Arnold GA, Mathews KG, Roe S, Mente P, Seaboch T. Department of Clinical Sciences, College of Veterinary Medicine, North Carolina State University, 4700 Hillsborough Street, Raleigh, NC 27606, USA. Vet Surg 2009 Oct 38 7 834-44 OBJECTIVE: To compare mechanical performance of 4 soft tissue replacement materials. STUDY DESIGN: Experimental. SAMPLE POPULATION: Polypropylene mesh (PM), single-layer porcine small intestinal submucosa (SIS), multilaminate (4-layer) porcine small intestinal submucosa (MLSIS), and canine fascia lata (FL). METHODS: The mechanical properties of each material were determined by testing to failure on a materials testing machine. Samples of each material (n=10) were tested in 3 different modes: resistance to suture pullout, tensile testing, and push-through testing. PM was tested both parallel (PMa) to and perpendicular (PMb) to its longitudinal cord orientation. SIS and FL were similarly tested in 2 orthogonal directions. RESULTS: With some exceptions, the following generalizations can be made regarding the mechanical performance of the materials tested: Suture pullout-FL>PMa=PMb>MLSIS>SIS (P< or =.04). Tensile testing-FL>PMa>PMb>MLSIS>SIS (P< or =.02). Push-through testing-FL>PM>MLSIS>SIS (P< or =.003). CONCLUSIONS: PM accommodated a significantly higher load and energy to yield when its longitudinal cords were oriented parallel with the tension axis (PMa). FL performed similarly to the PM, with the exception of limited elongation in tension. MLSIS had biomechanical characteristics that were inferior to FL and PM but superior to SIS. CLINICAL RELEVANCE: PM's orientation may need to be considered when used clinically. FL is a biomechanically suitable soft tissue replacement material but its use may be limited by currently available sizes. SIS cannot be recommended in high-strain environments.