Week 7

This week I observed several hip and knee revision surgeries in the OR. The most interesting case for me was a patient receiving their second knee revision surgery. The first revision involved implanting a rather large tibial stem, but unfortunately that stem did not osteointegrate as well as the surgeons had hoped. Over time, the combination of the forces applied while walking and poor osteointegration drove the stem deeper and deeper into the tibia, leading to misalignment of the joint. Preforming a second revision is pretty uncommon and can be really tricky because so much of the bone has already been removed. Because this case was so unique, an engineer in the biomechanics group designed a custom implant. He came into the surgery to answer any questions the surgeons had about his implant during the operation, but during the opening incision and preparation he took some time to chat with me about the mechanics of the revision. It’s exciting to see how engineers directly impact patients outcomes. The tibial portion of the implant had cone leading into the tibial shaft. The wider area of the cone should prevent the tibial component from sinking down like the first revision. The tibial component was connected with a hinge joint to the femoral component. The hinge increases stability of the joint, but it does restrict motion. The hinge joint isn’t a true hinge like you might see on a door; it is more like a loose hinge that allows for some extra rotation and extension besides the main flexion and extension. Maintaining these extra degrees of freedom helps make walking more natural. Luckily, the femoral stem component was well fixed in the bone, so they only had to change the surface. This was a good reminder to me about the importance of modular components. Overall this revision was an impressive feat, and I found it so satisfying to seeing the engineering and surgical aspects come together.

On the research side, we did our first trial of crystal violet staining this week. Crystal violet is a way of quantifying bacterial biofilm formation. Eventually the lab would like to use this technique and others to assess the amount and maturity of biofilms on the mouse tibial implants. This week we confirmed that we could grow biofilms in six well plates on the shaking incubator and the biofilms were visible using crystal violet stain. In the future the lab would like to be able to correlate crystal violet absorbance directly to the colony forming unit count.

It’s hard to believe that summer immersion is already over. I appreciate that everyone here welcomed me and gave me this clinical experience. I am excited to take what I have learned back to Ithaca!