Effectiveness of Lower Energy Density Extracorporeal Shock Wave Therapy in the Early Stage of Avascular Necrosis of the Femoral Head

OBJECTIVE To evaluate the effectiveness of lower energy flux density (EFD) extracorporeal shock wave therapy (ESWT) in the early stage of avascular necrosis (AVN) of the femoral head. METHODS Nineteen patients and 30 hips were enrolled. All subjects received 4 weekly sessions of ESWT, at different energy levels; group A (n=15; 1,000 shocks/session, EFD per shock 0.12 mJ/mm2) and group B (n=15; 1,000 shocks/session, EFD per shock 0.32 mJ/mm2). We measured pain by using the visual analog scale (VAS), and disability by using the Harris hip score, Hip dysfunction and Osteoarthritis Outcome Score (HOOS), and the Western Ontario and McMaster University Osteoarthritis Index (WOMAC). To determine the effect of the lower EFD ESWT, we assessed the VAS, Harris hip score, HOOS, WOMAC of the subjects before and at 1, 3, and 6 months. RESULTS In both groups, the VAS, Harris hip score, HOOS, and WOMAC scores improved over time (p<0.05). CONCLUSION Lower EFD ESWT may be an effective method to improve the function and to relieve pain in the early stage of AVN.