Accuracy of radiography, computed tomography and magnetic resonance imaging in diagnosing foreign bodies in the foot.

PURPOSE: The purpose of this study was to determine the accuracy of conventional radiography, computed tomography (CT) and magnetic resonance imaging (MRI) in detecting foreign bodies by using cadaver feet. MATERIALS AND METHODS: One hundred and sixty foreign bodies consisting of 5 × 2-mm fresh wood, dry wood, glass, porcelain and plastic fragments were randomly placed in the plantar soft tissue of the forefoot and sole. An additional 160 incisions were made without the insertion of foreign bodies. Radiographs, CT and MRI scans were assessed in a blinded fashion for the presence of a foreign body. RESULTS: Overall sensitivity and specificity for foreign body detection was 29% and 100% for radiographs, 63% and 98% for CT and 58% and 100% for MRI. The sensitivity of radiography was lower in the forefoot. CT and MRI detection rates depended on the attenuation values of the foreign bodies and on the susceptibility artefact, respectively. CT was superior to MRI in identifying water-rich fresh wood. CONCLUSIONS: Radiography, CT and MRI are highly specific in detecting foreign bodies but sensitivity is poor. The detection rate depends on the type of foreign body for all techniques and on location for radiography. To identify foreign bodies with MRI, pulse sequences should be used to enhance the susceptibility artefact. In water-rich wood, as in chronically retained wood, CT is more accurate than MRI.

Biomechanical comparison of three fixation techniques used for four-corner arthrodesis.

Clinical results following four-corner arthrodesis vary and suggest that nonunion may be related to certain fixation techniques. The purpose of our study was to examine the displacement between the lunate and capitate following a simulated four-corner arthrodesis with the hypothesis that three types of fixation (Kirschner wires, dorsal circular plate, and a locked dorsal circular plate) would allow different amounts of displacement during simulated wrist flexion and extension. Cadaver wrists with simulated four-corner arthrodeses were loaded cyclically either to implant failure or until the lunocapitate displacement exceeded 1 mm. The locked dorsal circular plate group was significantly more stable than the dorsal circular plate and K-wire groups (p = 0.018 and p = 0.006). While these locked dorsal circular plates appear to be very stable our results are limited only to the biomechanical behavior of these fixation techniques within a cadaver model.

Pulmonary and biceps function after intercostal and phrenic nerve transfer for brachial plexus injuries.

This pseudo-randomized study was performed to compare the pulmonary function and biceps recovery after intercostal (19 cases) and phrenic (17 cases) nerve transfer to the musculocutaneous nerve for brachial plexus injury patients with nerve root avulsions. Pulmonary function was assessed pre-operatively and postoperatively by measuring the forced vital capacity, forced expiratory volume in 1 second, vital capacity, and tidal volume. Motor recovery of biceps was serially recorded. Our results revealed that pulmonary function in the phrenic nerve transfer group was still significantly reduced 1 year after surgery. In the intercostal nerve transfer group, pulmonary function was normal after 3 months. Motor recovery of biceps in the intercostal nerve group was significantly earlier than that in phrenic nerve group. We conclude that pulmonary and biceps functions are better after intercostal nerve transfer than after phrenic nerve transfer in the short term at least.