Abstract
Introduction: New flexor tendon repair techniques have been proposed to withstand the increased loads of active mobilisation. Most reports on the biomechanics of tendon repair are based on static testing. Cyclic testing more closely replicates the clinical situation and leads to gap formation at lower loads than in static testing.
Aim: To examine three types of tendon repair using a new cyclic testing protocol.
Methods: Thirty fresh-frozen cadaveric tendons were randomly assigned to three groups; Kessler repair with simple or cross-stitch epitendinous suture or Savage repair with simple epitendinous suture. All repairs were performed in situ in Verdan’s zone 2. Samples underwent tensile cyclic testing in a saline bath at a rate of 0.1Hz. Each specimen was subjected to two phases of testing replicating passive and active motion. Gap formation, stiffness and the mode of failure were recorded for each.
Results: The Savage repairs were stiffer and more resistant to gap formation than the Kessler repairs. The simple epitendinous suture seemed to be more resistant to gap formation than the cross-stitch suture although there was no significant difference in ultimate strength.
Conclusions: Cyclic testing is a more rigorous testing protocol that more closely replicates the clinical situation. This study showed that some repairs formed significant gaps at lower loads than the reported ultimate load-to-failure seen with static testing. Although cyclic testing has its limitations, we believe it is essential to assess fully tendon repair techniques, especially those considered for active mobilisation post-operatively. This study suggests the Savage repair may be a better option for active mobilisation protocols.
The abstracts were prepared by Professor A. J. Thurston. Correspondence should be addressed to him at the Department of Surgery, Wellington School of Medicine, PO Box 7343, Wellington South, New Zealand
