Femur acid, the common clinical causes are hip synovitis, osteoporosis, soft tissue inflammation and so on. 1. Hip synovitis: this disease refers to the inflammation of the synovial membrane in the hip joint due to trauma, joint disorders, metabolic reactions, bacterial or viral infections and other stimuli, with clinical manifestations such as hip joint soreness, swelling, and joint dysfunction. 2. Osteoporosis: this disease is mostly seen in the elderly group over 60 years old, which is usually related to the destruction of bone tissue microstructure, loss and decrease of bone mass, increase of bone brittleness and other factors, with clinical manifestations such as easy fracture of the body, generalized bone pain and fatigue. 3. Inflammation of soft tissues: some people frequently engage in strenuous exercise, such as running and jumping, marathon, etc., which may cause damage to the soft tissues around the femur, with clinical manifestations such as swelling, soreness and discomfort in the affected area. If the above situation exists, it is recommended to consult a doctor for a clear diagnosis and symptomatic treatment if the symptoms of pain and soreness are more serious.