EE working on 992C Loader in shop. EE removed the Shut-Off Solenoid from RR of loader; it dropped to the floor. EE descended loader to pick up the part. EE slightly bent knees & bent over at waist to pick up part when ee felt a pop & pain right knee; ee then fell to the floor holding the knee. EE suffered a Transient Patella Dislocation (small knee cap dislocation).