knee swelling

might seem like a silly question but....

what injuries will cause a gross knee effusion?
player was trainin for rugby (6 pm), valgus force to the knee in about 50 degrees flexion with the foot planted. very sore. went home. next morning knee is grossly swollen. i saw the guy, a friend of mine, told him to rice.. said come back in a couple o days thinkin o probably meniscus but when he came back is c/o vague pain around belly of lateral head of gastroc. meniscus tests are negative. ligament tests all negative. cant reproduce this pain at all in examination.... anyway! sorry back to the point! what else will cause gross knee effusion

thanks

The initial thing to look at with knee swelling, is how soon after the injury the swelling developed. If it was immeadiate then you are looking at cruciate damage or fracture. Cruciate injuries can be missed originally due to spasm of the hamstrings.

If the swelling comes on overnight then you are dealing with something within the capsule of the knee. So obviously check collateral ligs and muscle attachments. Meniscal injuries alnoe tend not to swell, normally asscoiated with a different structure.

When does he get the pain then if it is not reproducable?

I agree with the above. Immediate swelling (within an hour or so) is likely to be one of two issues - an anterior cruciate tear or a patella dislocation. Of course an intrcapsular fracture would also cause this. The PCL is less likely as it tends to tear the posterior aspect of the capsule and bleeds down the calf looking a lot like a large bruise.

Effusions post injury (not spontaneous) that take a lot longer to come up are more likely to be meniscal in origin.

Don't underestimate the power of GOUT. This alone could cause swelling. Check history, especially family. Our experience with similar patients taught us "not all swelling" is trauma-based...remember Gout arthritis can escalate w/ exercises.
conclusion: aspiration of fluid & tested. then follow basic PT protocol. patient may need to have multiple aspirations.
Regards

yep I agree with the anterior cruciate or patellar disocation theory. Keep re-testing as you can often get false negatives with gross swelling due to capsular distension etc. Often as the swelling goes down your ligament testing becomes more accurate and you may find some tests are more positive.