Sharp pain at night at the connection between the inner thigh and knee mostly refers to pain in the inner knee joint, and the common causes are trauma, osteoarthritis of the knee joint, goosefoot bursitis, lumbar disc herniation, osteosarcoma, etc. 1. Trauma: Because of car accidents, knocking with sticks, falling down with strenuous exercise, etc., soft tissue injuries such as tendons, ligaments and meniscus on the inside of the knee joint, or fracture of the lower end of the femur or fracture of the tibia, etc., which cause pain on the inside of the knee joint. 2. Osteoarthritis of the knee joint: mostly seen in the elderly. Because of the degenerative changes in the knee joint, it leads to the destruction of the knee joint bone and synovial inflammation, which causes pain in the knee joint, and the pain can be aggravated when going up and down the stairs, hiking and other activities. 3. Goosefoot bursitis: Goosefoot bursitis is an aseptic inflammation of the bursa on the inside of the knee joint, which can be triggered by trauma, sports strain, etc. Because of the inflammation stimulation, the pain on the inside of the knee joint can occur. 4. Lumbar intervertebral disc herniation: Because of degenerative changes of intervertebral disc, the nucleus pulposus protrudes and compresses the sciatic nerve, which leads to radiating pain and numbness in the lower limbs. 5. Osteosarcoma: Osteosarcoma is a malignant tumor originated from bone, because of tumor cell erosion, inflammation and stimulation, resulting in bone destruction and causing severe pain in knee joint. Causes of knee pain on the inside of the knee joint are more reasons, may also be related to infection, rheumatic diseases, gout and other diseases, if the symptoms continue to be unrelieved, it is recommended to consult the doctor in time, to clarify the cause of the disease, and to carry out targeted treatment.