ABOS Self Assessment Questions

Please submit at least 10 questions covering your topic area in your symposium. 
 
You can write original questions or select questions from COA's Library of SAE questions.    Library of SAE Questions 
 
Please Note:  You must cover the questions selected at some point during the symposium. It could be during your talk or in the Q&A. 
 
When finished, hit SUBMIT at the bottom of the form to send your questions to COA.
 
Original Questions 
Please note
- The questions CANNOT be True/False questions 
- You MUST include a Discussion and Reference for each question
- Answers CANNOT include "all of the above" 
- Images are optional
  
Sample Question: 
 
Answer _C_

Work-up of a painful metal-on-metal total hip arthroplasty demonstrated a large effusion on MRI.   ESR and CRP were within normal limits. Metal ion levels were found to be highly elevated.  Preoperative cell count demonstrated 917 WBCs and 51% PMNs and cultures were negative.  Intra-op pathologic specimens demonstrated all areas <5 WBCs/HPF.  Imaging demonstrated well fixed components with a vertically oriented acetabular cup and appropriately oriented femoral component.  What is the likely best course of treatment?

  1. Total hip arthroplasty explant and placement of antibiotic spacer
  2. Femoral head and liner exchange to a ceramic on polyethylene bearing with retention of acetabular and femoral components
  3. Acetabular cup and femoral component revision
  4. Femoral component revision and conversion to a ceramic on polyethylene bearing with retention of acetabular cup
  5. Acetabular cup revision and conversion to a ceramic on polyethylene bearing with retention of femoral component

Discussion: Infection needs to be investigated, as a reason for MOM THA failure.  However, one needs to be aware that distinction between septic failure and MOM-related failures can, at times, be difficult to differentiate.  MOM reactions can mimic infection with elevated inflammatory markers (ESR and CRP), elevated synovial cell counts (need a manual count ordered) and effusions that grossly resemble purulent material. 

With a stable ingrown cup that is malpositioned and with associated elevated metal ion levels, acetabular cup revision should be considered particularly with a vertical component as this can predict an increase in the risk of polyethylene liner edge-loading and ultimately early failure either via liner fracture or early liner wear from edge-loading. 

Reference:  Hsu AR, Kim JD, Fabi D, Levine BR. Adverse reactions in metal-on-metal total hip arthroplasty: two cases presenting as pseudoseptic acetabular component loosening. Am J Orthop (Belle Mead NJ). 2011 Oct;40 (10):509-513.