Pain Inside of Knee - Pes Anserinus

Also known as or related to: pes anserine bursitis, pes anserine tendinopathy, inside knee pain, medial knee pain, inner knee pain, goose foot tendon pain.

Description

Pes anserinus is a quite common pain on the inside of the knee that we see with people playing sport and running, hiking or walking regularly. It is often misdiagnosed as medial knee arthritis, meniscal damage or a collateral ligament injury, because these structures are all on the inside part of the knee. However, the pes anserine tendon wraps over the top of all of these and attaches just below the knee joint — a few centimetres down the inside of the shin bone at the top of the tibia.

Most people feel their pain right at the knee joint area or just past it, a few centimetres below the joint line on the inside of the shin bone.

There are three muscles on the inside of the upper leg and groin — the sartorius, gracilis and semitendinosus — that come down and join together onto the pes anserine tendon, which is where the name "goose foot" comes from. All three meet and attach onto the inside of the shin bone together.

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Symptoms

When these muscles work hard they become tight, which increases tension on the tendon. With repetitive knee movement, the friction of the tendon as it crosses the knee causes the tendon lining to become inflamed and painful.

When the tendon lining is really inflamed, you will even feel a fullness or pressure on the inside of the knee as you bend it fully. Patients typically describe:

- Pain on the inside of the knee, a few centimetres below the joint line

- Tenderness to touch on the inner shin just below the knee

- Pain that worsens with running, hiking, climbing stairs or rising from a seated position

- A feeling of fullness or pressure when bending the knee fully in severe cases

Causes

Dynamic Sport and Adductor Load

People get pes anserinus from side-to-side dynamic sports because the adductor muscles on the inside of the leg have to work quite hard with lateral movements. This increases tension through the tendon and drives the friction and inflammation.

Foot Position and Function

For most straight-line activity such as running, hiking and walking, the cause is feet that tip outwards. If your foot supinates or tips outward as you push off, that causes your foot to head outwards and your knee to head outwards with it. The muscles on the inside of your leg then have to work very hard to pull your knee back in so that you can keep heading straight instead of tipping off to the outside.

When these muscles have to do that with every single step, they tighten up, that tension increases the friction on the tendon lining, and you get pes anserinus pain.

So the key is to stop your foot tipping outwards. Things that contribute to this include:

Why Common Explanations Get This Wrong

Older explanations found on the internet suggest that the foot and knee rotating inwards causes tension on the pes anserine tendon. This is actually false and the opposite of what we see clinically with our runners and hikers.

The tension in the tendon comes from how hard the muscles pull. The job of these muscles is to resist knee abduction and external rotation — that is, to stop the knee going outwards. High arch feet tip outwards and cause the knee to follow and go outwards, which makes these adductor muscles work very hard with every step and tensions the pes anserine tendon.

This explains why patients with pes anserinus often prefer firmer, more laterally stable shoes, and why standard supportive orthotics or motion control shoes can actually make it worse rather than better.

Incorrect Footwear

If you have a higher arch foot type and you are fitted to a shoe designed for flatter feet or lower arches, that extra support will actually encourage your foot to tip outwards. Similarly, shoes that are too cushioned and unstable can cause you to tip out more, increasing the tension through the pes anserine tendon. Getting the right shoe matched to your foot type is critical. Browse our range of running and walking shoes here.

Orthotic Design

If you are given a standard orthotic designed for the bulk of the population — one that reduces foot rolling inward — it will actually increase your foot tipping outward and make things worse. A different orthotic design matched specifically for higher arch feet and pushing off straight is very effective for this condition. This is one of the most commonly missed factors in treatment.

Treatments

The root cause is the high workload created by the foot tipping outwards. If you can get the foot tracking straight and pushing off straight, those muscles relax and you get a great long-term solution. Our clinical approach typically progresses as follows:

Correct footwear -> specific orthotic design for high arch feet -> muscle release and rolling -> adductor stretching -> strengthening exercises -> training modifications

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Releasing Muscle Tension

If the adductor muscles are tight and overworked, rolling is really effective. Putting your leg over the side of a foam roller to massage and roll those muscles gives fast relief. Specific stretching exercises for the adductors on the inside of the leg are also important.

Rehabilitation Exercises

If you have actually strained the tendon, strengthening exercises need to be done. These two exercises target the muscles that attach via the pes anserine tendon. Perform every second day for 3 sets of 8 repetitions or as prescribed by your podiatrist.

Summary

Pes anserinus is very treatable when the underlying cause is correctly identified. Because it is so commonly misdiagnosed as arthritis or meniscal damage, and because the foot mechanics driving it are so frequently overlooked, getting an accurate assessment from an experienced sports podiatrist is the key to a fast and lasting recovery.

"The root cause is getting to that high workload of your foot tipping outwards. If you can get that foot tracking straight and pushing off straight, those muscles relax and you get a great long-term solution."
— Peter Charles, Sports Podiatrist & Owner, Shoes Feet Gear Bardon

Our Bardon clinic serves patients from Paddington, Ashgrove, Toowong, Red Hill and across Brisbane's inner west. Book online or call today.