Hydrodissection

Sorry, I only just saw the YouTube video link. I think hydrodissection could be a safer way (compared to surgery or MUA) to force apart adhesions between the fat pad to tendon, but this won't address a fat pad that remains enlarged from inflammation, and which sticks out and gets pinched between the bones of the knee. And, as both you and I mentioned, there will be some damage and inflammation as a result.

Kayley

Hi Mike,

Thanks for your question. Hydrodissection is an interesting treatment, and I’ve been reading about it. Hydrodissection involves inserting a needle, usually guided by ultrasound, and injecting carefully targeted high pressure fluid to separate adhered tissues.

I haven't seen hydrodissection being used for treating arthrofibrosis (although hydrodilation is used), and would be interested to know of any accounts. But as you say, ultrasound guided hydrodissection is used to break the adhesions that tether nerves to surrounding tissues (nerve decompression), and it’s also used in eye treatment. In these contexts it’s considered to be safer than surgery, and doesn’t damage nerves.

A 2020 paper by Song et.al. used hydrodissection to free an adhered fibular nerve with fat pad impingement. However, in one area the scar tissue around the nerve was too dense and it required surgery to free it.

A 2022 paper by Dosal et.al. reports they successfully used hydrodissection to separate scar tissue and adhesions in Achilles tendinopathy. They state that Achilles tendinopathy is a fibrotic disease that involves the associated Kager’s fat pad (fat pads and fibrosis again!). The authors state that in addition to freeing the tendon from the fat pad, hydrodissection may help to break down scar tissue. However, there are “crucial variables such as fluid type, dose, and frequency are not well defined” and if corticosteroids are used there is an increased risk of tendon rupture. This means there are large differences in how hydrodissection is used in practice. Small amounts of injected fluid (usually anaesthetic and saline) seem to be less damaging than larger volumes.

My feeling is that hydrodissection could be a safer alternative than manipulation under anaesthesia or surgical lysis in cases where the scar tissue hasn’t matured (less than 12 months post diagnosis) and isn’t too extensive. If there is a small area of adhesions that can be freed, then in theory hydrodissection could be a useful option, since there will be much less tissue trauma than MUA and surgery. However, even in experienced hands there will be some amount of trauma and associated discomfit, so as with everything, there are no guarantees. If hydrodissection was (mis)used to destroy an area of the fat pad then that would likely create a strong fibrotic reaction.

I hope that helps,

Kayley

is it possible Hydrodissection injection could be like an injury that would trigger more inflammation?