Background Rigid bone fixation is the standard of care for all bone reconstructions except that after sternotomy. Sternal reconstruction after median sternotomy using rigid fixation with plates may improve bone healing and reduce pain when compared with wire cerclage. Methods One-hundred forty patients at six centers who were determined preoperatively to be at high risk for sternal wound complications were randomly assigned to sternal closure with rigid plate fixation (n = 70) or wire cerclage (n = 70). Sternal healing was evaluated at 3 or 6 months by a core laboratory using computed tomography. Pain and function were evaluated at postoperative day 3 through discharge, 3 weeks, 6 weeks, 3 months, and 6 months. Results Sternal healing was superior in rigid plate fixation patients at both 3 and 6 months. Mean computed tomography scores in the rigid plate fixation and wire cerclage groups at 3 months were 1.7 ± 1.1 and 0.9 ± 0.8 (p = 0.003). At 6 months, the scores were 3.2 ± 1.6 and 2.2 ± 1.1, respectively (p = 0.01). At 6 months, 70% of rigid plate fixation patients had achieved sternal union, compared with 24% of conventional wire cerclage patients (p = 0.003). Pain scores and narcotic usage were lower in rigid plate fixation patients. Significant differences in pain scores were observed at 3 weeks for total pain (p = 0.020) and pain with coughing (p = 0.0084) or sneezing (p = 0.030). Complication rates were similar in both groups. Conclusions Sternal reconstruction using rigid fixation with plates improved bone healing and reduced early postoperative pain compared with wire cerclage.