A mild calcium deficiency will not cause knee pain, if the deficiency is significant there will be knee pain. 1. A mild calcium deficiency usually does not cause knee pain, and occasionally there may be cramps in the calves. 2. If the calcium deficiency is more serious, osteoporosis will occur, and there will be pain in the joints of the whole body and in the lower back. There will also be symptoms of knee pain. There is no fixed pain point and the pain is diffuse. The pain is aggravated by prolonged walking or excessive weight-bearing activities. Bone densitometry can be used to make a definitive diagnosis. 3. In addition to calcium deficiency, osteoarthritis, gout, rheumatoid arthritis, synovitis, meniscus injury can also appear knee pain. Therefore, when knee pain occurs, you need to go to the hospital for examination. If it is caused by calcium deficiency, you need to supplement calcium and vitamin D under the guidance of the doctor and avoid strenuous exercise.