Ground up rooster combs. The job I had required me to kneel a lot (No jokes please). I repaired HVAC equipment in schools so I was on the roof a lot fixing rooftop AC units (Look at the roof at your neighborhood school and try to count the units) and kitchen eq. One day working in a kitchen I rocked back and felt a pop and pain. I was wearing a pad and kneeling on a foam mat. Workman's comp BS followed. MRI showed nothing.
Therapy no help. Finally they "authorized" the gel shot. I needed help to get to my truck after it. Didn't help the knee at all. Then we fought for exploratory surgery. Since there was no evidence of damage in the MRI Comp didn't want to pay but they finally relented.
Then covid hit so surgery was delayed. Finally it happen and I had a major meniscus tear and a plica membrane tear. Most of the meniscus is gone. Can't kneel for any length of time any more so I retired at 62. Doctor told me structurely my knee is that of a 20 yr. old. I told him to give it back to him!