I’ve previously [written](http://gforge.se/2012/07/cartilage-defects-part-iv/) about some interesting studies on treatment of cartilage defects. I was therefore thrilled to see Knutsen et al’s 15 year follow-up study. Unfortunately the results were rather disappointing; autologous chondorcyte implantation failed at a higher rate than microfractures, 40% vs 30%.
## Study details
The core sections in the study protocol:
– 80 patients were included and only 2 were lost to follow-up.
– Randomization was to either (1) chondrocyte implantation or (2) microfracturing.
– The subjects were not blinded.
– All injuries were in the knee and the injuries were substantial, between 1.5 to 11 cm2.
– Failure was defined if the patient required re-operation due to symptoms from the knee.
## Minor notes
Important to remember is that the study included chronic lesions and combined with the large size it may be that these knees are beyond our current methods. While the method is adequately described it is hard to know how the surgery was actually performed, especially as this was a multi-center study. I do hope that more will follow in Knutsen et al’s footsteps and search their archives for cohorts with this type of long-term follow-up.
[G. Knutsen, J. O. Drogset, L. Engebretsen, T. Grøntvedt, T. C. Ludvigsen, S. Løken, E. Solheim, T. Strand, and O. Johansen, “A Randomized Multicenter Trial Comparing Autologous Chondrocyte Implantation with Microfracture,” J Bone Joint Surg Am, vol. 98, no. 16, pp. 1332–1339, Aug. 2016.](http://dx.doi.org/10.2106/JBJS.15.01208)