Avascular necrosis: Is there a role for biomechanical examination as a potential modality for its detection and treatment?

Abstract

Background: Avascular necrosis (AVN) is often idiopathic and has an incidence of 3/100 000. The prevalence is much higher however in patients who have received steroid therapy such as leukaemia survivors, who have an incidence of 1.2–29%. AVN is most commonly found in weight-bearing epiphyses with the most affected site being the femoral head, so gait abnormalities are to be expected with its progression. Most authors agree that early recognition and treatment of the condition, reduces the disabling effects of it. This review looks at the role of gait analysis in the recognition and treatment of AVN. Discussion: The quality of life of patients with AVN is known to be significantly worse than those without it. Early diagnosis and effective bone protective intervention are thought to be essential for the successful treatment of AVN with high-risk patients likely to benefit from early screening for it. As the majority of AVN is in the lower limb, and the vast majority of that is in the hip, one may assume that gait would be affected when it is present, but very little research has used gait analysis to assess this condition. We postulate that structured gait analysis could form the basis of a conservative approach to the management of hip AVN in cancer survivors. This has the potential to be a more cost effective detection strategy than MRI as well as a method of informing and evaluating conservative therapy for it. Summary: The markedly increased risk of AVN in cancer survivors has the potential to further reduce their quality of life and expose them to invasive surgery. Exploring this issue from a mechanical perspective might not only constitute a novel approach to its detection and treatment, but also reduce the socioeconomic burden related to it. Biomechanical gait analysis has the potential to improve patient experience and improve outcomes.