This is the first known report of the response of the newer generation of sutures to shear forces which appear to be an important mode of failure during arthroscopic surgery.
Although the tensile strengths of the newer generation of sutures have been well described, no studies to date have examined the resistance of these sutures to abrasion and shear forces. We feel that resistance to shear forces is an important characteristic of sutures that are used arthroscopically, as one of the most common methods of failure is fraying during knot tying. The purpose of this study was to define these characteristics for five sutures commonly used in arthroscopic procedures.
Ethibond, Orthocord, Fiberwire, Ultrabraid and Maxbraid were used for this study. Abrasion resistance was determined using a simple mechanical device with a scalpel blade for abrasion force. Shear force was tested using the same device but with the suture passing through an arthroscopic knot pusher mimicking what occurs during surgery. Twenty strands of each suture type were used for testing resistance to each kind of force. Each was tested in a cyclical fashion in a saline envrionment, recording the cycles to failure.
Ethibond performed the most poorly of all suture types against both abrasion (18 cycles) and shear forces (23 cycles). When examining abrasion resistance, Orthocord (251 cycles) was significantly more susceptible than Fiberwire (479 cycles), Maxbraid (441 cycles) and Ultrabraid (467 cycles). However, when facing shear stress Fiberwire (102 cycles) failed much more rapidly than Orthocord (393 cycles), Maxbraid (473 cycles) and Ultrabraid (635 cycles).
Resistance to abrasion and shear forces are characteristics that have not been previously described for the newer suture types. Orthocord was found to have significantly less resistance to abrasion forces while Fiberwire was found to fail much more rapidly under shear stress. The mode of failure was usually stripping of the braided external sheath of the suture exposing the parallel oriented core fibers. Both Maxbraid and Ultrabraid performed well under both testing conditions. Nothing is more frustrating than to have a suture fail during an arthroscopic procedure, particularly where an anchor is involved. This is the first known report of the response of these sutures to shear forces which appear to be an important mode of failure during arthroscopic surgery.
© 2007 Arthroscopy Association of North America. Published by Elsevier Inc. All rights reserved.