MUA (Manipulation under Anaesthetic) and adhesions


Nurse Director
Jun 8, 2007
The North
United Kingdom United Kingdom
First let me first put your mind at rest - this is quite probably nothing to do with not having done enough PT or been 'good enough' in following orders. Here is my standard mini-lecture on the subject so read and absorb ...

All the structures in the body, muscles, tendons, ligaments, even gut and lungs, need to be able to glide over one another smoothly to let our bodies work. To enable this ‘glide-ability’, the body produces a special viscous fluid, approximately the consistence of egg white, which lubricates everything with great efficiency.

Now when the surgeon opens up any part of our body, these internal tissues gets exposed to the air which is, by comparison to the inside of the body, very cool and dry. The natural reaction is that fluids evaporate and tissues cool. This makes the organs and structures dry so when the wound is closed, part of the healing process is for the body to go into overdrive, producing extra fluid to replace what is lost. This is one of the reasons IV fluids are required during and after an operation.

Now as a general rule, about 96% of people manage to make up this fluid loss and normality is quickly restored. But in the other 4%, for a variety of unknown reasons, their bodies are deficient in making up this loss and lacking the necessary lubrication, the ligaments and muscles lose their 'glide-ability' and begin to stick or adhere to one another. This is why they are often referred to as 'adhesions'.

Scar tissue or adhesions?
Where the confusion often comes is when a) one tissue, like the skin, is cut and has to mend or b) when two bodies of tissues, like muscles, ligaments and surrounding structures, are split apart and then nature sticks them back together again.

a) skin generally makes itself a nice thin little line of fibrous tissue which will fade and disappear over time. This is a scar.

b) where split apart muscles come back together, they usually 'resume normal relations' in terms of being close together but with glide-ability. But sometimes they fail to restore the lovely moistness that allows this and get stuck together - the result is adhesions. Mostly this process isn't too aggressive so the normal 'glide-ability' of the structures ultimately gets back to normal anyway. But problems occur when the fluid isn’t produced quickly enough and the structures get stuck fast.

So, to recap:
~ all cut, split or otherwise divided tissues are going to create a scar when they heal back together. Primary scarring is simply a small, thin line of scar tissue which joins the two edges of cut tissue together
~ secondary scarring, or adhesions, is when two structures which should have movement between them haven't restored the needed amount of moistness and gets tuck together! This is when MUAs are sometimes discussed!

I would however, put in this warning about too much PT/physio done too aggressively and especially that causing excessive pain. What this does very effectively is cause the tissues to become over warm and even hot. (though a warm knee during recovery is normal and a sign of healing). This I am referring to is excessive heat. This means that the structures are becoming dry within and dry structures (muscles and ligaments) will get stuck together, resulting in the dreaded adhesions (image below)! So when you find yourself questioning the BoneSmart suggestions of rest and gentle exercising, remember that this is what we are trying to protect you from!

Interestingly, in a recent xray of my own knee, the outline of the quads muscle shows up clearly so I took advantage of it and marked the areas where adhesions tend to occur with red dotted lines. So you can see that they are quite different from the scar tissues that are the healing substance of the incisions the surgeon makes.


An MUA is Manipulation Under Anaesthetic.

MUA 1-horz.jpg

This can be a general or spinal anaesthetic and the patient usually goes home the same day. Though there are surgeons who prefer to keep the patient in overnight to ensure adequate pain management. This procedure can result in an aftermath of pain. For a few people it is extensive but the rest find it only average and able to be controlled with the usual doses of morphine.

With the patient asleep and totally relaxed, the surgeon forcibly bends the knee until the adhesions give way. Applying enough force to break the adhesions without breaking bones is a skill but the risk is often greatly overplayed.

There may also be a backlash of swelling which at first results in poor flexion and/or extension. This can be depressing as it seems like the procedure was all for nothing but given time - sometimes a few weeks – and with pain management, icing and elevation, it will subside and then the real flexion will surface.

Return to work may be possible in a few days but it depends on the pain level afterwards. Having it done on a Thursday or Friday would enable advantage to be taken of the weekend.

Some PTs or surgeons like to recommend therapeutic massage either from a PT, a masseur or the patient to help free up the internal structures which will enable a faster and less painful road to good ROM (range of movement). Some may also put the patient in a CPM machine (continuous passive movement machine) so they are immediately confident of the degree of improvement.

Release of adhesions by a therapist:
Here is how one therapist described her technique to reduce scar tissue in a patient: "Start slowly... applying pressure to the scar with fingertips, hands next to each other. Picture you're playing the piano and the scar is where the keys are. Then pull and stretch the scar gently in as many opposite directions as possible to break up all the collagen fibre adhesions. Eventually work in one specific line of force (only stretching the tissue in one way) to align all the collagen fibrils in one direction instead of the chaotic "mesh-like" pattern they can be in when you started. And lastly, keep working on it on a regular basis. The longer the scar has been there, the longer it will take to work it out."
Here are a couple of contrasting papers about MUAs

Clinic records of 37 manipulations in 767 consecutive primary total knee arthroplasties (TKAs) were analyzed to identify any predictors of manipulation outcome. Factors studied were sex, age, body mass index, tibiofemoral alignment, surgical history, smoking history, range of motion before TKA and manipulation, intraoperative lateral release, implant design and manufacturer, and manipulation interval. Measures of outcome were gains in extension and flexion from manipulation and range of motion at 1-year follow-up.

Patients gained an average of 4° of extension and 22° of flexion after manipulation, resulting in average extension of 1° and average flexion of 105° at 1-year follow-up. Restored flexion was similar to that measured preoperatively. Manipulation was most effective in patients manipulated within 8 weeks, with full extension and <90° of flexion prior to manipulation, and those receiving a lateral release during arthroplasty.

However, in this study, things seem not so cut and dried:

Published 2006 UK

Between April 2000 and May 2007, this surgeon did 2,762 Total Knee Replacements
During that time he did 30 MUAs = 1.086%

He proposed the question "What if these patients hadn't had an MUA?"

He cited one patient
pre-op ROM of 0/130
achieved 25/70 by 12 weeks post op.
Refused MUA.
at 12 months was -5/120!​

Also Physio or no physio? A randomised trial:
Had physio - 71 patients in study
Pre-op passive was ROM 98.3*
Post-op passive was ROM 108 at 12 months​

No physio - 72 patients in study
Pre-op passive was ROM 100.2*
Post-op passive was ROM 108.1* at 12 months​

Here's a photo of the MUA I had done last Wednesday. I hope I can bend my knee this far (or at least something close to it) after my healing process is complete. Pretty amazing stuff eh? JMB

(Josephine's edit: I make that somewhere between 125 and 130 degrees!)

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