What could be the reason why my right leg collapsed under me? it happened twice, once in december and again yesterday in feb. i had a hip replacement 10 years ago. it is the same leg that collapsed twice. i don't know if there could be a link.

Important : Important things to know is if you are having pain in the hip, leg, or knee on the affected side? Do you hear any noises in any of the above mentioned joints? Regardless, when your leg collapses it is usually due to a problem in the tendons or ligaments that support a joint. You could also have a problem with the hardware in your hip. You will need to see your doctor for an evaluation of this problem, which will include an examination and imaging studies (x rays and possible an mri). Best of luck.

There : There are a number of reasons your leg could be collapsing. Your prior hip surgery could play a role, of course, and you should first see an orthopedic surgeon to evaluate the stability of your hip prosthesis. (most implants last at least ten years; in fact, depending on the type of prosthesis used, your age, gender, weight, and activity level, the chance of a hip replacement lasting 20 years is around 80%.) other potential causes for your leg instability include internal knee derangement (e.g., a meniscal tear) or a neurological problem, such as a TIA (if the leg simply "gives way" without a warning or other symptoms -- numbness, weakness, tingling, etc. -- a neurological disorder is unlikely). If your hip proves to be stable, your orthopedist could also determine whether there's anything amiss with your knee. If orthopedic problems are ruled out, see your family doctor to determine the next step in your evaluation. I hope things work out well!