Injury Focus: Pes Anserine (Goosefoot) Bursitis

Introduction
A common injury seen in runners, athletes and even the general population is a sharp pain that radiates on the internal portion of the shinbone, just below the knee. This injury is typically diagnosed as Per Anserine (Goosefoot) Bursitis. A bursitis injury occurs when constant friction on the bursa — a small sac that cushions the bones and tissues from tendons that rub over these surfaces — causes inflammation. Once the bursa becomes inflamed and irritated, pain and tenderness are usually soon to follow.

Anatomy – What parts of the body are involved?
The pes anserine bursa is a small lubricating sac between the shinbone (tibia) and the hamstring muscle, which is located along the back of the thigh.

The hamstring has three tendons, one of which is called the semitendinosus, which wraps around from the back of the leg to the front and connects to the internal portion of the shinbone and deep connective tissue of the lower leg.

Just above the insertion of the semitendinosus tendon is the gracilis tendon. The gracilis muscle moves the leg toward the body, also called adduction. The semitendinosus tendon is also just behind the attachment of the sartorius muscle, which bends and externally rotates the hip. Together, these three tendons splay out on the tibia and look like a Goosefoot. This area is called the pes anserine or pes anserinus.

The pes anserine bursa provides lubricant for motion that occurs between these three tendons and the MCL (medial collateral ligament), which is located underneath the semitendinosus tendon.

Causes – What causes this problem?
Overuse of the hamstrings, especially in athletes with tight hamstrings is a common cause of Goosefoot. Runners are affected most often and improper training or sudden increases in distance running and/or running up hills can contribute to this condition.

Another cause can be from a direct blow to this part of the knee which can cause the bursa to become inflamed, tender and/or painful. Conditions such as osteoarthritis of the knee, improper alignment of the leg and/or having flat feet can also be leading factors in developing Goosefoot.

Symptoms – What does the condition feel like?
The pes anserine is located about two to three inches below the joint on the inside of the knee, which is often the area where pain is reported.

Some patients also have pain in the center of the shinbone. This occurs when other structures are also damaged such as the cartilage (meniscus). The pain is made worse by exercise, climbing stairs, or activities that cause resistance to any of these tendons.

Diagnosis – How do practitioners diagnose this problem?
A history and clinical exam will help the physician differentiate pes anserine bursitis from other causes of anterior knee pain. An X-ray and/or MRI may be needed to rule out damage in other surrounding regions. Also, fluid from the bursa may be removed and tested if infection is suspected.

Hamstring tightness is also assessed. This is done while lying on your back and flexing your hip to 90 degrees. In this position, the knee is straightened as far as possible. If you can straighten your knee all the way in this position, then you do not have tight hamstrings.

Treatment – What treatment options are available?
The goal of treatment for overuse injuries such as Goosefoot is to reduce the strain on the injured tissues. Stopping the activity that brings on or aggravates the symptoms is the first step toward pain reduction. Ideally non-surgical treatment should be used when possible to correct an injury. Below is a list of ways to treat Goosefoot that you can do on your own:

1. Bedrest is not required but it may be necessary to modify some of your activities, such as climbing stairs or getting up out a chair or seated position excessively. This will give time for the bursa to quiet down and for the pain to subside and is referred to as relative rest.
2. Ice and anti-inflammatory medications can be used early on. The ice is wrapped in a thin cloth and applied three or four times each day for 20 minutes at a time.
3. Ice massaging also works. Here, a cup of water is frozen in a Styrofoam container and the top edge of the container is torn away leaving a one-inch surface of ice that can be rubbed around the area. The pes anserine area is massaged with the ice for 10 minutes or until the skin is numb. Caution is advised to avoid frostbite.
4. Over-the-counter nonsteroidal anti-inflammatory drugs (NSAIDs) such as Ibuprofen may be advised. In some cases, the physician will prescribe stronger NSAIDs. Speak with your doctor about the best method for you.
5. Improving flexibility is a key part of the prevention and treatment of this condition. At first, hamstring stretching should be performed every couple hours for 30-60 seconds before being reduced to a few times a day. Hold the position at a point of feeling the stretch but not so far that it is painful or uncomfortable and do not bounce. Remember to take deep breaths while stretching and push the stretch a little further as you exhale.
6. Quadriceps strengthening is very important, especially if other areas of the knee affected. The quadriceps muscle along the front of the thigh extends the knee and helps balance the pull of the hamstrings. An exercise program prescribed by a physical therapist or a certified personal trainer is best and should be progressed with supervision.

Rehabilitation – What should I expect after treatment?
Goosefoot is considered a self-limiting condition, meaning it usually responds well to treatment and will resolve without further intervention. Athletes may have to continue a program of hamstring stretching and quadriceps strengthening on a regular basis.

You may return to your normal routine once the symptoms are gone and are no longer aggravated by certain activities, but protective gear for the knee may be needed for those individuals who participate in contact sports. During the rehab process, activity level and duration are gradually increased to ensure symptoms don’t return and you can keep on living pain free!