The ankle is a complex joint consisting of seven bones that join the tibia and fibula of the lower leg to the five metatarsal bones of the foot. Because the foot moves through many different planes of motion, the ankle includes a large number of muscles and ligaments. Because the foot is the body's point of contact with the ground, the ankle must absorb tremendous amounts of impact stress during running and is susceptible to a host of injuries, many of them on the medial, or inner, aspect of the joint.
Posterior Tibialis Tendonitis
The posterior tibialis muscle runs down the inside of your leg, behind the medial malleolus — the bony "bump" on the inside of the ankle — and attaches to the arch of your foot. Its job is to support the arch and prevent it from collapsing. When you run, the muscle and its tendon can become overworked and incur small tears, leading to inner ankle pain. People who overpronate or run on uneven surfaces are especially susceptible to this injury, the Northcoast Footcare website warns. If you suffer this injury, take a break from running, ice the area and try a stiffer and more supportive running shoe.
Deltoid Ligament Sprain
Sprains of the inside of the ankle are much less common than sprains of the outside of the joint, but when they do occur, damage can be significant. The deltoid ligament, the structure affected by a medial sprain, is very strong, and when you sprain it, the ligament may actually pull the medial malleolus, to which it attaches, off the fibula. Medial ankle sprains are also associated with fractures of the talus, an intrinsic ankle bone. Symptoms include pain, rapid swelling and limited mobility. Avoid putting weight on a sprained ankle, and apply an ice compress and elevate the ankle as soon as possible.
The synovial membrane and the fluid it secretes surround the support structures of the ankle and provide both cushioning and lubrication to the joint. Like any tissue this membrane is subject to inflammation, and this can result from injury, bacterial or viral infection, or underlying chronic diseases such as arthritis and gout. The pain of synovitis is often accompanied by a sensation of heat. Treatment includes rest, ice, anti-inflammatory medications, and in advanced cases, steroid injections and a walking cast.
A stress fracture of the medial malleolus manifests as pain made worse with weight-bearing activities, such as running and jumping. This injury may not be visible on a standard X-ray, but a bone scan, computer tomography scan or magnetic resonance imaging will reveal the fracture. Treatment includes the avoidance of weight-bearing activities for approximately six weeks. An ankle air cast can be used during this time to protect and support the joint. If the injury has progressed to a Lisfranc fracture, surgery is necessary.
Do not attempt to diagnose any pain in your ankle by yourself; you should consult your doctor if the pain persists or worsens. Always follow your doctor's treatment advice, and discuss ways to avoid future ankle pain.