Bone infarction is a medical condition where bone tissue dies due to an interruption of its blood supply. This prevents oxygen and nutrients from reaching bone cells, leading to their demise. It affects the structural integrity and function of the affected bone.
What is Bone Infarction?
Bone infarction, also known as avascular necrosis, occurs when the blood supply to a segment of bone is disrupted, causing bone cells to die. This cellular death weakens the bone structure over time. Without consistent blood flow, the bone’s internal framework begins to collapse.
This condition can affect any bone in the body, but it most frequently impacts the ends of long bones that form part of a joint. Common sites include the femoral head in the hip, the humeral head in the shoulder, and bones in the knee, ankle, and jaw. Over time, the dead bone tissue can collapse, leading to joint pain and dysfunction.
What Causes Bone Infarction?
Bone infarction can arise from various factors that compromise blood flow to bone tissue. Prolonged use of corticosteroids is a significant risk factor, as these medications can interfere with fat metabolism, potentially leading to fat embolisms that block small blood vessels supplying bone. Excessive alcohol consumption is also linked to the condition, possibly by increasing lipid levels in the blood, which can obstruct capillaries in the bone.
Traumatic injuries, including fractures or dislocations, can directly damage the blood vessels that nourish the bone. Certain medical conditions also predispose individuals to bone infarction, including sickle cell disease, lupus, Gaucher disease, and pancreatitis.
Deep sea diving poses a risk due to decompression sickness, where nitrogen bubbles form in the blood and can block vessels. Radiation therapy can damage bone cells and their blood supply. Organ transplantation often requires high-dose corticosteroid use, increasing the likelihood of bone infarction.
How Bone Infarction is Identified
Individuals with bone infarction often experience pain that gradually worsens, especially with activity or weight-bearing. This pain can be localized to the affected bone or joint, and it may become more persistent over time, even at rest. As the condition progresses, a person might notice a limited range of motion in the affected joint and increasing stiffness.
The diagnostic process typically begins with a physical examination, where a doctor assesses the patient’s pain, tenderness, and joint mobility. Imaging techniques are then used to confirm the diagnosis and determine the extent of bone damage. X-rays may show changes in the bone structure, but these changes often appear in later stages.
Magnetic resonance imaging (MRI) is considered the most sensitive imaging method for early detection of bone infarction, as it can reveal changes in bone marrow before structural collapse occurs. Computerized tomography (CT) scans can provide detailed cross-sectional images of the bone, helping to assess the degree of collapse and joint surface damage. Bone scans can also identify areas of reduced blood flow or increased bone turnover.
Managing Bone Infarction
Managing bone infarction aims to alleviate pain, preserve joint function, and prevent further bone damage or collapse. Non-surgical approaches are often the first line of treatment, particularly in early stages. These include rest, which reduces stress on the affected bone, and pain medication, such as non-steroidal anti-inflammatory drugs (NSAIDs), to manage discomfort.
Physical therapy can help maintain joint mobility and strengthen surrounding muscles. Using crutches or other assistive devices can reduce weight-bearing on the affected limb, allowing the bone to heal. In some cases, blood thinners may be prescribed to improve blood flow, and bisphosphonates might be used to slow bone breakdown.
When non-surgical methods are insufficient or the condition progresses, surgical interventions become necessary. Core decompression is a common procedure where small holes are drilled into the affected bone to reduce pressure and promote new blood vessel growth, potentially preventing collapse.
Bone grafting involves transplanting healthy bone tissue from another part of the body or a donor to replace the damaged area. Osteotomy is a procedure that involves cutting and realigning the bone to shift weight-bearing away from the damaged area. In advanced stages, particularly when the joint has collapsed significantly, joint replacement surgery, such as total hip replacement, may be the most effective option to restore function and relieve pain.
Living with Bone Infarction
Living with bone infarction often involves ongoing management to address the condition’s progression and potential complications. Without intervention, the affected bone may continue to weaken and collapse, potentially leading to severe joint damage.
Regular medical monitoring, including follow-up imaging, is important to track the condition’s stability or progression. Lifestyle adjustments, such as avoiding high-impact activities or prolonged weight-bearing on the affected joint, can help minimize stress on the bone. Rehabilitation through physical therapy plays a role in maintaining joint flexibility and strength, helping individuals adapt to the long-term implications of bone infarction.