Hello, You tripped, fell and hurt your knees. You had an X-ray that showed a small left knee effusion. You cannot bend your knees. To get relief from knee pain you are suggested to give rest to the affected knee, applying ice, elevation and compression may help. To reduce stiffness, get connected to a physical therapist, to do stretch & other exercises. You can take pain relieving medicines to reduce inflammation and swelling. Reduced range of motion due to increased fluid is treated with oral medications, steroid injections directly into the knee. Knee effusion should get reduced. If not, you will be recommended to get surgery done to remove excess fluid. Take care. Hope I have answered your question. Let me know if I can assist you further. Regards, Dr. Nupur K., General & Family Physician