A biomechanical comparison of patellar tendon repair materials in a bovine model

We evaluated the biomechanical properties of FiberWire (Arthrex, Inc, Naples, Florida), a new suture material, for both repair and augmentation as compared to standard Ethibond suture (Ethicon, Inc, Somerville, New Jersey), hypothesizing that primary repair and cerclage augmentation with the new suture material would have similar biomechanical properties as a standard repair with wire augmentation. Forty-five fresh bovine knees were placed in 3 groups of equal size: (1) #5 Ethibond tendon repair plus 18-gauge wire augmentation; (2) #5 FiberWire repair plus #5 FiberWire augmentation; and (3) #5 Ethibond repair plus #5 FiberWire augmentation. A straight static pullout test was performed, randomly alternating between the different groups. Gap formation was measured at the center of the repair by a metric ruler, with the examiner blinded to the developing force-tension readout. For each millimeter of gap formation (1-10 mm), the force on the repair was recorded, as well as the force at the ultimate failure of the repair, designated by breakage of any repair material. Analysis showed no significant difference between the standard Ethibond/wire repair and the FiberWire/FiberWire repair. The Ethibond/FiberWire repair was shown to be significantly weaker than the other 2 groups. Ultimate failure data indicated that the Ethibond/wire repair was significantly stronger than both other groups. No significant differences were found between the FiberWire/FiberWire repair and the Ethibond/FiberWire repair. Newer, stronger suture material for both primary repair and augmentation may provide equivalent biomechanical strength at clinically significant levels.