Hip Osteonecrosis

Osteonecrosis, also known as avascular necrosis, is a condition in which the blood supply to the femoral head is disrupted, causing significant hip pain. The term “osteonecrosis” translates to “bone death.” When the blood flow to the femoral head is compromised, a section of the bone dies, resulting in pain and stiffness. Initially, only the femoral head, the ball-shaped top of the thigh bone, is affected. However, as the condition advances, the joint surface of the femoral head can collapse, causing painful arthritis.

Causes of Hip Osteonecrosis

Osteonecrosis of the hip occurs when blood flow to the femoral head is interrupted, leading to the death of bone cells in the area and eventual collapse. This can also cause damage to the articular cartilage, leading to arthritis that can cause disability. Although anyone can develop osteonecrosis, it is more common in individuals aged 40-65 and men are more likely to develop the condition than women. While the cause of the lack of blood supply is not always clear, several risk factors have been identified, including hip injury, excessive alcohol consumption, long-term corticosteroid use for conditions such as asthma and arthritis, and certain medical conditions such as sickle cell disease and lupus. Osteonecrosis has also been linked to other conditions, including arterial embolism, thrombosis, vasculitis, and Caisson disease.

Symptoms of Hip Osteonecrosis

The symptoms of hip osteonecrosis can vary depending on the severity and progression of the condition. In the early stages, there may be no symptoms at all. However, as the condition worsens, the following symptoms may occur:

Pain: The most common symptom of hip osteonecrosis is pain, which can be severe and persistent. The pain may be felt in the hip joint, groin, buttocks, or thigh, and may worsen with activity.
Stiffness: Another common symptom is stiffness in the hip joint, which can make it difficult to move the leg.
Limited range of motion: As the condition progresses, the range of motion in the hip joint may become limited, making it difficult to perform normal activities like walking or standing.
Limping: Due to the pain and stiffness, a person with hip osteonecrosis may develop a limp when walking.
Muscle atrophy: In some cases, the muscles surrounding the hip joint may become weaker and smaller due to lack of use.

It is important to note that these symptoms may not appear until the condition has progressed significantly, which is why early diagnosis and treatment is important. If you are experiencing any of these symptoms or have concerns about your hip health, you should see a doctor for evaluation.

Diagnostics of Hip Osteonecrosis

The diagnosis of hip osteonecrosis typically involves a combination of a physical exam, medical history review, and diagnostic tests. Here are some of the methods that doctors use to diagnose hip osteonecrosis:

Physical exam: A doctor will perform a physical examination to assess the range of motion in the hip joint, check for any signs of pain, and look for any visible signs of inflammation or swelling.
Imaging tests: Imaging tests can help to confirm the diagnosis and determine the extent of the damage. The most commonly used imaging tests include X-rays, magnetic resonance imaging (MRI), and computed tomography (CT) scans.
Bone scan: A bone scan is a nuclear imaging test that uses a small amount of radioactive material to detect areas of bone damage or injury. This test can be helpful in diagnosing early stages of osteonecrosis.
Blood tests: In some cases, blood tests may be used to rule out other possible causes of hip pain and inflammation, such as infection or autoimmune disorders.
Biopsy: A biopsy is a more invasive procedure that involves taking a small sample of bone tissue for examination in a laboratory. This test is rarely used for the diagnosis of hip osteonecrosis but may be helpful in certain cases.

If you are experiencing hip pain or have concerns about hip osteonecrosis, it is important to see a doctor for evaluation and diagnosis. Early diagnosis and treatment can help to prevent further damage to the hip joint and improve outcomes

Complications of Hip Osteonecrosis

If left untreated, hip osteonecrosis can lead to serious complications and long-term disability. Here are some of the risks associated with untreated hip osteonecrosis:

Collapse of the femoral head: As the condition progresses, the bone in the femoral head can collapse, leading to significant pain and disability.
Osteoarthritis: The collapse of the femoral head can also cause damage to the articular cartilage, which can lead to osteoarthritis in the hip joint.
Hip replacement surgery: In severe cases, hip replacement surgery may be necessary to replace the damaged joint with an artificial joint.
Limited mobility: The pain and stiffness associated with hip osteonecrosis can make it difficult to perform normal daily activities, such as walking, standing, or climbing stairs
Reduced quality of life: The chronic pain and disability associated with hip osteonecrosis can lead to a reduced quality of life and can impact mental health and well-being.
Increased risk of fractures: The weakened bone in the hip joint can increase the risk of fractures, particularly in older individuals.

It is important to seek treatment for hip osteonecrosis as early as possible to prevent these complications and improve outcomes. Treatment options may include medications, physical therapy, and in some cases, surgery.

Treatment of Hip Osteonecrosis

Depending on the severity of cartilage damage and the response to nonsurgical treatments, your physician may recommend orthopedic surgery.

Synovectomy: A synovectomy involves removing the synovial lining of the joint affected by rheumatoid arthritis to reduce pain and swelling. This procedure is usually used in the early stages of the disease when it is limited to the joint lining and has not yet severely affected the articular cartilage. However, synovitis can recur without ongoing medical management, though synovectomy is now required less frequently due to newer treatments.

Tendon Surgery: If tendons rupture, reconstructive surgery may be necessary to restore function. This may involve tendon repairs or transfers, which can be highly successful in the hand. Trigger fingers and tenosynovitis in the hand and wrist may require partial release of tight tunnels, partial flexor tendon excision in the finger, and tenosynovectomy to prevent tendon ruptures.

Joint Rebalancing: In the early stages of rheumatoid arthritis, joints can become loose and unbalanced, leading to deformities and contractures that interfere with function. If the cartilage is still intact, a surgeon can perform procedures to release tight structures, transfer tendons, and tighten loose ligaments to rebalance the joint alignment and improve function.

Fusion: Fusion of affected joints is the most common type of surgery for RA. During fusion, the bones that form a joint are fused together, eliminating motion in the joint. This is mainly used in joints of the foot and hand and relieves symptoms while allowing good function. Fusion surgery eliminates pain and improves function, but patients may notice a lack of motion.

Joint Replacement Surgery: Joint replacement surgery can be effective in restoring painless joint movement. This procedure involves removing the damaged cartilage and bone and positioning new metal or plastic joint surfaces to restore function. It is especially effective in the hand, and a combination of specific small joint fusions and/or joint replacement improves function significantly. For larger joints such as the elbow, shoulder, hip, and knee, joint replacement surgery can be the difference between disability and an active life.