Killer hip implants?

A cemitary with a lonely tree at the center

An article in BMJ indicates that the best hip implants may actually be killing patients – an outrage or a statistical fluke? The image is CC by Wayne Wilkinson

An important question was raised by McMinn et al.: Can choice of hip arthroplasty have an impact on life & death?

While uncemented total hip arthroplasty implants are very popular, they’re often slightly more expensive, have a higher risk of peroperative fractures, and a have a higher overall risk of re-operations/revisions (although this has recently been put in question, as it may be part due to a few bad implants). McMinn’s study is interesting because it might add a new dimension to the choice of implants: should we also look at the mortality rates when choosing the best implant?

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Getting started with Sweave & knitr

Cool woven artwork on the campus of Kansas University. The image is CC by

Cool woven artwork on the campus of Kansas University. The image is CC by Patrick Emerson

I recently started to work with Sweave (by Friedrich Leisch) and found it a truly awesome package. The ease of use is amazing. In this post I’ll try to get you started with first Sweave and then the knitr (by Yihui Xie). The knitr package is a more advanced version of Sweave, update: Start with knitr as it’s really well integrated into RStudio and is more actively developed.

Reasons for learning LaTeX & Sweave/knitr:

  • You can export formatted tables (ready for publication)
  • You connect the results with the actual calculations, minimizing risk of “copy->paste” errors
  • The code is “automatically documented” as you explain the results in the text
  • You can easily re-run the report on a new dataset

Now lets get started… Continue reading