The clinical manifestations of age-related osteoporosis are divided into a preclinical phase (low BMD stage) and a clinical phase (fragility fracture stage). The preclinical phase is called the “quiet epidemic” because most patients are often asymptomatic, but it can also cause weight-bearing pain due to accelerated bone turnover and decreased skeletal weight-bearing tolerance. After the fracture, the entire biomechanical environment changes and symptoms develop. Pain, stature shortening, spinal deformation, and fractures are common signs and symptoms of age-related osteoporosis, which generally occur after a slow decline in the rate of bone formation and after bone volume has decreased to a certain level. Clinical symptoms mostly appear after the middle of the disease process. According to statistics, most patients do not show clinical symptoms until the bone mass is reduced by 12% to 30%, and about 80% of patients can have bone pain and other symptoms, and a small number of patients do not show the above symptoms until after pathological fracture (caused by osteoporosis) occurs. 1, pain Pain is the most common and main symptom of osteoporosis, including muscle pain and bone pain. Age-related osteoporosis is progressive, and the appearance of pain is closely related to the degree of increased bone resorption and the rate of bone loss. Once a fracture occurs it often leads to pain or increased pain, and pain is the main symptom of a fresh fracture. ① Causes of pain: Increased bone resorption is the initiating factor for pain in osteoporosis. In the course of senile osteoporosis, the morphology and structure of the bone are damaged as a result of increasing bone resorption and severe loss of bone mass. In the trabeculae, this is manifested by thinning, thinning, perforation or even fracture of the trabeculae, and in the bone cortex by thinning of the cortex and enlargement of the medullary cavity. These pathological changes not only affect the internal environment of the bone, but also affect the tissues surrounding the bone. For example, a microfracture of the vertebral body causes compression and deformation of the vertebral body, which is accompanied by loss of stability of the spine and compensatory increase in muscle tension to maintain stability. Another example is that pathological changes in the trabeculae and bone cortex can cause increased intraosseous pressure, affecting microcirculation to produce bruising, and increased periosteal stress to cause tension pain. In addition, inflammatory pain is caused by the production of pain-causing factors such as prostaglandins after tissue injury. In addition, some conditions promoted or induced by osteoporosis in the elderly can also cause pain. The location of pain: the most common pain is in the low back, and the pain is centered on the spine and spreads to both sides, and changes in position can reduce or aggravate the pain. The pain can be alleviated or aggravated by changes in position, such as supine or short sitting position, and aggravated by prolonged sitting, standing, lying, twisting the body, forward bending and backward stretching. Pain may also occur in other areas, such as pain in the pelvis, hip, buttocks, sacrococcygeal region, knee and ankle, foot and plantar regions or persistent heel pain, and in more severe patients, generalized pain may occur. ③Time and frequency of pain occurrence: at the beginning, the pain is intermittent with the change of the body’s dynamic state, and later it becomes persistent with the development of osteoporosis, with the characteristics of light day and heavy night. ④Nature of pain: mainly soreness, distension, dull pain, deep pain, when there is a fracture can cause acute severe pain, and about half of the patients feel pain or pain aggravated when vertebral compression fracture. ⑤ Other symptoms accompanying pain: such as muscle spasms, mostly in the lower legs, soles, abdomen, ribs or hands, followed by numbness of the limbs, weakness, insomnia, mental anxiety or fear. A few are also accompanied by intercostal neuralgia or abdominal pain. In addition, osteoporosis is a contributing factor to degenerative spine pathology. When the vertebrae are compressed and deformed, it can aggravate the intervertebral disc lesion and bone redundancy and cause chest pain, lower back pain, lower limb radiating pain or intermittent claudication, and if the cauda equina is compressed, symptoms such as abnormal stool and urination can occur. 2. Shortening of the body and spinal deformation Shortening of the body and spinal deformation (mainly hunchback) are the most common signs of senile osteoporosis. Wedge deformation of vertebrae or compression fracture of multiple vertebrae can lead to shortening of height or hunchback deformity. Vertebral wedge and compression fractures often occur under the influence of gravity on the trunk and do not necessarily involve definite traumatic violence. The front of the spine consists of the vertebral body and the intervertebral joints. The vertebral body is composed mainly of osteoporotic material. When osteoporosis occurs, the vertebral trabeculae are first damaged (the transverse trabeculae are the first to be affected, followed by the anterior and posterior trabeculae), and the pathological changes in the number, morphology, and structure of the trabeculae cause a significant decrease in bone strength, resulting in microfractures and compression of the vertebral body under repeated loading. In severe osteoporosis, the length of the spine can be shortened by about 10 to 15 cm, far exceeding the shortening of the body due to age. When the vertebral body is compressed, the posterior functional units of the spine (including the vertebral plate, the pedicle, and the spinal prominence, which consists of cortical bone) remain unchanged in height and cause the spine to flex forward and protrude backward to form a hunchback. In elderly patients with osteoporosis, the vertebral compression is mostly wedge-shaped, with thoracic 11 and 12 and lumbar 1 and 2 predominant, thus causing a significant increase in the angle of posterior protrusion. In osteoporosis, the bone resorption of the vertebrae is not homogeneous, and with the influence of external forces, lateral protrusion deformity of the spine can also occur. 3, fracture There is an obvious causal relationship between osteoporosis and fracture. The prevalence of fracture in elderly patients with osteoporosis is about 20%, and it is often the first symptom or the first cause of diagnosis in some patients with osteoporosis. Once a fracture occurs, signs and symptoms of pain, deformity and functional impairment at the fracture site are present. Some elderly people have poor sensitivity to pain, and patients with embedded femoral neck fractures can even walk, which can easily lead to underdiagnosis and misdiagnosis and should be taken seriously. Excessive bone resorption is the essence of osteoporosis, which causes the decay of bone mass, bone structure and biological properties of bone. In the process of this chronic change, microdamage of bone accumulates over time, and bone reconstruction and repair lose their compensation and balance, which eventually decreases bone strength and increases brittleness, which is the pathological basis of fracture and an intrinsic factor that predisposes patients with osteoporosis to fracture. Osteoporotic fractures are the most serious consequence of osteoporosis. Extravertebral fractures are generally violence induced but fractures can be induced by minor injuries. Minor violence is the degree of violence that results from a fall at one’s own height level during the patient’s activities of daily living. Vertebral fractures can be caused by the body’s own gravity and do not necessarily have applied violence. In contrast, most patients with osteoporosis have vision, balance, muscle strength and concentration deficits that predispose them to falls, and falls are the main external factor in osteoporotic fractures. Osteoporotic fractures occur in the epiphysis of the bone and in the thoracic and lumbar spine. They are most commonly found in the upper end of the femur and the thoracic and lumbar spine (wedge fractures). 4.Other clinical manifestations As patients develop spinal deformity, it can cause symptoms such as chest tightness and ventilation disorders, and some patients can also develop digestive system symptoms such as constipation, abdominal distension and epigastric discomfort. Hair loss and loose and easily fractured teeth are also not uncommon.