Description

• The pes anserinus is the combined insertion of the sartorius, gracilis, and semitendinosus tendons on the anteromedial tibia (approximately 5 cm distal to the medial joint line).
  • The sartorius, gracilis, and semitendinosus muscles help flex the knee and also protect the knee against valgus and rotational stresses.
• The pes anserine bursa lies deep to the pes anserinus and the medial collateral ligament (MCL).
• Pes anserine tendino-bursitis (PATB) is due to irritation of the bursa and/or tendons in this area. Clinically, it is difficult to distinguish pes anserine tendonitis from pes anserine bursitis due to proximity of the structures.

Etiology and Pathophysiology

PATB is thought to occur due to the following:

• Excessive valgus and rotational stresses on the knee (due to overuse or underlying biomechanical factors)
• Degenerative changes
• Direct trauma

Risk Factors

• More common in middle age, overweight females
• Other risk factors include the following:
  • Pes planus; genu valgum
  • Long distance/hill running, cycling, swimming (“breaststroker’s knee”)
  • Sports with side-to-side/cutting activity (soccer, basketball, racquet sports)

General Prevention

• Avoid repetitive valgus/rotational stresses to the knee and treat underlying biomechanical risk factors
• Control weight
• Adequate hamstring stretching

Commonly Associated Conditions

• Osteoarthritis (OA)
  • Increased incidence of PATB in patients with symptomatic OA; PATB commonly contributes to knee pain in patients with OA.
  • Higher grades of OA are associated with a thicker pes anserine bursa and a larger area of bursitis.
• Medial meniscal tear
• Type 2 diabetes, rheumatoid arthritis, gout (chronic PATB)