It's week 4. i feel stiffness on my leg after arthroscopic surgery. what's the cause and solution? i can barely bend 60 degree.

Postop swelling: It is common to recover quickly from a "simple" knee scope. However, if more extensive work was done, the recover can take up to 12 weeks. The stiffness is likely from swelling after blood pooling in the joint after the procedure. The range of motion at 0-60 is a bit behind schedule, but can be overcome. You need aggressive therapy and regular ice therapy. See your surgeon for advice.