Pes Anserine Bursitis: Symptoms, Causes, Diagnosis & Physiotherapy Treatment
What Is Pes Anserine Bursitis?
Pes anserine bursitis is a painful condition involving inflammation of the pes anserine bursa — a small, fluid-filled sac located on the inner side of the knee, just below the joint. This bursa sits between the shinbone (tibia) and the conjoined tendons of three muscles: the sartorius, gracilis, and semitendinosus.
The name “pes anserinus” comes from the Latin term for “goose’s foot,” referring to the webbed, fan-like shape formed where these three tendons merge and attach to the shin bone. When this bursa becomes irritated, it produces excess fluid, causing it to swell and exert pressure on the surrounding structures — resulting in pain and discomfort on the medial (inner) side of the knee, typically 2 to 3 inches below the knee joint.
The three muscles involved each play a distinct role in leg movement:
Sartorius — The longest muscle in the human body, running diagonally across the front of the thigh. It assists in bending both the knee and the hip.
Gracilis — A hip adductor that draws the leg inward toward the body’s midline.
Semitendinosus — One of the three hamstring muscles, primarily responsible for bending the knee.
What Are the Symptoms of Pes Anserine Bursitis?
Unlike acute injuries, pes anserine bursitis symptoms typically develop gradually rather than appearing suddenly. Many patients notice the pain worsening with physical activity, particularly climbing stairs, running, or stretching the hamstrings.
Common symptoms include:
Pain and Tenderness — A dull, aching pain develops on the inside of the knee or along the upper shinbone, approximately 2–3 inches below the joint line. The area is often tender to touch.
Knee Swelling — Localized swelling may be visible or felt around the inner knee.
Pain with Activity — Discomfort intensifies with exercise, climbing stairs, running, or resisted knee flexion.
Stiffness and Weakness — The knee may feel stiff, especially in the morning or after prolonged rest.
Sleep Disturbance — Night-time pain is common, particularly when the knees press against each other while sleeping.
How Does the Bursa Become Inflamed?
When there is excessive pressure at the insertion of the pes anserinus tendons, the bursa releases more synovial fluid than usual. This accumulation of fluid leads to swelling, inflammation, and pain — the hallmarks of bursitis. Continuous friction or mechanical irritation at this site perpetuates the cycle of inflammation.
What Are the Causes of Pes Anserine Bursitis?
Pes anserine bursitis typically results from repetitive friction or stress over the inner knee region. Several factors can increase the risk of developing this condition:
Biomechanical Factors
- More common in women due to a wider pelvis and a greater angle at the knee joint (valgus alignment)
- Being knock-kneed (valgus knees) or duck-footed
- Tight or weak hamstring muscles
- Obesity, which increases load on the knee
Activity-Related Causes
- Repetitive stress or overuse of the knee
- Athletes, especially long-distance runners
- Excessive hill running
- Incorrect training techniques or sudden increase in training intensity
- Neglecting proper warm-up and stretching routines
Medical Conditions
- Osteoarthritis of the knee — one of the most common associated conditions
- Type 2 Diabetes
- Osgood-Schlatter disease
Trauma
- A direct blow or injury to the inner knee area
Diagnosis of Pes Anserine Bursitis
Diagnosis typically involves a combination of clinical examination and imaging studies:
Physical Examination — The physiotherapist or physician assesses the knee for tenderness, swelling, and range of motion. Pain on palpation 2–3 cm below the medial joint line is a key clinical indicator.
X-Ray — Used to rule out bony abnormalities such as fractures or severe arthritis that may mimic or coexist with bursitis.
MRI (Magnetic Resonance Imaging) — Provides detailed images of soft tissue, helping assess the extent of bursal inflammation and any associated ligament or tendon damage.
Bone Scan — Helps identify stress fractures within the joint, which can cause similar symptoms.
Laboratory Tests — Blood tests such as erythrocyte sedimentation rate (ESR), complete blood cell count (CBC), and antinuclear antibody (ANA) tests may be ordered to rule out systemic or inflammatory conditions.
Treatment for Pes Anserine Bursitis
Treatment follows a stepwise approach, starting with conservative management and progressing to more invasive options only if necessary.
Medications Non-steroidal anti-inflammatory drugs (NSAIDs) such as ibuprofen or naproxen are commonly used to reduce pain and inflammation. In more persistent cases, corticosteroid injections or local anesthetic injections may be administered directly into the bursa. All medications should be taken only under a doctor’s prescription.
Surgery In rare cases where conservative treatment fails to provide relief, surgical intervention such as bursectomy (removal of the inflamed bursa) may be recommended.
Physiotherapy Treatment for Pes Anserine Bursitis
Physiotherapy is the cornerstone of conservative management for pes anserine bursitis. A well-structured physiotherapy program addresses pain, inflammation, muscle tightness, and the underlying biomechanical factors contributing to the condition.
Rest and Activity Modification The initial step involves reducing or temporarily stopping activities that aggravate pain — such as running, climbing stairs, or squatting. Modifying daily activities allows the inflammation to settle before gradual rehabilitation begins.
Ice Therapy (Cryotherapy) Applying ice packs to the inner knee for 15–20 minutes, three to four times per day, helps significantly reduce pain and swelling. Ice should always be wrapped in a cloth to avoid direct skin contact.
Ultrasound Therapy Therapeutic ultrasound uses sound waves to penetrate deep tissues, promoting reduction of the inflammatory process and accelerating tissue healing.
TENS (Transcutaneous Electrical Nerve Stimulation) TENS therapy delivers mild electrical impulses to the affected area, effectively modulating pain signals and providing relief without medication.
Low-Level Laser Therapy (LLLT) Laser therapy is used to promote healing at the cellular level, reducing inflammation in the bursa and surrounding soft tissues.
Massage Therapy Soft tissue massage helps relieve muscle tightness around the knee, improves blood circulation, and restores normal joint range of motion.
Strengthening Exercises A progressive strengthening program targets the muscles around the knee to reduce the load on the bursa. Exercises typically progress as follows:
Early stage: Isometric hamstring contractions, quadriceps sets, gluteal squeezes, straight leg raises.
Progressive stage: Single knee dips, squats, leg presses, lunges, and resisted leg pulls using elastic resistance bands or tubing.
Stretching Exercises Flexibility exercises help reduce tightness in the muscles that attach at the pes anserine. Key stretches include:
- Hamstring stretch (semitendinosus)
- Quadriceps stretch
- Sartorius stretch
- Calf stretch
- Seated adductor stretch
Consistent stretching improves flexibility, reduces tension at the tendon insertion site, and helps prevent recurrence.
Activity Modification Advice Physiotherapists also provide guidance on long-term lifestyle adjustments, such as reducing the duration and intensity of high-impact activities, achieving a healthy body weight to reduce knee load, and using a pillow between the thighs during sleep to reduce medial knee compression.
Patient Education and Recovery
Recovery from pes anserine bursitis requires patience and a commitment to rehabilitation. Key patient education points include:
- Never ignore pain during or after exercise — it is the body’s signal that the tissue needs rest.
- Begin returning to activity gradually: start with non-weight-bearing exercises such as swimming or cycling before progressing to walking and running.
- When returning to running, alternate between walking and running over short distances before building up.
- Maintain consistency with stretching and strengthening even after pain resolves, to prevent recurrence.
- Patients who have undergone surgery should follow a guided post-operative physiotherapy protocol and avoid rushing their recovery.
Who Is Most at Risk?
Pes anserine bursitis is particularly common among middle-aged to older adults, overweight individuals, women (due to anatomical differences in the knee angle), and athletes — especially runners. People with osteoarthritis or diabetes are also at significantly higher risk and should be proactive about knee health and any early signs of inner knee pain.
When to See a Physiotherapist
If you experience persistent inner knee pain, tenderness below the knee joint, swelling, or difficulty walking up stairs, it is advisable to consult a physiotherapist promptly. Early diagnosis and targeted physiotherapy can prevent the condition from becoming chronic and help you return to your normal activities faster.