Differential Diagnosis for Proximal Medial Tibial Pain in a New Runner

Single Most Likely Diagnosis

• Medial Tibial Stress Syndrome (MTSS): This is the most common cause of proximal medial tibial pain in runners, especially new runners who have recently increased their mileage or intensity. MTSS is characterized by pain and inflammation in the medial (inner) aspect of the tibia, often due to overuse or repetitive stress.

Other Likely Diagnoses

• Stress Fracture: A stress fracture of the tibia can cause pain in the proximal medial area, especially if the runner has recently changed their training regimen or has a history of osteoporosis or other risk factors for stress fractures.
• Shin Splints (Periostitis): While often used interchangeably with MTSS, shin splints can refer to inflammation of the periosteum, the layer surrounding the bone, which can cause pain in the medial tibial area.
• Overuse Injury (Muscle Strain): Strains of the muscles in the lower leg, such as the tibialis posterior or flexor digitorum longus, can cause pain in the proximal medial tibial area, especially if the runner has recently increased their activity level.

Do Not Miss Diagnoses

• Deep Vein Thrombosis (DVT): Although less common, DVT can cause pain and swelling in the lower leg, including the proximal medial tibial area. It is essential to consider DVT in the differential diagnosis, especially if the runner has risk factors such as recent travel, immobilization, or family history.
• Compartment Syndrome: Acute or chronic compartment syndrome can cause pain, swelling, and weakness in the lower leg, including the proximal medial tibial area. This condition requires prompt medical attention to prevent long-term damage.
• Osteomyelitis: Infection of the bone can cause pain, swelling, and redness in the affected area, including the proximal medial tibia. Although rare, osteomyelitis is a serious condition that requires prompt diagnosis and treatment.

Rare Diagnoses

• Tumor (e.g., Osteosarcoma): Although extremely rare, a tumor in the proximal medial tibia can cause pain and swelling in the area. This diagnosis should be considered if the pain is persistent, worsening, or accompanied by other systemic symptoms such as weight loss or fatigue.
• Nerve Entrapment (e.g., Tibial Nerve Entrapment): Entrapment of the tibial nerve can cause pain, numbness, and tingling in the lower leg, including the proximal medial tibial area. This diagnosis should be considered if the runner experiences neurological symptoms in addition to pain.