I suffered with knee problems for years, tried numerous pedals with lots of float (of which Time were probably the worst), settled on Speedplay Frogs quite a few years back, and they helped a lot, but didn’t solve it. An expensive Cyclefit session in London proved the bike was near spot-on, and cleat wedges were deemed the answer. Another year or two of perserverance, with little improvement saw me in the hands of a physio called Andy Berry, who deals with cyclists and cycle fitting, and within five minutes he’d made a diagnosis,then showed me exercises to prove it, and gave me excercises to sort the issue (weak muscles in the left butt cheek). Within a week, I was riding virtually pain free, and with occasional repeats of the exercise, have remained so ever since.