Infection is common in this bursa. Swelling may occur as late as 7-10 days after a single blow to the area, usually from a fall. When restrained by the 3 tendons, the bursa looks like a goose's foot. This type of bursitis is most often seen in people with arthritis, especially overweight middle-aged women with osteoarthritis. The pain is typically produced when the knee is bent and is particularly troublesome at night.
People often seek comfort by sleeping with a pillow between their thighs.
The pain can radiate to the inner thigh and midcalf and usually increases on climbing stairs and at extremes of bending and extending. The area of tenderness is on the middle part of the knee. Anserine bursitis also occurs as an overuse or traumatic injury among athletes, particularly long-distance runners. Retrocalcaneal bursitis occurs when the bursa near the Achilles tendon in the ankle becomes inflamed. It can also occur with Achilles tendonitis.