A clinical trial was performed to evaluate sternal closure with the controlled tension osteosynthesis system and closure with twisted stainless steel wires. Some 451 consecutive patients who underwent isolated coronary bypass surgery between January 1991 and December 1991 were subdivided into three groups. Patients in group A (94 patients) and group B (98 patients) were all operated on by one surgeon, to reduce variability before, at the time of and after surgery, which might influence sternal wound healing. To exclude a possible preference of the surgeon in the study, group C was formed, consisting of 259 patients operated on by other hospital surgeons. In groups A and C, sternal closure was performed with the controlled tension osteosynthesis system. In group B, sternal closure was performed with (six) twisted stainless steel wires. Among groups A, B and C, no statistical significant difference could be found between the rate and the type of sternal wound complications. Despite this finding, there were significantly more reoperations, a longer cross-clamp time and more extensive use of the internal mammary artery as a graft in group B. Despite the non-randomization of the study, and the small patient numbers being a limitation, the use of the controlled tension osteosynthesis system in adults did not result in a decrease of early sternal wound complications.