What Causes Fluid in the Hip Joint?

The hip joint contains bones, tendons, muscles, ligaments and fluid filled sacs called bursa. It is a ball and socket joint that allows the leg to be lifted out to the side, to the front, to the back, and it also allows a small amount of rotation. The structures within the hip joint can become inflamed due to injury or disease, which can cause a buildup of fluid in the hip. If this occurs, it is important to get a proper diagnosis, as different conditions call for different treatment approaches.

Arthritis

Like any joint in the body, the hip joint can develop arthritis. The two most common forms that occur in the hip are osteoarthritis and rheumatoid arthritis. Osteoarthritis occurs when the cartilage in the joint wears away and the bones rub against each other. Rheumatoid arthritis is an autoimmune condition in which the synovial lining of the joint becomes inflamed.

Both of these conditions can cause pain, stiffness and a buildup of fluid in the hip, states the American Academy of Orthopaedic Surgeons 1. X-rays and MRIs can help detect any excess fluid and a physician may need to aspirate some of the fluid to test for disease.

Bursitis

The bursa or fluid filled sacs located within the hip joint, help to provide lubrication and cushioning. However, overuse of the hip area can cause these sacs to become inflamed leading to bursitis, warns MayoClinic.com. Along with fluid accumulation in the joint, there may be pain, stiffness, redness and swelling. This condition can be diagnosed during a physical exam, although other tests may be run to rule out other causes.

Infection

When an infection occurs in the body, the immune system responds in part by causing swelling or a build up of fluid in the affected area. This can happen anywhere in the body, including the hip joint. Infections can occur after surgery, such as a hip replacement, or when bacteria enter the joint through a cut. Infections that start somewhere else in the body that are left untreated, can travel through the bloodstream and enter the hip joint. An infection requires treatment with antibiotics and in severe cases, surgery may be required.

Osteonecrosis

Osteonecrosis is a condition in which the bones do not receive an adequate supply of blood, which causes them to break down. The exact cause of this condition remains unknown; however, the risk is higher in those with inflammatory diseases or who have received treatment for cancer. This condition can also occur in the absence of disease and the hip joint is a common site.

According to the National Institute of Arthritis and Musculoskeletal and Skin Diseases, treatment is required to help prevent permanent disability and it will usually include medications to help reduce swelling in the joint 4. It may be necessary to refrain from weight bearing on the affected hip while it is healing, along with receiving other treatments to help stimulate bone growth.