The pes anserine (Latin: “goose foot”) is the area on the inside part of the knee where the tendons for the gracilis, sartorius and semitendinosus muscles attach. Under these tendons is a bursa, which is a fluid-filled sac important in reducing friction forces between the tendons and bone. These structures can become inflamed causing pes anserine bursitis & tendonitis, a painful conditions of the inner knee. There are several causes of pes anserine bursitis & tendonitis and equally many evidence-based management strategies.
Important anatomy of pes anserine bursitis & tendonitis
The pes anserine bursa is a fluid-filled vesicle or sac that secretes synovial fluid to reduce friction between the tendons of the pes anserine and cushions one of the shin bones called the tibia and the surrounding soft tissue.
The pes anserine is the insertion of the sartorius, gracilis and semitendinosus muscles, which join together on the inner aspect of the tibia bone. The sartorius and gracilis muscles are adductors of the leg (i.e., they pull the leg towards the middle of the body). The semitendinosus muscle is part of the hamstrings muscle group located at the back of the upper leg. Together, these three muscles assist to flex and internally (inward) rotate the knee.
Cause of pes anserine bursitis & tendonitis
Pes anserine bursitis and tendinitis arises when the above related muscles are repeatedly overused. The main mechanism for this is repeated knee flexion and leg adduction. Repeated muscle action can lead to increased friction and microscopic injury to the tendons. This friction also increases pressure on the underlying bursa leading to bursitis. However, bursitis can also be caused by direct trauma of the pes anserine region, such as those seen in contact sports. Inflammation in the tendons and contusion to this area results in an increased release of synovial fluid in the lining of the bursa, which further perpetuates inflammatory processes, tenderness and knee pain. Repeated damage to these tissues and prolonged inflammation can potentially lead to early-onset knee osteoarthritis.
The exact incidence ofpes anserine bursitis & tendonitis is unknown, because studies on its incidence and prevalence do not exist. However, a review of 509 magnetic resonance imaging (MRI) scans of adults with knee pain found that pes anserine bursitis and tendinitis was evident in 2.5%.
Risk factors for pes anserine bursitis & tendonitis
There appear to be a few confirmed risk factors for pes anserine bursitis & tendonitis. These include:
- Overweight individuals. More pressure/load is being placed on the above tissues.
- Females. Owing to different anatomical angulation of the female knee-hip-pelvis complex.
- Previous history of pes anserine bursitis & tendonitis.
- Activities and sports. Especially those involving repetitive use of above muscles, including: running, dancing, and sports that require directional changes such as soccer and basketball
- Underlying knee pathology. Such as knee osteoarthritis and inflammatory arthritides.
- Sudden increase in activity: Refers to level/sports training and inadequate warm-up and stretching prior to and following exercise.
How does pes anserine bursitis & tendonitis present?
The most common presentation of pes anserine bursitis & tendonitis is pain on the inner aspect of the affected knee and tenderness at the attachment site. There may also be swelling if the bursitis is particularly affected. The pain may be spontaneous when performing activities such as running, climbing or descending stairs.
Other clinical presentations may include:
- Decreased muscle strength
- Abnormal gait (walking pattern)
- Decreased range of motion of the knee
How is pes anserine bursitis & tendonitis conservatively managed?
Pes anserine tendonitis is managed like any tendinitis or tendinopathy: a progressive tendon loading strategy is recommended. Each management strategy will be different, accounting for the patient’s presenting condition and their needs and expectations.
1. Pain relief and isometric exercises
The first step to consider in conservatively managing pes anserine bursitis & tendonitis is to reduce the pain and inflammation in the affected knee. This is achieved by adopting the P.O.L.I.C.E (Protect, Optimally Load, Ice, Compress and Elevate) principle. Protect the affected area to avoid further tissue damage, optimally load the tissue to stimulate the healing process and using an ice pack, compression bandage and elevating the leg to reduce inflammation and prevent further swelling.
The patient is instructed to avoid stairs, climbing or irritating activities to quite down the bursa and pain. At this stage, gentle isometric exercises (i.e., muscle contracts without lengthening or shortening) can be useful to help manage pain levels. These may include supine and prone straight leg raises, isometric wall squats and isometric warrior 1-3 exercises.
2. Isotonic strength endurance where appropriate.
Once pain and inflammation has been managed, the next step is to regain muscle strength and conditioning in the pes anserine and normal range of motion in the knee and hip. Muscle isotonic (i.e., muscle changes length as it contracts) exercises aim to restore normal function to the pes anserine and surrounding musculature. These may include exercises such as standard squats leading into deep squats and single-leg squats, and progressive stair climbing exercises.
Regaining normal range of motion is achieved by the patient actively bending and extending the knee either with or without theraband or weighted assistance, and also passively with the clinician assisting through the passive knee range.
3. Energy storage exercises.
Exercise in this stage places faster loads through the tendon and muscles. Example of these types of exercises for pes anserine bursitis & tendonitis include jumping progressing to box jumps and single-legged jumps, and faster stair climbing with or without resistance or incline.
4. Energy storage and release exercises.
These exercises are a progression from stage 3, where the speed increases and the release of energy from the tendon occurs. Examples include faster running, stair climbing and skipping drills with directional changes, deadlifts with or without lunges, lateral and frontal box jumps on/off increasing height and distance.
It is always important to consult a clinician before attempting these exercises. At Sydney Spine & Sports Centre (S3C), our Balmain chiropractors are highly qualified in diagnosing and managing pes anserine bursitis & tendonitis. Our clinicians use current evidence-based management strategies to prescribe an individualised rehabilitation program for patients with pes anserine bursitis & tendonitis.
Please visit our S3C website articles and blog page for more information about knee and leg pain:
- Hamstring Injuries and the Askling L-Protocol
- Thermotherapy vs. Cryotherapy: Mechanisms & Evidence
- Tendinopathy: Evidence-Based Management Strategies
- How Can Chiropractic Help After a Sports Injury?
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- Medial meniscus tear
- Anterior cruciate ligament tear
- Iliotibial band syndrome
- Jumpers knee
- Osgood Schlatters disease
- Patellofemoral pain syndrome
- Lateral collateral ligament (LCL) injury
- Shin splints
- Calf pain
- Calf strain
- Achilles tendonitis
- Peroneal tendonitis