[Does low intensity, pulsed ultrasound speed healing of scaphoid fractures?].

Since pulsed low-intensity ultrasound (frequency: 1.5 MHz, pulsed by 1 kHz, signal burst width: 200 microseconds, intensity: 30 mW/cm2) has been proven to stimulate fracture healing both clinically and experimentally, our question was whether this therapy also accelerates healing of fresh stable scaphoid fractures. Addressing this question, we did the following prospective randomized clinical trial. Regarding the results of former clinical fresh fracture studies by Heckman and Kristiansen, we postulated that low intensity ultrasound accelerates healing by about 30%. Based on this thesis, we calculated that 30 patients divided into two groups would be necessary to show significant differences between the standard treatment (treated by casting) and an adjunctive ultrasound treatment (treated by casting and additional daily 20 minutes ultrasound treatment) if present. Diagnosis and healing was assessed by CT scans every two weeks. CT's were analyzed by two independent radiologists and one hand surgeon. Furthermore, areas of cancellous bone bridging in correlation to the diameter of the scaphoid was measured in each CT scan. The results showed ultrasounded fractures healing in 43.2 +/- 10.9 days versus 62 +/- 19.2 days in the control group (p < 0.01). Trabecular bridging six weeks after injury showed 81.2% +/- 10.4% healed in the ultrasound-stimulated fractures versus 54.6% +/- 29% in the control (p < 0.05). Our study results confirm those of Heckman and Kristiansen and show a similar acceleration of bone healing. Low intensity ultrasound is successful in accelerating the healing of fresh scaphoid fractures.