In Vitro Mechanical Testing of Monofilament Nylon Fishing Line, for the Extracapsular Stabilisation of Canine Stifle Joint

Cranial cruciate ligament (CCL) rupture is a common injury in the dogs and major cause of degenerative joint disease. A common method to restore stifle joint stability is an extra capsular repair with a lateral fabella-tibial suture using heavy nylon wire. Aims: to compare the mechanical properties (force at failure and elongation) of three diameters of nylon fishing line before and after steam sterilizer with loops secured by knot (two types) and by crimped system. Materials and methods: Two monofilament nylon fishing lines (1 and 1.2 mm) were used to determine the effect of steam sterilization on strength and elongation of the material. A strand of each diameter of monofilament nylon fishing material was knotted or crimped to form a loop around 2 rods on a materials-testing machine. Material testing was performed using a servo-hydraulic materials-testing machine (MULTITEST 5-i) and analyzed by Emperor Force soft. Twenty trials of each diameter of unsterilized and steam-sterilized nylon per each type of secured methods (square knot, surgical knot, and with a crimp clamp) were tested. A strand of each material was elongated to failure at a constant displacement of 10 mm/min to determine strength. A strand of each material was cycled 10 times to a load of 50 N to determine percent elongation. Results: All the loops failed by breaking or slipping within the knot or clamp. The surgeons knot had significantly greater elongation than all other loops, but required the most force to failure. With incremental loading, knotted loops elongated more than crimped loops. The loops secured by indigene crimp system were weaker strength than knotted loops. Conclusion: All materials tested exceeded the necessary strength of neutralizing the load in the canine walk but none exceeded the estimated highest load during canine higher activity.