The Centers for Advanced Orthopaedics
Maryland Orthopedic Specialists
A Division of The Centers for Advanced Orthopaedics
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Knee

Pes Anserine Bursitis

Pes anserine bursitis is a common but underdiagnosed source of medial knee pain located below the joint line — not at the joint line. It is particularly prevalent in overweight or obese patients with knee osteoarthritis and is frequently mistaken for an OA flare or a meniscal problem. Identifying and treating pes anserine bursitis separately from the underlying joint disease leads to faster, more targeted symptom relief. At Maryland Orthopedic Specialists, our physicians carefully distinguish bursitis from intra-articular pathology and tailor treatment to address both.

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What is pes anserine bursitis?

The pes anserine ("goose's foot") is the combined insertion of three medial knee tendons — the sartorius, gracilis, and semitendinosus — onto the proximal medial tibia, approximately 2–3 cm below and medial to the tibial joint line. The pes anserine bursa sits between this combined tendon and the proximal tibial shaft and medial collateral ligament.

The pes anserine ("goose's foot") is the combined insertion of three medial knee tendons — the sartorius, gracilis, and semitendinosus — onto the proximal medial tibia, approximately 2–3 cm below and medial to the tibial joint line. The pes anserine bursa sits between this combined tendon and the proximal tibial shaft and medial collateral ligament. Repetitive friction and compression from altered gait mechanics, obesity, or valgus knee alignment leads to bursal inflammation.

Risk factors and associated conditions:

  • Knee osteoarthritis — the most common associated condition; altered gait mechanics and medial compartment overloading predispose the bursa to irritation
  • Obesity — increases compressive forces across the medial knee
  • Flat feet (pes planus) — valgus stress applied to the medial knee structures
  • Diabetes mellitus — independently associated with pes anserine bursitis
  • Tight hamstrings — the semitendinosus component of the pes is part of the hamstring group; tightness increases bursal shear forces
  • Running, cycling, and swimming (breaststroke kick)

Treatment options

Pes anserine bursitis almost always responds to conservative management — the key is addressing both the bursal inflammation and the underlying biomechanical and arthritic contributors. Surgery is rarely needed, and the great majority of patients achieve lasting relief through a combination of physical therapy, injections, and management of co-existing knee osteoarthritis.

Physical Therapy

Physical therapy is the foundation of long-term recovery and focuses on correcting the mechanical factors that drive bursal irritation. Targeted hamstring and quadriceps stretching reduces traction forces at the pes anserine footprint, while hip abductor and external rotator strengthening decreases the valgus stress transmitted to the medial knee with each step. Gait retraining further minimizes medial compartment loading during daily activities. For patients who are obese or weight-restricted and cannot tolerate land-based exercise, aquatic therapy provides an effective, low-impact alternative that achieves the same therapeutic goals.

Corticosteroid Injection

Ultrasound-guided corticosteroid injection into the pes anserine bursa is highly effective and typically provides 70–90% short-term pain relief. Ultrasound guidance is important because the bursa is not reliably palpable on clinical examination, and blind injections frequently miss the target; real-time imaging ensures accurate bursal placement and maximizes the therapeutic effect. Repeat injections are appropriate when the initial response is good but symptoms recur over time, and injections are most effective when combined with a concurrent physical therapy program to address the biomechanical contributors.

Treating the Underlying Cause

Because pes anserine bursitis is so frequently driven by co-existing knee osteoarthritis, managing the OA directly is an essential part of treatment. Weight loss reduces medial compartment compressive forces and is one of the most impactful interventions available; physical therapy, NSAIDs, and knee joint injections address the intra-articular inflammation that contributes to secondary bursal irritation. When a bursal fluid collection is tense and acutely painful, aspiration — combined with corticosteroid injection at the same visit — provides immediate relief and can accelerate the response to subsequent conservative care.

Surgical Procedure

Knee Arthroscopy

Minimally invasive joint scope using small portals to directly visualize and treat intra-articular knee pathology — meniscal tears, cartilage defects, loose bodies, synovitis, and ligament assessment — as an outpatient procedure.

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Frequently Asked Questions

How do I know if my medial knee pain is bursitis or a meniscus tear?
Location is the key distinguishing feature: pes anserine bursitis produces tenderness 2–3 cm below the joint line on the medial tibia, while medial meniscal tears produce joint-line tenderness. Both conditions can coexist, particularly in patients with knee OA, and MRI or arthroscopy may be needed to fully characterize the pain source.
Will losing weight help my pes anserine bursitis?
Yes — obesity is an independent risk factor for both pes anserine bursitis and knee OA. Weight reduction reduces medial compartment compressive forces and is one of the most effective long-term strategies for managing both conditions.
What treatments are available for pes anserine bursitis?
Most cases of pes anserine bursitis respond well to conservative treatment. Initial management typically includes activity modification, ice application, anti-inflammatory medications, and physical therapy to address any underlying hip or knee muscle weakness. If symptoms persist, a corticosteroid injection into the bursa provides rapid pain relief for most patients. Surgery to remove the bursa is rarely necessary and is reserved for cases that have failed all non-operative measures over an extended period.
How long does pes anserine bursitis last?
With appropriate treatment, most patients experience significant improvement within four to eight weeks. However, pes anserine bursitis frequently recurs if the contributing factors — such as obesity, osteoarthritis, or tight hamstrings — are not addressed. Addressing these underlying factors through weight management, knee arthritis treatment, and ongoing stretching and strengthening exercises gives you the best chance of long-term relief. Your MOS provider will help develop a plan that targets the root cause, not just the immediate pain.
Is pes anserine bursitis related to my knee arthritis?
Yes, there is a well-established association between pes anserine bursitis and knee osteoarthritis, particularly in overweight patients. The altered gait and joint mechanics caused by arthritis can increase stress on the pes anserine tendons and bursa over time. Treating the arthritis — whether through injections, physical therapy, bracing, or eventually knee replacement — often reduces the recurrence of bursitis flares. At MOS we evaluate the knee as a whole to ensure both conditions are addressed together.

Meet the specialists

Christopher S. Raffo, MD

Christopher S. Raffo, MD

Orthopedic Surgery · Sports Medicine

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John J. Christoforetti, MD

John J. Christoforetti, MD

Orthopedic Surgery · Sports Medicine · Hip Preservation Surgery

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James S. Gardiner, MD

James S. Gardiner, MD

Orthopedic Surgery · Sports Medicine

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Related conditions

Knee OsteoarthritisMeniscus Tear
Medically reviewed by Christopher S. Raffo, MD
Last reviewed May 1, 2026

References

  1. Rennie WJ, Saifuddin A. "Pes anserine bursitis: incidence in symptomatic knees and clinical presentation." Skeletal Radiology. 2005;34(7):395–398. doi:10.1007/s00256-005-0918-7
  2. Alvarez-Nemegyei J, Canoso JJ. "Evidence-based soft tissue rheumatology: III. Pes anserine bursitis." Journal of Clinical Rheumatology. 2004;10(4):215–216. doi:10.1097/01.rhu.0000134534.69870.b8
  3. de Oliveira Silva D, et al. "Pes anserine pain and soft tissue swelling: the need for a standard definition in knee osteoarthritis research." BMC Musculoskeletal Disorders. 2019;20(1):235. doi:10.1186/s12891-019-2614-4
  4. OrthoInfo — AAOS. "Pes Anserine Bursitis (Knee)." American Academy of Orthopaedic Surgeons. https://orthoinfo.aaos.org/en/diseases--conditions/pes-anserine-bursitis-knee