Description

The term medial tibial stress syndrome (MTSS) is preferred to “shin splints.” MTSS is an aching pain along the inner edge of the tibial shaft that develops when the musculature and/or periosteum in the (lower) leg become irritated by repetitive activity. The condition is part of a continuum of stress-related injuries to the lower leg and is not related to pain from ischemia (compartment syndrome) or stress fractures.

• Related pathology: tendonitis/periostitis of the medial soleus muscles, anterior tibialis, and posterior tibialis muscles
• Synonyms: tibial stress reaction, anterior muscle syndrome, tibial periostitis, perimyositis, soleus syndrome, shin splints

Epidemiology

Incidence
Common, can account for 4–35% of reported running injuries; frequently occurs bilaterally (1)

Pediatric Considerations
MTSS may account for up to 31% of all overuse injuries in high school athletes.

Etiology and Pathophysiology

• Multifactorial anatomic and biomechanical factors
  • Overuse injuries caused or limited by
    • Microtrauma from repetitive motion leading to periosteal inflammation
    • Overpronation of the subtalar joint and tight gastrocnemius/soleus complex with increased eccentric loading of musculature inserting along the medial shin
    • Interosseous membrane pain
    • Periostitis
    • Tears of collagen fibers
    • Enthesopathy
  • Anatomic structures affected include the following:
    • Flexor hallucis longus
    • Tibialis anterior
    • Tibialis posterior
    • Soleus
    • Crural fascia
• Pathogenesis is theorized to be due to the following:
  • Calf muscle traction on periosteum
  • Persistent repetitive loading on tibia, which leads to inadequate bone remodeling with subsequent tibial cortex changes
  • Possible microfissures causing pain without evidence of fracture or ischemia

Risk Factors

• Intrinsic (personal) risk factors (1):
  • Greater ranges of internal and external (>65 degrees) hip rotation
  • Significant overpronation at the ankle
  • Imbalance of musculature of the ankle and foot (inversion/eversion misbalance)
  • Female gender
  • Lean calf girth
  • Femoral neck anteversion
  • Navicular drop
  • Genu varum
  • History of previous MTSS
• External (environmental) risk factors (1):
  • Lack of physical fitness
  • Inexperienced runners—particularly those with rapid increases in mileage and inadequate prior conditioning
  • Excessive overuse or distance running, particularly on hard or inclined (crowned) surfaces
  • Prior injury
  • Equipment (shoe) failure
• Other risk factors:
  • Elevated BMI
  • Lower bone mineral density
  • Tobacco use
• Those typically affected by MTSS include the following:
  • Runners
  • Military personnel—common in recruit/boot camp
  • Gymnasts, soccer, and basketball players
  • Ballet dancers

General Prevention

• Proper technique for guided calf stretching and lower extremity strength training, although supplementary gastrocnemius and soleus stretching has no statistical significance in reducing risk of shin splints
• Rehabilitate prior injuries adequately.
• Other recommendations
  • Gait analysis and retraining, particularly for overpronation
  • Orthotic footwear inserts were found to be preventative in naval recruits.

Commonly Associated Conditions

Pes planus (flat feet)