Ankle and Foot Injuries in Runners

Introduction and Epidemiology

Injuries of the foot and ankle are common among elite and recreational runners, accounting for nearly one-third of all running injuries. Foot injuries alone account for 10%–20% of all running injuries, and ankle injuries account for 15% of all sports injuries. Achilles tendinopathy, plantar fasciopathy, and ankle sprains are three of the five most commonly sustained foot and ankle injuries in runners.

Significant biomechanical stress is placed on the foot and ankle during ground contact. The foot receives an equal and opposite force upon landing known as the ground reaction force, which increases 50%–70% from walking and can be more than two times the runner's body weight. Excessive stress or abnormalities in biomechanical stress can translate into overuse and traumatic injuries.

The foot serves as a link between the ground surface and the kinetic chain and acts a lever for forward propulsion. The movement patterns of the foot enable the body to adapt to uneven surfaces, gain traction for movement, and receive proprioception for balance.

The ability of the foot to adapt to the ground and provide forward propulsion is complex and subject to many variations. A runner's foot strike pattern, speed, stride length, footwear, and training intensity may influence the ground reaction force and injury.

Anatomy and Biomechanics of the Foot

The foot can be divided into three distinct regions, each with bony and associated soft tissue structures: (1) the hindfoot, (2) the midfoot, and (3) the forefoot. (1) The hindfoot consists of the talus and calcaneus bones as well as the subtalar joint at the talus and calcaneus articulation. (2) The midfoot consists of the cuboid, navicular, and cuneiform bones. (3) The forefoot consists of the five metatarsal bones and 14 phalanges. The connection of hindfoot to midfoot is at the midtarsal joint (Chopart joint) and midfoot to forefoot is at the tarsometatarsal joints.

The hindfoot contributes to the complex motions of inversion and eversion during the gait cycle and enables motion through several planes at once. Proximally, the talus of the hindfoot forms a synovial articulation with the distal tibia and fibula (the tibiofibular joint) forming the talocrural joint. Distally, the talus articulates with the inferior calcaneus through three talar facets (anterior, middle, and posterior) to form the subtalar joint. Abnormalities or excessive motion in the subtalar joint can contribute to running injuries in the foot and ankle.

In contrast to the hindfoot, isolated motion of the midfoot joints spans from just a few degrees of dorsiflexion to approximately 15 degrees of plantarflexion . The midfoot begins at the midtarsal joint, which is formed by the articulation of the talus with the navicular as well as the calcaneus with the cuboid. The bones of the midfoot provide stability for the arch of the foot.

Although isolated motion of the midfoot joints is minimal, the combined motion of tarsal and tarsometatarsal joints in the midfoot and forefoot significantly influences the shape of the longitudinal and transverse arches. The elastic properties of the foot arches enable energy return from running and help spread ground reaction forces over a longer time period.

The forefoot begins at the tarsometatarsal joint complex, also known as the Lisfranc joint. The tarsus (composed of the seven bones of the hindfoot and midfoot) articulates with the five metatarsal bones at their bases. Within the Lisfranc joint, the medial joint complex is composed of the first metatarsal and medial cuneiform; the middle joint complex contains the second and third metatarsals and intermediate and lateral cuneiforms respectively; and the lateral joint complex holds the fourth and fifth metatarsals and the cuboid.

The first ray includes the first metatarsal and medial cuneiform, with an articulation that intersects the transverse and medial longitudinal arches. The first ray has numerous functions including shock absorption, maintenance of medial longitudinal arch integrity during midstance, and stability during propulsion. Pathology related to first-ray mobility is complex. Reduced first ray dorsiflexion is associated with a variety of foot and ankle injuries.

The plantar aponeurosis originates from the calcaneal tuberosity and runs distally, before fanning out into five slips to course under the five metatarsal heads and attach to the proximal phalanges. Due to its distal insertions, the plantar aponeurosis becomes tight when the metatarsophalangeal joints dorsiflex in late stance phase, creating elevation of the longitudinal arch. Known as the “windlass mechanism,” this synchrony is responsible for medial longitudinal arch integrity and foot stiffness to enable forward propulsion.

Anatomy and Biomechanics of the Ankle

The ankle joint complex and supporting ligamentous structure enable the lower limb to interact with the ground and function with a high degree of stability. The talocalcaneal (subtalar), tibiotalar (talocrural), midtarsal (Chopart), and the inferior tibiofibular joint compose the ankle joint complex.

The ankle joint complex is supported medially by the deltoid ligament and laterally by the fan-like arrangement of the lateral collateral ligament complex, which consists of the anterior talofibular ligament (ATFL), the calcaneofibular ligament (CFL), and posterior talofibular ligament (PTFL).

The deltoid ligament attaches the medial malleolus to the talus, navicular, and calcaneus and consists of a superficial and deep layer. Given the strength of the deltoid ligament, injury is rare but can occur with eversion and/or pronation injuries and is associated with lateral ankle fractures.

The ATFL arises from the anterior margin of the lateral malleolus and inserts on the talus and is the most commonly injured ligament in inversion sprains. The CFL arises from the lateral malleolus and inserts on the lateral calcaneus, and the PTFL arises from the lateral malleolus and inserts on the lateral tubercle of the posterior talar process.

Motion within the foot and ankle is generated by 12 extrinsic muscles, which are separated in four compartments in the leg: the anterior, lateral, superficial posterior, and deep posterior.

The Achilles tendon is the conjoined tendon of the medial and lateral gastrocnemius and soleus muscles. The Achilles tendon receives tensile loads up to 10 times body weight during running and is the strongest and largest tendon in the body.

Physical Examination of the Ankle and Foot

The physical exam outlined in this section provides an introductory look at common approaches to foot and ankle evaluation. More complex exam maneuvers and additional special tests are highlighted in our specific foot and ankle injury sections.

Inspection

1.
With the patient seated, inspect the foot and ankle for abrasions, lacerations, discoloration, swelling, or deformity.
2.
Inspect for big and lesser toe deformities and anatomic variants of the foot. Inspect posteriorly for hindfoot varus or valgus deformity as well as forefoot varus (best done in the prone position). If able to walk, instruct the patient to walk barefoot to assess foot progression angle, supination/pronation, and navicular drop.
3.
If clinically indicated, examine the patient's running shoes for pattern of wear.

Palpation

1.
With the patient seated, follow a systematic method of palpation for tenderness in a proximal to distal manner. Palpate the most painful area last to avoid patient discomfort.
2.
During palpation, examine for tenderness, crepitus, and elasticity. Deeper structures might require varying degrees of pressure and active foot movement for adequate palpation.

Range of Motion

1.
Start with active movement and instruct the patient to perform dorsiflexion, plantarflexion, inversion, and eversion of the ankle with the knee flexed and extended. If unilateral, start with the unaffected foot first to establish normal range of motion.
2.
To assess ankle passive range of motion, use one hand to stabilize the patient's heel and place the other hand on the midfoot as a lever to dorsiflex and plantarflex the ankle joint.
3.
To assess subtalar passive range of motion, place one hand around the ankle to provide stabilization and the other hand around the calcaneus to manipulate and examine eversion and inversion.
4.
To assess first metatarsal-phalangeal mobility, passively dorsiflex the joint with the goal of at least 30 degrees with a flexed knee and the ankle at 10 degrees of dorsiflexion.
5.
Examine for pain, catching, locking, laxity, or inappropriate end position through joints.

Muscle Testing

1.
Resist ankle and toe dorsiflexion and plantarflexion to assess muscle strength and visualize tendon tension.
2.
To isolate the posterior tibialis muscle, instruct the patient to maximally plantarflex and invert the foot. Place a hand on the tendon to palpate contraction and with the other hand apply pressure through dorsiflexion and eversion.
3.
To isolate the peroneus longus and brevis muscles, instruct the patient to maximally plantarflex and evert the foot. Place a hand on the peroneals from the back of the ankle to palpate contraction and with the other hand apply pressure through inversion.
4.
If clinically indicated, assess functional strength by having the patient walk on heels and toes and perform single- or double-leg heel raises.

Neurologic and Vascular Testing

1.
If concern for neurological deficits or referral from the lumbar spine, perform a neurological assessment for reflexes and assess any dermatomal or myotomal pattern of sensory or motor loss, respectively.
2.
If concern for vascular compromise, palpate the dorsalis pedis artery, posterior tibial artery, anterior tibial artery, and peroneal artery. Palpation may be limited at injury site from swelling or deformity.

Special Tests

The following common tests are specific to foot and ankle pathology and can evaluate for ligamentous instability or impingement of the foot and ankle joints. Additional tests are highlighted in the foot and ankle injury sections.

1.
Anterior drawer test:

Purpose: This tests for ligamentous instability in the ankle and assesses for injury of the ATFL.

Process: Perform with patient seated with knee flexed to eliminate gastrocnemius involvement. Place the foot into 10–15 degrees of plantarflexion and anteriorly translate the foot. Repeat the motion and combine with internal rotation of the talus to assess lateral ankle instability. Note reproduction of pain, apprehension, laxity, and joint instability during motion.
2.
Talar tilt test:

Purpose: This is a variant of the anterior drawer test that tests for combined injury of the ATFL and CFL.

Process: Incorporate anterior drawer test positioning, and apply a slow inversion force to the hindfoot. Palpate the lateral aspect of talus during inversion force to assess for pain and determine if tilt is present.
3.
Impingement sign:

Purpose: Tests for anterior impingement of the talocrural joint.

Process: With the foot in plantarflexion, place one hand behind the calcaneus with fingers around the calcaneal tuberosity and the thumb in the anterolateral aspect of the talocrural joint. Apply pressure through the thumb and bring the foot from the “open,” plantarflexion position to the “closed,” dorsiflexion position. This movement can reproduce soft tissue impingement and pain.
4.
External rotation test:

Purpose: This tests for tibiofibular syndesmotic injury.

Process: Perform with patient's knee flexed to 90 degrees and the heel locked in neutral. Stabilize the tibia with one hand, and use the other hand to apply an external rotational force to the foot and ankle. Assess for reproduction of pain in the anterolateral ankle, which is indicative of a syndesmotic injury.

Ankle and Foot Injuries

This chapter provides a framework for differential diagnoses of ankle and foot injuries sustained in runners and outlines evidence-based medicine and rehabilitation principles for prevention, evaluation, and management of injury. In this framework, injuries are grouped based on structure: tendon, ligament/fascia, nerve, and bone disorders. When developing a differential diagnosis, it is important to consider region of pain and mechanism of injury as well.

Tendon Injuries

Achilles tendinopathy

The Achilles tendon insertion area is cushioned anteriorly and posteriorly by the subcutaneous and subtendinous calcaneal bursae, respectively. The poorest blood supply of the gastrocnemius-soleus muscle complex is 2–6 cm distal to the calcaneal insertion point. This hypovascularity can prevent adequate healing from recurrent microtrauma sustained while running.

In the absence of a tear or rupture, the term Achilles tendinopathy refers to acute and chronic pain associated with the Achilles tendon. The role of inflammation in the pathogenesis of tendon disease is a subject of ongoing debate, with more recent studies suggesting both an acute and chronic inflammatory process.

Achilles tendinopathy is further broken down by location: Achilles paratendinopathy is classified as acute or chronic inflammation and/or degeneration at the paratenon surrounding the Achilles tendon. Midportion Achilles tendinopathy includes pathology and/or tendinosis of the main body of the Achilles tendon (2–6 cm distal to the calcaneal insertion point). Finally, insertional Achilles tendinopathy occurs where the Achilles tendon inserts on the calcaneus and can involve bone spurs and calcifications at the insertion site.

Achilles tendinopathy in recreational runners accounts for 6%–17% of all running injuries, and among competitive runners, the lifetime incidence may be as high as 40%–50%. Inappropriate footwear, changes in training regimen, poor biomechanics, and cold weather training are risk factors for tendon pain. In addition, rheumatologic, vascular, and other systemic diseases such as metabolic syndrome can cause tendon degeneration.

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