Knee bone gap medical term is joint gap, joint gap consists of two parts, the gap between the femur and tibia that constitute the joint, commonly known as the bone gap; knee joint in front of the patella, and the femur skid between the bone gap. There are two bone joints, the first bone joint is between the tibia and femur, tibial joint bone joint pain common causes are as follows: 1, sports injuries: if young people, sports more, consider the medial and lateral collateral ligament strain disease, such as fat pad injury or meniscal injury, especially meniscal injury is most common, to consider whether it can be the cause of this and cause bone joint pain. Young people also have patellar and femoral skid pain, may also be sports injuries or often used to mountaineering, squatting movements, patellofemoral articular cartilage softening bone pain; 2, degenerative diseases: the elderly bone pain consider more degenerative diseases, such as osteoarthritis, osteoarthritis late joint instability, bone spur formation, stimulation of the surrounding joint capsule tissue, will also appear bone pain, meniscal degeneration Injuries can also occur; 3, inflammatory diseases: In addition, patellofemoral joint pain, most elderly people consider patellofemoral arthritis, long bone spurs around the patella, patellar instability, stimulation of the surrounding soft tissue and cause pain. Of course other inflammatory diseases can also cause bone crevice pain, but bone crevice pain is the whole knee joint swelling, no fixed position of back pain, to consider inflammatory diseases.