A bursa (plural: bursae) is a closed, fluid-filled sac that functions as a gliding surface to reduce friction between tissues of the body, for example, where tendons or muscles pass over bone. The major bursae are located adjacent to the tendons near the large joints, such as the shoulders, elbows, hips and knees.
A bursa normally contains very little fluid. If injured through strain or trauma, however, it becomes inflamed and may fill with fluid. When this happens, the condition is known as bursitis. Most commonly, this is a non-infectious condition (aseptic bursitis). On rare occasions, the hip bursae can become infected with bacteria – septic bursitis.
Bursitis can be caused by chronic overuse, injury, gout, pseudogout, rheumatoid arthritis or infections. Often the cause is unknown.
Bursitis causes pain and tends to limit movement, but the specific symptoms depend on the location of the inflamed bursa. There are two major bursae of the hip, which can both be associated with stiffness and pain around the hip joint:
- The trochanteric bursa is located on the side of the hip. It is separated significantly from the actual hip joint by tissue and bone. Trochanteric bursitis frequently causes tenderness of the outer hip, making it difficult for patients to lie on the affected side. It also causes a dull, burning pain on the outer hip that is often made worse by excessive walking, driving or use of stairs.
- The ischial bursa is located on the upper buttock area. It can cause dull pain in this area that is most noticeable when climbing up hills, or rising from a chair and taking the first few steps. The pain sometimes occurs after prolonged sitting on hard surfaces, hence the names “weaver’s bottom” and “tailor’s bottom”.
A doctor suspects bursitis if the area around a bursa is sore when touched and specific joint movements are painful. If the bursa is noticeably swollen, the doctor may remove a sample of fluid from the bursa with a needle and syringe to test for causes of the inflammation, such as infection or gout.
Bursitis of the hip is diagnosed based on your history of hip pain and an examination of the specific areas of tenderness. A diagnosis is usually confirmed when a local injection of anaesthetic relieves the pain. Occasionally, X-rays of the hip are used to rule out other conditions that may be causing the pain, such as arthritis.
While symptoms are present, avoid activities that force one side of the pelvis higher than the other, such as using stairs or walking sideways on a slope. Wear flat, well-cushioned footwear. Sleep on your uninjured side with a pillow between your knees, or on your back with pillows beneath your knees. After activity, try gentle stretching exercises, when your muscles are warm. Some patients benefit from weight reduction.
Medication and surgery
The treatment of any bursitis depends on whether or not it involves infection. Aseptic hip bursitis can be treated with ice compresses, rest, temporary immobilisation of the hip joint, and anti-inflammatory and pain medications such as indometacin, ibuprofen or naproxen. Occasionally it requires aspiration. This procedure involves removal of the bursa fluid with a needle and syringe under sterile conditions. It can be performed in the doctor’s office. Sometimes the fluid is sent to the laboratory for further analysis. Non-infectious hip bursitis can also be treated with an injection of cortisone medication, often with an anaesthetic, into the swollen bursa. This is sometimes done at the same time as the aspiration procedure.
Septic bursitis is unusual in the hip bursae, but does occur. Infected bursae must be drained and appropriate antibiotics taken, often intravenously. The bursal fluid can be examined in a laboratory for the microbes causing the infection. Repeated aspiration of the inflamed fluid may be required.
Bursitis frequently recurs if the underlying cause, such as gout, rheumatoid arthritis or chronic overuse isn’t corrected.
In severe, recurring cases, surgical drainage and removal of the infected bursa sac (bursectomy) may be necessary.
Reviewed by Dr Joe de Beer