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

492 S.T. Sauer and P.S. Cooper

mity. This tendonitis is also associated with a retrocalcaneal bursitis, which is inflammation of the bursa directly anterior to the Achilles tendon at its insertion. Conservative treatment includes a period of immobilization, heel lifts to shorten the Achilles tendon and take the pressure off the insertion, stretching exercises through physical therapy, and modification of shoe wear. When conservative measures fail, surgery, with debridement of the insertion and removal of the Haglund’s deformity as well as a reattachment of the Achilles tendon, is done.

Ruptures of the Achilles tendon can be acute or chronic. These ruptures commonly occur in middle-aged men at the hypovascular zone of the Achilles tendon approximately 3 to 5 cm above its insertion site. Ruptures occur because of forceful eccentric contraction of the elongating tendon; they rarely result from direct trauma. Symptoms include severe pain at the back of the calf. Patients often describe being hit in the back of the leg and an audible “pop.” Diagnosis is made by a palpable defect above the Achilles insertion with the patient in a prone position. Two findings are consistent with rupture of the tendon. The first is loss of passive resting tension in comparison to the opposite extremity, which causes the foot to be at a right angle to the remainder of the lower extremity. The second finding is performing the Thompson test, which is done with the patient’s foot hanging over the edge of the examination table in a prone position. The midcalf is squeezed. If the tendon is intact, the ankle passively plantarflexes. If the tendon is ruptured, no plantarflexion occurs. In difficult cases, MRI or ultrasound can confirm the diagnosis. Treatment of an acute rupture of the Achilles tendon can be conservative or surgical. Nonoperative management includes immobilization in a plantarflexed position, nonweightbearing, for approximately 3 months; this should be reserved for elderly, less active patients with a medical history that makes surgery dangerous. Disadvantages of conservative management include a higher rerupture rate than surgical repair. Surgical repair includes direct repair of the ends of the Achilles tendon. Advantages include a lower rerupture rate than conservative treatment. Disadvantages include wound complications, infection, and sural nerve injury. Treatment of chronic neglected ruptures includes bracing with an ankle-foot orthosis and other complex surgical reconstructions including flexor hallucis longus tendon transfer.

Posterior Tibial Tendon

Overuse of the posterior tibial tendon causes conditions that range from mild tendonitis to complete rupture and asymmetrical flatfoot deformity.

Posterior tibial tendon dysfunction etiologies include trauma, inflammatory arthropathies, or nutritional degenerative conditions. Predisposing factors include hypertension, obesity, diabetes, steroid exposure, and prior surgery or trauma. Early stages include pain, swelling, and fullness localized to the posterior and medial hindfoot. As the tendon continues to

deteriorate and becomes incompetent, a progressive asymmetrical flatfoot deformity develops with lateral hindfoot impingement.

Clinical examination may show tenderness and swelling over the posterior medial hindfoot posterior to the medial malleolus, a secondary Achilles tendon contracture, and weakness in inversion. Patients are unable to perform a single heel-toe rise and often show a “too-many-toes sign” when visualizing the foot from behind when a patient is in a standing position. Too-many-toes sign refers to an advanced collapse of the arch with the heel in significant valgus. The toes are abducted more on the affected foot than the unaffected foot and show more prominently on exam. Weight-bearing X-rays may show uncovering of the talar head by the navicular as the forefoot and midfoot abduct. The lateral view may show talonavicular sagging. MRI can confirm tendinosis and peritendonitis. Treatment options are determined by the stage of dysfunction and presentation. Stage I, which is very mild tendon weakness without flatfoot deformity, can be addressed with orthotics, antiinflammatory medicines, and physical therapy. Sometimes immobilization is needed to allow a decrease in inflammation. Stage II, which involves posterior tibial tendon disruption and the presence of a flatfoot deformity with a flexible hindfoot, can be treated conservatively with orthotics or surgically, which involves reconstruction of the posterior tibial tendon using a flexor digitorum longus tendon transfer and calcaneal osteotomy. There are other surgical options available, and the decision is based on the clinical presentation of the patient. Stage III, which involves posterior tibial tendon dysfunction or disruption, with advanced arthritis and a rigid hindfoot, can be treated conservatively with orthotics or surgically with the appropriate joint fusions. Typically, a triple arthrodesis, or a fusion of the subtalar joint, talonavicular joint, and calcaneocuboid joints, is preferred.

Heel Pain

Plantar heel pain is one of the most common and most disabling conditions of the foot. There are many causes including tumors, infection, stress fractures, inflammatory arthropathies, and neuropathies. The most common cause of plantar heel pain is associated with chronic injury of the plantar fascial origin. This heel pain syndrome is also known as heel spur syndrome and plantar fascitis. Typical pain occurs at the plantarmedial aspect of the heel. Onset is insidious, and often patients recall no trauma. Classic pain and stiffness occurs when arising from bed and taking the first step on the floor in the morning. Symptoms often decrease after prolonged walking. High-heeled shoes typically alleviate symptoms, whereas barefoot walking and wearing flat shoes may increase symptoms. Physical examination shows point tenderness on the plantarmedial heel. Often there is a tight Achilles tendon complex with limited ankle dorsiflexion; occasionally, fat pad or heel pad atrophy is present. Radiographs include a lateral

494 S.T. Sauer and P.S. Cooper

FIGURE 13-17. Calcaneal spurs. The normal plantar spur (open arrow) has smooth margins, no sclerosis or erosion, and no adjacent soft tissue swelling. Very small spurs are present at the insertions of the long plantar ligament (arrow) and the Achilles tendon. (From Weissman BNW, Sledge CB. Orthopedic Radiology. Philadelphia: Saunders, 1986. Reprinted with permission.)

X-ray, which may show a plantar heel spur (Fig. 13-17); this is often associated with a flexor digitorum brevis origin and can signify a chronic fascitis.

It is important to rule out a calcaneal stress fracture and tumor via X-rays.

Treatment is almost always conservative, consisting of rest, antiinflammatory medication, orthotic devices, and aggressive stretching. Isolated stretching of the gastrocnemius–soleus complex and plantar fascia is important. Surgery, typically reserved for chronic conditions that have lasted more than 6 six months to a year, involves partial release of the plantar fascial origin.

Arthritic Conditions of the Foot and Ankle

Causes of ankle joint degeneration include primary osteoarthritis, posttraumatic arthritis, avascular necrosis, osteochondritis dissecans, synovial chondromatosis, and other rheumatologic conditions. Conservative management includes antiinflammatory medications, bracing, and intraarticular cortisone injections. Surgical management is dependent on the extent and location of the arthrosis. Options range from joint debridement,

arthroscopic versus open, ankle arthrodesis (fusion), or a total ankle replacement. It is important to note that in extensive arthritis of the ankle the standard surgical treatment is arthrodesis (fusion). Total ankle replacement, although available and helpful in patients with a low-demand lifestyle, has not proven effective in long-term management of the osteoarthritic ankle.

Rheumatoid Arthritis

Rheumatoid arthritis is a systemic disease that commonly involves the foot because there are many joints lined with synovium (Fig. 13-18). It affects both the synovial lining of the joint and the tendons of the foot and ankle.

A B

FIGURE 13-18. Plantar (A) and dorsal (B) views of the foot of a patient with rheumatoid arthritis with characteristic dislocation of all toes, which tend to drift off into marked hallux valgus with dorsal displacement of the phalanges onto the metacarpals. The metacarpal heads become very prominent in the sole of the foot, and large, painful callosities are common. (From Bogumill GP. Orthopaedic Pathology: A Synopsis with Clinical and Radiographic Correlation. Philadelphia: Saunders, 1984. Reprinted with permission.)

A

B

FIGURE 13-20. (A) Bilateral infected ingrowing of both edges of the big toenails. The toenail of the right big toe was practically completely separated from its bed and was avulsed. The operation, which was performed under a local anesthetic, consisted of bilateral resection of all onychogenic tissue in the longitudinal grooves.

(B) Sixteen months after surgery. (From Lapidus PW. The toenails. In: Jahss M (ed) Disorders of the Foot, vol I. Philadelphia: Saunders, 1982. Reprinted with permission.)

occasionally be abnormal. Standard radiographs and a bone scan can confirm the diagnosis. When bone or joint involvement is extensive, aggressive surgical debridement is mandatory for satisfactory resolution. Appropriate antibiotic coverage is required until the infection has resolved.

Paronychia

A paronychia is an infection of the medial or lateral nail fold, often seen in the great toe (Fig. 13-20). Paronychiae are often seen in an abnormally growing nail, which penetrates the skin of the lateral nail fold, introducing bacteria. A soft tissue abscess forms and a paronychia develops. Decom-

FIGURE 13-22. One day of new shoe wear produced the ulcers seen over the fifth metatarsal head and lateral sides of the fourth and fifth toes. (From Harrelson JM. Management of the diabetic foot. Orthop Clin N Am 1989;20(4):606. Reprinted by permission.)

Soft Tissue Lesions

The anterolateral ankle is the common site for the development of a ganglion cyst as well as soft tissue lipomas. These are both benign lesions, and excision can be performed if symptoms warrant. Thickening of the plantar fascia on the plantar surface of the foot can be palpated on some patients. Sometimes, these thickenings are large, firm nodules known as plantar fibromas. They are benign and should at all costs be treated conservatively.

Bone Tumors

Common bone tumors include enchondroma, a benign cartilage tumor that can occur in the short tubular bones such as the phalanges. The chondromyxoid fibroma (Fig. 13-23) is another benign cartilage tumor that can affect the bones of the foot. It is usually managed by curettage of the lesion.

Occasionally, a bone cyst can form in the calcaneus. Pathologic fracture through this can occur and may, in fact, be the chief complaint at a patient’s presentation. Treatment usually requires curettage and bone grafting. It is uncommon to have metastatic disease to the small bones of the foot.

500 S.T. Sauer and P.S. Cooper

FIGURE 13-23. Chondromyxoid fibroma. This lesion has a tendency for localization in the small bones of the hands and feet. A sharply circumscribed defect in the proximal phalanx of the great toe is shown here. (From Bogumill GP. Orthopaedic Pathology: A Synopsis with Clinical and Radiographic Correlation. Philadelphia: Saunders, 1984. Reprinted with permission.)

When seen, one should suspect the lung as the primary site of the patient’s disease.

Complex Regional Pain Syndrome

This disabling disorder of unknown pathophysiology has a variable symptom complex with many hypothesized causes and mechanisms. Renamed from the limited descriptive term reflex sympathetic dystrophy, Complex Regional Pain Syndrome (CRPS) is more common in women than men and more common in adults than children. It can occur after a minor injury with no nerve involvement, or after a significant injury with nerve involvement. Patients present with disproportionate extremity pain, swelling, autonomic symptoms (e.g., changes in sweating, skin discoloration), and motor symptoms (e.g., weakness). Diagnosis of any obvious, treatable causes of pain should be done before definitively selecting CRPS as the diagnosis. Treatment involves extensive therapy and pain relief with desensitization through medication or nerve blockade.

Summary and Conclusions

Numerous conditions affect the foot and ankle, and foot pain remains a very common presenting complaint. A knowledge of anatomy and common foot and ankle problems can provide the diagnostician adequate tools to treat patients. The last three figures in this chapter provide algorithms that can assist in the diagnosis and treatment of foot and ankle pain. Figure 13-24 can assist in the diagnosis and treatment of patients with foot and ankle complaints resulting from an acute injury. Figure 13-25 provides steps to evaluate and treat patients who have foot and ankle pain without a history of an acute injury but do have radiographic evidence of deformity or pathology. Figure 13-26 should provide some structure to the diagnosis and treatment of patients with foot and ankle complaints without injury and no radiographic evidence of deformity or pathology. These algorithms

FIGURE 13-24. Algorithm for diagnosis and treatment of foot and ankle pain with acute injury.