Oh, My Aching Feet!

Describe some common foot maladies: Lisfranc injury

A disruption of the articulation between the medial cuneiform and base of the second metatarsal. It can be a partial tear of the Lisfranc ligament, a complete tear of this ligament, or an avulsion of the ligament off the bones. It can also be associated with dislocations of the Lisfranc or tarsometatarsal joint. On imaging, a subtle widening may be all that identifies the injury. Or it may be much more obvious.

Describe some common foot maladies: Arthritis

Arthritis can develop in any of the joints of the foot. It can occur as the sequelae of traumatic injury or from normal wear and tear.

Describe some common foot maladies: Clubfoot

Clubfoot aka Congenital talipes equinovarus is a developmental abnormality that begins in utero. The foot is positioned in adduction, varus and plantar flexed. The cause is unknown but believed to be a combination of environmental and genetic factors and is more common in families with a history of clubfeet. It may occur in one or both feet, with a ~50% incidence of each. It is twice as common in males. Its incidence is ~1:1,000 live births. It can be idiopathic or it can be a feature of a more extensive genetic syndrome (ie. Spina bifida).

Describe pes planus and pes cavus

Congenital arch abnormalities: Pes planus (flat foot) is characterized by an abnormally low or absent medial longitudinal arch. It can be due to failure of development of the arch (which generally develops between the age of 4-6 years) or from collapse. The talar head displaces medially and the Spring ligament and tibialis posterior tendon are stretched and may tear. If the arch is present when seated or when standing on toes but disappears with weight-bearing, it is called a flexible flatfoot. If it is absent both with and without weight-bearing it is called a rigid flatfoot. Pes cavus (overarched foot) is characterized by an abnormally high medial longitudinal arch. It is commonly associated with an inverted hindfoot, a plantarflexed first ray, an adducted forefoot and dorsal toe contracture. It is frequently seen in neuromuscular disorders such as Charcot-Marie-Tooth disease (Hereditary Motor and Sensory Neuropathy HMSN) but can also be idiopathic. It can be hereditary or acquired.

Describe some common foot maladies: Fractures

Fractures can occur as a result of trauma, either in isolated bones of the foot or a combination of bones may be involved depending on the mechanism of injury and amount of force applied. Fractures may also be caused by overuse injury when no trauma is involved-a stress fracture. This is a pathologic fracture (normal stress to abnormal bone). A common location for a stress fracture in the foot is the base of the 5th metatarsal.

Describe some common foot maladies: Deformity of the toes

Including but not limited to Bunion (Hallux valgus), claw toe (w/calluses), hammer toe, mallet toes are degenerative conditions attributable to muscle imbalance within the foot, possibly shoe wear and joint degeneration.

Describe some common foot maladies: Vascular abnormalities

Kohler's disease and Freiberg's disease are a result of vascular disruption of blood supply to a bone. In Kohler's disease the navicular is affected and in Freiberg's disease a metatarsal is affected (most commonly the 2nd). Kohler's disease is generally idiopathic and occurs in children between the ages of 6-9 years. Freiberg's disease is believed due to repetitive stress causing decreased circulation to the metatarsal. It is more common in women, athletes and in patients with abnormally long metatarsals. NB: Gout

Describe some common foot maladies: Infectious Diseases

Osteomyelitis, ulcers, abscesses, and cellulitis are commonly seen in the foot and are most frequently seen in association with diabetes and/or peripheral neuropathy. Infection can progress rapidly in these individuals and necessitate amputation for cure and result in significant disability.

Describe some common foot maladies: Peripheral neuropathy

Peripheral neuropathy of the foot can develop as a result of diabetes, B12 or folate vitamin deficiencies, drugs (chemotherapy and other medications), toxins (insecticides and solvents), cancers (lymphoma or multiple myeloma), alcohol abuse, and more. It can result in chronic pain and ultimately, an increased risk of wounds/infections of the feet. Hereditary Motor and Sensory Neuropathy, of which Charcot-Marie-Tooth is an example, are another neurologic abnormality affecting the feet. These disorders cause an imbalance in muscle function of the feet and legs which can alter the position of the foot, i.e., Pes cavus.

Describe some common foot maladies: Plantar fasciitis

Plantar fasciitis is another degenerative condition of the foot that is generally believed to be an overuse injury. Factors which can contribute are: tight gastrocnemius/soleus muscles and Achilles tendon, obesity, pes cavus, repetitive impact activity (i.e., Running/jumping), new or increased activity. Often associated with calcaneal/heel spurs, the spurs are not the cause of the pain because only 5% of people with calcaneal spurs have pain. The plantar fascia becomes inflamed and is the source of pain and can often be resolved with stretching, rest and anti-inflammatories.

Name the components of the subtalar joint, *Chopart joint*, and Lisfranc joints

The Chopart joint is also called the transverse tarsal joint or midtarsal joint and is composed of the calcaneocuboid and the talonavicular joints. This joint allows a complex motion which produces a rotation (pronation/supination) within the foot.

Name the components of the subtalar joint, Charcot joint, and *Lisfranc joints*

The Lisfranc joint or tarsometatarsal joint is an articulation between the bases of the metatarsals and the cuneiforms and cuboid. This joint acts as a Roman arch in which the second metatarsal base is the keystone. This is a fairly immobile joint which is central to rigidity during the push-off phase of locomotion.

Describe the function of the Spring ligament and *Lisfranc ligament*

The Lisfranc ligament connects the medial cuneiform to the base of the second metatarsal and thereby secures the entire tarsometatarsal articulation. The bases of the four lateral metatarsals are secured together via a transverse ligament, but this ligament does not secure the four lateral metatarsals to the first. A disruption of this ligament or its bony attachments is an uncommon injury but is associated with high morbidity: including severe pain, swelling and inability to bear weight.

Describe the function of the *Spring ligament* and Lisfranc ligament

The Spring ligament or the plantar calcaneonavicular ligament complex. This is a thick fibrous band that connects the plantar navicular with the sustentaculum (a facet) of the calcaneus. This ligament supports the head of the talus, stabilizes the medial longitudinal arch and thus contributes to the ability of the foot to bear weight. Helps keep arch in place. A tear/deficiency of this ligament can lead to acquired flatfoot deformity.

Name the components of the *subtalar joint*, Charcot joint, and Lisfranc joints

This joint is a complex articulation of the talus and calcaneus. The subtalar joint is primarily responsible for foot inversion and eversion.

Describe some common foot maladies: Turf Toe

Turf toe is a traumatic injury seen in athletes. It is caused by forceful hyperextension of the 1st MTP joint and results in sprain of the ligaments of that joint.

Name the major bones of the foot

▪ Hindfoot - Calcaneus, Talus - Absorbs shock during locomotion ▪ Midfoot - Navicular, Cuboid, Cuneiforms - Translates force and provides rotational stability of foot ▪ Forefoot - Metatarsals and Phalanges - Returns energy during "toe-off"

Name the two functions of the foot

▪ Stable base for standing and locomotion ▪ Absorption of energy and transfer back to the ground