Shin pain, a common complaint among individuals engaged in physical activities, often arises due to changes in the intensity or type of exercise. The most frequent conditions associated with shin pain include:
The assessment involves a detailed history and physical examination:
- History: Inquiries should focus on exercise patterns, changes in intensity and type, and a detailed account of the pain and swelling, including location, onset, and progression. Other relevant factors include footwear, training surfaces, past foot problems, weight changes, and any history of malignancy.
- Risk Factors: These encompass excessive alcohol consumption, bisphosphonate use, inadequate rest periods, the female athlete triad syndrome, low vitamin D levels, recreational running over 40 km per week, smoking, sudden increases in physical activity, and track running.
- Physical Examination: This includes an evaluation of gait, palpation for tenderness and swelling, and assessment of the range of motion. Special attention should be given to signs indicative of full tibial shaft fracture, shin splints, tibial stress fracture, exertional compartment syndrome, fibula stress fracture, tarsal navicular stress fracture, and metatarsal stress fracture.
- Imaging: X-rays, nuclear medicine bone scans, or MRIs may be employed for diagnostic confirmation, particularly if there's suspicion of a stress fracture.
- Differential Diagnosis: This should include a consideration of other musculoskeletal disorders, nerve or artery entrapment, compartment syndromes, avascular necrosis, neoplasms, and infections.
- Medial tibial stress syndrome - This is a prevalent cause of leg pain in athletes, typically linked to biomechanical abnormalities. The progression of MTSS is characterized initially by pain during exertional activities, which gradually begins to occur with less intense activities and eventually even at rest. Typically there is diffuse tenderness along the length of the posteromedial tibial shaft and a lack of oedema. The patient will commonly have a tight Achilles tendon and pes planus. In the early stages the pain decreases with exercise.
- Tibial stress fracture - These injuries result from repetitive stress on normal or abnormal bone, leading to microfractures. There is tenderness over a specific area along with swelling
- Exertional compartment syndrome - This condition involves swelling of the tibialis anterior muscle, potentially leading to muscle ischemia. The pain is generally aching or burning and experienced in the lateral shin that comes on with exercise and is relieved with rest. Patients may describe the exact degree of exercise that can bring it on and how long it will last after stopping exercise. The patient may have numbness in the great toe.
- Fibula stress fracture - Presents in patients undertaking excessive training along with poor footwear on an irregular terrain. There may be inflexibility or weakness of the calf muscles leading to uneven distribution of stress. Anatomic variances may be found such as leg length discrepancy, pes planus, or pes cavus. There is localised tenderness over the site of the fracture. The pain is worsened with exercise.
- Tendinopathy or enthesopathy
- Radicular pain or local nerve entrapment
- Peripheral vascular disease
- Avascular necrosis
- Neoplasm (osteosarcoma, metastasis)
Obtain an x-ray or other appropriate imaging if there is suspicion of a stress fracture. X-rays may show a stress fracture between 2-12 weeks of symptom onset. Bone scan or MRI may be considered if suspicion remains.
Management strategies vary based on the specific diagnosis:
- For Full Tibial Shaft Fracture: Immediate orthopaedic consultation is necessary.
- For Shin Splints: The patient should avoid aggravating activities for 8-10 weeks. Running distance and frequency should be reduced by 50%. Use low impact and cross-training exercise during the rehabilitation period and undertake regular stretching and strengthening. Running on a synthetic track may reduce symptoms. Avoid hills, uneven, or hard surfaces. Consider podiatry assessment for persistent symptoms.
- For Tibial Stress Fracture: Similar to shin splints, with an emphasis on the potential long healing time. Stress fractures can take up to a year to fully heal.
- For Exertional Compartment Syndrome: Rest, shoe cushioning, NSAIDs, and potentially orthopaedic assessment for surgery if conservative treatments fail.
- For Fibula Stress Fracture: Weight-bearing as tolerated, limited walking, and possibly physiotherapy. Non-weight bearing exercise is preferred such as swimming.
Referrals should be considered in cases of full tibial shaft fractures, persistent symptoms post-conservative treatment, high-level athletes, and for specific assessments in shin splints, tibia or fibula stress fractures, and metatarsal stress fractures requiring specific bracing or orthotic interventions.