101 patients who had suffered a fracture to the tibial shaft, and for whom delayed union was confirmed were randomized to undergo 16 weeks of active low-intensity pulsed ultrasound (LIPUS) or a sham device, to determine whether LIPUS is effective in promoting bone healing in this population. Results indicated that improvements in bone mineral density (BMD) and gap area at the fracture site were significantly higher in patients treated with LIPUS compared to those treated with a sham device, with a medium degree of effectiveness in patients who completed the protocol. Furthermore, regardless of group allocations, patients whose time since fracture was 48 weeks or more experienced significantly poorer radiological outcomes, compared to fractures experienced <48 weeks prior.