Dorsal-enhanced sutures improve tension resistance of tendon repair

Thirty-six fresh pig flexor tendons were repaired using either the modified Kessler method or the Tang method. Nine tendons from each group were tested in an Instron tensile testing machine with the tendons passing 90 degrees around a pulley. The other nine tendons from each group were pulled linearly by the testing machine. The 2 mm gap formation force of the tendons repaired with the modified Kessler and Tang methods and pulled at 90 degrees were 64%+/-5% and 79%+/-9% respectively of those forces recorded during linear testing. The ultimate strengths of tendons repaired by the modified Kessler and Tang methods and pulled at 90 degrees were 76%+/-6% and 81%+/-8% respectively of the forces measured during linear testing. The percentage gap formation and ultimate strength of the Tang method was significantly higher than that of the modified Kessler suture when the tendons were pulled around a pulley. This demonstrates that the Tang suture, with its main components in the dorsal part of the repaired tendon, has greater tension resistance capacity than conventional tendon sutures which are placed in the middle of the tendon. This study suggests that dorsally-enhanced multiple tendon sutures are better placed to sustain the tension generated during active finger flexion.