Efficacy of alendronate, a bisphosphonate, in the treatment of AVN of the hip. A prospective open-label study

Objective. To study the efficacy of alendronate, in the treatment of avascular necrosis (AVN) of the hip. Methods. Sixty patients with AVN of the hip (100 hips with AVN) were studied. The follow-up period ranged from 3 months to 5 yr. The most common cause of AVN was steroids. Parameters studied were walking time, standing time, pain and disability on a visual analogue scale (VAS), range of motion of the hip, X-ray and MRI of the hip. All patients were treated with alendronate 10 mg/day (or 70 mg/week) along with 500-1000 mg of daily calcium and vitamin D supplements, and were advised to avoid weight-bearing. NSAIDs and analgesics were permitted as needed and were recorded. Results. Forty-one patients (71 AVN hips) with AVN have been followed up for a minimum of 1 yr, 24 patients (42 AVN hips) for 2 yr and 21 patients (37 AVN hips) for more than 2 yr (average 37 month). Fourteen patients have been followed up for less than 1 yr (3-9 months). Significant reduction in pain and disability scores (P<0.001) and significant increase in standing and walking time (P<0.001) were observed. All hip movements improved at 1 yr (P value 0.000-0.009) with an insignificant decline after that (P>0.001). Radiologically, the hips either stabilized in the same grade or progressed by one grade. MRI showed a decrease in marrow oedema in most cases at the 1-yr follow-up. Six patients (10 hips) required surgery and there were two (three hips) dropouts. The drug was well tolerated and there was a reduction in NSAID requirement. Conclusion. Alendronate reduces pain, improves function and retards AVN progression. Early surgical intervention can be avoided in most patients.