So what is it that you have when you have hip pain? There are 20 to 30 different diseases that cause hip pain. First, if you are a sports enthusiast, the most common diseases that cause hip pain are hip impingement, glenoid labral injury, hip cartilage injury, and round ligament injury. If you are a young woman, the most common hip disorder is congenital hip dysplasia. If you are an older patient, the most common form is degenerative osteoarthritis, or aging of the joint. In addition, if the hip joint is painful and swollen, it is commonly associated with various synovial and inflammatory diseases such as ankylosing crestitis and rheumatoid arthritis, as well as the relatively uncommon pigmented villous nodular synovitis and synovial chondromas. If the skin around the hip joint is red, swollen, and hot, along with a generalized fever, then the most likely cause is a hip infection, such as Staphylococcus aureus, tuberculosis, or Borrelia burgdorferi infection. If there is a popping sound around the hip joint, the possible diseases are iliotibial tract contracture, gluteus contracture, and iliopsoas impingement. Damage to the muscles and tendons around the hip joint, such as damage to the gluteus medius tendon, damage to the hamstring tendon, and damage to the femoral square muscle caused by sciatic impingement of the femur, can also cause hip pain. Finally, it should be reminded that lumbar disc herniation, lumbar spinal stenosis, lumbar myofasciitis, sacroiliac arthritis, and pear-shaped muscle syndrome causing sciatic nerve entrapment, in addition to inguinal hernia, femoral hernia, and closed-hole internal muscle hernia may all cause painful discomfort around the hip joint. Therefore, it can be seen that there are many diseases that can cause pain and discomfort in the hip joint, and careful differential diagnosis is needed. For the majority of patients, we need to understand the three main characteristics of hip disease: 1, the pain is mostly in front of the thigh root, less pain in the rear; 2, the scope of hip pain generally does not exceed the knee downward, upward not higher than the waist; 3, crossed legs or sedentary symptoms aggravated.