Avascualar Necrosis Hip
What is avascular necrosis of the femoral head (aseptic necrosis)?
Avascular necrosis also known as osteonecrosis means death of bone tissue due to insufficient availability of blood supply. The femoral head is the most common site of avascular necrosis (AVN) as its blood supply renders it vulnerable to ischaemia. The given condition can result into initial breakage of bone and eventually may even collapse it. Multiple hypotheses remain to explain the development of AVN, which include ischaemia (restricted blood supply), direct cellular toxicity and altered differentiation of mesenchyme stem cells. The condition may or may not cause pain.
Causes of aseptic necrosis
Causes of aseptic necrosis include-
- Excess alcohol consumption
- Use of costicosteroids
- Traumatic hip dislocations
- Gaucher’s disease
- Sickle-cell anaemia
- Chemo and radiotherapy
- Primary cushing syndrome
- Decompression sickness
- Radiation exposure
- Pancreatitis
- Smoking cigarettes
- Radiation exposure
- Damage to blood vessels that supply the bone oxygen
- Abnormally thick blood
What are the symptoms of aseptic necrosis?
The beginning of aseptic necrosis is characterized as painless. The affected bone in the later stages develops the following symptoms-
- New onset of hip pain (i.e. occurrence of pain when the hip moves)
- Pain in the groin
- Difficulty in walking
Diagnosis
- Plain X-rays are often normal in the early stages of AVN and the first signs usually occur 6 months after the occurrence of bone death. When present, these changes reflect increased density in the adjacent living bone are most commonly seen as increased density/sclerosis.
- MRI scans facilitate earlier diagnosis and show characteristics changes in the marrow, long before any abnormality is visible on plain radiographs.
Treatment
Pre-collapse AVN
Pre-collapse AVN offers the opportunity for joint preservation and the non-surgical management of AVN for symptomatic (patients with symptoms) or non-symptomatic patients. Protected weight-bearing, bisphosphonates and anticoagulation for AVN associated with hypercoagulability have been reported with variable success.
Post-collapse AVN
There is a general consensus that hip preservation procedures are not recommended in post-collapse AVN. In these cases it is more judicious to consider total hip arthroplasty because the results are more reliable.