loose cleat = knee pain?

I've been having some pain in my left knee while cycling for the last couple of months. It's been an occassional twinge of pain when I mash hard for a couple pedal strokes, especially when starting from a stop. If I gear down at stops and keep the cadence high, I'm usually OK. Standing is always OK. I started thinking that maybe my foot was too outboard on the pedal and I should try adjusting my cleat. It turned out that my cleat was missing a screw and was loose enough it could slide sideways and had. The cleats were also very worn on both shoes. Since I had a spare set of Speedplay X cleats, I put on new ones. On a 28 mile ride last night, not a single complaint from the knee. Not sure if the loose/out of place cleat was the only reason for my knee problems, but right now I'm happy.

Lesson learned: check your cleats frequently.
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Yup, amazing what the difference makes. I had my newish bike in for a proper fitting and wound up getting new cleats in the process. Now my knees aren't quite as mad at me.