Differential Diagnosis for Injury and Insertional Achilles Pain

• Single most likely diagnosis
  • Achilles Tendinosis/Tendinitis: This is the most common cause of insertional Achilles pain, often resulting from overuse or repetitive strain on the tendon, leading to inflammation and degeneration.
• Other Likely diagnoses
  • Achilles Tendon Rupture: Although more commonly associated with sudden, severe pain and a palpable gap in the tendon, partial ruptures can present with insertional pain.
  • Haglund's Deformity: A bony prominence at the back of the heel can cause irritation and pain at the insertion of the Achilles tendon.
  • Retrocalcaneal Bursitis: Inflammation of the bursa located between the Achilles tendon and the calcaneus can cause pain in the insertional area.
• Do Not Miss diagnoses
  • Infectious Tendinitis: Although rare, infections such as those caused by bacterial or fungal pathogens can lead to severe consequences if not promptly treated.
  • Tumor or Cyst: Rarely, tumors or cysts can occur in the Achilles tendon or surrounding tissues, causing pain and necessitating early diagnosis for appropriate management.
• Rare diagnoses
  • Seronegative Spondyloarthropathies (e.g., Ankylosing Spondylitis, Psoriatic Arthritis): These conditions can cause enthesitis, leading to insertional Achilles pain, but are less common causes.
  • Rheumatoid Arthritis: Although more commonly associated with small joint inflammation, rheumatoid arthritis can also cause insertional Achilles tendinitis.
  • Gout or Pseudogout: Crystal deposition diseases can rarely cause insertional Achilles pain due to deposition of urate or pyrophosphate crystals in the tendon or surrounding bursae.