TENOSYNOVITIS AND TENDINITIS
Tenosynovitis and tendinitis may occur in the foot, usually due to overuse. Patients present with pain over the involved tendon (Figure 285-3). The flexor hallucis longus, posterior tibialis, and Achilles tendon are most commonly involved.34 Treatment consists of rest, ice, and oral nonsteroidal anti-inflammatory drugs.34
Flexor hallucis longus tenosynovitis classically affects ballet dancers, but can also be seen in runners and nonathletes. Presentation is similar to plantar fasciitis and tarsal tunnel syndrome. Posteromedial ankle pain, medial arch pain, and a positive Tinel sign (see earlier description in "Tarsal Tunnel Syndrome") are seen. Conservative management (rest, mobilization, orthotic shoe implant, nonsteroidal anti-inflammatory drugs) is usually successful. Surgery is reserved for refractory cases.
Tendon lacerations can result from penetrating injuries to the dorsal or plantar aspect of the foot. Tendon repairs in the foot are complex, and orthopedic consultation is needed for repair.34
The foot should be casted in dorsiflexion after the repair of extensor tendons and in equinus after repair of flexor tendons.
Spontaneous rupture of the Achilles tendon is common. Rupture of the anterior tibialis and posterior tibialis tendons may also occur.34 Age and chronic corticosteroid and fluoroquinolone use are risk factors for spontaneous rupture. Diagnosis is usually clinical but is aided by US or MRI studies in difficult cases.
Achilles tendon rupture occurs when a sudden shear stress, such as sudden pivoting on a foot or rapid acceleration, is applied to an already weakened or degenerative tendon. Many patients report immediate sharp pain, and some hear an audible "pop." The peak age for rupture is 30 to 40 years, and rupture is four to five times more common in men than women.35 Over 80% of ruptures occur during recreational sports ("weekend warrior"). Patients often present with pain, a palpable defect in the area of the tendon, and inability to stand on tiptoes. A minority of patients with complete tendon ruptures are able to ambulate and may be misdiagnosed as having an ankle sprain. Squeezing the calf of the prone patient whose knee is flexed at 90 degrees will normally cause the foot to plantar flex (calf squeeze or Thompson test. The absence of plantar flexion indicates a positive test indicative of rupture. Initial ED treatment consists of ice, analgesics, immobilization of ankle/foot in plantar flexion, crutches, and referral to an orthopedic surgeon. Definitive treatment is generally surgical in younger patients and conservative (casting in equinus or plantar flexion) in older patients.34,36,37 For further discussion, see chapter 44, "Leg and Foot Lacerations," and Figure 44-1 (Thompson test) in that chapter, in Section 6, "Wound Management."
Ruptures of the anterior tibialis tendon are rare. Ruptures usually occur after the fourth decade and are not excessively painful. Patients present with varying degrees of foot drop and a palpable defect distal to the ankle joint in the area of the tendon. In most cases, disability is minimal, and surgery is not necessary.34
Spontaneous ruptures of the posterior tibialis tendon also occur after the fourth decade. Two thirds of these cases occur in women. The presentation is usually chronic and insidious. Patients notice a gradual flattening of their arch, with modest discomfort and swelling over the medial ankle. Examination reveals absence of the tendon's normal prominence and weakness on inversion of the foot. Patients find it impossible to stand on tiptoes. Treatment may be conservative or surgical, depending on the duration of the tear and activity of the patient.22
Flexor hallucis longus rupture presents as a loss of plantar flexion of the great toe. The need for surgery will depend on the patient's occupation and lifestyle.34
Disruption of the peroneal retinaculum can occur as a result of direct trauma during dorsiflexion of the foot. Besides pain localized to the peroneal tendon behind the lateral malleolus, the patient complains of a clicking when walking as the tendon subluxes. Peroneal tendon injuries may lead to lateral ankle instability. Treatment is generally surgical repair.34