The most common cause of knee inability to squat and bend is age-related arthritis and degenerative arthritis, usually due to long-term strain causing joint damage and cartilage destruction, resulting in more severe pain when squatting or bending, with the femur and tibia rubbing against each other, manifesting as squatting and not being able to get up or squatting and bending with severe pain and inability to squat completely. Pay attention to whether there is redness, heat and swelling around the knee, if the swelling is serious, you need to consider synovitis, etc., when squatting and bending is also more difficult will be limited. Other long-term causes of trauma can also cause damage to the ligaments, soft tissues and meniscus, when the whole knee activity is limited, squat bending will also be affected, check the knee joint, can not squat bending the most effective method is to check the MRI is better.