ROM measurement

[maumeefootball]

OK this isn't anything that is going to really matter in the grand scheme of things but since I am feeling good and haven't posted for a while I thought I would throw this one out to the medical people on the site. I am a high school math teacher and had a discussion with my PT yesterday at my last appt. It concerned how they read the ROM measurement. Don't know if anyone else realizes this but they are not giving you the angle that is formed by the bent leg. They are actually giving you the supplement of the angle. Supplementary angles add up to 180, so when they say your ROM is 120 that means your leg is bent at a 60 gegree angle. Why not give the angle of the bend since that is what you really want to know. If your leg was bent at a 120 dgree angle you would have a very limited ability to bend. This would mean that the more you improved the smaller the angle would be.​

I will toss this out to my 3 Geometry classes this fall when we talk about angles, that should blow everyone's mind. If you think rehab is tough try explaining Euclid to 16 year olds.

 

[calling_all_angels]

Wow you are kidding right???? I am completely at a loss now!!

 

[RickB]

Maumee,
I own a goniometer that PTs and doctors use to measure ROM and I promise it reads the amount in degrees that your knee bends. Some how your PT was confused.

 

[FrogFeathers]

My PT always made me lie on my back on the table, then bend my knee. I could (and still can) bend it much farther by sitting in a chair with my foot on the floor. My surgeon measured it that way in his office three weeks after my MUA. He was pleased, but the PT people were prissy about it, saying I needed more.

I'm interested in what geometry students make of any of this.

 

[Hope810]

My thoughts... the ROM is ability to bend the leg from a straight position of 0 degrees; thus, 90 degrees is a right angle and 120 degrees is an addition 30 degrees of bend. The measurement is normally taken laying on your back on a table but is more clearly understood when sitting in a chair (90 degrees is foot directly under knee). Some start with 60-80 degrees when they leave the hospital and must sit with their leg out prone.

ELEV is the degree to straighten your leg straight out as 0 degrees with -2 degrees as just a bit bent (not fully straight). Again this is best understood from a standing position of fully straight up and down as 0 degrees, but is usually taken laying on a table.

I also found my OS to be not as concerned with every "last degree" as my PT. I feel it is the training where the physical therapist is looking to measure the exact work while the surgeon is examining his "handiwork" and how the knee is mending. Not sure if this helps.

Hope
Engineer
LTKR Feb 23, 2009
RTKR June 8, 2009

 

[loggon]

When your leg is straight it is 180. If your rom is 120 then that means you are 120 from the straight. So from your leg where you have bent it back to the butt it should be 60. Have you seen the instrument to measure rom with? It has a starting pt of 0 on one side and 180 on the other. This represents the 180 degree.

You are correct with the 60 degrees just they are not measuring from the butt to the leg, but from the straight to the leg.

Jo has a pic on here some where which I think my show it better.
Plus unless you have the instrument that they use, you will not
see how it is figured.

 

[Josephine]

That's right, loggon. It a medical/anatomical definition not a mathematical one. The range of 180-360 degrees is not factored in, presumably because the lower leg cannot describe an entire circle!

To measure degrees of flexion using the goniometer, the zero is on the ankle and the 180 on the hip. Thus full extension is 0 degrees.

As the foot moves towards to hip, so the numbers go up - the right angle at the knee being (hardly surprisingly) 90 degrees, and so on.

Any extension with the knees going backwards (hyper-extension) uses the 0-180 degrees on the opposite arc so a knee is said to have (for instance) -5 degrees of hyper-extension.

 

[maumeefootball]

I thought this would get some discussion going. I wanted to see how different people responded because that is how a classroom of students would respond. The reason for asking the question as to why they measured from a straight leg and not measuring the angle that is formed by the ankle to the knee to the hip is this. We all live for these numbers so we have a fairly good understanding of ROM. But have you ever tried to explain to your spouse or someone else what the numbers mean. They all pretend to listen then just walk away with no idea what you are talking about. When you tell them that 120 ROM means I can bend my leg at a 60 degree angle they at least seem to be able to visualize what I am talking about more easily.


So maybe I should try and talk my principal into letting me buy a goniometer for my classroom for some hands on work with supplemental angles. Don't bet on that one.

Don Green ltkr 3/18/09 rtkr 5/26/09

 

[Jamie]

I got my goniometer on eBay for under $10....certainly not a big expense for a good classroom project! Hope it works out for you!

 

[Josephine]

Well, you don't tell them it's 60 degrees. It's 140 degrees from the straight extended leg!

 

[maumeefootball]

Thanks Jamie just bought one for $6.90 on EBAY. Should be fun.

 

[Texas]

Im so confused lol...but I know I can bend my leg...

 

[loggon]

Kim Kim Kim I could not stop laughing.