Biomechanical comparison of a modified three-loop pulley technique and a three-level self-locking technique for repair of patellar tendon rupture in dogs

Am J Vet Res. 2019 Apr;80(4):335-341. doi: 10.2460/ajvr.80.4.335.


Objective: To compare use of a 3-level self-locking suture (3LSLS) technique with use of a previously described modified 3-loop pulley (M3LP) technique to repair rupture of the proximal aspect of patellar tendons in limbs from canine cadavers.

Sample: Paired hind limbs of 6 adult mixed-breed dogs.

Procedures: A limb from each pair was randomly assigned to be repaired by the 3LSLS technique or M3LP technique with size-2 ultrahigh-molecular-weight polyethylene and size-0 monofilament polypropylene suture, respectively. Limbs were prepared, and each patellar tendon was transected at a site chosen to simulate rupture at the proximal aspect. Tendons were repaired with the assigned techniques and mechanically tested with a biaxial servohydraulic test system; the clamp was distracted until the repair failed. Force at 1 -mm gap formation, 3-mm gap formation, and repair failure and gap size at failure were measured and compared between methods. Mode of failure was recorded.

Results: There was no significant difference between methods for the force required to produce a 1 - or 3-mm gap in the repair. The 3LSLS technique required a significantly higher load for complete failure; gap formation immediately before failure was significantly greater for this method than for the M3LP technique. Four of 6 repairs with the M3LP technique and 0 of 6 repairs with the 3LSLS technique failed by suture breakage.

Conclusions and clinical relevance: The 3LSLS technique with size-2 ultrahigh-molecular-weight polyethylene suture was as effective at resistance to 1 - and 3-mm gap formation as the M3LP with size-0 monofilament polypropylene suture.

Publication types

  • Comparative Study
  • Evaluation Study

MeSH terms

  • Animals
  • Biomechanical Phenomena
  • Dogs / injuries*
  • Dogs / surgery
  • Hindlimb
  • Patellar Ligament / surgery*
  • Polypropylenes
  • Rupture / surgery
  • Rupture / veterinary
  • Suture Techniques / veterinary*
  • Sutures / veterinary*
  • Tendon Injuries / surgery
  • Tendon Injuries / veterinary*
  • Tensile Strength


  • Polypropylenes