Bursitis, Pes Anserine (Pes Anserine Syndrome)
Basics
- Pes anserinus: insertion site of sartorius, gracilis, semitendinosus tendons on anteromedial tibia, ~5 cm distal to medial joint line
- These muscles flex the knee and stabilize against valgus/rotational stress
- Bursa lies deep to pes anserinus and medial collateral ligament (MCL)
- Tendino-bursitis includes irritation of bursa and/or tendons; clinically hard to distinguish
Etiology and Pathophysiology
- Excessive valgus and rotational knee stresses (overuse, biomechanical)
- Degenerative changes
- Direct trauma
Risk Factors
- Middle-aged, overweight females (more common)
- Pes planus, genu valgum
- Activities: long-distance/hill running, cycling, swimming ("breaststroker's knee")
- Sports with cutting/side-to-side movements (soccer, basketball, racquet sports)
General Prevention
- Avoid repetitive valgus/rotational knee stresses
- Address biomechanical abnormalities
- Weight control
- Hamstring stretching
Commonly Associated Conditions
- Osteoarthritis (OA), especially medial compartment
- Medial meniscal tear
- Type 2 diabetes, rheumatoid arthritis, gout (in chronic cases)
Diagnosis
History
- Medial knee pain 4–6 cm below medial joint line at pes anserine insertion
- Pain worsened by knee flexion: stairs, rising from chair, sitting cross-legged
Physical Exam
- Tenderness/swelling at pes anserine insertion
- Pain with resisted knee flexion
- Examine for alternative diagnoses: joint effusion, joint line tenderness, locking, systemic signs (fever)
Differential Diagnosis
- Medial compartment OA
- MCL injury
- Medial meniscal injury
- Medial plica syndrome
- Tibial stress fracture
- Septic arthritis
Diagnostic Tests
- Primarily clinical diagnosis
- Imaging not routinely required unless suspect fracture, ligament, or meniscal injury
- X-ray: assess OA
- Ultrasound: can show bursal edema, though may not correlate clinically
- MRI (T2 axial): may show fluid in bursa; not always correlates with symptoms
Treatment
General Measures
- Usually self-limited; conservative therapy preferred
- Relative rest and activity modification avoiding offending knee flexion
- Ice application
- NSAIDs for pain control
- Physical therapy: strengthening and addressing underlying pathology
- Kinesio taping may be more effective than PT + NSAIDs for pain reduction
- Weight loss for biomechanical improvement
Medications
- First line:
- NSAIDs (e.g., ibuprofen 800 mg TID, naproxen 500 mg BID)
- Corticosteroid injection with local anesthetic: ~2 mL lidocaine + 1 mL methylprednisolone, aseptic technique, US-guided preferred
- Second line:
- Platelet-rich plasma injections for pain relief
Additional Therapies
- Hamstring and Achilles stretching
- Quadriceps and adductor strengthening
Surgery
- No routine role in isolated cases
- Bursa drainage/removal for severe/refractory cases
Ongoing Care
- Physical therapy with home exercise program focusing on flexibility and strength
Diet
- Weight loss strategies if obesity contributes
Prognosis
- Most respond well to conservative treatment
- Recurrence common; may require multiple treatments
References
- Atici A, Ulger FEB, Akpinar P, et al. Poor accuracy of clinical diagnosis in pes anserine tendinitis bursitis syndrome. Indian J Orthop. 2021;56(1):116-124.
- Homayouni K, Foruzi S, Kalhori F. Effects of kinesiotaping versus NSAIDs and PT for pes anserinus tendino-bursitis: a randomized trial. Phys Sportsmed. 2016;44(3):252-256.
- Majidi L, Saeb F, Alaei B, et al. Local corticosteroid injection vs extracorporeal shockwave therapy for pes anserine bursitis: RCT. Med J Islam Repub Iran. 2023;37:10.
Clinical Pearls
- Consider pes anserine syndrome in patients with medial knee pain, especially with medial OA
- Tenderness at pes anserine insertion common even in asymptomatic patients; correlate clinically
- Conservative treatment with PT or kinesio taping effective
- Corticosteroid/anesthetic injection offers temporary pain relief and aids rehab
- Extracorporeal shock wave therapy is a safe, effective alternative