Using Bisphosphonate Therapy to Treat Avascular Necrosis of the Femoral Head

By: Dr. Sanjay Agarwala and Dr. Sameer Chaudhari

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Avascular necrosis of the femoral head (AVNFH) is reported to be the most common etiologic factor leading to total hip arthroplasty (THA). AVNFH is known to cause a structural failure of the bone in the femoral head, eventually collapsing the architecture and hence causing dysfunction. Following the onset of AVNFH, collapse and arthritis occur at an average of 3 years. The severe symptoms of this disease greatly affect patients’ ability to perform the routine activities of daily life.

To date, various treatment modalities—both conservative and surgical—have been described for the management of AVNFH. Although THA is the most promising surgery for treating patients with this disease, a medical management option that defers surgery is worth exploring.

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Ficat Stage I after 8 years of bisphosphonate therapy.
Courtesy of Drs. Sanjay Agarwala and Sameer Chaudhari

I—Dr. Agarwala—and my fellow researchers were the first from India to report on the beneficial effects of alendronates/bisphosphonates (BPNs) in the management of AVNFH. The rationale behind the use of this therapy is that BPN retards the progression of the disease, which prevents the collapse and hence avoids the need for THA. Our research, which appeared in The Journal of Bone & Joint Surgery, suggested that the progression of the disease can be controlled using BPN therapy. In fact, the study found radiologic improvement of 98 percent in Ficat stage I hips, 92 percent in Ficat stage II hips, and 67 percent in Ficat stage III hips.

Alendronate is considered by many to be the drug of first choice for this progressive disease, regardless of the stage of presentation. In studies, it has been shown that early stages of the disease respond better than the advanced stages, but a significant percentage of AVNFH in advanced stages has been brought under control with BPN therapy, which halted the disease’s progression. Although the results vary depending on the stage of the disease, BPN therapy is a worthwhile option for treating patients with AVNFH, as studies have shown that it may have an immediate and significant response, thereby improving clinical function and slowing disease progression.

A study published The Journal of Arthroplasty found that AVNFH patients who underwent 3 years of BPN therapy benefitted from this therapy for as long as 10 years. A protocol for managing AVNFH may include an initial loading dose of 5 mg of zolendronic acid, with a twice-weekly dosage of 35 mg of alendronate supplemented with calcium and vitamin D. (A smaller dose is known to be absorbed better.) Anti-inflammatory and antacid drugs may be prescribed, as needed. Patients may require a cane or walker during the initial 4 to 6 weeks of therapy until the structural integrity is regained. Similar protocols are followed regardless of patient age or stage of disease unless there is a definitive contraindication for the use of BPN.

In summary, clinical and radiologic results of BPN therapy in the treatment of AVNFH are promising compared to those of patients who are untreated or are treated with other medical modalities or surgeries such as core decompression and osteotomies. BPN therapy favorably alters the natural history of AVNFH and defers the need for THA, especially in younger patients.                    

Dr. Sanjay Agarwala is director, professional services, head of department and chief of surgery, and Dr. Sameer Chaudhari is an associate consultant in the department of orthopedics at P.D. Hinduja National Hospital, in Mahim, Mumbai, India. Drs. Agarwala and Chaudhari are members of the Indian Orthopaedic Association. 

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