Biomechanical evaluation of meniscal repair systems - A comparison of the Meniscal Viper Repair System, the vertical mattress FasT-Fix device, and vertical mattress ethibond sutures

Background: The biomechanical characteristics of the Meniscal Viper Repair System have not been previously studied. Hypothesis: Comparable meniscal lesion fixation standards will exist among the Meniscal Viper Repair System, the vertical FasT-Fix device, and vertical mattress sutures. Study Design: Controlled laboratory study. Methods: Porcine menisci (3 groups of 7 menisci each) were repaired using different devices. A servohydraulic device cycled each construct between 5 N and 50 N for 500 cycles before load to failure (5 mm/min). Group differences were evaluated with 1-way analysis of variance and Tukey post hoc tests. Results: During cyclic testing, the vertical mattress suture group (2.3 +/- 0.2 mm) showed less mean displacement than did the vertical FasT-Fix or the Viper system groups (3.9 +/- 0.7 mm and 3.9 +/- 0.5 mm, respectively); the vertical mattress suture group (21.8 +/- 2 N/mm) also displayed superior mean stiffness to the vertical FasT-Fix or the Viper system groups (13.2 +/- 2 N/mm and 13.1 +/- 1.8 N/mm, respectively). During load-to-failure testing, the vertical FasT-Fix group (145.9 +/- 9 N) withstood greater mean loads than did the Viper system group (111.2 +/- 30 N), but it did not differ significantly from loads withstood by the vertical mattress suture group (133.4 +/- 10 N). The Viper system and vertical FasT-Fix groups (14.6 +/- 2 N/mm and 12.1 +/- 1 N/mm, respectively) displayed superior mean stiffness to the vertical mattress suture group (9.8 +/- 0.5 N/mm) during load-to-failure testing. Clinical Relevance: Standard vertical mattress sutures provided superior fixation during cyclic loading compared with the 2 all-inside methods of suture fixation, suggesting a potential for better meniscal lesion healing with vertical mattress sutures when confronted with the stresses associated with early, progressive rehabilitation activities. Stronger sutures and less meniscal segment purchase in tears located 3 to 4 mm from the periphery may contribute to the failure of the Viper repair system.