Osteoporosis means your bones are weak and need long-term care, while swelling in one knee may be due to arthritis, strain, or fluid buildup, so both issues should be managed together. Treatment usually includes a calcium- and vitamin D-rich diet or supplements (as prescribed), along with medicines specifically for osteoporosis (like bone-strengthening drugs) if advised by your doctor. For the knee swelling, rest, avoiding excessive strain, gentle physiotherapy exercises, and using cold or warm compresses can help, and pain-relief medicines may be used if needed. Regular low-impact exercise, like walking and strengthening exercises, is important to improve both bone strength and joint function. Maintain a healthy weight, avoid falls, and use supportive footwear. If swelling persists, worsens, or is associated with severe pain, redness, or fever, you should consult a doctor for further evaluation, such as an X-ray or joint fluid assessment, to identify the exact cause and guide proper treatment.