Nucleofection-based ex vivo nonviral gene delivery to human stem cells as a platform for tissue regeneration.

There are several gene therapy approaches to tissue regeneration. Although usually efficient, virusbased approaches may elicit an immune response against the viral proteins. An alternative approach, nonviral transfer, is safer, and can be controlled and reproduced.

Dynamic force distribution during level walking under the feet of patients with chronic ankle instability.

Objectives: To examine changes in the pattern of force transfer between the foot and the floor associated with chronically sprained ankles by measuring the peak forces and their timing under several regions of the feet during level walking.

Methods: Twelve young male subjects (mean (SD) age 21 (2) years) with recurrent ankle sprains were studied. Seven of them had unilateral and bilateral chronic instability and laxity, and five had bilateral instability.

Subtalar distraction arthrodesis using a ramp cage.

Subtalar distraction bone block arthrodesis has been described to treat late complications of displaced calcaneal fractures. A "ramp cage" can be used to restore the talocalcaneal relationship by providing stable correction in the coronal and sagittal dimensions.

Outcome of resection of a symptomatic os trigonum.

Background: While an os trigonum at the posterolateral aspect of the talus is usually asymptomatic, this inconsistently present accessory bone has been associated with persistent posterior ankle pain, which has been described as the os trigonum syndrome. We present the clinical results of excision of the os trigonum through a posterolateral approach and report several factors affecting the clinical outcome.

Methods: During a five-year period from 1994 through 1999, forty-one patients had a failure of nonoperative treatment of os trigonum syndrome and underwent excision of a symptomatic os trigonum.