Pes Anserine Bursitis: Inner Knee Pain Below the Joint

You have a nagging pain on the inside of your knee, a few centimetres below the joint. It is worse when you climb stairs, get up from a chair or try to run. You press into the tender spot and it is right there, on the bone. It is not your meniscus, it is not arthritis, but it will not go away.

That pattern is typical of pes anserine bursitis, one of the most underdiagnosed causes of inner knee pain. It is common, it responds well to treatment and in most cases it does not need injections or surgery.

What is the pes anserinus?

The name comes from the Latin for “goose’s foot.” Three tendons (sartorius, gracilis and semitendinosus) come together and attach on the inner surface of your shinbone, about five centimetres below the knee joint. The way they fan out at the attachment point looks a bit like the shape of a goose’s foot.

Between these tendons and the bone sits a small fluid-filled sac called the pes anserine bursa. Its job is to reduce friction as the tendons glide over the bone during movement. When the bursa becomes irritated and inflamed, you get pes anserine bursitis. When the tendons themselves are also involved, the condition is sometimes called pes anserinus syndrome.

The distinction matters less than understanding the cause: repeated mechanical stress at the tendon attachment leads to pain, tenderness and sometimes localised swelling on the inner knee.

What causes it?

There is rarely a single cause. Pes anserine bursitis usually develops when a combination of factors increases the load on the inner knee beyond what the tissue can handle.

Tight hamstrings. All three pes anserine muscles help bend the knee and rotate the lower leg inward. When they are tight, they pull harder on the attachment and overload the bursa. This is the most common and most modifiable contributor.

Knee osteoarthritis. The altered joint mechanics that come with arthritis change the way load is distributed through the knee, placing more stress on the inner side. Studies suggest pes anserine bursitis affects around one in five patients with symptomatic knee osteoarthritis (Uysal et al., 2015).

Knee alignment. If your knees tend to angle inward (sometimes called knock-kneed alignment), the inner compartment of the knee takes on more load with every step. This is more common in women, partly due to wider pelvis angles.

Flat feet. When the arch drops, it changes the alignment of the whole lower limb and shifts more force through the inner knee.

Increased load. Any increase in load through the knee, whether from a change in training volume, prolonged time on your feet or carrying more body weight, can push the pes anserine tendons past their tolerance.

Diabetes. Changes in connective tissue quality and increased systemic inflammation in people with diabetes appear to make the condition more likely.

Running and court sports. Runners, tennis players, padel players and anyone whose sport involves sudden direction changes or repetitive knee loading is at higher risk.

What does it feel like?

The pain sits on the inner side of your knee, slightly below the joint line. It can feel like a deep ache or a sharper, more burning sensation. The key features that help distinguish it from other causes of inner knee pain:

Tenderness on the bone, not in the joint. The sore spot is about five centimetres below the inner edge of the joint. If the pain is right on the joint line, a meniscus or ligament issue is more likely.
Pain with stairs. Going up and down stairs is usually the worst because the pes anserine tendons have to work hard to stabilise the knee during stair climbing.
Pain getting up from sitting. The transition from a bent to a straight knee loads the tendons at their attachment.
Pain at night. Many people find it uncomfortable to sleep with their knees touching. Placing a pillow between the knees often helps immediately.
Morning stiffness that eases. The area can feel stiff first thing and loosen up as you move around, similar to many tendon conditions.

How it is diagnosed

Pes anserine bursitis is diagnosed clinically. A careful history and examination, including pressing over the pes anserine attachment and checking hamstring tightness, hip strength and knee alignment, is usually enough.

Imaging is not always necessary, but ultrasound can confirm thickening or fluid in the bursa, and MRI can help rule out other causes of inner knee pain such as meniscal tears or stress fractures. X-rays may be useful if osteoarthritis is suspected as a contributing factor.

The more important step is working out why the bursa became irritated. Without addressing the contributing factors, the pain comes back.

How chiropractic care helps

Manual therapy and joint mobilisation

The knee does not work in isolation. Stiffness in the hip, altered pelvic mechanics and restrictions in the lower back all change the way load passes through the inner knee. Mobilisation of the knee, hip and lumbar spine, combined with soft tissue work on the hamstrings, adductors and calf muscles, restores normal movement patterns and takes mechanical stress off the pes anserine attachment.

Fascial release and IASTM

The pes anserine tendons are embedded in fascial tissue that connects them to the hamstrings, adductors and surrounding structures. When this fascia is restricted or tight, it increases the mechanical pull on the attachment and keeps the bursa irritated. Instrument-assisted soft tissue mobilisation (IASTM) allows us to identify and treat these restrictions with greater precision than hands alone, breaking down adhesions and restoring normal tissue movement through the area. This is particularly effective when chronic hamstring or adductor tightness has not responded to stretching alone.

Targeted rehabilitation

This is the foundation of lasting improvement:

Hamstring flexibility. Tight hamstrings directly overload the pes anserine tendons. Consistent stretching reduces the pull on the attachment.
Quadriceps strengthening. Strong quadriceps, particularly the inner portion (vastus medialis), support the knee and reduce the demand on the inner stabilisers.
Hip and glute strengthening. Weak hip muscles allow the knee to drop inward during loading. Strengthening the gluteus medius corrects this and reduces stress on the inner knee.
Progressive loading. Controlled, gradual loading of the tendon stimulates repair and builds tolerance.

Shockwave therapy

Shockwave therapy is one of the most effective non-invasive tools we have for pes anserine bursitis, and the research backs it up.

Khosrawi and colleagues (2017) tested shockwave against a sham treatment in patients with chronic pes anserine bursitis that had not improved with other conservative measures. Three weekly sessions of shockwave produced significantly greater pain relief than the sham group, with the benefit sustained at eight weeks. The authors concluded that shockwave is an effective and safe treatment for this condition.

Majidi and colleagues (2023) compared shockwave with corticosteroid injection and found that while both reduced pain, the shockwave group had better pain relief and quality-of-life outcomes. Gouda and colleagues (2023) confirmed meaningful improvements with shockwave in a larger trial of 180 patients. And Khazraji and colleagues (2024) showed that shockwave is effective for both newer and longer-standing cases, not just chronic pain that has been there for months.

The combined evidence across these trials shows shockwave consistently reduces pain and improves function in pes anserine bursitis. At our practice we use the EMS Swiss DolorClast Smart20 and typically deliver three to four weekly sessions, combined with manual therapy and rehabilitation in the same visit, because that combination consistently produces the best results.

What you can do at home

While you are having treatment, these steps make a meaningful difference:

Hamstring stretches. Hold for 30 seconds, three times each side, at least once daily. Use both a straight-leg and a bent-knee position to target all three pes anserine muscles.
Glute strengthening. Side-lying hip abduction, clamshells and single-leg bridges all target the muscles that stop the knee collapsing inward.
Ice after activity. 15 to 20 minutes of ice over the tender area after exercise or at the end of the day can help settle irritation.
Pillow between the knees at night. This reduces direct pressure on the bursa and most people find it helps with night pain straight away.
Modify, do not stop. You do not need to stop exercising. Reduce stair repetitions, shorten your run distance or switch to lower-impact exercise while the tissue settles, then build back up gradually.

When to get help

Do not wait months for this to sort itself out. Pes anserine bursitis responds best to early treatment, and the longer it persists, the more the surrounding muscles weaken and compensatory patterns develop. See a professional if:

Your inner knee pain has lasted more than two weeks and is not improving
The pain is affecting your ability to exercise, climb stairs or walk comfortably
You have tried rest and stretching and it keeps coming back
You have knee osteoarthritis and are unsure whether the inner knee pain is the arthritis or something else

A proper assessment can distinguish pes anserine bursitis from meniscal injury, ligament sprain, stress fracture and other causes of inner knee pain, and get you on the right treatment path.

If your inner knee pain is not settling, get in touch or book an appointment. We will work out what is driving it and get you moving properly again.

References

PES ANSERINE BURSITIS: INNER KNEE PAIN BELOW THE JOINT