Tibiofibular pain is an uncommon cause of pain on the outside of the knee joint. The tibia and fibula are two bones that support the lower leg. There is a joint that forms between those two bones. This joint may communicate with the knee joint and diseases that affect the knee may also affect this joint. Tibiofibular pain occurs on the outside of the knee. It is worse with motion, particularly pointing the ankle up and climbing up stairs. There can be swelling, limited knee motion and locking or popping of the knee. The pain is usually caused by injuries sustained through sports activities but may also occur with diseases such as arthritis , tumors, ganglion cysts, Lyme disease, collagen vascular disease and Pigmented Villonodular Synovitis. X-rays and MRI scans of the area may be useful to look for tumors and fractures. Bone scans can also be used to look for more subtle disease. Laboratory test are used to screen for collagen vascular diseases. Initial treatment includes conservative management such as non-steroidal anti-inflammatory medications, rest, heat, ice and physical therapy. An injection into the joint of a local anesthetic and a steroid can be helpful.