A hand-held, pen-like device that converts high frequency electrical current into high frequency mechanical oscillation (ultrasonic vibration) in an ultrasonic osteosynthesis system. The ultrasonic vibration is used to produce friction and heat for the implantation of a resorbable fixation pin in a surgically-drilled bone tunnel. This device holds a dedicated detachable sonotrode tip at one end and has permanently attached cables at the other. The power switch is operated through a foot-pedal connected to the generator allowing the surgeon to control the welding process. This is a reusable device.