> Table of Contents > Bursitis, Pes Anserine (Pes Anserine Syndrome)
Bursitis, Pes Anserine (Pes Anserine Syndrome)
Jennifer B. Schwartz, MD
image BASICS
DESCRIPTION
  • The pes anserinus (“goosefoot”) is the combined insertion of the sartorius, gracilis, and semitendinosus (“SGT”-from medial to lateral) tendons on the anteromedial tibia.
  • The pes anserine muscles help flex the knee and resist valgus stress
  • The pes anserine bursa lies deep to the SGT tendons and superficial to the tibial attachment of the medial collateral ligament.
  • Pes anserine syndrome is due to irritation of the bursa and/or tendons in this area
EPIDEMIOLOGY
Incidence
Inflammation of the pes anserine bursa is detected in up to 2.5% of MRI studies of patients with knee pain. The overall incidence is likely higher.
ETIOLOGY AND PATHOPHYSIOLOGY
Pes anserine bursitis occurs due to:
  • Overuse injury
  • Excessive valgus and rotary stresses
  • Mechanical forces and degenerative changes
  • Direct trauma
RISK FACTORS
  • Obesity
  • Age, female gender
  • Pes planus; genu valgum
  • Knee joint laxity/ligamentous injury
  • Long distance running, hill running; change in mileage
  • Swimming (“breaststroker's knee”); cycling
  • Sports with side-to-side (cutting) activity (soccer, basketball, racquet sports)
COMMONLY ASSOCIATED CONDITIONS
  • Osteoarthritis (OA)
    • Knee pain due to OA is often associated with pes anserine bursitis, both of which may need specific treatment.
    • Higher grades of OA associated with a thicker pes anserine bursa and larger area of bursitis (1,2)[C]
  • Valgus knee deformity
  • Obesity
  • Diabetes mellitus (questionable association)
image DIAGNOSIS
PHYSICAL EXAM
  • Common findings include:
    • Tenderness to palpation at the pes anserine insertion
      • 30% of asymptomatic patients will have tenderness to deep palpation in this area.
    • Pain worsens with flexion of the knee against resistance.
    • Localized swelling of the pes anserine insertion
  • Findings that suggest an alternative diagnosis: joint effusion, tenderness directly over the joint line, erythema or warmth, locking of the knee, systemic signs such as fever or pain with passive knee movement
DIFFERENTIAL DIAGNOSIS
  • Medial collateral ligament injury
  • Medial meniscal injury
  • Medial plica syndrome
  • Medial compartment OA
  • Semimembranosus bursitis
  • Popliteal/meniscal cyst
  • Tibial stress fracture
  • Septic arthritis
DIAGNOSTIC TESTS & INTERPRETATION
Initial Tests (lab, imaging)
  • Primarily a clinical diagnosis
  • Lab work not indicated. If infection is suspected: CBC, ESR, C-reactive protein, and joint fluid analysis are indicated.
  • Imaging is not indicated unless there is concern for bony injury/fracture, ligamentous injury, or meniscal tear.
Follow-Up Tests & Special Considerations
  • Ultrasound (US)
    • Can demonstrate focal edema within the pes anserine bursa but has poor correlation with clinical findings
    • Many patients with the clinical diagnosis of pes anserine bursitis have no morphologic changes of the pes anserine complex on US (3)[C].
  • MRI: can demonstrate inflammation of the bursa, and delineate the pes anserine bursa from other structures. T2-weighted axial images are best on MRI (4)[C].
    • No large studies have evaluated the correlation between the clinical diagnosis of pes anserine bursitis and radiographic evidence of pes anserine pathology on MRI.
    • May see fluid in the pes bursa on MRI in 5% of asymptomatic patients (5)[C]
image TREATMENT
Pes anserine bursitis is often self-limited. Conservative therapy is most common:
  • Relative rest and activity modification to avoid offending movements (especially knee flexion)
  • Ice to the affected area
  • Physical therapy for knee strengthening and range of motion activities
  • NSAIDs for pain control
  • Corticosteroid injection for pain relief and as an antiinflammatory
  • Weight loss to improve biomechanical forces at the knee
MEDICATION
First Line
NSAIDs, such as ibuprofen (800 mg PO TID) or naproxen (500 mg PO BID), are common 1st-line therapy.
Second Line
  • Corticosteroid injection combined with local anesthetic provides relief in many patients (6)[C].
    • Inject at the point of maximal tenderness using standard aseptic technique
    • ˜2 mL of anesthetic (i.e., 1% lidocaine) and 1 mL of steroid (i.e., 40 mg of methylprednisolone ) is injected into the bursa using a small (e.g., 25-gauge, 1-inch) needle.
    • P.155

    • Insert needle perpendicular to the skin until bone is felt and then withdraw slightly before injecting.
    • Avoid injecting directly into the tendon (7)[C].
  • US-guided injection is superior to blind injection (8)[C].
  • Platelet-rich plasma injections also provide pain relief (9)[C].
  • Injection of steroid and anesthetic provides pain relief, which allows for physical therapy and rehabilitative efforts.
ADDITIONAL THERAPIES
Physical therapy
  • Hamstring and Achilles stretching
  • Quadriceps strengthening—particularly of the vastus medialis (terminal 30 degrees of knee extension)
  • Adductor strengthening
SURGERY/OTHER PROCEDURES
  • No role for surgery in routine isolated cases
  • Drainage or removal of bursa may be used in severe/refractory cases.
image ONGOING CARE
Home exercise program focusing on flexibility and strengthening
DIET
Consider dietary changes as part of a comprehensive weight-loss program if obesity is a contributing factor.
PROGNOSIS
Most cases of pes anserine syndrome respond to conservative therapy. Recurrence is common, and multiple treatments may be required.
REFERENCES
1. Toktas H, Dundar U, Adar S, et al. Ultrasonographic assessment of pes anserinus tendon and pes anserinus tendinitis bursitis syndrome in patients with knee osteoarthritis. Mod Rheumatol. 2015;25(1):128-133.
2. Uysal F, Akbal A, Gökmen F, et al. Prevalence of pes anserine bursitis in symptomatic osteoarthritis patients: an ultrasonographic prospective study. Clin Rheumatol. 2015;34(3):529-533.
3. Helfenstein M Jr, Kuromoto J. Anserine syndrome [in English, Portuguese]. Rev Bras Reumatol. 2010;50(3):313-327.
4. Chatra PS. Bursae around the knee joints. Indian J Radiol Imaging. 2012;22(1):27-30.
5. Rennie WJ, Saifuddin A. Pes anserine bursitis: incidence in symptomatic knees and clinical presentation. Skeletal Radiol. 2005;34(7):395-398.
6. Yoon HS, Kim SE, Suh YR, et al. Correlation between ultrasonographic findings and the response to corticosteroid injection in pes anserinus tendinobursitis syndrome in knee osteoarthritis patients. J Korean Med Sci. 2005;20(1):109-112.
7. Stephens MB, Beutler AI, O'Connor FG. Musculoskeletal injections: a review of the evidence. Am Fam Physician. 2008;78(8):971-976.
8. Finnoff JT, Nutz DJ, Henning PT, et al. Accuracy of ultrasound-guided versus unguided pes anserinus bursa injections. PM R. 2010;2(8):732-739.
9. Rowicki K, Płomiński J, Bachta A. Evaluation of the effectiveness of platelet rich plasma in treatment of chronic pes anserinus pain syndrome. Ortop Traumatol Rehabil. 2014;16(3):307-318.
Additional Reading
  • Alvarez-Nemegyei J. Risk factors for pes anserinus tendinitis/bursitis syndrome: a case control study. J Clin Rheumatol. 2007;13(2):63-65.
  • Wittich CM, Ficalora RD, Mason TG, et al. Musculoskeletal injection. Mayo Clin Proc. 2009;84(9): 831-836; quiz 837.
Codes
ICD10
  • M70.50 Other bursitis of knee, unspecified knee
  • M70.51 Other bursitis of knee, right knee
  • M70.52 Other bursitis of knee, left knee
Clinical Pearls
  • Consider pes anserine syndrome in patients presenting with medial knee pain.
  • Pes anserine syndrome is relatively common in athletes and in older, obese patients with OA.
  • Tenderness over the insertion of the pes anserine tendon on the medial aspect of the tibia 4 to 6 cm distal to the joint line is common in asymptomatic patients as well—correlation of the entire clinical picture is necessary for accurate diagnosis.
  • Consider pes anserine syndrome in patients who have persistent symptoms associated with medialsided OA
  • Treatment is typically conservative. A local steroid/anesthetic injection may provide pain relief and enhance rehabilitation.