Avascular necrosis of the femoral head (AVNFH) is a condition that involves osteonecrosis of the femoral head, due to regional ischemia. It may be caused by trauma or other non-traumatic pathologies, and may ultimately lead to a collapse of the femoral section that has suffered osteonecrosis.
Avascular necrosis of the femoral head (AVNFH) is a pathological condition that is otherwise referred to as osteonecrosis of the femoral head or hip osteonecrosis, is more commonly diagnosed amongst individuals aged 20 to 40 and does not tend to subside spontaneously .
It is a disorder that usually develops insidiously and does not produce symptoms at the initial stage. Radiating pain that extends to the ipsilateral buttock or knee is frequently reported in symptomatic patients, alongside restricted hip mobility. Particular movements, such as an intense internal rotation, or weight-bearing, can exacerbate the pain. Bilateral participation of the femoral heads has been documented, although the most common presentation involves unilateral involvement . As the disease progresses, pain is aggravated; it eventually appears both when the patient moves and at rest. Limping may be present as well. Accompanying symptoms include tenderness in the region of the hip and a deformed joint with muscle wasting in severely progressed stages. The vast majority of individuals affected by AVNFH who have not received treatment in time appear with a collapse of the head of the femur   .
The workup involved in a potential case of AVNFH includes plain hip radiographs and a magnetic resonance imaging scan (MRI scan) of the area. Laboratory evaluation is of no diagnostic value, and, even though a biopsy can ascertain the diagnosis, it is not commonly required.
The radiographic depiction of the presumably affected hip is the first step in the evaluation process of patients who report pain in the femoral region and are in risk for AVNFH . Plain anteroposterior and frog-leg lateral images are obtained in order to assess a potential AVNFH. Subtle lucencies, sclerotic or cystic lesions do raise suspicion for an osteonecrotic state, in which case an MRI is performed . The latter is more sensitive in the initial phase, when a plain radiograph may be inconclusive .
In general, AVNFH is classified with the Ficat and Arlet and the Steinberg University of Pennsylvania systems . The former utilizes radiographs, MRI findings and patient symptoms to categorize the condition . A more recent classification system is that of the Association Research Circulation Osseous (ARCO), which proposes that plain radiographs, MRI scans, and histology should all be used in order to produce an accurate classification status. Computerized tomography scans (CT scans) can be performed in the evaluation process, but not in a diagnostic sense. They are used to facilitate surgical planning and to illustrate the severity of a potential femoral head collapse .