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

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.