Dr. John Grant (11/10/22)

Interviewers: James Galbraith, Zach Fiske, and Alex Barlow

Interviewee: John Grant, MD, PhD, FRCSC (Clinical Associate Professor and Orthopedic Surgeon, University of Michigan)

Key Takeaways:

  • Lemaire LET for ACL reconstruction is a relatively new procedure with lots of opportunity for innovation
  • LET tunnel drill location is currently determined by generally eyeballing it; however, if we are creating a guide to determine the ideal drill angle, we would need to specify a drill location using anatomical landmarks
  • There are multiple fixation methods to attach the harvested end of the IT band to the lateral side of the femur close to the knee, which is something to consider when ideating a design
  • An effective way to ensure no conflict between the ACL femoral tunnel and the LET tunnel would be to design a device that has both a guide for the ACL femoral tunnel and a guide for the LET tunnel; however, there are also drawbacks to this approach

 

Raw Interview Notes:  

  • Lemaire LET for ACL reconstruction is a relatively new procedure with lots of opportunity for innovation
  • LET tunnel drill location is currently determined by generally eyeballing it; however, if we are creating a guide to determine the ideal drill angle, we would need to specify a drill location
    • LET tunnel hole should be drilled (approximately) 8 mm proximal and 3 mm anterior to lateral epicondyle (literature slightly varies here)
  • Current drill guides for ACL surgeries:
    • Inside-out
    • Outside-in (retro reamers)
      • 4-10 mm drill guide diameter size for reamer
  • There are multiple fixation methods to attach the harvested end of the IT band to the lateral side of the femur close to the knee:
    • Stapling (angle of staple doesn’t really matter here because staple needs to be flush to surface)
      • Has to be perpendicular to the line of the fibers of the IT band
    • Sew it to the surface, no insertion into the femur required
    • Drill a tunnel
      • Flippable button (TightRope (Arthrex) or ENDOBUTTON (Smith & Nephew))
      • Screw (about 20 mm in length)
  • Grant suggested doing the LET at the same time as the femoral tunnel so it can be certain they don’t converge (a device that has both a guide for the ACL femoral tunnel and a guide for the LET tunnel)
    • Potential drawbacks
      • Bulky
      • Perhaps difficult to do arthroscopically, you would need to make an extra incision (want to make least amount of incisions as possible to avoid potential additional morbidities, longer recovery times)
        • It sounds like LET has to be open to harvest the IT? Would make an incision for the femoral tunnel, an incision for LET, and the IT harvest
        • For LET, Grant uses an oblique incision from Gerdy’s tubercle to the condyle
      • ACL and LET guides would have to be different in spatial orientation (move freely from each other)
    • LET tunnel starts low in the lateral epicondyle…anterior angulation should be adequate to avoid the ACL (femoral) tunnel