Pes Anserine Bursitis (Inner Knee Pain)

Overview

The pes anserinus ("goose's foot") is the point on the inner shin, about two to three finger-widths below the knee joint line, where three hamstring and thigh tendons attach. A small fluid-filled sac called a bursa sits between these tendons and the bone to reduce friction. When the tendons are overloaded or the bursa becomes irritated, the area becomes tender and achy — this is pes anserine bursitis, sometimes called pes anserine tendinopathy because the tendons are often involved too.

It is frequently confused with a meniscus tear or knee arthritis because the pain is on the inner side of the knee. The key difference is location: pes anserine pain sits below the joint line, on the bone of the shin, and is tender to direct pressure. Many people notice it most at night when their knees touch in bed, when climbing stairs, or when getting up from a chair.

It is common in runners and in people over 50 with knee osteoarthritis, and it generally settles well with the right combination of load management and strengthening.

Causes and risk factors

• Sudden increases in running, hill walking or stair climbing
• Tight or weak hamstrings and inner thigh muscles
• Knee osteoarthritis — the two often occur together
• Knock-knee alignment or flat feet, which increase strain on the inner knee
• Being overweight
• Diabetes, which is associated with a higher rate of tendon and bursa problems
• Direct pressure on the inner knee, such as from sitting cross-legged on the floor

How we may be able to help

Because inner knee pain has several possible sources, assessment comes first. We identify exactly where the pain is coming from, check the joint and meniscus, assess hamstring flexibility and strength, and look at your foot and knee alignment when standing and walking.

Physiotherapy usually combines a short period of reduced loading with a graded strengthening programme for the hamstrings, inner thigh and hip muscles, so the tendons become more tolerant of stairs and walking. Manual therapy and soft-tissue work can ease tension in the hamstrings. If knee OA is present, we treat both together.

Therapeutic ultrasound may be used as an adjunct to support the irritated tissue, and interferential therapy may help with pain. Where flat feet or knock-knee alignment is contributing, a 3D foot scan and custom orthotics may reduce strain on the inner knee. If the bursa stays painful despite these changes, an injection may be discussed after assessment.

What you can do at home

• Apply a wrapped ice pack to the inner knee for 10–15 minutes after activity or before bed
• Place a pillow between your knees at night if the knees touching is painful
• Temporarily reduce stairs, hills and running distance
• Stretch your hamstrings gently once or twice a day
• Begin gentle strengthening such as bridges and sit-to-stands when the tenderness allows
• Avoid sitting cross-legged on the floor or kneeling directly on the area