Avascular Bone Necrosis (osteonecrosis/aseptic Necrosis/ Ischemic Bone Necrosis)

Question 1

What is avascular necrosis?

Answer 1

ellular death of bone components due to interruption of the blood supply; the bone structures then collapse, resulting in pain, loss of joint function and long-term joint damage.

AVN usually involves the epiphysis (end part of a long bone), such as the femoral and humeral heads and the femoral condyles, but small bones can also be affected. In clinical practice, AVN is most commonly encountered in the hip

Early diagnosis and appropriate intervention can delay the need for joint replacement. However, most patients present late in the disease course. Without treatment, the process is almost always progressive, leading to joint destruction within 5 years.

Question 2

Etiology

Answer 2

• Injuries to bone (broken bone/ dislocated joint)
• Excessive alcohol intake (can cause fatty substances to build up in the blood vessels and decrease blood flow to the bones)
• Long term use of steroids

Less common

• radiation and chemotherapy
• lupus
• Sickle cell anemia
• Decompression disease

Question 3

Clinical presentation

Answer 3

May be asymptomatic

Pain/loss of motion in the affected joint

In the hip, there may be groin pain that spreads down the thigh and knee

In the wrist, there may be wrist pain and weakness in the fingers

In the shoulder, there may be pain and stiffness in the upper arm

In the knee , there may be pain in the lower end of the femur

Question 4

Diagnosis

Answer 4

Usually by x ray ( cannot always detect avascular necrosis)

Earlier indications of avascular necrosis by MRI/ CT/ biopsy

Question 5

Treatment

Answer 5

Based on various factors (age, amount and location of bone, underlying cause, stage of the disease)

Meant to ensure bone and joint survival, prevent additional damage and allow better use of affected joint

• reduced weight bearing
• core decompression
• Osteotomy
• bone graft
• arthroplasty/ total joint replacement
  Other exploratory treatments include medications, combination therapies meant to increase the growth of new bone and blood vessels (electrical stimulation)
  Used alone/ in conjunction with other treatments like core decompression

Question 6

Reduced weight bearing

Answer 6

When diagnosed early, reduced weight bearing may be helpful in removing stress from the affected joint

This may involve the use of crutches/ limitation of certain activities

Question 7

Core decompression

Answer 7

Surgery by which the inner layer of the bone is removed

Most effective for people in the earliest stages of the disease

Question 8

Osteotomy

Answer 8

Surgery reshapes the bone in order to lessen stress in the area affected

Most effective for patients with advanced forms of the disease and when it affects a large are of the bone

Question 9

Bone graft

Answer 9

Healthy bone is transplanted from one part of the patient to the area afffected

This procedure is complex and its effectiveness has not yet been proven

Question 10

Arthroplasty/ total joint replacement

Answer 10

For late stage/destroyed joint

The diseased joint is replaced with artificial parts