Avascular Necrosis

Overview

Avascular necrosis is a process through which bone tissue dies due to not receiving an adequate blood supply. This can occur anywhere in the body, however, there are certain locations that are more prone to develop avascular necrosis – for example, femoral head, talus and scaphoid.

Causes

There are numerous different possible causes of avascular necrosis: it is associated with the use of certain drugs (e.g. prednisone), it can occur after a major trauma, is associated with other medical problems such as antiphospholipid syndrome or protein C and S deficiency, is linked to smoking, is a complication of certain chemotherapy drugs and has also been shown to be associated with deep sea divers who experience “the bends”. However, there are many cases of avascular necrosis that do not have an obvious identifiable cause. These cases are sometimes referred to as “idiopathic”.

X-ray showing avascular necrosis of the hip joint

X-ray showing avascular necrosis of the hip joint.

Symptoms

For many, the first sign that they might be suffering from avascular necrosis is development of pain in or around the affected area. In cases where avascular necrosis develops in the femoral head this will present as hip pain, for patients with avascular necrosis of the talus this will present as ankle or foot pain and more generally, whichever area of the body has suffered avascular necrosis will begin to become painful, particularly with movement or weight-bearing.

It is important to seek medical attention for any persistent pain in or around a joint, as avascular necrosis can show up on an x-ray even early on in the process. However, even if it does not, there are other ways to be able to diagnose the early stages of avascular necrosis. CT scans and, more commonly, MRI scans can give your physician more information regarding the bone itself as well as the cartilage in joints and the soft tissue reaction that may also be occurring

Treatment

There are a number of surgical procedures that have been shown to be beneficial in avascular necrosis patients, particularly in bones that form joints. It is also important to establish a clear cause of the avascular necrosis. If possible, cessation of the offending drug or treatment plays an equally important role in the treatment as does any surgical procedure available.

This can prove challenging, as patients are often taking these medications in relation to other medical conditions, and so may be unable to stop taking these medications. In these instances it becomes especially important to discuss with your orthopedic surgeon and the physician treating you for any other medical condition that you have developed avascular necrosis, and discuss the consequences of continuing to take the medication as well as the possible consequences of stopping the medication and any possible alternatives to the medication that may be available to you.

Unfortunately, in cases of advanced avascular necrosis, it may not be possible to halt the progression as it may have caused destruction of the bony anatomy to such a degree that more invasive surgery may be necessary. These surgical procedures can include osteochondral allograft, resections, arthroplasty and possibly even fusion.

Summary

Avascular necrosis is a problematic condition that causes gradual death of bone tissue as a result of inadequate blood supply to that part of the bone. It has numerous possible causes, which are important to identify as early as possible so that they may be removed or at least mitigated. Catching the process early gives the patient a greater chance of recovering from it without requiring surgery, however more advanced cases may require surgical intervention to relieve symptoms.

Dr. Sebastian Heaven
Orthopedic surgeon at London Health Sciences Centre (LHSC)

I provide Orthopaedic patient care at several different locations, including a Regional Joint Assessment Centre, a Level 1 Trauma Centre and a District General Hospital. My scope of practice is broad and includes Trauma, Arthroplasty and Sports Orthopaedics.

My areas of special interest include Primary and Revision Arthroplasty, Periprosthetic Fracture Management and general orthopaedic trauma management in isolation and in the context of complex polytrauma patients. I also have clinical research interests in these areas, as well the development of interprofessional relationships between trauma team members and fellow healthcare professionals.

I have personally written all or most of what's on this page for Complete Orthopedics, and approve the use of my content.