Biomechanical study on the suture strength of ligament in cruciate ligament reconstruction

To test the suture strength on the tendon or ligament end and evaluate the stitch in the reconstruction of cruciate ligament and its clinical application.

Twenty-four specimens of patellar tendon with free ends were divided into 3 groups: Group I (3 Krackow stitches), Group II (2 Krackow stitches) and Group III (2 Krackow stitches with the first stitch passing through the tendon tissue as a modified Krackow stitch). These 3 groups were further divided into 6 subgroups according to different suture materials, No 1 Ethilon or stainless steel wire (phi=0.4 mm). Tensile test was undertaken to find out the least stitches with efficient suture pattern.

Two Krackow locking stitches had stronger strength than 0.4 mm-diameter stainless steel wire. The fixation strength of 2 stitches with No 1 Ethilon was more than 80 N, superior to the failure strength of the material itself. The same strength was maintained if the first stitch was across the tendon tissue transversely. There was no statistically significant difference in the suture strength between 2 and 3 Krackow locking stitches.

The suture strength is greater than the failure strength of the suture material. Less suture exposure can be achieved when the first stitch is across the tendon tissue while maintaining a comparable strength to other sutures. To attain higher suture strength, stronger materials or multiple strands rather than more stitches are preferred. Therefore, a rapid early rehabilitation of range of motion (ROM) is possible and reliable in practice.