Pes Anserine Bursitis
Pes anserine bursitis is the medical term for inflammation of the pes anserine bursa in the knee.
Muscles are joined to bones by tendons. The tendons from three hamstring muscles in the thigh, the sartorius, gracilis and semitendinosus, conjoin to form the pes anserinus (Latin for ‘goosefoot’ due to the tendons webbed shape). The tendon has its insertion into the tibia (shinbone) about an inch or two below the knee joint, on the inner (medial) side of the knee. The medial collateral ligament (MCL) also has its tibial insertion at this point, and lies just deep to the pes anserinus. Between these structures and the tibia is a bursa, a potential space lined with a synovial membrane that secretes lubricating and nourishing synovial fluid. When constant friction irritates the bursa, the synovium produces more fluid, causing swelling and pain.
Tight hamstring muscles are the predominant cause of pes anserine bursitis. Athletes, particularly runners, are prone to this condition although any sport that requires side-to-side movement, such as basketball, soccer and racket sports, can trigger bursitis as well.
Older patients who already suffer from osteoarthritis are at increased risk. It is thought that up to 75% of people with degenerative knee joint disease have symptoms. People with flat feet, knock-knees or certain other anatomical conditions that might increase stress on the tendon at that point are also vulnerable. Pes anserine bursitis can also be found in conjunction with other knee conditions and injuries, such as a meniscal tear or Osgood-Schlatter disease.
Women, especially if they are middle-aged and obese, can develop pes anserine bursitis. It is thought that the wider female pelvis, the angle of the legs at the knees, and extra body weight, all of which increase stress on the knee joint, might be responsible.
Direct trauma to the inner knee can cause the synovial lining of the bursa to produce more fluid, leading to inflammation and pain.
- Tenderness over a diffuse area of the inner knee
- Mild to moderate pain
- Local swelling
- Discomfort increased when climbing stairs (occasionally when going down) and standing up from a seated position
- Little or no pain when walking on a level surface
Your doctor will make a diagnosis based on your medical history, current symptoms and a physical examination of the knee. Palpation (touch) of the area will help to pinpoint the exact location of the pain. The tightness of your hamstrings will be assessed.
An x-ray image will be taken to rule out a bone fracture, as the symptoms caused by a fracture can be very similar to those caused by pes anserine bursitis. MRI scans are used to look at the soft tissues of the knee.
If infection is suspected, synovial fluid from the bursa may be removed for testing.
Surgery is rarely needed for this condition as most cases resolve with time and non-operative treatment. If surgery is necessary, it will be to remove the bursa and any bony spur present. Rehabilitation would include keeping the knee immobilized for 1-2 weeks post-surgery, followed by a gradual return to activity, and the treatments listed below.
- Rest: Reduce activities that aggravate the condition. Such activities might include climbing stairs or playing sports.
- Ice: Apply ice to the area, crushed and in a bag, covered with a towel, for 15 minutes at a time, several times a day.
- Medication: Non-steroidal anti-inflammatory drugs (NSAIDs) such as ibuprofen (Advil), naproxen (Aleve) or aspirin will reduce inflammation and relieve pain.
- Corticosteroid injection: This may be used as part of the diagnostic testing: if an injection into the bursa improves symptoms, it is indicative of pes anserine bursitis. The injection, usually given in conjunction with an anesthetic, will relieve symptoms for several weeks and in some cases longer. Up to 3 injections may be given in any year.
- Physiotherapy may make use of ultrasound to promote healing. Your physiotherapist will devise an individualized and progressive exercise program, which will focus on stretching the hamstring muscles and strengthening the quadriceps. This program will probably last for 6-8 weeks, although athletes would benefit from continuing with such exercises on a regular basis.
- Athletes may wish to wear a protective pad over the knee when returning to sports.
Follow the advice of your physiotherapist or doctor.
Lie on your back on the floor, near a doorway, so that you are able to raise one leg and rest it on the wall next to the doorframe. Your other leg should remain straight out in front of you, extending through the doorway. Hold the stretch in the back of your thigh for 20-30 seconds. Repeat 3 times. Switch legs and repeat the exercise.
Put your hands against a wall for support. Place one lege behind you with the heel on the floor, and keep the other leg forward. Slowly lean into the wall until you feel a stretch in the back of your calf. Hold for 20- 30 seconds. Repeat 3 times. Switch legs and repeat the exercise. This can be done several times each day.
Place the left hand on a wall for support. Hold the right foot with your right hand and gently pull the foot up and behind you towards the buttocks, stopping when you feel a stretch. Keep your knees together. Hold the stretch for 10 seconds then relax. Switch legs and repeat exercise.
Hip Adductor stretch:
Lie on your back on the floor with bent knees and feet flat on the floor. Let your knees fall open as far as they will comfortably go. Hold the position for 20-30 seconds. Repeat 3 times.
Sitting on a table or lying down, press the knee down against the table or floor by tightening the quadriceps muscles in the top of your thigh. Hold the position for 5-10 seconds then relax. Repeat 10 times for 1 set. Do 3 sets.
Lie on your back on the floor with your legs straight out in front on you and together. Slide the heel towards the buttocks as far as possible. Hold for 5 seconds then straighten. Repeat 10 times for 1 set. Do 3 sets.
For older patients with pes anserine bursitis, exercise is important in order to avoid atrophy of the muscles. For younger patients, maintain flexibility and strength in the leg muscles.