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 →

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 →

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 →

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 →

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 →