Essentials of Orthopedic Surgery, third edition / 13-The Foot and Ankle

482 S.T. Sauer and P.S. Cooper

Clinical Evaluation of the Foot and the Ankle

History and Physical Examination

A complete medical and surgical history, the mechanism of injury, and the duration of the symptoms should be elicited. The location and quality of pain should be documented. Existing systemic disorders should be ruled out, with an emphasis on diabetes and gout. Musculoskeletal history involving the spine and lower extremities is helpful. A physical examination should be done with both stockings and shoes removed. Gait patterns should be determined with the patient walking both toward and away from the examiner. The stance phase or station should be examined with emphasis placed on the relationship of the hindfoot with the forefoot and longitudinal arch. Once inspection has been completed, examination of the bony and soft tissue structures follows. The area should be examined for the presence of edema, effusion, skin temperature changes, and previous sites of surgery or trauma. Systemic examination can be divided into the ankle, hindfoot, midfoot, and forefoot subgroups. When examining the ankle, note any effusion. Range of motion of the ankle is normally 20 degrees of dorsiflexion and 40 to 50 degrees of plantarflexion. Loss of ankle dorsiflexion may be associated with a tight Achilles tendon, posterior capsular contracture, or bony impingement. Limitation of dorsiflexion with the knee in full extension that improves passively with the knee flexed to 90 degrees indicates a contracture of the gastrocnemius muscle. Ligamentous laxity should be evaluated in comparison with the contralateral ankle joint, and palpation of the tendons should be performed to note evidence of subluxation or dislocation. Midfoot examination involves selective palpation of the bony anatomy to isolate specific joint or joint involvement. Forefoot examination should include MTP joint motion with any documentation of subluxation and pain.

Radiology of the Foot and Ankle

Radiographic studies of the foot and ankle require weight-bearing X-rays when possible. Important views involve the anteroposterior (AP), lateral, and oblique views of the foot, and AP, lateral, and mortise views of the ankle. The AP view of the foot can be used to assess forefoot and midfoot pathology. The lateral view of the foot shows the relationship of the talus and calcaneus to that of the midfoot, forefoot, and ankle joint. The medial oblique view is used to evaluate the lateral tarsometatarsal joints. Other studies are available to assess the sesamoids, the calcaneus, or the subtalar joint. The sesamoid view involves the X-ray beam directed tangential to the plantar surface of the sesamoid region while the patient’s toes are in hyperextension. The Harris axial heel view is used to assess the calcaneal tuberosity and is important in calcaneus fractures or tarsal coalitions.

FIGURE 13-9. Normal anatomy seen on computerized tomography: coronal section through the ankle and subtalar joint. C, calcaneus; F, fibula; T, talus. (From Weissman BNW, Sledge CB. Orthopedic Radiology. Philadelphia: Saunders, 1986. Reprinted with permission.)

Ancillary radiographic studies include computed tomography (CT) (Fig. 13-9), magnetic resonance imaging (MRI), and radionuclide studies. MRI can be used to assess soft tissue structures such as soft tissue tumors, osteomyelitis, avascular necrosis, bone tumors, chondral lesions, and tendon abnormalities.

Diseases of the Foot and Ankle

This overview discusses the pathologic states that affect the foot and the ankle by diagnostic category. It is not meant to be an exhaustive catalogue of every affliction, but rather a representative sampling of the more common disease states that mandate medical care.

Trauma

Ankle

Injuries of the ankle mortise include pilon fractures, ankle fractures, and syndesmotic injuries.

484 S.T. Sauer and P.S. Cooper

Pilon Fractures

Pilon fractures involve the intraarticular fractures of the tibial metaphysis that extend to the weight-bearing portion of the tibia. There is often extensive comminution. Nondisplaced pilon fractures may be treated nonoperatively with immobilization in a cast; however, because these are often displaced injuries, treatment consists of some type of operative fixation. Initially and temporarily, an ankle-spanning external fixator may be applied to maintain length and ankle joint reduction until soft tissue swelling subsides, within 1 to 2 weeks. At that point, open reduction and internal fixation using screws and a plate can be done. In high-energy injuries with soft tissue compromise, external fixation may be the definitive treatment.

Ankle Fractures

Ankle fractures are discussed in Chapter 2.

Syndesmosis Injuries

With disruption of the syndesmotic ligaments, a diastasis, or separation, of the distal tibia and fibula can occur. This injury is often associated with higher grades of ankle fractures when medial stability is compromised by a medial malleolar fracture or a deltoid tear. Definitive diagnosis of a syndesmotic injury can be made with stress X-rays, which show a diastasis at the distal tibial and fibular joint. If this exists, reduction and stabilization of the syndesmosis are achieved with screw placement across the tibial and fibular joint or tibial and fibular syndesmosis. The screw should remain in place for a minimum of 10 to 12 weeks and is then removed.

Fractures to the Hindfoot

Fractures of the hindfoot involve the calcaneus, talus, and navicular bones.

Talus Fractures

The talus articulates with the ankle, calcaneus, and navicular bones and is covered by articular cartilage on 60% of its surface (Fig. 13-10). Because most of the talus is covered by articular cartilage and there are no muscle or tendinous attachments, there is limited space for blood vessels to enter this bone. Therefore, the blood supply is tenuous. The blood supply enters the talus at the neck and travels retrograde into the body and the dome (Fig. 13-11). Fractures of the talus, depending on the severity, can often disrupt this blood supply. Fractures of the talus typically occur through the neck and result from an acute dorsiflexion injury. Standard radiographs with CT scans are usually adequate to demonstrate the nature of the fracture. Treatment is tailored to restore normal talar anatomy. If nondisplaced, conservative nonsurgical treatment can be used. If displaced, often

486 S.T. Sauer and P.S. Cooper

FIGURE 13-12. Classification of talus neck fractures: (A) Class I; (B) class II; (C) class III. (Modified from Hawkins LG. Fractures of the neck of the talus. J Bone Joint Surg 1970;52A:991–1002; and from Adelaar RS. The treatment of complex fractures of the talus. Orthop Clin N Am 1989;20(4):696. Reprinted by permission.)

anatomic reduction and rigid fixation is the best approach; this is done in an effort to prevent avascular necrosis, which can result as a disruption of the tenuous blood supply. Hawkins’ classification of talar neck fractures categorizes these fractures into three patterns (Fig. 13-12): type I is a nondisplaced fracture of the neck, type II is a displacement of the neck fracture with subluxation or dislocation of the talar body from the subtalar joint, and type III is a neck displacement fracture with subluxation or dislocation of the body from both the ankle and the subtalar joints. A fourth pattern, which has been described, involves a displaced neck fracture that includes dislocation of the talonavicular joint. The incidence of avascular necrosis increases significantly with each increase in type.

Calcaneus Fractures

The calcaneus is the most commonly fractured tarsal bone. Fractures are classified as intraarticular or extraarticular. Calcaneus fractures are often seen when an axial load is applied to the foot, resulting from falls or motor vehicle accidents. Patients typically present with severe pain and swelling. Radiographs including the axial heel view in addition to CT scanning can fully define the injury. Closed treatment of these fractures is reserved for nondisplaced fractures or poor surgical candidates with severe soft tissue compromise or complicated medical conditions. Open reduction and internal fixation is indicated for displaced intraarticular fractures and significantly displaced extraarticular fractures. Surgical intervention should not proceed until the soft tissues and excessive swelling have stabilized. Assessment of this can be done by observation of wrinkling of the lateral hindfoot soft tissues. If soft tissues are not amenable to open reduction and internal fixation, other techniques including percutaneous fixation and external fixation may be utilized. Despite anatomic reduction and adequate treatment, these patients often develop subtalar stiffness and osteoarthritis.

Injury to the Midfoot

The midfoot injuries include those of the tarsonavicular, cuboid, cuneiform, and tarsometatarsal joints. Injuries to the Lisfranc (tarsometatarsal) joints include subtle sprains to frank fracture dislocations. Bony architecture is similar to that of a Roman arch and designed for stability. The keystone of the arch is the second metatarsal, which has a wedge-shaped base that is recessed between the medial and lateral cuneiform bones.

Strong plantar interosseous ligaments provide the main support for the tarsometatarsal joints. There is an absence of an intermetatarsal ligament between the first and second metatarsal joint, which makes this area susceptible to injury. The “Lisfranc ligament” spans the plantar lateral aspect of the medial cuneiform bone and the medial base of the second metatarsal and resists lateral translation of the lesser metatarsals. Mechanisms of Lisfranc injury include a direct crush injury to the midfoot and an indirect twisting-type injury when an axial load is applied to the heel with the foot in fixed equinus, as in motor vehicle accidents or sporting activities. Up to 20% of these injuries are missed on initial evaluation because of the potential subtle nature of these injuries. It is important to obtain standard threeview radiographs of the injured foot and look for the appropriate signs of injury.

Treatment involves conservative nonsurgical treatment for stable injuries versus anatomic reduction of the involved joints with rigid fixation via percutaneous method or open reduction internal fixation for unstable injuries. Patients often develop posttraumatic arthrosis and stiffness.

Ankle Sprains

Ligamentous disruptions, partial and complete, are common about the ankle. The most common ligament to be injured is the anterior talofibular ligament (Fig. 13-13). Inversion stress testing can elicit pain and demonstrate instability on radiographs (Fig. 13-14). Partial injuries can be treated with either a cast or fracture boot or a brace. A complete ligament disruption, particularly of the deltoid, may require surgical repair.

Injuries of the Forefoot

Fractures of the sesamoid bones occur relative to direct trauma or use or both injuries, associated with hyperdorsiflexion of the first metatarsal phalangeal joint. Bipartite sesamoid bones (congenital separation of the two poles of the sesamoid) occur in approximately 25% of individuals, the majority involving the tibial sesamoid bone. Management is mostly conservative. Phalangeal fractures may be either displaced or nondisplaced and angulated. Closed manipulation is often needed under local anesthetic; then the affected toe is taped to the adjacent toe as a splint mechanism, or “buddy taping” is done with wearing of a stiff-soled shoe or sandal.

488 S.T. Sauer and P.S. Cooper

Calcareofibular lig.

Ant. talofibular lig.

FIGURE 13-13. Inversion stress testing, or the talar tilt. (From Lasseter TE Jr, Malone TR, Garrett WE Jr. Injury to the lateral ligaments of the ankle. Orthop Clin N Am 1989;20(4):631. Reprinted by permission.)

23°

A B

FIGURE 13-14. (A) Anteroposterior view of the ankle prestress. (B) Anteroposterior view of the ankle with inversion stress reveals marked lateral ligament injury. (From Lasseter TE Jr, Malone TR, Garrett WE Jr. Injury to the lateral ligaments of the ankle. Orthop Clin N Am 1989;20(4):632. Reprinted by permission.)

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to a high, wide toe box and a soft leather upper portion of the shoe. Orthotic devices can be helpful. When conservative measures are not successful, surgical procedures are recommended; these include a simple exostectomy, soft tissue repair, proximal metatarsal osteotomy, distal metatarsal osteotomy, resection arthroplasty, proximal phalangeal osteotomy, and arthrodesis. Contraindications to surgery include generalized spasticity, ligamentous laxity as seen in Marfan’s and Ehlers–Danlos’ syndromes, and vascular skin insufficiency.

Hallux Varus

Hallux varus is a medial deviation of the great toe at the MTP joint. Causes include complications to hallux valgus surgery or rupture of the conjoined tendon as seen in rheumatic conditions.

Hallux Rigidus

Hallux rigidus is painful loss of motion at the first MTP joint (Fig. 13-16). Patients present with an enlarged, warm, and swollen first MTP joint, with a decreased range of motion, predominantly in dorsiflexion. Shoes with elevated heels tend to increase pain. Initial treatment is conservative with orthotic devices and shoe modifications to reduce the stress across the first MTP joint. Surgical intervention includes resection arthroplasty, cheilectomy, metatarsal or phalangeal osteotomy, or arthrodesis.

FIGURE 13-16. Hallux rigidus. The posteroanterior view of the great toe metatarsophalangeal joint show the marked cartilage loss, flattening of articular surfaces, and hypertrophic lipping that resulted in severe loss of motion. (From Weissman BNW, Sledge CB. Orthopedic Radiology. Philadelphia: Saunders, 1986. Reprinted with permission.)

Injuries of the Tendons of the Foot and Ankle

Tendonitis is a nonspecific term for a variety of pathologic conditions of tendons. Tendonitis is the inflammatory process of the connective tissue structure surrounding a tendon. Tendonosis is intratendinous degeneration. Management is often conservative, with rest and immobilization with antiinflammatory medications. Common disorders of tendons are those involving the peroneal tendon complex, the anterior tibial tendon, the Achilles tendon, the posterior tibial tendon, and the FHL tendon.

Peroneal Tendon Pathology

Peroneal tendon disorders include injury and degeneration of the peroneus brevis or longus and instability of the peroneal tendon complex. Peroneal brevis tendon injuries may manifest as tenosynovitis, a longitudinal split in the tendon, and subluxation or frank dislocation of the tendon. The patient may have a history of an inversion supination sprain. Radiographic studies are often normal. Indications for operative treatment are persistent pain and failure of conservative treatment with cast immobilization for 2 to 3 weeks and physical therapy. Goals of surgery are to reconstruct the superior peroneal retinaculum, perform a tenosynovectomy when applicable, and to repair any tendon injury.

Anterior Tibial Tendon Pathology

Injuries of the anterior tibial tendon are rare. Tendosynovitis may result from irritation by shoe wear, but is often attributed to an underlying rheumatic condition. Surgery is indicated for a young, active individual with an acute rupture.

Achilles Tendon Disorders

Disorders of the Achilles tendon include peritendonitis, tendinosis, partial and complete rupture, and insertional tendonitis with retrocalcaneal bursitis. Achilles tendonitis is painful inflammation and degeneration of either the surrounding peritenon (peritendonitis) or tendon (tendinosis) or both that occurs proximal to the insertion site of the Achilles in the calcaneus. This condition is often seen in runners with tight Achilles tendons and poor flexibility. Treatment is often conservative, with a period of immobilization to allow inflammation to subside, followed by physical therapy and stretching of the Achilles tendon daily. When conservative measures fail, debridement of the Achilles tendon can be done surgically. When tendonitis occurs at the Achilles tendon insertion onto the posterior aspect of the calcaneus, it is called insertional Achilles tendonitis. Often, there is an enlarged posterior superior calcaneal process called a Haglund’s defor-