A surgical apparatus for tightening a strap loop to a predetermined tension about split tissue portions includes a frame, an advancing mechanism for tightening the strap loop, a linkage mechanism which severs excess strap material not used in securing the tissue portions together and a control mechanism for controlling operation of the apparatus. The advancing mechanism includes a tensioning lever and a gear mechanism. The gear mechanism includes a tensioning hub and a clutch which releases when the tension in the strap loop exceeds a predetermined value. The control mechanism includes a safety feature for preventing inadvertent activation of the linkage mechanism. A buckle and a method for use with the surgical apparatus is also disclosed. The invention is particularly contemplated for repair of the human sternum when the sternum has been split during surgical procedures.