Neurological complications of dynamic reduction of Colles' fractures without anesthesia compared with traditional manipulation after local infiltration anesthesia.

To investigate whether or not injection of local anesthetic into the fracture hematoma on reduction of a Colles' fracture increases the risk of neurological complications, a prospective randomized trial was conducted. The outcome in 62 patients whose Colles' fractures were reduced in a new bone-alignment device without anesthesia was compared with that in 54 patients with Colles' fractures that were reduced manually after injection of local anesthetic. At follow-up, any symptoms and signs of nerve damage were recorded. Four cases of such damage were noted in the group treated without local anesthesia, as opposed to 14 in the group in which a local anesthetic was used. The difference is significant (p less than 0.01). The authors have previously shown that injection of local anesthetic into the hematoma of Colles' fractures increases the carpal tunnel pressure. Neurological complications after the use of local anesthesia in reducing Colles' fractures is considered to be secondary to the scarring and fibrosis caused by this increase in pressure.