The Achilles tendon, or heel cord, is the largest tendon in the body. It is very important for normal gait patterns and is the main generator of force for push off strength during walking. Throughout the stance phase of gait, the Achilles tendon and its associated muscles contract both eccentrically (as the muscle lengthens) and concentrically (as the muscle shortens). The tendon experiences forces nearly 4x body weight during walking and 7x body weight during running. Due to these constant forces, and the fact that many of us take over 10,000 steps a day, this tendon is a very common site of pathology.A cavus foot is less flexible than a flatfoot. For this reason, during walking, cavus feet do not absorb shock as well as feet with lower arches. Due to this rigidity, a cavus type foot is more prone to arthritic changes particularly in the midfoot and hindfoot. These arthritic changes may cause the bone to remodel and grow spurs, which can exacerbate the painful bossing on top of the foot. The arthritic changes may also cause achiness in the arches and the midfoot after a long day of standing or walking. This lack of flexibility and shock absorption may also predispose to plantar fasciitis related heel pain (see section on plantar fasciitis).
Patients with cavus feet can also present with symptoms of lateral ankle instability (see section on ankle instability). Ankle instability is a diagnosis in which patients have recurrent ankle sprains, or the feeling that their ankle is unstable or will give way. The causes of ankle instability are variable but are generally based on foot shape and a lack of ligamentous and tendinous support. Patients with cavus feet tend to walk on the outer border of the sole, or the side of the foot. Based on laws of physics, walking on the outside of the foot renders these individuals more prone to roll the foot and ankle, and experience an ankle sprain. Severe ankle sprains can lead to permanent damage of the lateral ligaments and tendons, which leads to even more sprains or ankle instability.
In patients with cavus feet who don’t experience severe sprains or ankle instability, the peroneal tendons (see section on peroneal tendons), which serve to stabilize the ankle, may become overworked. As the patient walks on the outer border of the foot the peroneal tendons stabilize the foot to keep it from rolling and prevent sprains. This can lead to soreness or painful spasm of the tendons and sometimes even peroneal tendon tears. Often times, in order to repair and appropriately address peroneal tendon damage, the cavus shape of the foot must be addressed as well.
Occasionally, the Achilles tendon will directly rupture into two halves and nearly all push off strength can be lost. This often happens during sports activities such as tennis or basketball. Many patients describe a popping sound and state they felt like someone kicked them in the back of the leg, only to turn around and see that nobody is behind them (see youtube video of ‘Kobe Bryant Ruptured Achilles’). There are multiple studies supporting both operative and non-operative treatment of acute Achilles tendon ruptures. Generally, in active patients, surgeons in the U.S. recommend surgical repair with the goal of primarily repairing the tendon in an effort to regain push off strength, decrease chances of re-rupture, and rehabilitate faster.
Commonly, the tendon may gradually become swollen or painful proximal to its insertion on the bone, but without an acute event or rupture. This is known as Achilles tendinopathy, and may preclude a rupture. Patients may feel a knot on the back of the calf area. In these instances, conservative treatment may be beneficial. Treatment is often initiated with a period of rest in a cast or a walking boot. This may be accompanied by anti-inflammatory medications, ice, compression, or activity modifications. Eventually, physical therapy modalities and a stretching and strengthening program may be instituted. Most studies indicate that conservative treatment is effective about 50% of the time. If your physician institutes some of these treatment regimens and you experience little relief, then you may benefit from surgery. At the time of the operation, an incision is made on the back of the calf and the tendon is evaluated. Often times, unhealthy tissue is encountered in place of healthy tendon tissue. This diseased tissue is excised to debulk the swollen area and to remove the pain generation. Rarely, if a substantial amount of Achilles tendon has to be removed, a different tendon can be transferred into position to replace the Achilles tendon.
The insertion of the Achilles tendon on the heel bone (calcaneus) can also become painful. This is usually a slow chronic process to develop, and with time, calcifications at the Achilles tendon insertion may develop and large bony heel spurs can be seen on x-ray. Sometimes the spurs become so large and the surrounding soft tissue proliferation becomes so severe, that the heel area swells significantly. It may become painful to simply wear a shoe. Conservative treatment options may be the initial mainstay of treatment. A shoe with a roomy heel counter may relieve pain. Oral and topical anti-inflammatories can be beneficial.
Many patients eventually choose to have operative intervention for unrelenting pain. This is generally performed utilizing a small incision on the heel to remove the bone spurs and the degenerative tissue, and to reattach good healthy tendon to the heel bone. This is generally highly effective in eradicating the severe swelling and relieving the pain. Very rarely, if substantial amounts of diseased tissue have to be removed, then another tendon may be transferred into position to replace or reinforce the Achilles tendon.