Medial Shin Splints—Now Called Medial Tibial Stress Syndrome (MTSS)
The outmoded term medial shin splints has been replaced by medial tibial stress syndrome (MTSS). Either term suffices to describe pain at the medial aspect of the leg, adjacent to the medial tibia. Tenderness is usually found between 3 and 12 centimeters above the tip of the medial malleolus (the inner knob of your ankle) along the tibia.
Periostitis (inflammation of the connective tissue that covers bone) sometimes occurs at the painful site. The sore, inflamed structures also usually include the adjacent muscles and tendons.
Stress fractures can also occur in this same area. The definitive test for stress fracture is a bone scan, but false negatives and false positives sometimes occur because of the soft tissue and periosteal involvement in this injury. A physician's clinical examination is used to differentiate between medial tibial stress syndrome (MTSS) and a stress fracture.
With MTSS, the tenderness extends along a considerable vertical distance of the tibia. When a stress fracture is present, tenderness usually extends horizontally across the inside and front of the tibia.
Risk Factors for MTSS
The first risk factor is overtraining. Evaluate your schedule to determine what training errors you may have made. Mechanically, overpronation is most likely to be the culprit. When the foot pronates too much, the medial structures of the leg are stretched and stressed, which increases the likelihood of injury. Running on a cambered surface, such as the side of a crowned road, can put the upper leg at risk to develop this problem because the corresponding foot is functioning in a pronated position.
Decrease training immediately. Do not run if pain occurs during or following your run. Nonweight-bearing exercise such as swimming, biking, and deep-water running may be necessary to maintain fitness. Although running on soft surfaces has been recommended for this problem, it is not likely to help a pure MTSS. The foot is more likely to pronate excessively on mushy grass or sand. Packed dirt is ideal, and avoiding concrete is also helpful.
In many cases, shoes rated high for control of pronation might help. Gentle calf stretching exercises are important, but control of pronation is more direct. Ice applications following running can offer some pain relief but are not curative. If symptoms persist, it is important to seek professional medical attention.
In the doctor's office, a thorough medical evaluation of your training schedule, racing schedule, and shoes is followed by a biomechanical evaluation. Anti-inflammatory medication can be prescribed. The use of physical therapy modalities and skilled interventions can also be helpful to treat this problem. Excessive pronation, which is a major contributing factor to this syndrome, can be corrected by the right running shoe, an over-the-counter shoe insert such as Superfeet®, or possibly custom orthotics.