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Author Topic: need some differentials  (Read 848 times)

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Offline drladybug

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need some differentials
« on: April 17, 2006, 05:16:16 AM »
I have a patient who has complained of knee pain.  Here is the low down.

31 year old male.  This knee pain only occurs while sitting.  It occurs only once in a while, but when it does it is the worst pain the patient has felt in his life.  The patient has had this intermittent pain for as long as he can remember and can not associate it with anything (exercise, trauma, change in activity, stretch, medications, diet, etc).  The pain is deep and sharp and on the posterior aspect of the knee, but the pain diffuse and the patient could not localize it.  When the patient experiences this pain he can no longer remain seated and he has to get up.  "smoking a joint" relieves the pain and, other than sitting for long periods of time, which may or may not cause the pain, the patient cannot think of anything that aggravates the condition.  The pain does not spread to any other area of the body.  This complaint only occurs on the left knee.

Upon entering my office, the patient did not have any knee pain and was simply inquiring.  I did a knee exam, consisting of observation (unremarkable with respect to size, edema, discolouration, and deformity.  No varicose veins were observed) range of motion (full and pain free), muscle testing (quadriceps, hamstrings, gastrocs are all strong against resistance), palpation (no structure-muscle, ligament, joint line or bone could reproduce the pain), orthopeadic testing (valgus and varus stretch, bounce home, reverse pivot shift, mcmurray were negative)  I could have tried every orthopaedic test in my text, but there did not seem to be any indication from the history to do this,and the negative reuslts that I got so far left me stumped as to where to go next.  DVT test was also negative

The patient does have high blood pressure.  Is there a vascular condition that I should be considering?  Any other test that I could/should do to point me in the right direction?  Should I send the patient for diagnostic imaging or just tell him not to be concerned?  No other health care professional that this patient has sought out has had an answer for him either.  Any suggestions or suspicions would be greatly appreciated


Offline Heather M.

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Re: need some differentials
« Reply #1 on: April 17, 2006, 07:25:47 AM »
Most of us aren't doctors, we're mostly patients.  So I can speak from that perspective, but definitely not on the vascular problems question...but one thing you mentioned definitely is familiar...pain upon sitting.  Especially pain that is relieved once the patient begins to stand and walk around.  This is so common with PFS (patello-femoral syndrome, anterior knee pain, etc.) that it even has a name:  Theatre Sign in England and Movie-Goer's Knee in the US.  It is most commonly attributed to damaged cartilage on the back of the kneecap, which used to be called chondromalacia before that term fell out of favor.  When the knee is bent to 90 degrees or more, the back of the kneecap is 'loaded' or at the point with the most contact with the other bones of the joint.  Any areas of softened or damaged cartilage will have pressure on them with the knee bent, and usually patients with this condition will try to alleviate the pain by either getting up or straightening leg out as much as possible.

And diffuse posterior pain that is difficult to localize is also fairly familiar to those of us with damaged articular cartilage.  I've been told in my case it's related to swelling inside the knee capsule itself.  A visual examination can't always find this swelling, as it takes a good bit of excess fluid inside the capsule before it will begin to swell and bulge out, producing visible effusion.

Here's a pretty good article (from a kneeguru link) on this condition, and how to test for it (complete with diagrams/drawings).

Another possibility mentioned to me as a cause of severe but intermittent pain would be something that blocks the knee mechanics, like a loose body or knee mouse, a flip of torn meniscus, or a chondral flap that gets dislodged and put back into place.  I'm sure there could be some relation to any of these and pain with a bent knee, and most are also related to degeneration of articular or meniscal cartilage.  It actually turned out that I didn't have any of these problems, instead I had an overgrowth of synovial tissue (synovitis) and also of fibrotic adhesions (arthrofibrosis) due to previous surgeries.  Plica syndrome can also cause this type of pinching, impingement sensation, and is often found with PFS patients.  But I'd think the symptoms would be rather more frequent, unless perhaps the patient is sedentary or something. 

Some further research:  This is just a starting point, as there is a lot of other information contained in links from this page.  Another great explanation of PFS is here:  Obviously it's written for patients, but it might be a good resource to direct your patient to for more info.

Anyway, I'm not sure what your specialty is, but if one hasn't seen this guy already, it may be time to bring in an Orthopedic Surgeon who specializes in knees to get to the bottom of this.  Most cases of PFS can be resolved with a decent course of physical therapy if the patient continues with home exercises indefinitely to keep the VMO strong and balanced.  There are quite a few good tests that can be done to check for damage in the patello-femoral compartment.  Check out the links above and you should come across a few of these tests.  You might also want to send a private message to the Kneeguru and see if she can send you the link directly.

Good luck.  It sounds like you're a wonderful, thorough doctor to be doing this research for your patient! 


PS Keywords for further research include theatre or theater sign, movie goer's knee, chodromalacia, chondral lesion, patellar load, and anything else you see on the link I gave above, which leads to the patella section of the kneeguru's knee anatomy page.

PPS A test which always elicits my patellar pain is the following:  have patient sit on end of raised exam table with legs dangling, bent to 90 degrees.  Have patient extend both legs out to full extension and lock; then have patient unlock legs and lower them back to 90 degrees flexion.  Quiz for pain.  Next, repeat the test while doctor places hands lightly over each kneecap, trying to sense any grinding, rubbing, crepitation, and/or popping/snapping/clicking sensations.  This can be done again with doctor pressing firmly down on the kneecap while patient goes to full extension--this almost always causes aching and even sharp pain in my knees, because again it 'loads' the kneecaps.  I'm sure there are plenty of other tests, but this is the one that without fail can reproduce my patellar pain--the same pain I get when I sit with legs bent.
« Last Edit: April 17, 2006, 07:55:53 AM by Heather M. »
Scope #1: LR, part. menisectomy w/cyst, chondroplasty
#2-#5: Lysis of adhesions/scar tissue, AIR, patellar tendon debridement, infections, MUA, insufflation
#6: IT band release / Z-Plasty, synovectomy, LOA/AIR, chondroplasty
2006 Arthrofibrosis, patella baja

Offline nlb

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Re: need some differentials
« Reply #2 on: April 17, 2006, 07:34:52 AM »
Have you check his lower back.  If you cant find anything wrong with the knee there could be a problem in his lower back.  Its just a suggestion. 

Good Luck