sogood said:
The tiny bit of movement per your suggestion can only be detected by instruments and for all practical purposes it's non-anatonomical.
I'm not an orthopaedic surgeon, nor am I a rheumatologist, so I'm not an expert on joint pathology by any means. But I do know my anatomy pretty well (I suspect I know it better than most people, particularly on a non-medical forum), and I do stand by the above.
There are a few degrees (very low single digits) of lateral flexion at each knee joint, more so laterally than medially. It's easily detectable on physical examination, and as I've said, it's perfectly anatomical.
I examine knees a few times every week (recently as a final year medical student, and now as a junior doctor), and to diagnose a busted collateral +/- meniscus, you need to know what's normal (especially if the person is taking painkillers, which they often do if they have knee injuries).
Measuring it precisely would require the biomechanical instruments you're talking about.
Surgery isn't always the first answer. It depends on the cause of the weak ligaments, how long they've been there, and under what circumstances the "rocking" occurs. The orthopods don't always jump straight for the arthroscope. Sometimes, letting it heal spontaneously, or physiotherapy to strengthen the muscles supporting the knee joint are enough, and sometimes, they aren't.
The rocking sensation the other have described is probably due to lateral flexion slightly beyond what they normally experience. The proprioceptive nerves inside a joint that detect the joint's position are incredibly sensitive, and can detect movements that are as little as 2deg, especially when the movements are outside of the normal range where your brain doesn't expect to detect them. It may or may not occur with walking - I suspect that will depend on the condition of the rest of the joint.
You are right, on one point. If there is enough laxity to cause rocking, then it wont matter what pedal system you use.
Otherwise, sogood, I think you need to swallow a smidgen of humble pie.
n