Kristiansen 1997.

Methods	Randomised, placebo‐controlled study
Participants	Setting: multicentre trial, USA. Size: a total of 85 fractures in 83 patients. Of the 40 fractures in the test group, there were 10 withdrawn, leaving 30. Of the 45 fractures in the control group, 3 were lost to follow‐up and 11 were withdrawn, leaving 31. Baseline characteristics: there were 6 males and 24 females in the intervention group and 4 males and 27 females in the control group. Inclusion: men and non‐pregnant women who were at least 20 years old, who had closed dorsally angulated metaphyseal fractures of the distal radius. Exclusion: fracture extending beyond 4 cm proximally from the tip of the radial styloid, failure to satisfactorily reduce closed and immobilise in a below elbow cast, requirement for additional reduction after ultrasound treatment had begun, associated fracture of the ulnar shaft, current prescription of steroids or anticoagulant, any medical history of thrombophlebitis or vascular insuffiencey of the upper limb, current nutritional deficiency or alcohol dependency.
Interventions	Patients underwent closed reduction and immobilisation of the limb in a cast with volar flexion and ulnar deviation. A window was created on the dorsal aspect of the cast overlying the fracture and a retaining alignment fixture was placed in the window. The patients were given a device within 7 days of the fracture, were told to use it for 20 minutes a day, until their 10‐week appointment. Test: ultrasound probe that fitted into the retaining fixture was given to each participant. The ultrasound signal was composed of a 200 µs burst of 1.5 MHz sine waves, with a repetition rate of 1 kHz and a spatial average intensity of 30 mW/cm². Control: a visually and audibly similar device was given to each participant.
Outcomes	Follow‐up schedule was weekly until week 6 and then 8, 10, 12 and 16 weeks. End point was defined as combined clinical and radiographic healing. Primary: time to radiographic union. Secondary: time to early trabecular healing, time to cortical bridging, percentage of organised trabecular healing, loss of reduction.
Notes	The protocol specified combined clinical and radiographic healing, but investigators were reluctant to remove casts, therefore no clinical data are reported and radiographic union was used as the primary outcome measure. It was confirmed in personal communication with Joan McCabe that multiple reports with similar titles were all from the same study. Cook 1997 describes a subgroup analysis of the study by Kristiansen 1997. Smoking status before and during the study was retrospectively collected. There were 30 participants in the active group and 31 in the control group. These numbers correspond with the numbers of participants that successfully completed the study by Kristiansen 1997. There were 10 participants who could not be located for a retrospective analysis of smoking status.
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	Quote: "Randomly assigned...according to a computer generated code, developed by an independent consultant".
Allocation concealment (selection bias)	Unclear risk	Comments: Concealment of the codes is not reported.
Blinding (performance bias and detection bias) Objective measures	Low risk	Quote: "The placebo device...was identical to the active unit". "The principle investigator and the independent radiologist...were blinded...performed independent central assessments...of the radiographic parameters of union.
Incomplete outcome data (attrition bias) Objective measures	High risk	Comments: The protocol specified combined clinical and radiographic healing, but investigators were reluctant to remove casts, therefore no clinical data is reported. All patients lost to follow‐up accounted for but approximately 30% loss to follow‐up
Selective reporting (reporting bias)	Unclear risk	No protocol available.
Other bias	High risk	Two patients had bilateral fractures and they were treated with alternate devices. These fractures were analysed as independent events
Selection bias (imbalance in baseline characteristics)	Unclear risk	Gender, age and fracture characteristics were similar. Smoking status is not reported.