Gliding Resistance and Strength of Composite Sutures in Human Flexor Digitorum Profundus Tendon Repair: An In Vitro Biomechanical Study

Purpose: Although the strength of a tendon repair is clearly important, the friction of the repair is also a relevant consideration. The purpose of this study was to characterize the frictional coefficient, gliding resistance, and breaking strength of suture materials and a suture construct commonly used for flexor tendon repair. Methods: We measured the friction coefficients of 3-0 braided nylon enclosed in a smooth nylon outer shell (Supramid, S. Jackson, Alexandria, VA), 3-0 braided polyester coated with polybutilate (Ethibond, Ethicon, Somerville, NJ), and 3-0 braided polyester/monofilament polyethylene composite (FiberWire, Arthrex, Naples, FL) sutures. We also measured the gliding resistance, linear breaking strength, and resistance to gapping of zone 2 modified Pennington tendon repairs with the 2 lowest-friction sutures in 20 human cadaveric flexor digitorum profundus tendons. Results: The braided polyester/monofilament polyethylene composite had a significantly lower friction coefficient (0.054) than either the coated polyester (0.076) or nylon (0.130) sutures. The gliding resistances of the repaired tendons with braided/monofilament polyethylene composite suture and those of coated, braided polyester were similar. The strength of the 2 repairs (force to produce a 2 mm gap) and resistance to gap formation were also not significantly different. Conclusions: Braided polyester composite is a low-friction suture material. However, when this suture was used for tendon repair with a locking suture technique, it did not show a significant effect on the gliding resistance and repair strength compared with the same repair using a coated polyester suture.