Shin Splints

Medial tibial stress syndrome: exercise induced pain along the posteromedial border of the distal two thirds of the tibia, from periosteal and bone stress reaction at the soleus and tibialis posterior attachments. It lies on a continuum with tibial stress fracture.

• It accounts for about 13 to 17% of running injuries and up to 20 to 35% of injuries in military recruits and dancers. Common in runners, soldiers, dancers, and athletes in jumping and field sports.
• Risk factors: female sex, previous history, high body mass index, increased navicular drop and pronated foot, increased internal or external hip rotation range, sudden increase in training, hard surfaces, poor footwear, low bone density, calcium and vitamin D deficiency, and the relative energy deficiency seen in athletes with low energy availability, amenorrhoea and low bone density.
• Most cases settle with 2 to 6 weeks of relative rest and graded loading, though about 10% persist or progress to stress fracture.

• Diffuse, dull, aching pain over at least 5 cm of the posteromedial tibial border, usually in the middle to lower third, starting at the beginning of exercise, easing during warm up and returning afterward. In later stages, the pain is present during activity and with walking, and may disturb rest.
• Examination: diffuse tenderness along the posteromedial tibial border over 5 cm or more, mild swelling, pain on resisted plantarflexion and toe raises, pain on single leg hopping that is mild and diffuse, and often a pronated foot and tight calf. Neurovascular examination is normal.
• Differential diagnosis: tibial stress fracture (focal tenderness over 2 to 3 cm, pain on hopping, pain at rest and at night, percussion pain), chronic exertional compartment syndrome (tightness and cramping at a consistent point in exercise, with numbness or foot drop, which resolves within 15 to 30 minutes of rest), popliteal artery entrapment (calf claudication in young athletes, reduced pulses with plantarflexion), tibialis posterior tendinopathy, nerve entrapment, fascial herniation, deep vein thrombosis, osteomyelitis, bone tumour (osteoid osteoma, Ewing sarcoma), and referred lumbar pain.
• Red flags: focal bony tenderness, night or rest pain, pain on walking, swelling and warmth, fever, unexplained weight loss, and a history of cancer.
• Complications: stress fracture, chronic recurrence, prolonged absence from sport, and a displaced tibial fracture if loaded.

• Clinical. Ask about training changes, surfaces, shoes, menstrual history, diet, previous fracture and family history of osteoporosis.
• X-ray is usually normal early, and a positive finding appears after 2 to 4 weeks (periosteal reaction or cortical thickening). It is requested when focal tenderness or persistent pain suggests a stress fracture.
• MRI is the best test: periosteal oedema without a fracture line in shin splints, and marrow oedema with a fracture line in stress fracture. Bone scintigraphy shows a diffuse linear tracer uptake in shin splints and a focal intense uptake in stress fracture.
• For exertional compartment syndrome: post-exercise compartment pressure measurement (resting pressure above 15 mmHg, or above 30 mmHg at 1 minute, or above 20 mmHg at 5 minutes after exercise).
• In women athletes with recurrent bone stress injuries, check ferritin, 25-hydroxyvitamin D, calcium, thyroid function, menstrual history, and consider a bone density scan.

• Relative rest for 2 to 6 weeks: stop running and impact, and replace with low impact cross training (swimming, deep water running, cycling, elliptical) that does not provoke pain. Return to running is staged and begins when walking, hopping and stairs are pain free.
• Analgesia and symptom relief: ice for 10 to 15 minutes after activity, paracetamol 1 g orally 6 hourly. NSAIDs have limited value and may delay bone healing, so use ibuprofen 400 mg 8 hourly with food only for short periods (3 to 5 days) if needed, or topical diclofenac 1% gel.
• Rehabilitation:
  • Calf stretching (gastrocnemius and soleus) and calf strengthening (double then single leg heel raises, 3 sets of 15, progressing to loaded and slow eccentric), tibialis posterior and anterior strengthening, and foot intrinsic strengthening.
  • Hip abductor and core strengthening, and correction of poor landing and running mechanics.
  • Orthoses: a prefabricated or custom insole for pronated feet, or a compression sleeve, may reduce pain. Shock absorbing insoles for hard surfaces.
  • Footwear review: replace running shoes every 500 to 800 km.
• Graded return to running: walk run intervals on soft flat surfaces, beginning at 10 to 20 minutes with 1 minute of running and increasing weekly by about 10%, every second day, with no more than mild pain (2 out of 10) that settles within 24 hours. Full return usually takes 6 to 12 weeks.
• Adjuncts with limited evidence: extracorporeal shock wave therapy (3 to 5 weekly sessions) for persistent disease, and periosteal pecking or fasciotomy (posteromedial fascia release) in refractory cases after 6 to 12 months, with variable success of about 60 to 80%.
• Stress fracture: stop impact, protected weight bearing or a pneumatic boot for 4 to 8 weeks for posteromedial lesions, and urgent orthopaedic review for anterior tibial cortex ("dreaded black line") fractures, which have a high risk of delayed union and complete fracture and need intramedullary nailing in athletes or non-union. Correct vitamin D deficiency with cholecalciferol 1000 to 2000 IU daily (or a loading dose of 50,000 IU weekly for 6 to 8 weeks if below 30 nmol/L) and calcium intake of 1000 to 1300 mg daily.
• Chronic exertional compartment syndrome: confirmed by pressure measurement, treated by fasciotomy in athletes who fail activity modification, with about 80 to 90% success.
• Prevention: gradual increase in training load (no more than 10% weekly), suitable footwear, varied surfaces, adequate energy intake and bone health, and strength training.
• Special groups:
  • Female athletes: assess for low energy availability, menstrual disturbance and low bone density. Nutritional rehabilitation is a core part of treatment.
  • Adolescents: monitor growth and avoid early specialisation.
  • Military recruits: gradual load progression and footwear fitting.
  • Pregnancy: low impact activity, paracetamol, and calcium and vitamin D adequacy.
• Follow up: review at 2 to 4 weeks. Refer to sports medicine or orthopaedics for focal bony tenderness, failure to improve by 6 weeks, suspected stress fracture, compartment syndrome or recurrent disease.