Abstract OBJECTIVES We sought to compare the effects of conventional wire cerclage with that of the band and plate fixation of the sternum. METHODS A parallel randomized open-label trial with 1:1 allocation ratio compared healing after adult cardiac surgery using ‘figure-of-8’ stainless steel wire cerclage or a band and plate system (plates). The primary end point was maximal sternal edge displacement during active coughing of ≥2 mm in ≥2 of 4 sites measured with ultrasound by 2 assessors blinded to the other at 6 weeks postoperatively. Secondary end points at 12 weeks included ultrasound assessment, computed tomography (CT) scan and multidimensional assessment of quality of recovery using the Postoperative Quality of Recovery Scale. RESULTS Of 50 patients, 26 received plates and 24 wires. Two patients died and 1 withdrew consent leaving 25 plates and 22 wires for primary end point analysis. Operations included 37 coronary, 5 valve and 8 combined coronary and valve procedures. At 6 weeks, less sternal movement was observed in patients with plates than those with wires, 4% (1/25) vs 32% (7/22), P = 0.018. Agreement between observers was high, kappa = 0.850. At 12 weeks, less ultrasound motion was seen in patients with plates, 0% (0/23) than those with wires, 25% (5/20), P = 0.014. Recovery from pain was higher for patients with plates 92% (22/24) than those with wires 67% (14/21), P = 0.004. CT bone edge separation was less for plates 38% (9/24) than wires 71% (15/21), P = 0.036. CT mild bone synthesis or greater was similar between patients with plates 21% (5/24) and wires 14% (3/21), P = 0.71. CONCLUSIONS Patients receiving the band and plate system had significantly less sternal edge motion than those receiving wires, 6 and 12 weeks after cardiac surgery and experienced less pain. Clinical trial registration clinicaltrials.gov NCT03282578.