Rationale for Bisphosphonate (Ibandronate/Zoledronate) Injection
Avascular necrosis of the femoral head and talar head is a potentially disabling condition that can lead to premature arthritis in young patients. The condition involves interruption of the blood supply to the femoral head from various etiologies including trauma, sickle cell disease, steroid use, liver disease, alcoholism, and idiopathic causes.
The bone ischemia causes cell death and calcification of the marrow space in the bone. As the bone revascularizes, the dead bone is removed by new cells called osteoclasts before another type of cells called osteoblasts lay down new bone. The process of bone removal usually outpaces new bone formation leaving the bone structurally weak and vulnerable to compression fractures from physiologic stresses. These fractures cause deformation of the normal shape of the bone, leading to cartilage damage and arthritis.
Several surgical interventions like core decompression, bone grafting, and bone marrow injection were attempted to prevent bone deformation with unsatisfactory results. Several animal studies and a few clinical studies showed that administration of bisphosphonates can decrease the incidence of femoral head deformation. They act on osteoclasts and inhibit their weakening effect on the bone.
Treatment and Prevention of Osteoporosis
Treatment and prevention of osteoporosis remains the most common indication for bisphosphonate use, and a number of drugs, including etidronate, alendronate, risedronate, and Zoledronate/Ibandronate, have gained FDA approval for this indication. These drugs have proven useful in both the primary and secondary prevention, as well as treatment, of osteoporosis and osteoporosis-related fractures.
The list of off-label uses and indications for bisphosphonates continues to expand. They have been used in patients following total joint arthroplasty to prevent osteolytic-associated complications, and increasingly in the management of pediatric conditions associated with osteopenia and osteoporosis, including cerebral palsy, fibrous dysplasia, and osteogenesis imperfecta.
Oral and Intravenous Administration
Bisphosphonates are approved for oral and intravenous administration. Oral bisphosphonates can cause gastro-esophageal ulcers; intravenous bisphosphonates can cause febrile reactions. Both routes of administration can rarely cause hypocalcaemia, stress fractures, severe pain, atrial fibrillation, and jaw necrosis in elderly cancer patients.
Direct Injection (Off-label Use)
Direct injection of bisphosphonates into the affected bone has been studied as an alternative to systemic administration. This approach may allow a higher local concentration with potentially fewer systemic side effects. This use is investigational and not FDA-approved for avascular necrosis.
Patient Consent Forms