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Kayley Usher

Hi again Mike,

I’ll summarise what I know about Xiaflex – well actually what I know about about collagenase from the bacterium Clostridium, as this is what Xiaflex is. As you know it’s a relatively new treatment for Dupuytrens and Peyronies diseases, which are related to (are forms of) fibrosis. It is currently being trialled for a couple of types of fibrosis and it is an interesting potential therapy, but comes with risks.
PROS – being a collagenase (an enzyme that breaks down the collagen that makes up scar tissue) it will probably help to break down the scar tissue in joints, and increase ROM. This might help to settle the fibrosis down, but this is not known.

CONS – 1. there is a lot of structural collagen in joints, including in tendons and ligaments, and there is a real risk that you could rupture one or more after treatment. Our 2019 paper on says ” collagenase may damage articular cartilage, ligaments and tendons, but trials show no negative effect on these structures. Repeated injections needed, increases ROM in shoulder arthrofibrosis. More trials are needed”. There is some recent research using rats that suggests that collagenase might prevent arthrofibrosis, but this is a different thing to treating established AF.

2. Collagenase will create an inflammatory response, since both the collagenase and the resulting collagen fragments activate immune cells. As you know, inflammation causes fibrosis, and because the cells that make the scar tissue (myofibroblasts) remain, they may become more activated and create more scar tissue, in a similar way to surgery.

I think that a procedure such as an MUA where the joint is forced to bend and/or straighten after a collagenase injection would greatly increase the risk of tendon/ligament rupture, and I feel that this would not be wise. MUAs are well known to cause this type of damage without collagenase treatment.

Even if the collagenase injections worked (you would need more than one injection) there is a real possibility of the arthrofibrosis returning.

Thanks for suggesting Xiaflex and sorry I can’t be more positive about it, maybe in the future there will be evidence to show that collagenases are safe and effective to use in large joints, and I would be very happy about that!


  • This reply was modified 8 months, 2 weeks ago by Kayley Usher.