Confused on a higher level – the haunted degenerative meniscus

Where is the evidence actually pointing? The image has been kindly provided by Rinna-Ranna.
Where is the evidence actually pointing? The image has been kindly provided by Rinna-Ranna.

One, never-ending thread on this blog seems to be the degenerative meniscus. Gauffin et al. recently published a randomized controlled trial comparing surgery vs physiotherapy with favorable results for surgery regarding pain. Could this be the turnaround for one of the most controversial, but common orthopaedic procedures? Continue reading

flattr this!

Posted in Orthopaedic surgery | Leave a comment

We all have our trigger

Every surgeon likes surgery, it is therefore nice to see a study examining what happens if we refrain from cutting. The image is CC by Andrew E. Russell
Every surgeon likes to cut. It is therefore nice to see what happens if we refrain from cutting. The image is CC by Andrew E. Russell

Surgical treatment for trigger finger consists of cleaving the A1 pulley, a simple procedure, considered to be low risk. Even so, there can still be scar tenderness, nerve injury, tendon bowing, and infection. It is therefore nice to see Wojahn et al.’s paper on long-term follow-up after cortisone injections.  Injection is a simple alternative that consists of an injection angling 45° distally at the A1 pulley with 1 mL 40 mg/mL Depo-Medrol. Continue reading

flattr this!

Posted in Orthopaedic surgery | Leave a comment

ACL-reconstruction in vain?

How does the knee age after ACL-surgery? The image is CC by  Thomas Mues.
How does the knee age after ACL-surgery? The image is CC by Thomas Mues.

Nordenvall et al. [1] recently report in PLOS ONE an interesting study on cruciate ligament (CL) injuries where they could not find any protective effect on knee osteoarthritis (OA) from reconstructive surgery. It is a nation-wide study based on > 60,000 patients where they used the National Swedish Patient Register in order to find ICD-codes and surgical procedures code to identify patients with CL injury and those with a subsequent procedure. While the early results showed slightly less OA, there was an increased risk of 1.4 (95% confidence interval, 1.2 to 1.7) after > 10 years for those with surgery. Continue reading

flattr this!

Posted in Orthopaedic surgery | Leave a comment

Keeping the cast dry

The image is CC by  Mattieu Guionnet.
The image is CC by Mattieu Guionnet.

I love the study from McDowell et al. where they tested different methods for keeping casts dry. It is simple but takes up a both common and important issue that we doctors frequently forget about. They compare six different methods and it seems that double plastic bags secured with duct tape provide the best protection for the money. Continue reading

flattr this!

Posted in Orthopaedic surgery | Leave a comment

An exercise in non-linear modeling

Finding the right curve can be tricky. The image is CC by Martin Gommel.
Finding the right curve can be tricky. The image is CC by Martin Gommel.

In my previous post I wrote about the importance of age and why it is a good idea to try avoiding modeling it as a linear variable. In this post I will go through multiple options for (1) modeling non-linear effects in a linear regression setting, (2) benchmark the methods on a real dataset, and (3) look at how the non-linearities actually look. The post is based on the supplement in my article on age and health-related quality of life (HRQoL). Continue reading

flattr this!

Posted in R | 6 Comments

Does age matter for THR-outcomes?

Age is perhaps one of the most important confounder that none of us can escape. The image is CC by Sara.
Age is perhaps one of the most important confounder that none of us can escape. The image is CC by Sara.

Age is an important confounder in studying most health related outcomes [1, s 5], and perhaps the most commonly adjusted variable. In this and next post I will go into (1) what we know about the age effect in relation to total hip replacements (THR) re-operations and mortality, (2) what I found in my study on age and health-related quality of life (HRQoL) using splines, and (3) how I implemented and evaluated different splines using R for this study. Continue reading

flattr this!

Posted in Orthopaedic surgery, Research | Leave a comment

Fast-track publishing using the new R markdown – a tutorial and a quick look behind the scenes

The new rmarkdown revolution has started. The image is CC by Jonathan Cohen.
The new rmarkdown revolution has started. The image is CC by Jonathan Cohen.

The new R Markdown (rmarkdown-package) introduced in Rstudio 0.98.978 provides some neat features by combining the awesome knitr-package and the pandoc-system. The system allows for some neat simplifications of the fast-track-publishing (ftp) idea using so called formats. I’ve created a new package, the Grmd-package, with an extension to the html_document format, called the docx_document. The formatter allows an almost pain-free preparing of MS Word compatible web-pages.

In this post I’ll (1) give a tutorial on how to use the docx_document, (2) go behind the scenes of the new rmarkdown-package and RStudio ≥ 0.98.978, (3) show what problems currently exists when skipping some of the steps outlined in the tutorial. Continue reading

flattr this!

Posted in R, Tutorial | Tagged , | 7 Comments

My thesis: patient-related factors & hip arthroplasty outcomes

Title: Evaluation of patient related factors influencing outcomes after total hip replacement
Title: Evaluation of patient related factors influencing outcomes after total hip replacement

On May 29:th I successfully defended my thesis at the Karolinska Institute and I’m now a “Doctor of Philosophy“, i.e. PhD. It has been a fun and rewarding project that spurred me into starting this blog and diving into R. Below you can find the thesis abstract and my reflections on the subject. Continue reading

flattr this!

Posted in Orthopaedic surgery, Research | 3 Comments

Drawing a directed acyclic graph (DAG) for blood transfusions after surgery

A directed acyclic graph (DAG) can help you take the right path. The image is CC by Ian Sane
A DAG can help you take the right path. The image is CC by Ian Sane

I recently wrote about blood transfusions and their inherent risk of postoperative infections. This post is a tutorial on some of the basics of drawing a directed acyclic graph (DAG). Blood transfusions and infections is a great topic as most are familiar with risk factors for infections. Continue reading

flattr this!

Posted in General, Orthopaedic surgery, Research | Leave a comment