In a recent survey of injured runners of various levels, it was found that “shin splints” are the fourth most common condition holding them back from running.
What is it?
“Shin splints” is a vague symptom of leg pain most commonly along the inner aspect of the tibia, involving a third or more of the bone. The most common cause of “shin splints” is medial tibial stress syndrome (MTSS) also known as medial tibial traction stress syndrome. Recent studies suggest this process is similar to a stress injury of the bone rather than an inflammatory process. During the mid-stance phase of the running sequence the feet will pronate (flatten) to provide shock absorption and accommodation to the varied surface. The medial soleus muscle, the inner lower part of the calf complex, acts to resist pronation by contracting this leads to foot plantar flexion (pointing of the toes) and inversion (turning the foot inwards). The medial soleus is the strongest plantar flexor and invertor of the foot, however the tibialis posterior and flexor digitorum longus muscles also play a part in this movement. Excessive pronation due to the condition of pes planus (flat feet) or overuse with repetitive impact loading leads to chronic traction over the insertion of the soleus onto the tibial bone which may progress to MTSS.
Athletes with MTSS will often report that their pain usually decreases with warm up and therefore they can complete their training session with their pain gradually recurring after exercise and worsening the following morning. The inner aspect of the tibia will be tender to touch, with no area more tender than another. There may be also be mild swelling in the lower leg. MTSS is more common in novice runners with an incidence of 4-35% in military personnel and athletes.
Why does it occur?
Predisposing factors for MTSS include a training program that does not allow for a gradual increase in loads and adequate rest as well as running on hard or uneven surfaces. Individuals whom excessively pronate, have poor lumbopelvic strength or increased calf girth as well as a high BMI and poor flexibility are more at risk of developing MTSS. Poor footwear choice or wearing worn out running shoes on hard or uneven surfaces can contribute to the development of MTSS. Individuals with a history of previous stress fractures may also be more likely to develop MTSS. Interestingly female athletes have a higher incidence of MTSS, with female military recruits three times more likely to develop MTSS than men, potentially due to reduced bone mineral density and/or bone tolerance to increasing loads.
What can you do?
Focus on altering body mechanics and your amount of activity.
In resistant cases protected weight bearing or foot taping to control foot pronation may be required to reduce chronic tension on the region of soleus attachment on the tibia. There have been mixed results with treatment options such as ultrasound, electrical stimulation, iontophoresis, shock wave therapy and corticosteroid injections. There is also very limited evidence for procedures such as PRP and prolotherapy, therefore at this point in time their use is not recommended. Surgical intervention is only indicated if all treatment options have failed to provide relief. Surgery for MTSS has a success rate of 70% in elite, high-performance athletes.
What else could it be? Should you see a Doctor?
If your pain persists and/or becomes more localized, you might have a chronic compartment syndrome or a stress fracture, conditions that require review by a Doctor. Your Doctor may send you for imaging, such as an MRI, to further investigate. Even if imaging is normal the diagnosis of MTSS can still be made based on the clinical history and examination.
To learn more about Dr. Kendall Brooks visit http://www.opsmc.com.au/person/dr-kendall-brooks/
