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Basic Science Knee Research Shoulder Research


Basic Science Research


bulletCyclic Testing of Arthroscopic Knot Security. Presented at the 2003 annual meeting of the Arthroscopy Association of North America and published in the journal Arthroscopy in 2004, this investigation evaluated the holding power of several arthroscopic knots. Surgeons have long used knots to secure soft tissue repairs. The knots hold the tissue apposed until tissue healing occurs. Some tissues (such as skin) heal within days, whereas others (such as tendons) take many weeks or even months. During this time, the knot is subjected to hundreds and possibly even thousands of cyclic loads with daily use of the repaired joint or extremity. The standard knot of open surgery for secure repairs that can withstand such prolonged and repetitive loading is the hand-tied surgical square knot. Recently, minimally invasive arthroscopic techniques have evolved to the point of allowing surgeons to repair soft tissue without open surgery. However, because tying square knots is not feasible with arthroscopic techniques, many different arthroscopic knots have been introduced into current use. Prior to this TASMI funded investigation, none of these knots had been tested under hundreds of cyclic loads to see if they hold up to these stresses as well as traditional square knots. This investigation revealed that one of the three different types of arthroscopic knots tested was just as secure as the traditional square knot hand-tied using open surgical means. However the other two arthroscopic knots proved to be inferior to the square knot. This was the first published study of its kind, as each knot was tested for more than 2000 cycles!


bulletSecurity of Knots Tied with Ethibond, Fiberwire, Orthocord, or Ultrabraid.  This laboratory investigation, published in late 2008 in the American Journal of Sports Medicine, compared the strength of several popular arthroscopic knots, including one knot developed at TASMI, to knots tied in open surgery. What distinguished this from all prior work was that these numerous sutures were tested with a stepwise, incremental, cyclic loading protocol that comes closer to reproducing the forces seen on repaired structures after surgery than any other published protocol. Fortunately, all of the arthroscopic knots proved to be as secure as the openly tied knots. However, the SAK knot, developed at TASMI, had the lowest profile, making it the least likely to cause tissue irritation following surgery. The investigation went on to test newer super-strong sutures that were introduced only a few years ago. Knots tied with these newer sutures were much more secure than those tied with traditional suture.


Copyright 2003 Texas Arthroscopy & Sports Medicine Institute, LLC
Last modified: 06/05/12