What is osteonecrosis (avascular necrosis) of the hip? Osteonecrosis of the hip is also known as avascular necrosis (AVN). This is a condition that is brought about by a permanent or temporary loss of blood circulation to the bone. Lack of fresh blood in the bone may result in the death of bone tissue, which may ultimately cause the bone to collapse. 

Worse still, if osteonecrosis occurs near a joint, the joint surface will also collapse. Avascular necrosis can happen in any type of bone within your body. However, it often occurs in the ends or epiphysis of long bones such as the femur or thigh bone. 

Hip Osteonecrosis Anatomy

Typically, your hip consists of a ball and socket joint. The hip socket is the acetabulum (a section of the large pelvis bone), while the ball is the femoral head.  The  ball is the uppermost end of the thigh bone or the femur. The surface area of the ball and socket is protected by articular cartilage. This is a smooth and slippery substance that covers the bones and makes them glide effortlessly against each other. 

Causes of Osteonecrosis of the Hip

Avascular necrosis of the femoral head may develop when the blood supply to your thigh bone is disrupted. As you may know, without adequate nourishment, your hip bone head will die gradually and eventually collapse.  

This collapse of the femoral head in your hip can cause the articular cartilage that protects the hip bones to collapse. The whole process can potentially lead to disabling arthritis. Reduced blood in the femoral head can be due to these reasons: 

• Bone or joint trauma resulting from dislocated joint or any other injury. Bone or joint trauma can damage nearby nerves and blood vessels. 
• Radiation from cancer treatment may weaken your hip bone and damage blood vessels, leading to disruption of the blood supply into the femoral head.
• The lipids (fat) may block tiny blood vessels, making it difficult for fresh blood to reach the inside part of the femoral head. 
• Diseases such as Gaucher’s disease and sickle cell anemia may contribute to the limited blood supply to the bones.
• Some lifestyle activities such as smoking, excessive consumption of alcohol, and prolonged corticosteroid use can also cause avascular necrosis. 

Osteonecrosis of the hip is a condition that can affect anyone regardless of age. But the most affected individuals are those aged between 40 and 65 years. Furthermore, more men are likely to develop avascular necrosis hip than women.

Symptoms of Osteonecrosis (avascular necrosis) of the Hip

Unlike many other conditions, avascular necrosis does not show symptoms during the first days. It takes weeks or months before symptoms appear. Below are some of the common symptoms associated with avascular necrosis:

• Stiff joints in the pelvic region – groin/buttocks
• Chronic pain around the hip
• Reduced range of motion
• Difficulty going up the stairs, walking, or standing
• Limping due to avascular necrosis hip
• Intermittent pain and discomfort come at ease when you exert some pressure on your hip bone. 

Symptoms of avascular necrosis are almost similar to those of other medical conditions, particularly bone problems. Therefore, make sure to consult with your physician for diagnosis and treatment at the right time if you notice some of the above-mentioned osteonecrosis symptoms.

Risk Factors of Osteonecrosis of the Hip

There is no known major cause of osteonecrosis or lack of blood supply to the hip bone. Regardless, a number of medical professionals have managed to identify several risk factors that can lead to avascular necrosis of the femoral head. These risk factors include:

Injury: This happens more often due to hip fractures, hip dislocations, and other injuries that damage the blood vessels in the femur bone. These injuries impair blood circulation in and out of the femoral head.

Excessive alcohol consumption: Overconsumption of alcoholic beverages for a long time can contribute to the formation of fatty deposits in your blood vessels. The presence of fatty deposits in the blood vessels may elevate cortisone levels, causing a decrease in the blood that flows into the femur.

Corticosteroid medicines. Even though most steroid medications treat conditions such as rheumatoid arthritis, asthma, or systemic lupus erythematosus, they can also become the leading cause of avascular necrosis hip. However, there is no research connecting long-term corticosteroid use to avascular necrosis, though the correlation exists.

Medical conditions: Avascular necrosis is associated with medical conditions that include Caisson disease, Gaucher’s disease, sickle cell anemia, vasculitis, arterial embolism, thrombosis, Crohn’s disease, and systemic lupus erythematosus. 

Other risk factors are HIV, autoimmune disease, hyperlipidemia, decompression disease, chemotherapy, and radiation treatment options. 

How To Diagnose Osteonecrosis (Avascular Necrosis) of the Hip?

Your doctor may use a physical examination and medical history to perform a diagnostic test for avascular necrosis. In addition, the doctor may order one or more of these tests to be done to rule out the possibility of other medical conditions:

1. X-Ray: This type of diagnosis uses powerful invisible electromagnetic beams to create images of bones, organs, and internal tissues onto film for further analysis.
2. MRI: Magnetic resonance imaging test uses powerful magnets, a computer, and radio frequencies to produce detailed images of structures and organs within the body. Your doctor will use these images to determine if you have avascular necrosis or not. 
3. Lab Tests: Different laboratory tests may also be used during the diagnosis process of avascular necrosis hip. 

Osteonecrosis (avascular necrosis) of the Hip Treatments

Once the diagnosis of avascular necrosis of the hip is over and the results turn out to be positive, your doctor may suggest the most appropriate  osteonecrosis treatment option such as:

Nonsurgical Treatment

With this option, your healthcare provider will prescribe anti-inflammatory medications to help relieve pain in your hip joint. Also, the doctor will suggest the use of crutches to reduce pain and slow down the progression of avascular necrosis hip. In addition, activity changes may come in handy, especially at the earliest avascular necrosis stages. There are other medications your doctor may consider.  

Surgical Treatment

This is the most successful treatment option for patients with avascular necrosis. With this treatment option, different surgical procedures are used, including core decompression, osteochondral grafting, vascularized fibula graft, and total hip replacement.

Experts at Sforzo l  Dillingham l  Orthopedic + Sports Medicine will handle your osteonecrosis problem, from diagnosis to treatment to recovery. Dr. Charles E. Stewart can perform several procedures that involve minimally invasive techniques to speed recovery and protect nearby tissues, nerves, and tendons. All of the  doctors are board-certified orthopedic surgeons and fellow-trained in handling complex surgical procedures that involve hand, wrist, elbow, forearm, and shoulders. They also specialize in joint replacement, fracture repair, and arthritis surgery. 

Dr. Charles E. Stewart is a board-certified orthopedic surgeon at Sforzo l  Dillingham l Stewart  Orthopedics + Sports Medicines. In addition, he is  fellowship-trained in total hip arthroplasty, and anterior approach for total hip replacement, 

Prevention of Osteonecrosis (Avascular Necrosis) of the Hip

There are many ways to prevent the risk of avascular necrosis problems. These prevention measures are in place to help you improve your health and live happily. Some of these effective ways to prevent avascular necrosis hip include:

Limiting alcohol consumption: Heavy drinking of alcohol is one of the major reasons for developing avascular necrosis hip. 

Maintaining low cholesterol levels: Small bits of fat are considered the most common substances that block the blood supply to the hip bone. When your hip joint or hip bone lacks enough blood, avascular necrosis occurs, making your life a little bit difficult.

Monitoring steroid use: During the diagnosis, allow your healthcare provider to know more about your present and past medical history. This may include the use of steroids to treat other conditions. Higher doses of steroids can cause bone damage that may worsen over time.

Quit cigarette smoking: Heavy smoking of cigarettes is likely to increase the risk of avascular necrosis.

Final Thought

The exact cause of avascular necrosis is yet to be known, although common causes may include dislocated hips, broken bones, alcohol use/ abuse, and radiation therapy. In addition, those affected need a surgical operation that may involve joint operation to help relieve pain in joints and improve mobility. If you suspect that you have osteonecrosis, contact Sforzo | Dillingham | Stewart Orthopedics + Sports Medicine for consultation, diagnosis, and treatment.