Subtalar arthrography in recurrent instability of the ankle.

Subtalar arthrography was done in 37 feet of 35 patients in whom recurrent instability of the ankle was diagnosed. There were 16 male and 19 female patients, with a mean age of 29.1 years (range, 11-56 years). The mean interval between the injury and arthrography was 4 years 3 months (range, 6 months-22 years). Anteroposterior, lateral, and oblique radiographs were obtained for all patients. Any leakage during arthrography into the ankle, tendon sheaths, or sinus tarsi was recorded. An oblique view of the microrecess along the interosseous ligament and an anteroposterior view of the lateral recess just under the end of the fibula were examined. At surgery, 13 feet had combined injuries of the anterior talofibular and calcaneofibular ligaments, and 24 feet had isolated injury of the anterior talofibular ligament. The findings of the two groups were significantly different when examined for leakage into the ankle, leakage into the peroneal tendon sheath, and the presence of the lateral recess. Presence of contrast medium in at least two of these three positive arthrographic findings showed 92.3% sensitivity and 87.5% specificity in making the diagnosis of calcaneofibular ligament injury. Subtalar arthrography is valuable in making the diagnosis of calcaneofibular ligament injury in recurrent instability of the ankle.

Evaluation of the longitudinal arch of the foot with hallux valgus using a newly developed two-dimensional coordinate system.

The purposes of the present study were to establish a method for the evaluation of the longitudinal arch, using a two-dimensional coordinate system, and to clarify the main point of flattening of the foot in patients with hallux valgus. Measurements on a weight-bearing lateral radiograph of the foot were performed in 186 feet of 110 women with symptomatic hallux valgus and in 93 normal feet of 72 women. A two-dimensional coordinate system was used to perform the measurements. In this coordinate system, the line connecting the lowest point of the first metatarsal head and the lowest point (O) of the calcaneus is fixed as the x-axis, and the line that is perpendicular to the x-axis and intersects the x-axis at point O is fixed as the y-axis. The mean values of the y-coordinates at the points of the medial longitudinal arch of the foot in the patients with hallux valgus were significantly lower than those in the normal subjects (P < 0.001). The values were noticeably lower at points on the navicular. However, no change was observed in the posterior talus body. The new coordinate system indicated that the main points of flattening of the foot in patients with hallux valgus were the plantar flexion of the talus and the sinking of the navicular.

Subtalar arthrography in acute injuries of the calcaneofibular ligament.

We treated 43 acute tears of the calcaneofibular ligament by operation in 43 patients after subtalar arthrography. There were 22 men and 21 women with a mean age of 22.3 years (14 to 61). Anteroposterior (AP), lateral and oblique views were obtained with the foot in 45 degrees of internal rotation and the ankle in the neutral position. Any communication or leakage to the ankle, tendon sheaths, subcutaneous tissue and sinus tarsi was recorded. We examined an oblique view of the microrecess along the interosseous ligament and an AP view of the lateral recess just under the distal end of the fibula. We also studied a control group of 27 patients with isolated injuries of the anterior talofibular ligament without rupture of the calcaneofibular ligament. The findings in the two groups were significantly different when examined for leakage to the ankle (p=0.0002), to the peroneal tendon sheaths (p=0.0347) and to the subcutaneous tissue (p=0.0222), absence of the microrecess (p=0.0055) and presence of the lateral recess (p=0.0012). Many ankle sprains which involve tearing of the calcaneofibular ligament are accompanied by injuries of the subtalar joint. Combined injuries of the anterior talofibular ligament and calcaneofibular ligament, and isolated injury of the anterior talofibular ligament should be differentiated.

Varus tilt of the tibial plafond as a factor in chronic ligament instability of the ankle.

The authors performed a radiographic study of 136 patients with acute ligament sprains and 85 patients with chronic lateral ligament instability of the ankle. Varus angulation of the tibial plafond, varus angulation of the line passing both malleolar ends, and varus angulation of the medial malleolus were measured on the AP views, and dorsal angulation of the tibial plafond was measured on the lateral views. The varus angles of the tibial plafond, the line passing both malleolar ends, and the medial malleolus were larger as mean values in patients with chronic ligament instability than in the patients with acute ligament sprain. The varus tilt of the tibial plafond is more often seen in patients with chronic ligament instability of the ankle than in patients with acute ligament sprains.

Radiographic analysis of hallux valgus. A two-dimensional coordinate system.

A new method was devised for the evaluation of medial and lateral splaying of the foot on dorsoplantar radiographs made while the patient is bearing weight. This method involves use of a two-dimensional coordinate system; the axis of the shaft of the second metatarsal is the x axis, the intersection of the x axis with the proximal end of the second metatarsal is the point of origin, and the perpendicular to the x axis that passes through the point of origin is the y axis. This method was used to study the radiographs of 177 feet of 112 female patients who had symptomatic hallux valgus and those of ninety-four normal feet of sixty-four female subjects. The site of origin of metatarsus primus varus in the patients who had hallux valgus was the first metatarsocuneiform joint. The great toe and first metatarsal of the patients who had hallux valgus were longer, on the average, than those of the normal subjects. However, the x coordinates at the tip of the great toe and at the end of the first metatarsal were larger only in the patients who were less than twenty years old, because of the progression of angulation of the great toe and of the first metatarsal in the older patients.