Spinal vs general anesthesia

Drops from a needle. The image is CC by Evan Leeson

Drops from a needle. The image is CC by Evan Leeson

Many of us orthopaedic surgeons have been frustrated by waiting for the anesthesiologist to finish with the spinal anesthesia. It is therefore of great relief that Pugely et al. write that this frustration is not in vain. Patients that receive spinal anesthesia seem to have fewer complications after a total knee arthroplasty than those with general anesthesia. A conclusion based on a large registry study with 14 000 patients although the overall odds ratio was though not that alarming, 1.3. Continue reading

Chocolate and the Nobel Prize – a true story?

Chocolate - a close up picture

Few of us can resist chocolate, but the real question is: should we even try to resist it? The image is CC by Tasumi1968.

As a dark chocolate addict I was relieved to see Messerli’s ecological study on chocolate consumption and the relation to the Nobel prize. By scraping various on-line sources he made a robust case for that increased chocolate consumption correlates to the number of Nobel prizes. Combined with that it might have positive impact on blood pressure, the evidence is strong enough for me to avoid changing any habits, at least over Christmas 🙂

Tutorial: Scraping the chocolate data with R

Inspired by Messerli’s article I decided to look into how to repeat the analysis in R. Continue reading

How hard can it be – just glue some cartilage onto the bone (part IV)

It's nice to see some real orthopaedic rocket science

It’s nice to see some real orthopaedic rocket science. The picture (cc) is by Calsidyrose

It is rare to see long term follow-up studies ( > 5 years) and Bentley et al’s randomized controlled study on cartilage defects is therefore a rare bird! They randomized 1 00 consecutive patients to chondrocyte transplantation or mosaicplasty. After 10 years they were able to follow-up 94 % of all patients – a truly amazing accomplishment!

The method for chondrocyte transplantation was “simple”: harvest a few chondrocytes from the knee, grow them in a dish and the reinsert them and cover it up with a piece of tissue so that the cells don’t escape. I guess growing the cells requires a lot of expertise but apart from that no fancy gadgets were needed. Continue reading

How hard can it be – just glue some cartilage onto the bone (part III)

A picture of jello

A picture of jello – not really like the NeoCart-jello but it’s a cool picture. The picture (cc) is by Amayzun

Today’s blog is about gluing cartilage onto trauma-caused joint cartilage defects. Crawford et al report a new treatment option where they grow chondrocytes, attach them to a soft jelly (collagen matrix) and then glue it onto the defect! They randomized 21 to the NeoCart jelly and 9 patients to standard microfracturing and followed them for 2 years. Continue reading

How hard can it be – just glue some cartilage onto the bone (part II)

A mosaic representin the number 2

When doing a mosaicplasty you create a mosaic of ostechondral cylinders. These then cover the injury and protect the bone. The picture (cc) is by L D M

Although RCT’s are the golden standard for evaluating techniques, retrospective studies such as Krych et al’s study , “Activity Levels Are Higher After Osteochondral Autograft Transfer Mosaicplasty Than After Microfracture for Articular Cartilage Defects of the Knee: A Retrospective Comparative Study”, can be an interesting read.

They compare microfracturing (se previous post) with mosaicplasty. In mosaicplasty you harvest bone and cartilage cylinders (osteochondral transfer) from sites where it’s not needed and transfer it to the injury. The technique is nice and fairly straightforward although getting all the cylinders aligned perfectly so that none are higher/lower is virtually impossible. It can also be a problem that you don’t have enough unused cartilage to harvest.

The reason why Krych’s study is nice is that they implemented a prospective register in 1999 and have therefore good quality follow-up data. I think it’s really praiseworthy that they started a registry that early. These are rare injuries – it took the team 13 years to get this article published! Continue reading

How hard can it be – just glue some cartilage onto the bone (part I)

A figure skater representing the low cartilage friction coefficient

The friction coefficient of cartilage is very similar to ­ice skating. The picture (cc) is by Tsutomu Takasu

A systematic review by Jakobsen et al (2005) found that the average study quality on treating cartilage defects (= chondral injuries, traumatic, not osteoarthritis) was just 43 out of 100. They found only 260 randomized patients! We are therefore craving for new, good research.

In the June 2012 JBJS Am issue there were two nice articles on treatment of cartilage defects and together with Bentley et al’s awesome article in JBJS Br April issue there is now some new evidence, craving comments 🙂

I’m splitting this post into several:

  1. Basics about cartilage & microfracturing
  2. Krych retrospective study (JBJS Am)
  3. Crawford’s RCT (JBJS Am)
  4. Bentley’s 10 year follow-up RCT (JBJS Br)

Continue reading

Is roentgen stereophotogrammetric analysis (RSA) the new black?

A physician’s job is to avoid “trial and terror” as one of my senior colleagues taught me early on. Preventing bad implants from reaching the market is vital in orthopaedics. This is especially true since the current implants have a > 95 % 10 year survival. It is therefore great to see Göran Selvik’s RSA method (Selvik et al. 1983) generating headlines in both Acta Orthopaedica and JBJS Am.

In JBJS Am. a valuable 10 year follow-up of 41 hip arthroplasties (Nieuwenhuijse et al. 2012) validate the use of RSA. They could see an impressive correlation between micro motion at 2 years and late follow-up. About one fourth of all the cups turned out to be loose at the end of the follow-up. The C-statistic or area under the receiver operating curve statistic was 0.88 which is close to the ideal 1. The C-statistic is a measure of the specificity (that only the right patients are identified) and sensitivity (that all that later show movement actually are discovered). Continue reading

Creating nice flow diagrams

My favorite tool for creating flow diagram is Dia – it’s easy and open source. It’s homepage is not that impressive but the Facebook group seems to be pretty active. There you can also find that downloads increased by 23 % in 2011 to 1.4 million downloads.

In this tutorial I want to show you how easy you can create a great looking flow diagram like the one CONSORT recommends for publication of RCT:s. Continue reading

Swedish orthopaedic surgery gets a bronze

Time for some bragging: In a paper from 2010 The 100 classic papers of orthopaedic surgery you can read that Sweden comes in third when looking at the most cited articles throughout orthopaedic times 🙂

At the top is (of course) USA with 77 articles, then comes England with 10 articles and by beating Canada with 1 article Sweden gets the bronze with 5 articles. For a country with only 9.5 million inhabitants I think that it’s rather impressive. Continue reading

Encrypt your data

Keeping your stuff under lock and key. The image is CC by aussiegall

Keeping your stuff under lock and key. The image is CC by aussiegall.

We often have sensitive information that we want don’t want to fall into the wrong hands. When doing research this is extra important and while everyone talks about having a robust security few tell you how you should do this. I’ve therefore collected some useful tips on basic encryption and security. Continue reading