Table 2-1. Diagnostic Testing of the Foot and Ankle
tendons to click or pop, particularly in hyperlax patients, or for the extensor tendons to cause similar problems. In a dancer, however, persistent popping or catching on the medial side of the foot may suggest a tenosynovitis of the flexor hallucis longus (FHL) or “hallux saltans.” Deformities about the ankle and foot are usually congenital, insidious, or traumatic in origin. Only when the patient becomes symptomatic is the deformity noted, although it may have been present for a long time. Such is the case with pain over “pump bumps” or in the area of the accessory navicular and occasionally over the base of the fifth metatarsal.
FIGURE 2-1. Longitudinal arch. (A) Lateral view of medial longitudinal arch. (B) Posterior view of medial longitudinal arch. Note the transverse arch provided by the metatarsal heads. (Illustration by Susan Brust.)
FIGURE 2-3. Windlass mechanism. (A) Normal position of plantar aponeurosis. (B) Dorsiflexion with the toes increases the tension on the plantar aponeurosis, which causes the longitudinal arch to rise. (Illustration by Susan Brust.)
FIGURE 2-4. “Malicious malalignment” syndrome. The combination of increased Q-angles of the knee, hindfoot, and forefoot valgus, and femoral neck anteversion contribute to this problem. (Illustration by Susan Brust.)
A significantly increased anterior drawer suggests a double ligament tear (see Fig. 2-10).
FIGURE 2-9. Inversion stress test. A single ligament tear allows increased talar tilt (inset). A double ligament tear leads to significant talar tilt with inversion stress. (Illustration by Susan Brust.)
FIGURE 2-12. The external rotation stress test produces pain over the anterior and posterior inferior tibiofibular ligaments and the interosseous membrane when positive. (Illustration by Susan Brust.)
tarsal joint, in the other and bringing the subtalar joint into both inversion and eversion (Fig. 2-14). The most accurate method of determining subtalar motion is to place the patient prone and flex the knee to 135°.2 If motion is limited and considerable pain occurs on passive motion along with spasm, subtalar pathology should be suspected. Usually this is associated with tenderness along the sinus tarsi and posterior talocalcaneal joint and occasionally tenderness along the medial portion of the subtalar joint. If loss of subtalar motion is detected, the examiner should consider the possibility of an arthritic process in the subtalar joint, peroneal spastic flatfoot, or an anatomic abnormality such as tarsal coalition.
from the posterior aspect of the talus to the level of the sustentaculum tali and acts like a rope through a pulley. When injured, it begins to bind and a nodular partial tear may be present, causing triggering of the big toe or so-called hallux saltans6 (Fig. 2-16).
bunion surgery that produces shortening, dorsiflexion, or instability of the first metatarsophalangeal joint, a painful diffuse callus may develop beneath the second metatarsal. In contrast, the fourth metatarsal is the most mobile and is rarely associated with any significant pathologic condition.
FIGURE 2-15. Posterior tibial tendon testing. (A) Normal inversion with intact tendon. (B) Loss of inversion with ruptured posterior tibial tendon. (C) Testing the ruptured tendon, starting from an everted position. (Illustration by Susan Brust.)
FIGURE 2-16. Hallux saltans can develop from tendinitis of the flexor hallucis longus as it passes through the fibro-osseous tunnel on the medial side of the foot. (Illustration by Susan Brust.)
FIGURE 2-18. Pain in the foot can be referred from the back, hip, or knee. (Illustration by Susan Brust.)
1 cm proximal to the tibial plafond articular line on the AP and mortise views. This space is usually considered within normal limits if it is <6 mm. The tibiofibular overlap is the distance between the medial border of the fibula and the lateral border of the anterior tibia, measured 1 cm proximal to the tibial plafond articular line. A normal tibiofibular relationship is indicated by at least 1 mm overlap of the tibia and the fibula on the AP and mortise views. The medial clear space is the distance between the medial border of the talar dome and the lateral border of the medial malleolus, measured 1 cm distal from the tibial plafond articular line. The distance defines the integrity of the ankle mortise and is normally 2 to 3 mm. A medial clear space of more than 3 to 4 mm is associated with ankle fractures or syndesmotic injuries in which the talus shifts laterally. This finding also indicates a rupture of the deltoid ligament. In addition, a detailed evaluation of the tibiotalar joint congruity on the lateral view can be important in the overall evaluation of a syndesmosis injury. Anterior widening of the tibiotalar joint is consistent with a syndesmotic injury. It is always important to obtain comparison radiographs of the contralateral ankle to help with the assessment.8
FIGURE 2-20. Normal radiographic relationships that are important in evaluation of the tibiofibular articulation. (A, tibiofibular clear space; B, tibiofibular overlap; C, medial clear space.) (Illustration by Susan Brust.)
reliable indicator of injury to it. Gould and colleagues16 found that an increase of 4 mm indicated instability in the anterior drawer test. However, Laurin and associates17 considered an increase of more than 9 mm to be abnormal. Overall values of up to 4 mm separation between the talus and distal tibia are considered normal, values of 4 to 10 mm are probably abnormal, and values over 10 mm are grossly abnormal. These measurements are best performed at the posterior aspect of the talar and distal tibial articular surfaces (Fig. 2-25).
FIGURE 2-21. Normal foot x-rays. Degenerative joint disease, subluxation or dislocation, avascular necrosis, accessory bones, and other abnormalities can be noted on these x-rays. (A) Anterior posterior view; (B) true lateral view; (C) oblique view.
in different planes. Tomograms can be unidirectional (linear tomography) or pluridirectional (complex). The main indications for tomography include evaluations for nonunions, most arthrodeses, and occasionally Lisfranc fracture-dislocations. Infrequently, they are used to evaluate osteochondral fractures of the talus, navicular stress fractures, calcaneal fractures, and subtalar arthritis. The disadvantages of tomography include high radiation exposure and an inaccurate picture of the structures not exactly perpendicular to the plane of the tube motion. Conventional tomography is no longer widely available and has been replaced by CT. Recently, however, with digital radiography (DR), some manufacturers have included a tomographic technique into their DR systems, which may have limited utility.