in older individuals who are still active. It is often precipitated by a minor trauma. Symptoms are often subtle which can delay an accurate diagnosis. Often the main symptoms are a swelling in the front of the ankle (where the tendon has retracted); some mild-moderate discomfort in this area; and a sense of weakness in the foot. The condition is caused by attritional tearing of the tibialis anterior tendon from wear and tear. The loss of muscle-tendon attachment to the foot causes the weakness and partial dropfoot (two other tendons can still help left the foot up). The patient may have difficulty in walking. Any pain from the injury normally subsides in a few days and the patient may only notice weakness flexing the foot upwards towards the shin.
Physical exam often reveals a mass in the front of the ankle or slightly above the bony prominence on the inside of the ankle depending on where the tendon has retracted. The patient is able to walk on their toes but will have difficulty walking on their heels.
Gout, steroid injections, rheumatoid arthritis, and diabetes have all been identified as risk factors for an attritional rupture of the tibialis anterior tendon, though most patients with this injury will not have any of these conditions.
Plain x-rays of the foot and ankle are usually unremarkable as the injury is to the tendon of the tibialis anterior muscle
Magnetic resonance imaging (MRI) can be useful for surgical planning. It allows for differentiation of a complete versus partial tear; identifies the exact location of the tear; and shows how far the tendon has retracted.
Treatment of an Anterior Tibialis Tendon Rupture
Treatment depends on the patient’s desired level of activity. In sedentary older individuals an ankle-foot orthosis (AFO) functions well and is generally the suggested approach.
For younger and/or more active patients surgical intervention is recommended. Surgery may include a direct repair of the ruptured tendon, or the use of a tendon graft if the gap caused by the rupture is too great. Possible tendon grafts include a tendon taken from the patient (autograft) or from a cadaver (allograft). The exact surgery depends on the size of gap and location of the tear. Surgery to repair a tibialis anterior tendon rupture normally has a good functional result, although recovery from this type of surgery can take many months.
January 30th, 2024