AVASCULAR NECROSIS OF THE HIP

Osteonecrosis of the hip is a painful disorder resulting from disruption of blood supply to the femoral head. Bone cells require a continuous blood flow to maintain viability. When blood supply is compromised, osteonecrosis may develop, potentially leading to joint destruction and severe arthritis. Although osteonecrosis can affect any bone, it most commonly occurs in the hip. Collapse of the articular cartilage covering the hip joint may also occur, resulting in disabling arthritis.

What are the potential risk factors of avascular necrosis of the hip?

• Injuries such as hip fractures or hip dislocations, which may damage blood vessels and interrupt blood flow to the femoral head
• A broken bone or dislocated joint that stops blood supply to a section of bone
• Excessive alcohol consumption, which may lead to fatty deposits accumulating within blood vessels and reduce circulation to bone tissue
• Long-term use of high-dose corticosteroid medications prescribed for conditions such as systemic lupus erythematosus, rheumatoid arthritis, and asthma
• Certain underlying medical conditions that affect blood circulation and bone health

Medical conditions associated with avascular necrosis may include:

• Pancreatitis
• Gaucher disease
• HIV/AIDS
• Systemic lupus erythematosus
• Sickle cell anaemia
• Decompression sickness, also known as diver’s disease or the bends
• Certain cancers, such as leukaemia

Although avascular necrosis can affect anyone, it is most commonly diagnosed in adults between the ages of 30 and 50.

What are the common signs of avascular necrosis of the hip

Osteonecrosis progresses in stages, with hip pain as the initial symptom. Patients may experience a throbbing pain or dull ache in the buttock or groin. As the disease advances, standing and bearing weight on the joint becomes increasingly difficult, and hip movement becomes more painful. Disease progression may occur over several months to a year.

How is avascular necrosis of the hip diagnosed?

Dr van Niekerk will perform a thorough clinical assessment and discuss your symptoms, medical history, lifestyle factors, and any previous medical treatments that may increase the risk of avascular necrosis.

A physical examination is typically followed by imaging studies to evaluate the condition of the hip joint and surrounding bone structures. Diagnostic investigations may include:

• X-rays to assess bone damage and joint changes
• MRI scans, which are highly effective in detecting early signs of osteonecrosis before significant bone collapse occurs
• Additional imaging studies when required to determine the severity and progression of the condition

Early diagnosis of avascular necrosis is important, as prompt treatment may help slow disease progression and improve long-term outcomes.

Treatment of Avascular Necrosis of the Hip

Non-surgical treatments, including activity modification, assistive walking aids, and anti-inflammatory medications, provide temporary symptom relief and may delay disease progression. Surgical intervention is generally regarded as a more definitive treatment.

Surgical interventions consist of the following:

• A vascularised fibula graft entails transplanting a segment of the fibula along with its blood supply to restore circulation and promote healing in the area affected by osteonecrosis.
• Total hip replacement is indicated in advanced stages of the disease, when the femoral head has completely collapsed.