An ankle equinus deformity is basically one in which the achilles tendon is shorter than needed to allow adequate dorsiflexion during the gait cycle. If the foot is perpendicular to the leg and put through a range of motion where the foot cannot dorsiflex (move upward) more than 10 degrees this is thought of as an equinus deformity. The achilles tendon is a band of tissue that stems from a couple muscles in the lower leg, most importantly the gastrocnemius and soleus muscles. The type of equinus may differ depending on the cause.
Symptoms differ depending on how the foot compensates for the deformity and what is causing the equinus deformity. Typically this is seen in patients that tend to walk more on there toes, or have a bouncy gait. If the foot is unable to fully dorsiflex against the ground there may be early heel off giving this bouncy gait pattern.
Causes are varied. A spastic equinus may develop in patients with aneuromuscular disease such as cerebral palsy. If the muscles in the back of the leg overpower the muscles in the front of the leg then equinus may develop. Non-spastic equinus can be hereditarily acquired when one is born with a shorter achilles tendon. More often the acquired deformity maybe due to the foot structure and over time the achilles tendon becomes shortened. If the total length of the tendon is not used and not needed, it will contract over time, which happens with a flatfoot deformity. With hyperpronation(flattening of the arch) during the gait cycle the foot does not need to dorsiflex at the ankle as much and the achilles tendon is not used as much. A third type of equinus can exist when there is a bone block at the ankle not allowing the foot to dorsiflex (move upward) at the ankle. This type appears more commonly following trauma or arthritis.
Podiatric Care includes first determining what type of equinus is present and determining the cause. Usually a simple examination is required along with x-rays to evaluate the bone structure. Treatment is dependent on a variety of factors, most importantly the cause. A child with equinus deformity may be very normal for their stage of development.
Surgery is dependent on many factors as well. An achilles can be surgically lengthened in various fashions. If the gastrocnemius muscle is found to be the reason for the equinus then a gastroc recession may be performed which allows this portion of the muscle to be corrected instead of the complete tendon. The procedures can be done with one long incision, or several smaller “stab” incisions each with different advantages and disadvantages depending on procedure. Typically a surgery to correct for equinus is performed at the same time as other surgeries of the foot such as a correction for painful flatfeet.
Post-operative Care and Risks for an achilles tendon lengthening or gastroc recession depends upon the exact surgery performed or any other procedures at the same time. You may need a cast to protect you for a short time. Sometimes a soft bandage with a post-operative shoe is allowed. You should expect some pain following surgery as well as swelling. Especially for the first 48 hours you should keep your leg elevated and occasional ice placed over the area of surgery (about 20 minutes per hour). Surgical cuts are made through the skin so a scar is expected. If you are a keloid former, let your surgeon know. Surgical cuts are not only made through skin, but through other layers of tissue as well, a scar may form within your foot and lead toadhesions. You may be required to keep all the weight off of your foot for several weeks, typically 5-8 weeks or longer depending on procedure. You may use crutches, a walker, or wheelchair to help you keep weight off of this foot. Healing is influenced by many factors including your nutrition, circulation, and other medical conditions. If you are a smoker you can expect to take longer to heal. If you are required to keep pressure off of your foot your leg muscles are not being used as they were before surgery. This allows for slower movement of the blood through the leg vessels. Occasionally this can lead to a blood clot in the leg which can become life threatening. Hip and knee flexion and extension exercises as well as wiggling your toes gently can help prevent this from occurring. If you have a history of blood clots you should let your surgeon know.