If the knee is not swollen, does not hurt, and hurts when squatting, the main consideration is a lesion of the knee joint. If there is redness, swelling, heat and pain in the knee joint, synovitis of the knee joint is mainly considered. But no swelling, no pain, squatting pain is mainly active pain, the clinic usually need to do further MRI examination, its common diseases are mainly seen in two diseases: 1, osteoarthritis, if after conservative treatment is ineffective, the age of more than 60 years old, can be considered to perform a knee replacement surgery. 2, if the anterior cruciate ligament or posterior cruciate ligament injury, the diagnosis of the MRI examination is clear. At this time, you can usually consider knee arthroscopy treatment, the anterior cruciate ligament or posterior cruciate ligament knee arthroscopy suture, so as to achieve the purpose of treatment.