Jonathan- Week 4

This week, I spent one day with Dr. Bostrom in the clinic, one day with him in the OR and Tuesday and Friday working and the weekend working on my research project (Dr. Bostrom took off July 4th and 5th). In the OR, Dr. Bostrom did a combination of 8 hip and knee replacement surgeries. I found one case in the clinic very interesting this week. A 49 year old woman came in who suffered from hip dysplasia all of her light. Even with a tibial osteotomy as a child, she was still 6 in shorter on her left side than her right. Radiographically, her acetabulum was almost non-existent, making surgerical options difficult. She was forced to wear a uncomfortable prosthesis on her help leg. After seeing her case, Dr. Bostrom agreed to take her case and put in a specialized hip replacement in her left leg. In addition he recommended her to a doctor at HSS who specializes in lengthening bones. In tandem, she will hopefully have a functioning left hip joint and have two legs that are the same lengths.

I spent most of this week working on my research project for Dr. Bostrom in which I am studying the literature to determine the success of knee replacements using cementless fixation. Below is a summary of what I found.
Cementless knee replacements are used much less often than cemented knee replacements because early design flaws led to many of the implants failing early; however, the modern cementless knee replacements are having excellent clinical results rivaling and sometimes exceeding knee replacements fixated with bone cement. Cementless knee replacement achieve fixation by bone growing into the porous metal surface of the implant. New design utilize biomaterials such as porous tantalum (Trabecular Metal) and Hydroxyapatite coatings. These coatings have been shown to improve implant fixation and clinical outcomes of the patient. Cementless knee replacements should be considered for for younger, active patients who have increased failure rates with cemented knee replacements compared to the older poulation. Cementless knee replacements may be preferable because can achieve better long-term stability than cemented implants and can be implanted without losing as much bone.