Hi, Arthritis is a condition that can cause inflammation and pain in the joints of the body, including the knee joint. Pain in the calf muscle while suffering from arthritis in the knee could be due to several factors, including: * Overuse: If you have been walking or standing more than usual due to knee pain, it may put additional strain on the calf muscles, leading to pain. * Compensation: When you have pain in one area, you may subconsciously alter the way you walk or move, leading to compensation in other muscles, including the calf muscles. This can cause muscle fatigue, cramps, and pain. * Nerve Impingement: Sometimes, arthritis can cause nerve impingement or compression, which can lead to radiating pain in the calf. Regarding the fluid in your calf area, it is possible to have fluid accumulation in the calf muscles, which is known as a calf muscle strain or tear. This can happen due to overuse or sudden injury. Symptoms may include pain, swelling, and limited range of motion. However, it is important to rule out other potential causes of calf pain, such as blood clots, which can be a serious medical condition. If you suspect you may have fluid in your calf, it is best to consult with a medical professional for a proper diagnosis and treatment plan. They may recommend imaging tests such as an ultrasound to confirm the presence of fluid. Treatment may include rest, ice, compression, and elevation (RICE), as well as physical therapy or medication to manage pain and inflammation. Take care. Hope I have answered your question. Let me know if I can assist you further. Regards, Dr. Priyanka, General & Family Physician