Effects of aging on the plantar soft tissue properties under the metatarsal heads at different impact velocities.

The plantar soft tissue properties under the metatarsal heads at different impact velocities in different age groups were measured. Each metatarsus of the left foot in healthy young adults (n = 9, 19 to 35 years old) and in healthy older persons (n = 10, 42 to 72 years old) was examined in vivo using a self-constructed loading-unloading device at low, medium and high impact status; the impact velocities of the device were about 2.5, 5 and 10 cm/s, respectively. The device comprised a 5- to 12-MHz linear-array ultrasound transducer, a miniature load cell and a fixation frame. From low to high impact status, the elastic modulus (E) in young adults significantly increased from about 300 kPa to about 500 kPa. However, the E in the older group did not show this trend. From low to high impact status, the energy dissipation ratio (EDR) of the metatarsus significantly increased from about 30% to about 60% in the young group and significantly increased from about 40% to about 70% in the older group. Most of the metatarsus in the older subjects had significantly greater E and EDR than those in the younger persons.

Ultrasonographic examination for inversion ankle sprains associated with osseous injuries.

OBJECTIVE: The study attempted to evaluate the value of ultrasonography in determining the therapeutic strategy for patients with osseous injuries caused by ankle sprains. DESIGN: A 10-MHz compact linear-array ultrasound transducer was used to assess patients with inversion ankle sprains. Eleven female and 12 male patients who had fractures detected by sonograms were included in the study. All 23 patients underwent radiographic examination for identification of fractures. Bone scintigraphy was performed for those who had negative x-ray findings. RESULTS: Eighteen patients had distal fibular tip fractures, three patients had the fifth metatarsal base fractures, one patient had a talar neck fracture, and one patient had a navicular fracture. These fractures were all detected by ultrasonography and then proved even by radiography or by bone scans. All the 23 patients had anterior talofibular ligament injuries. Among these patients, 11 had anterior ankle-joint recess effusion, and two had additional anterioinferior tibiofibular ligament injuries. Six weeks of immobilization with the ankle fracture brace was prescribed for all the patients after the identification of fractures. Their ankle pain symptoms soon improved. CONCLUSIONS: Ultrasonography is valuable in evaluating tiny foot and ankle fractures and coexistent soft tissue injuries. It can guide the treatment for patients with osseous injuries caused by ankle sprains.