Not saying its your problem, but heres my viewpoint.
Knee, hip, back pain all definitely CAN originate in the feet. Your entire posture is dependent on a proper foundation. If the foot isnt right, the body will try to compensate by shifting the joints to maintain balance. No amount of cheap insoles, or even shoes can correct this. In fact, the vast majority of shoes are horrible for your feet, and designed with zero anatomical correctness. They CAUSE problems. Many women have hammertoes from wearing the ridiculous ladies shoes they make.
About 20+ yrs ago, my feet became flat, part heredity and Im sure part due to very heavy weightlifting. I became afflicted with plantar fasciitis. I couldnt even walk sometimes in non-athletic shoes like sperry topsiders due to the pain. Id be somewhere and become crippled by burning pain under my arches, and unable to walk to my car, etc. Generally I was OK in athletic shoes, except that when I got out of bed in the morning, I couldnt walk at first due to the pain under my arches until my feet warmed up. I lived with this problem for several years. One particular annoyance was that my expensive cowboy boots (boots are probably the best shoes for your feet) hurt my feet now under my arch, I couldnt wear them anymore. Proof my feet had changed, as if the solid blob of a wet footprint on concrete near a pool wasnt enough. No sign of arch.
Then I met this guy that ran a company called Body Balance? I think. He fit orthotics to re-shape the foot and fix problems. He had fit a lot of pro athletes and teams including the Pittsburgh Steelers at the time, including Franco Harris. He explained things to me, did a demonstration of stability with/without the orthotic under the foot. Immediately when putting these under your foot you noticed you stood up straighter, and more erect, and could resist a downward force on extended hands without tipping forward. By putting the foot in the proper position, it translated to the whole body.
The convincer for me was the customers that came in to get new ones to continue re-shaping their foot, and they all swore by it. Knee pain gone, back pain gone, etc.
Generally, it might take several years and two-three progressive pairs to get the problems corrected as good as possible. So I plunked down the $250 (a lot of money at the time for me 20 yrs ago), and got mine. One woman came in and inquired and left angry because a podiatrist had charged her $900 for the same thing.
So I was fitted with orthotics to re-shape my foot. The way they did this was to take an ink impression of the footprint your bare foot leaves on paper. They can tell from the impression where the pressure is, etc. Which toes are hammering, how collapsed the arch is, etc. Simply by comparing your imprint to a chart, and picked the orthotics from a selection of hundreds to begin to reshape the foot.
At first, it hurt, It was like having golf balls under my feet. They told you to start with 5 min per day and work up slowly. Not me, I started with 30 min and quickly wore them all day and just endured the pain and soreness. After about 3 weeks it didnt really hurt too bad anymore. After 6 months I barely felt them anymore. My plantar fasciitis and pain had totally gone away, and I was still lifting weights up to 600 lbs. I could see the arch again in my barefoot print on wet concrete!
At one year I had a checkup, planning to get a new pair to continue but I had misunderstood and not paid for the upgrade in advance, so it was going to be another $250 so I didnt. My feet werent perfect, but were pretty good, my pain was gone, I walked more erect, etc.
Anyway. 20 yrs later I still wear them in every pair of shoes I wear, wouldnt think of not wearing them lest my feet return to the way they were. Dont know what happened to that business, but there are likely podiatrist could do the same.
Sorry for the long post. But, your feet will truly shape to the shoes, poor footbeds, etc, and changes occur as you get older in many people. If that happens, it causes all kinds of problems in the knees, hips, back as the body tries to compensate. The ONLY way to fix it is to fix the foot. Thats the definition of an orthotic. Orthotic means to "reshape". So my recommendation for knee pain, is to have your feet evaluated in addition to whatever an orthopedic knee doctor says.
By the way when I had foot pain, an orthopedic foot doctor did nothing for me but charge me $$, say "you got plantar fasciitis", and prescibe 8x strength ibuprofen.