Week 4

We are still waiting for permission to perform our next round of knee implants on the mice, so this week was a little slow on the research side. I the meantime, I enjoyed getting to interact more with some of the surgeons who work at HSS.

On Thursday I observed an orthopaedic case study discussion. Fellows presented slightly odd or challenging cases they had faced recently, and the attending physicians, fellows, and residents discussed the notable points in the case. The discussion was formatted so that the less senior residents were asked to describe what they saw in the x-rays, why they thought the patient was experiencing pain, and what treatment they might recommend. Then the more senior physicians would offer their expertise and discuss a recommended course of action. I particularly enjoyed listening to the fellows "thinking out loud", because it gave me a glimpse into the methodical thought process doctors go through when making a diagnosis. Although many of the medical terms and concepts were new to me, the logical thought process felt familiar. Between doctors and engineers, we all just want to solve problems, and that process looks similar across the board.

During the case study discussion, one of the first questions the doctors asked was whether or not the implant was infected. Although my project is on implant infection, I realized I didn't actually know how infection is diagnosed clinically. When working with mice, you can simply collect a sample directly from the joint, but surgeons want to avoid opening up a patient's joint unless they are sure that a revision is necessary. One indirect method is to check the x-rays for signs of osteointegration. Poor osteointegration can be a sign of infection and is likely to cause the patient pain. Doctors can also order blood samples to check for serum biomarkers, such as erythrocyte sedimentation rate and C-reactive protein. If a revision is deemed necessary, a sample is taken from the joint and cultured to confirm the infection.

I was hoping to get some more clinical experience this week, but luck did not go my way. An orthodpaedic surgeon kindly offered to let me shadow him in an infected hip revision. Due to some other concerns with the patient, the surgery was postponed. However, I still was able to learn about some new techniques when he described the case to me. The patient suffered a pelvic fracture after receiving a hip replacement, and a custom pelvic plate was implanted. Now the patient has developed an infection. Normally an infected hip implant would require replacement during a revision, but the custom pelvic plate complicates things. The plan is to remove the custom pelvic implant, autoclave it to kill the bacteria, then re-implant it. Autoclaving and re-implanting is a technique I have never heard of before. A challenge is that the implant must cool enough in order to be re-implanted, but this is balanced with trying to reduce the surgery time.

Next week my mentor will return! I'm hoping his return will give me more access to clinical experience and more defined research goals once we can meet and talk!