Medial Tibial Stress Syndrome

Medial tibial stress syndrome (MTSS) is exercise-induced pain along the posteromedial border of the tibia, with tenderness spread over 5 cm or more of the bone.

It is one of the most common causes of exercise-related leg pain in runners, military recruits, dancers and jumping athletes, and is more common in women. The old label 'shin splints' is non-specific and best avoided.

It sits on a bone stress continuum with tibial stress fracture, which is managed differently and must be distinguished. Most cases settle with load management, though recovery often takes months.

The posteromedial border of the tibia gives attachment to the soleus, flexor digitorum longus, tibialis posterior and the deep crural fascia. Pain is usually over the middle and distal thirds, where the tibia bends most under impact loading.

Muscle traction on the periosteum was once thought to be the cause. Imaging and bone density studies now point to bony overload: periosteal oedema with cortical microdamage and lower bone density at the painful site, though which comes first is not settled. Continued loading can progress to a stress fracture.

Risk factors supported by systematic reviews:

• •Female sex
• •Higher body mass index or weight
• •Greater navicular drop or a pronated foot posture
• •Previous MTSS or running injury, and fewer years of running experience
• •Greater hip external rotation and ankle plantarflexion range

A recent rise in training volume or intensity commonly comes before symptoms. Reduced ankle dorsiflexion has not been shown to be a risk factor.