Common diseases in orthopaedic surgery are divided into the following categories: firstly, spinal diseases such as cervical disc herniation, cervical spondylosis, cervical longitudinal ligament ossification, scoliosis, lumbar disc herniation, lumbar spinal stenosis, spinal fracture and spinal cord injury; secondly, limb joint diseases such as ischaemic necrosis of the femoral head, osteoarthritis of the knee joint, osteoarthritis of the ankle joint and periarthritis of the shoulder joint; thirdly, hand surgery diseases such as tendon injury and stenosing tenosynovitis; fourthly, neoplastic diseases such as osteosarcoma, osteochondroma, chondrosarcoma, bone cyst, osteoid osteoma and metastatic cancer of bone.