Many foot conditions often stem from a biomechanical gait abnormality that can be treated with custom orthotics insole . Here are some common ailments related to poor foot biomechanics.
Achilles Tendonitis is an inflammation of the common tendon of the gastrocnemius and soleus muscles of the posterior compartment of the leg.
Patients that have equinis deformity and/or run up-hill are candidates for this disorder. As the tibia moves over the foot, the ankle joint needs to be able to dorsiflex at least 10 degrees. If this is not possible, due to tightness of the aforementioned musculature, the tissues of the tendon can be damaged.
In addition it is thought that over-pronation may reduce the blood supply to the area by “wringing out” the arterial blood supply to the tendon. This is due to the twisting movement of the tendon associated with over-pronation of the foot.
Iliotibial Band Syndrome
The iliotibial band which is a thick extension of the tensor fascia latae muscle slides over the lateral epicondyle. Iliotibial Band Syndrome is an inflammatory reaction at the side where this sliding occurs.
If the foot over-pronates, this is accompanied by internal rotation of the entire lower limb, producing a constant friction between the band and the bony prominence of the femur. It is therefore very common among runners especially if they run on a banked track or downhill.
Metatarsalgia is not an injury; it’s actually a symptom or a group of symptoms. These may include pain in the ball of the foot, with or without bruising, and inflammation. It is often localized in the metatarsal heads or it may be more isolated, in the area near the big toe. One of the hallmarks of this disorder is pain in the ball of the foot during weight-bearing activities.
Sharp or shooting pains in the toes also may be present, and pain in the toes and/or ball of the foot may increase when the toes are flexed. Accompanying symptoms may include tingling or numbness in the toes. It is common to experience acute, recurrent or chronic pain as a result of this problem.
Metatarsalgia develops when something changes or threatens the normal mechanics of the foot. Ultimately, this creates excessive pressure in the ball of the foot, and that leads to metatarsalgia. Some of the causes of metatarsalgia include:
- Being overweight: the more weight is brought to bear on the foot, the greater the pressure is on the forefoot when taking a step.
- As men and women age, the fat pad in the foot tends to thin out, creating less cushioning and making them more susceptible to pain in the ball of the foot.
- Wearing shoes that do not fit properly: Shoes with a narrow, tight toe box, or shoes that cause a great deal of pressure to be put on the ball of the foot (high heels, for example) are often the cause of metatarsalgia. Because such footwear inhibits the walking process and forces the wearer to alter his or her step to adjust to the shoe, the mechanics of the foot are compromised.
- Certain foot shapes contribute to metatarsalgia. A high-arched foot, or a foot with an extra-long metatarsal bone can cause pressure on the forefoot region and contribute to pain and inflammation there.
- Claw toes or hammertoes can press the metatarsals toward the ground and cause stress on the ball of the foot.
- Arthritis, gout or other inflammatory joint disorders can produce pain in the ball of the foot.
Morton’s Neuroma is a thickening of the tissue that surrounds the intermetatarsal nerve leading to the toes. When the nerve becomes squeezed and irritated, it causes painful symptoms. Neuroma patients occasionally complain of a “pins and needles” sensation that spreads through their fourth and fifth toes, or of a feeling akin to hitting their “funny bone.”
A neuroma can occur in response to the irritation of a nerve by one or more factors:
- Abnormal foot function or foot mechanics: primarily excessive pronation that causes strain on the nerve.
- Improper footwear: constricting, narrow, poor-fitting shoes with a tight or pointed toe box tend to compress the end of the foot, leading to excessive pressure in the area of the nerve. High-heeled shoes are a particular culprit here.
- Previous trauma to the foot: Those who engage in high-impact activities that bring repetitive trauma to the foot (running, aerobics, etc.) have a greater chance of developing a neuroma.
Plantar fasciitis is an inflammatory condition that occurs where the plantar fascia attaches to the medial tuberosity of the calcaneus.
Over-pronation results in a constant tugging of the aforementioned attachment site. Inflammation then results from this constant insult to the local tissues. When the patient is off-weight bearing, scar tissue begins to repair the site of injury. When the patient resumes weight-bearing, the scar tissue is torn resulting in acute pain. This explains why patients with this disorder typically experience the most pain when they get out of bed, or stand after a period of sitting.
The condition known as Shin Splints involves a muscular over-use scenario. There are Anterior Shin Splints and Posterior Shin Splints. Anterior Shin Splints involve the Tibialis anterior muscle of the anterior compartment of the leg, and Posterior Shin Splints involve the Tibialis posterior muscle of the posterior compartment of the leg.
Both of these muscles are involved in slowing down pronation during the stance phase of gait. Tibialis anterior functions early in the stance while Tibialis posterior functions a little later. If the patient over-pronates or pronates too rapidly, either or both of these muscles may be called upon to work harder than normal. As a result, fatigue sets in, leading to inefficient force production which leads to micro-tearing of the soft tissue and therefore and inflammatory reaction.
Since the muscle is wrapped in a fascial covering, the swelling that occurs from the aforementioned problem is restricted by this covering. Beyond the fact that much pain results from the entire process, the presuure within the fascial covering can be suffiecient to “choke-off” the blood supply to the involved musculature, further added to the insult on the tissue.
In severe circumstances the swelling can be severe enough to damage the deep peroneal nerve resulting in a permanent “foot drop,” as this nerve supplies the dorsiflexors of the foot. The scenario that typically brings on “shin splints” is a sedentary individual that suddenly starts running or walking long distances.
When that individual is also an over-pronator, the combination of having weak muscles from lack of activity and having this biomechanical fault increase the likelihood of injury. Even changing the type of shoe worn during walking or running can be sufficient to increase the pronation of the subtalar and transverse tarsal joints and lead to tissue injury.