Ultrasound in osteotomies and nonunions—basic research

10.1055/b-0034-86364

Ultrasound in osteotomies and nonunions—basic research

Peter A Nolte, Sjoerd Rutten

Introduction

Low-intensity ultrasound is used in various diagnostic and therapeutic indications. The therapeutic ultrasound signal is externally applied through a transducer. The intensity used is 30 mW/cm² with a frequency of 1.5 MHz. In fresh fractures of long bones, scaphoid fractures, osteotomies, and distraction osteosynthesis low-intensity pulsed ultrasound has been shown to enhance bone healing by up to 30–40%.

Mechanism of action

Low-intensity ultrasound has an anabolic effect on osteo-blasts and chondrocytes. The osteoblasts increase activity by low-intensity ultrasound. There is no proliferation of bone cells. Endochondral ossification is stimulated by ultrasound treatment. Maturation of callus tissue is seen. The vascularization at the fracture or nonunion site is also stimulated by ultrasound.

a Distal tibial fracture treated with external fixator. **b–c** After surgical procedures using autogenous bone grafts.

Techniques

Case

A 31-year-old man was involved in a motorbike accident. The distal tibial fracture was treated with an external fixator (Fig 1.3.2-1a). For a nonunion, two secondary surgical procedures were performed using autogenous bone grafts (Fig 1.3.2-1b–c). Despite this treatment, the oligotrophic tibial and fibular nonunions persisted. Even with plaster, the patient still experienced pain at the fracture site and discomfort when walking. Ultrasound treatment was started 35 weeks after the last surgical procedure and 1.5 years after the accident.

Ultrasound treatment

The transducer, which supplies the ultrasound energy, is connected to the holder (in a cast if necessary) and gel is applied to the skin (Fig 1.3.2-2). The device is turned on and switched off automatically after 20 minutes. The optimal treatment period is 20 minutes per day. Longer treatment is not necessary, however, it causes no negative side effects.

After 5 months of ultrasound treatment the tibial and fibular nonunions are healed (Fig 1.3.2-3a–b). The patient is pain-free and can walk without plaster.