By Erin Galway, Registered Physiotherapist at Burlington Sports Therapy.
Pain on the inside of your knee can be caused from injury to structures of the knee such as the medial collateral ligament or meniscus or over time it can be from wear and tear of the knee resulting in osteoarthritis. However, there is another cause that is common but sometimes overlooked. The pes anserine is formed by 3 muscles joining together just below your knee: sartorius, gracilis, and semitendinosus. These muscles originate from the hip and attach onto the tibia (the lower leg) over a bursa, they all act to bend the knee and rotate the tibia inwards. The role of these 3 muscles are to protect the knee from rotational and medial stress. However, if there is increased pressure on the insertion of these 3 muscles from overuse and friction a tendinitis (inflammation of a tendon) or a bursitis (inflammation of a bursa) can occur.
Pes Anserine Symptoms
People with this syndrome typically complain of pain just below the knee cap on the inside of the knee. The pain gradually worsens and usually occurs during activities such as going up and down stairs, getting in and out of a chair or doing exercises like squats or lunges. This syndrome is also common in runners that may have poor running mechanics. The area of the pes anserine can be swollen and tender to touch.
Pes Anserine Causes
Pes anserine syndrome/bursitis is an overuse injury. Pain may begin to present itself over time if the leg is allowed to move inwards during activities. This tends to lead to imbalances of the muscles of the hip. Tight hamstrings and hip adductors are very common while muscles that stabilize your hip become weak. These imbalances will continue if they are not addressed in rehabilitation. Interestingly, this syndrome is also more common in women than men due to a wider pelvis and an increased angle at the knee.
Pes Anserine Treatment
Initially, treatment may include rest from the aggravating activity, ice that is applied for 10 minutes at a time and laser or ultrasound to decrease the pain and inflammation. Rehabilitation should include a thorough assessment of movement patterns in the lower extremity to determine hip flexibility and strength. In my experience, fascial stretching for hamstrings, hip adductors and hip flexors has been beneficial for improving flexibility and preventing further pain. In addition, exercises to strengthen hip abductors are important to correct the strength imbalance. Once pain has subsided, a gradual return to activity is recommended.
Unsure of the source of your knee pain? It may be pes anserine syndrome. Give us a call and book an assessment to find out.
Helfenstein M., Kuromoto J. Anserine Syndrome. J Rheumatol 2010; 50(3): 313-27