I discovered I had knee problems getting ready for a backpacking trip.  After 5 miles on a practice hike, they became extremely painful.  One hiking pole didn't help, but two made a huge difference.  It took the weight off on the downhills enough that I could finish.
I tried Patella bands that go around the knee, below the kneecap and a wrap around neoprene support, with a kneecap hole, that fastened with velcro.  Neither helped.  The magic bullet was an ACE neoprene knee support that pulled on over the foot, had a kneecap hole, and had two flexible tubular side supports on either side of the knee.  They are found in most drug stores.
I bought a pair of Leki collapsable hiking poles for the trip.  Don't waste money on anti-shock.  They are a nuisance and noisy.  I used them during practice hikes and never could tell that it helped, so I ended up locking the anti-shock off for the main hike.  Mountainsmith makes a reasonably priced aluminum collapsible hiking sticks without antishock.  My son used those and was happy with them.
Between the knee supports and the hiking poles, I completed a Philmont trek with the scouts, pain free.  The knee supports are hot, but worth it.   
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The Seeker