Fei Zhang, Ye Tian, Zongyou Yang, and Tao Liu

A total of 201 patients with 202 foot fractures were investigated in the China National Fracture Study (CNFS). The fractures accounted for 11.40% of all patients with fractures and 11.02% of all types of fractures. The population-weighted incidence rate of foot fractures was 38 per 100,000 population.

The epidemiologic features of foot fractures in the CNFS are as follows:

• More males than females

• More right-side injuries than left-side injuries

• The highest risk age group is 15–64 years

• Injuries occurred most commonly via falls and crushing injury

Foot Fractures by Injury Side in CNFS

A total of 39,867 patients with 41,136 foot fractures were treated in 83 hospitals of China over a 2-year period from 2010 to 2011. All cases were reviewed and statistically studied; the fractures accounted for 9.61% of all patients with fractures and 9.53% of all types of fractures. Among these 39,867 patients, there were 2,466 pediatric patients (2,502 foot fractures) and 37,401 adults patients (38,634 foot fractures).

Epidemiologic features of foot fractures are as follows:

• More males than females

• Slightly more left-side than the right-side fractures

• The high-risk age group is 36–40 years, the same age group for males, whereas the high-risk age group for females is 46–50 years

• The most common foot fractures among adults are calcaneus fractures, in contrast to children, where the most common fractures are metatarsal

Fractures of the Foot by Fracture Side

Examining its anatomic region, the talus bone can be subdivided into three parts: head, neck, and body. Between 60 and 70% of the talar surface is articular, forming seven articulations with adjacent bones. The head is semicircular in form, carrying the articulate surface of the navicular bone. The neck, the constricted area between the body and head, is roughened for the attachment of the joint capsule. The irregular body is cuboid in shape, wide in the front and narrow in the back, which gives stability when the ankle is dorsiflexed. While its superior, medial, and lateral articulate surfaces join together to make up the trochlea of the talus, the posterior surface (facies articularis calcanea posterior) is separated by a furrow, the sulcustali, which, together with the sulcus calcanei, forms a cavity, the sinus tarsi. Behind the trochlea is a posterior process with medial and lateral tubercles separated by a groove for the flexor halluces longus tendon. The medial and lateral tubercles provide attachment for the medial talocalcaneal ligament and the posterior talofibular ligament, respectively. The medial articulate surface of the body, which is semilunar in shape, is only half the area of the lateral triangle surface of the body. The lateral surface projects laterally as a broad-based, wedge-shaped prominence, referred to as the lateral talar process, from which the lateral talocalcaneal ligament originates and passes immediately beneath its fibular facet to the lateral surface of the calcaneus.

A total of 1,140 adult patients with 1,143 talar fractures were treated in 83 hospitals of China over a 2-year period from 2010 to 2011. All cases were reviewed and statistically studied, including 561 patients with left-side fractures, 576 with right-side fractures, and 3 with bilateral fractures. There were 803 males and 337 females, with a male to female ratio of 2.38:1.

Epidemiologic features of talar fractures are as follows:

• More males than females

• The high-risk age group is 26–30 years, the same age group for males, whereas the high-risk age group for females is 36–40 years

• The most common fracture type is type 81-A, the same type for both males and females

• The most common fracture group is group 81-A2, the same group for males, while the common fracture group for females is group 81-A1

Talar Fractures (Segment 81) by Sex

Neck fractures are the most common talar fractures. The usual mechanism is associated with hyperdorsiflexion of the ankle as the talar neck impacts the anterior margin of the tibia, as may occur in an automobile accident or a fall from a height. The body of the talus locks in the ankle mortise following a talar neck fracture, and the remaining portion of the foot, including the head and calcaneus, is displaced medially. The continuous axial load may rupture the interosseous talocalcaneal ligament, the posterior talofibular ligament, and the posterior talocalcaneal ligament, causing the body of the talus to move out of the ankle mortise posteromedially. The resultant fracture line will run obliquely upward and laterally.

Body fractures of the talus occur most commonly as a result of axial compression load, as seen in a fall from a significant height. Ankle joint fractures may also accompany this injury. Fractures of the posterior and lateral processes are often results of violent contraction of nearby attached muscles as the injury occurs.

Talar head fractures are relatively uncommon, usually resulting from force transmitted along the metatarsal rays to the talar head.

Most talar fractures are marked by acute pain, considerable swelling and tenderness, and limited or partially limited motion. If fractures are displaced markedly or the injury results in dislocation, then deformity may be present. The anteroposterior (AP) view of the ankle joint can reveal most talar fractures, while the oblique view provides better visualization of the head and neck of the talus, even with small fragments. It is important to note the extension and direction of fracture displacement and the presence of fractures of adjacent articulations. Particular attention should be given to the ankle mortise, the distal tibia, and the remaining tarsal, to rule out possible fractures. Computed tomography (CT) scan and magnetic resonance imaging (MRI) can better reveal the nature of the fractures and provide accurate assessment of the articular involvement, as well as the degree of fracture displacement.

Stable nondisplaced talar body fractures and avulsion fractures can be treated with immobilization by casting. Nondisplaced, unstable fractures and displaced talar body fractures can be managed by fixation of compression screws with minimally invasive techniques. Comminuted fractures can be treated with secondary arthrodesis if there is persistent pain or swelling. Stable, nondisplaced talar neck fractures can be treated nonsurgically, in contrast to displaced talar neck fractures, which require surgical intervention. A displaced talar neck fracture with associated dislocation may be treated first with closed reduction. Emergency open reduction and internal fixation may be indicated if closed reduction fails.

Hawkins Classification of Talar Neck Fractures

The Hawkins classification of talar neck fractures is as follows:

• Type I: Nondisplaced

• Type II: Associated subtalar subluxation or dislocation

• Type III: Associated subtalar and ankle dislocation

• Type IV: Canale and Kelley

The calcaneus is the largest of the tarsal bones; rectangular in shape, it lies inferior to the talus. The calcaneus has six surfaces: superior, inferior, anterior, posterior, medial and lateral. It has three talocalcaneal facets on its upper surface, and one calcaneocuboid facet on its front.

• Superior: On its upper surface are three smooth facets, posterior, middle, and anterior, which articulate with the lower surface of the talus to form the subtalar joint. The middle one-third of the surface is the posterior facet, which is large and oval or oblong. It is anteriorly tilted, at an angle of 45 degrees from the midsagittal plane. The middle and anterior facets are located on the medial side of the upper calcaneal surface and are usually continuous with each other. On the medial side of the bone, below the middle talocalcaneal facet, is a shelf-like projection, the sustentaculum tali, which supports the talar neck and also serves for the attachment of several ligaments. The posterior one-third surface of the upper calcaneal surface is roughened and is in between the posterior aspect of the ankle joint and the Achilles tendon.

• Inferior: The inferior roughened area of the calcaneus gives attachment for the long plantar ligament and the quadratusplantae. The plantar-surface forepart of the calcaneus is a small rounded projection known as the small calcaneal tubercle, which gives attachment to the plantar calcaneocuboid ligament. The back part of the planter surface is an eminence called the calcaneal tubercle.

• Medial: The medial wall of the calcaneus is depressed. Under the surface of the sustentaculum tali of the calcaneus, there is a groove running obliquely downward from posterior to anterior, which contains the flexor hallucis longus tendon.

• Lateral: The lateral wall of the calcaneus is flat and smooth, except for a small ridge called the peroneal tubercle. Passing below the peroneal tubercle of the calcaneus is the groove for peroneus longus tendon.

• Anterior: The anterior surface of the calcaneus, which is square in shape, has the smallest surface of all and has a saddle-shaped articulation, forming the calcaneocuboid joint with the cuboid bone.

A total of 11,008 adult patients with 11,720 calcaneal fractures were treated in 83 hospitals of China over a 2-year period from 2010 to 2011. All cases were reviewed and statistically studied, including 5,092 patients with fractures on the left side, 5,204 on the right side, and 712 bilateral. There were 9,228 males and 1,780 females, with a male to female ratio of 5.18:1.

Epidemiologic features of calcaneal fractures are as follows:

• More males than females

• The high-risk age group is 36–40 years, the same age group for males, whereas the high-risk age groups for female are 36–40 and 46–50 years

• The most common fracture type is type 82-C