Avascular necrosis of the femoral head
Understanding this condition
Avascular necrosis (AVN) of the femoral head corresponds to the death of a zone of bone in the femoral head, due to interruption of its blood supply. Bone, as a living tissue, requires a permanent blood supply. When this supply is cut off, the affected area weakens and may eventually collapse.
Several causes are identified: prolonged corticosteroid use, excessive alcohol consumption, trauma, sickle cell disease, deep-sea diving, or sometimes no cause is found. It most often affects young adults between 30 and 50 years of age.
Symptoms
The first sign is generally a groin pain that appears fairly suddenly, sometimes at night, without a clear trigger. At an early stage it can be intermittent and may be mistaken for a simple tendinopathy.
When the necrotic area begins to collapse, pain becomes constant and mechanical, accompanied by a limp and stiffness. The hip loses range of motion.
How can it progress?
Without management, the weakened bone eventually collapses: the perfect sphericity of the femoral head is lost, and the joint becomes incongruent. At this stage, progression to osteoarthritis is rapid and inevitable, within months to a few years.
The earlier the diagnosis is made, the better the chance of preserving the patient's hip. This is why any sudden, unexplained groin pain in a young adult warrants an MRI scan.
Treatment options
At an early stage, before any collapse, core decompression can restore bone circulation and may halt progression. This is a minimally invasive procedure performed through a small incision.
If the femoral head has already collapsed and osteoarthritis is established, total hip replacement is the solution. Early diagnosis is key: a prompt consultation for any unusual hip pain is always worthwhile.