The knee is a very abused part of the body. Once damaged poisons like to accumulate in it.
Will BF&C help? Sure, will it be enough? Odds are NO, it all depends on what it took to make the knee bad in the first place and is the person willing to STOP and REVERSE and ALLOW the body to heal!
99.999999999999999% chance NO, this is why knee replacement surgery is very popular!
My right knee exploded at work many years ago after handleing 55 gallon drums. In a 15 minute period it swelled my pants tight at the knee and I walked around like Frankeinstine dragging my leg. Back then the factory sent me to their doctor who gave me a cortizone shot and said I would be fine by morning. Naturally I was not and my leg stayed swelled tight, after a few days my dad gave me some cayenne and said rub than on it and the swelling went down enough I culd walk. Eventually after 9 months of problems the factory sent me to their surgeon, luckily the surgeon was in a hurry that day and said he could operate, but suggested because of my age to let it be and do nothing. I took his advice and did nothing and my right knee hurt a full 5 years, but eventually did 100% heal on its own. "IF" I had chosen surgery I would had permanent lifetime problems.
Consider the fact women by age 50 will all have knee problems, unless they live extroidanary healthy lives. Men tend to have more hip problems.