Thread: knee physiology

What structures are responsible for holding a foot pointed in a certain direction -- say, parallel to the other foot? Skiing recently on what was admittedly very firm surfaces, I experienced one ski wavering around -- edging wasn't happening, and the ski tip would swing back and forth between 11 and 1 o'clock in the plane tangent to the snow surface. Possibly uncoincidentally, this is a leg that has suffered some ligamentous damage. What ligaments/tendons/muscles are involved in holding the foot steady in a certain alignment? Is this more ankle or knee?

A test I'm thinking of doing is to straighten my leg and present my foot to a volunteer who would attempt to twist the foot by pointing the toe-end inward toward the other foot. This might mimic the forces on the leg applied by twisting, e.g. in a twist-out release situation.

Much obliged for any ideas. Instability sucks, and I'm hoping I can lay the blame on poor technique or strength (curable) rather than musculoskeletal damage (less curable).

interesting.

There are several things at work here I think.

The wavering motion you describe could likely be explained by muscle weakness, ligament instability and or your unconsious brain attempting to prevent you from putting weight on the injured knee.

Lets start with the muscles. Since you have injured that knee before, there may be a possibiity that the muscles of your lower leg, thigh and hip are not as strong as they need to be resulting in less edge pressure than would be required to hold an edge on hard snow/ice. From here there is no way to tell which area you may deficient in but a general lower extremity/ski conditioning class would help.

Ligaments next. Define "some ligamentous damage" Without knowing what ligament(s) you are talking about it would be useless to prattle on about which ones do what.

Unconscious brain: Now I have worked with many, many peopl coming off a ligament injury/surgery etc who display this. the very hardest thing that someone who has experienced a corrective joint surgery (ACL, meniscus, etc..) has to do is be able to trust their knee.

The very first time I have a knee rehab person do squats they will automatically shift weight away from the repaired/injured side and not ever realize they are doing it until I put them in front of a mirror. Its just how the brain works, sort of a protective mechanism.

Is this what is going on with you? I don't know. but if it is then it might explain some of what you are experiencing.

your test of having the leg strait and having someone twist will not work sorry to say. The only way to test those ligaments would be to have an orthopedic type exam where each ligament is evaulated individually. The test you descibe could be influenced by muscles spanning over no fewer than 3 major joints.

Sorry i don't have more answers but the question you are asking is actually very complex and would need a in depth physcial and functional exam to answer.

I nominate Vinman for the mag of the year award for his medical advice. Thanks much.

History: I am 27, skier for life and telemarker for several seasons. March 2005 I had a situation where, telemarking through moguls poorly, my right ski hooked, I had a wet POP, collapsed and went down. Right knee twisted. I had rigid nonrelease bindings (Bombers). Immediate pain and swelling, but more instability than pain -- it just "didn't feel right". Able to ski down and have it evaluated. Based on Lachman test, slopeside doc diagnosed complete ACL tear, possible ankle fracture. X-ray negative for ankle fracture.

Over the next few weeks, the front of my knee below the patella felt "funny" and slightly sore, but the inside (left face) of right knee was very swollen and sore.

Saw an ortho surgeon one week later. Based on Lachman's test, this doc said the ACL was definitely at least partially intact (best guess, Grade I tear), but that the MCL was likely Grade III, plus meniscal damage and possible bone bruise to tibial plateau. Based on this, he said I could choose to have an MRI but that he would not recommend one, given that the Lachman snap-back was so distinct -- in fact better in the injured knee than in the left one; if the MCL didn't scar down and heal within a month, he'd do an MRI. (For this doc's Lachman tests, I was much more relaxed than slopeside; I know I tensed up hard for the slopeside exam.) I began PT, followed it religiously, wore a hinged brace, and scheduled another ortho appt for one month.

One month later, follow-up ortho. He said ACL fully recovered based on stability and Lachman's; MCL likely to recover fully, come back in a month if it's still bad. On his advice, I returned to gentle skiing ("anything but racing and drops"), having some pain but not much. (With the soft snows of April, I didn't notice any torsional instabilities.) One month later, ski season was nearly done and all was well. I last skied in July, and everything was solid.

Originally Posted by Vinman

Lets start with the muscles. Since you have injured that knee before, there may be a possibiity that the muscles of your lower leg, thigh and hip are not as strong as they need to be resulting in less edge pressure than would be required to hold an edge on hard snow/ice. From here there is no way to tell which area you may deficient in but a general lower extremity/ski conditioning class would help.

Since then, I've been running about 20-25 miles per week. Not sure how indicative it is of ski strength, but I mile in about 6:00 and average 7:30 pace for 5 miles.

Ligaments next. Define "some ligamentous damage" Without knowing what ligament(s) you are talking about it would be useless to prattle on about which ones do what.

ACL partial tear; MCL likely complete tear. Both should be healed as much as they're going to. I have not experienced any instability running or hiking. I also take glucosamine/chondroitin.

Unconscious brain: Now I have worked with many, many peopl coming off a ligament injury/surgery etc who display this. the very hardest thing that someone who has experienced a corrective joint surgery (ACL, meniscus, etc..) has to do is be able to trust their knee.

Here's where I'm hoping my problem lies. Sucks to say it, but the injury unnerved me. I know I lost some of the spirit/confidence/aggression with which I am used to skiing. As a telemarker, right turns have always been my strong side, but so far this season my lefts feel much more solid. I just don't feel that I can trust that knee. As I crank up the angulation, that right knee just freaks me out. (I know, "sack up and ski", but it makes me cringe -- not from pain.) It just seems like it's going to hook or collapse (which is how I fell in the first place).

Observers have told me that my biggest problem right now is that I'm skiing tentatively. Given what I expect from myself, that sucks. I want to fix it.

On a related note, I hit the local hardpack for 8 hours on Sunday, the first non-backcountry snow I've skied this season. In addition to feeling like a sore old man in my back and quads (typical for lift-serve day 1), the front of my right knee below my patella has had a constant dull ache (not aggravated by movement) since then, decreasing this morning but still not quite feeling right. This is consistent with how I was before my March fall, so it's not necessarily related.

ok that helps.

I think that you should definitly get into a ski conditioning class. this will do 2 things. 1 make you stronger and possibly get rid of some of the achy feeling in your knee. I'm guessing at either patellar tendonitis or patello-femoral pain for that part. Which is probably related to a genaeral lack of strength in that leg. 2. being stronger will make you more confident in your knee. which in turn may help out with your tentativeness (is that a real word?)

The other thing you may want to explore is the possibility of a brace for your MCL and or ACL. There are some off the shelf braces (non full custom) that do pretty good with injuries like your. You would have to go back to see your doc if this is an option you want to try. Which might not be a bad idea anyway. Maybe having another exam on your knee and hear that it is ok would help the mental parts of this problem...

Anyway, hope some of this is a help.