Avascular Necrosis

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 Definition/Description

avascular necrosis (also known as; osteonecrosis, bone infarction, aseptic necrosis, ischemic bone necrosis and AVN) is a condition where bone tissue dies due to a lack of blood supply. This decrease in blood supply causes a decrease in oxygen and nutrition delivery to the bone, which leads to multiple breaks in the bone and eventual collapse of the affected bone.

 Epidemiology/Etiology

Avascular necrosis can be a result from an earlier bone trauma, such as a break in the bone, a dislocation or medical conditions like Sickle cell anemia and Lupus. In most cases, avascular necrosis seems to be associated with steroid abuse or heavy drinking.

Clinical Presentation

The symptoms include pain and loss of motion in the affected joint. In some cases, the condition is diagnosed during routine x-ray imaging, due to a lack of symptoms.
The most common location for this condition to manifest, is the caput, collum of the femur, the humerus and the knee joint.

avascular necrosis can be classified into 5 different stages;

Stage 1: Radiographic changes are absent and MRI scan is required for identification.

Stage 2: First stage with radiographic changes. This stage is characterized by sclerosis of the superior central portion of the joint head.

Stage 3: In this stage, the articular surface is depressed so that the round contour is compromised, without being significantly deformed.

Stage 4: This stage is characterized by a wide collapse of the subchondral bone and destruction of the underlying trabecular pattern. This can lead to secondary arthritis.

Stage 5: The final stage where both articular surfaces are affected, which leads to a dysfunctional joint.

Diagnostic Procedures

osteonecrosis can be diagnosed with a thorough check of the historical background of the patient, combined with physical examination. Steroid exposure and alcohol abuse are important risk factors. The age of the patient can also provide clues to the disease, because patients with osteonecrosis are generally younger than those with osteoarthritis. Locking, popping, or a painful click during mobilization of the affected joint can point to the presence of loose osteochondral fragments.  In further stages of the desease, loss of mobilization and increased pain can be detected.
Once osteonecrosis is detected, the physician has to check the other joints at risk. Especially hip, shoulder and knee.
Standard radiographs can confirm the diagnose. If not, the MRI can help in the diagnose.

Outcome Measures

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Management / Interventions

appropriate treatment for avascular necrosis is necessary to keep joints from breaking down. If untreated, most patients will experience severe pain and limitation in movement within 2 years. Although physical therapy cannot cure avascular necrosis, it can slow down the progression of the disease and decrease the associated pain. It is suggested that patients with stage 1 and 2 osteonecrosis could have benefits from a physical therapy , but most patients will eventually need surgical treatment, such as core decompression or arthroplasty.

nonoperative treatment concludes 3 major goals;

1. Relief of symptoms
2. Prevention of disease progression
3. Improvement of functionality

Nonoperative treatment begins with patient education and addressing known risk factors, such as smoking and alcohol abuse. In addition, corticosteroids should be avoided.
To relieve the patient from symptoms crutches or other weight-bearing devices can be introduced. It is the job of the physical therapist to teach the patients how to correctly use them.
Physical therapy treatment focuses on exercices to maintain joint mobility and strengthen the muscles around the affected joint, which will decrease the weight on the joint. Electrical stimulation and ultrasound can be used to stimulate bone growth. During physical therapy, excessive compressive and shear forces need to be avoided.

Differential Diagnosis

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Key Evidence

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Resources

Gruson K, Kwon Y, “Atraumatic Osteonecrosis of the Humeral Head”, Bulletin of the NYU Hospital for Joint Diseases 2009;67(1):6-14[a1]
Lee MS, Hsieh PH, Shih CH, Wang CJ, “Non-traumatic Osteonecrosis of the Femoral Head – From Clinical to Bench”, Chang Gung Med J Vol. 33 No. 4, 2010 [a1]
Huijbregts P, “Osteonecrosis of the Humeral Head: A Literature Review and Two Case Studies”, The Journal of Manual & Manipulative Therapy, Vol. 8 No. 4 (2000), 175-182. [a1]
Hasan S, Romeo A, “Nontraumatic osteonecrosis of the humeral head”, Journal of Shoulder and Elbow Surgery, 2002[a1]

Case Studies

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References

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