Paget’s Disease of Bone Affecting Site With Orthopedic Hardware

Abstract

Introduction: Paget’s disease of bone is a focal disorder of accelerated bone remodeling which leads to bone hypertrophy, cortical expansion and abnormal bone architecture. Either a single bone (monostotic) or multiple bones (polyostotic) can be affected. Although it has been suggested to be caused by a chronic slow viral infection of the bone, a cause and effect relationship has not been clearly established. Therefore, the etiology of Paget’s disease remains an uncertain and controversial topic of discussion. Case Description: A 62-year-old African American male with a past medical history of a left tibial fracture presented with worsening left leg pain for the past 6 months. He denied any recent traumatic events, falls or strenuous physical activity. Since the pain started, his ambulation had been significantly affected requiring the use of a cane for gait stability. His left tibial fracture occurred over 20 years ago after landing on another person’s foot while playing basketball. It was surgically treated with intramedullary nailing and metal rod insertion into the canal of the tibia. Since then, he remained an active person with no physical limitations or ailments until the recent developments that brought him to clinic. A left leg CT-Scan ordered for evaluation of the tibial hardware revealed cortical thickening, marrow expansion and coarse trabeculae throughout the majority of the tibia consistent with Paget’s disease. The hardware was intact with no peri-hardware lucency to suggest loosening or infection. His laboratory workup showed a normal alkaline phosphatase level (94 U/L; normal range 40 - 115 U/L) and low 25-OH Vitamin D level of 14. A Radionuclide Bone Scan done for evaluation of location and extent of bone disease resulted in diffusely abnormal uptake present in the left tibia with no other locations of suspicious uptake. After his 25-OH Vitamin D levels were replenished, a dose of Zoledronic acid IV infusion was given with significant improvement of pain several months after. Discussion: Paget’s disease of bone is the second most common bone disease after osteoporosis. Affected skeletal sites develop a disorganized mosaic of woven and lamellar bone more susceptible to deformities and fractures than normal bone. It is often asymptomatic, but classical features include bone pain experienced either at rest or with motion, cutaneous erythema and warmth. The goal of medical therapy is to relieve symptoms and to prevent future complications with high potency bisphosphonates. Although it is well known that Paget’s disease increase the risk of fractures, this case brings up an interesting take about the possibility of fractures managed with hardware placement increasing the risk of Paget’s disease in the involved site.