I recently had a patient ask me about why her knee keeps collapsing when walking and descending steps. This is actually a lot more common than people think and, it's often a sign of very bad things to come.
Knee buckling, in most cases, has everything to do with the timing of muscle firing. The timing of the hip and knee provide stability for the moment that your foot hits the ground. The causes of mistiming and misfiring can run from serious to mild and can cause a myriad of problems. Here are some reasons why this can happen:
1) The pelvis may be rotated on either side creating a functional leg length difference. If you are misaligned at the pelvis you may have increased stress at the lower back, hip, knee, ankle and/or foot. Over prolonged periods of time, these joints wear out and can cause pain. So how do you fix it? The hip flexor has an inclination to rotate the pelvis out because it is dominant. It becomes dominate due to poor gait, sitting for extended periods of time and poor running form. Not to mention, your butt muscles are probably weak in comparison to the hip flexor. You fix this by stretching your hip flexor and hip extensions as well as abdominal bracing.
2) You may have a true anatomical leg length problem. The answer is to add a heel lift to your shoes to make up for the difference from one side to another. This, although difficult to physically correct, is an easier fix than a bad habit as long as you're diligent with using your heel lifts.
3) You may also have a weak vastus medialis obliquus (VMO) due to the above two reasons. This weakness makes it difficult to stabilize your knee at the right time. The VMO is a very important muscles and strengthening it can make a big difference.
Regardless of if it's one of the above three reasons or something else entirely causing your buckling knees, it's important to seek a professional opinion from a physical therapy and see where the real source is.
If you have buckling knees, I hope you take the time to try some exercises and seek the reason why it's happening!
Remember, we heal smarter, not harder!
Dr. Justin C. Lin