A Paradigm Shift in Osteonecrosis Treatment with Bisphosphonates: A 20-Year Study

Bisphosphonates are proven to be effective in obviating the need for surgical intervention in osteonecrosis of the femoral head. However, the late onset of pain relief hampers compliance. We present the clinical and radiographic outcome of a combination therapy compared with alendronate-only therapy for the management of osteonecrosis of the femoral head. METHODS: The data of patients diagnosed with osteonecrosis of the femoral head from January 2001 to January 2017 were retrospectively analyzed. The first group, the alendronate treatment group, comprised 432 hips (358 patients) diagnosed from January 2001 to January 2009 and treated with 10-mg oral alendronate daily for 3 years. The second group, the combination treatment group, comprised 442 hips (386 patients) diagnosed from February 2009 to January 2017 and treated with a combination therapy of 35-mg oral alendronate twice weekly and 5-mg intravenous zoledronic acid once annually for 3 years. Clinical assessment was performed using the Harris hip score, the visual analog scale (VAS) pain score, and the clinical failure rate. Radiographic assessment was performed for progression and collapse. RESULTS: In the alendronate treatment group, at a mean follow-up of 129.6 months (range, 60 to 220 months), 74.5% did not require a surgical procedure, and, in the combination treatment group, at a mean follow-up of 69 months (range, 37 to 105 months), 88.9% did not require a surgical procedure. The clinical failure rate at 3 years was 4% for stage I, 11% for stage II, and 29% for stage III in the alendronate treatment group, and it was 5% for stage I, 9% for stage II, and 32% for stage III in the combination treatment group. Patients in the combination treatment group had a significantly better improvement in VAS score at 6 weeks (from 7.10 to 3.66) compared with patients in the alendronate treatment group (from 7.93 to 7.00). CONCLUSIONS: Our study shows that both oral alendronate-only therapy and bisphosphonate combination therapy retard the progression of disease, reduce the rate of collapse, and, hence, reduce the need for joint replacement surgery. However, bisphosphonate combination therapy offers earlier improvement in pain and functional scores compared with oral alendronate therapy only. LEVEL OF EVIDENCE: Therapeutic Level III. See Instructions for Authors for a complete description of levels of evidence.