Objective: To assess the prevalence of osteoporosis (OP) in patients with osteoarthritis (OA) undergoing total knee arthroplasty (TKA) or total hip arthroplasty (THA).
Methods: In patients with OA undergoing TKA or THA, plain radiographs of thoracic and lumbar spine were examined for the presence of vertebral fracture (VFx) between T4-L5, using the semiquantative method advocated by Genant et al. Lumbar spine and femoral bone mineral density (BMD) were measured using dual-energy X-ray absorptiometry. OP was defined as a BMD of less than 70% of peak bone mass according to the criteria of the Japanese Society for Bone and Mineral Research.
Results: The prevalence of VFx in patients with OA undergoing THA in the 4th or less, 5th, 6th, 7th, or 8th decade of life and beyond were 0%, 10.0%, 14.3%, 15.4% and 25.0% for men, and 0%, 5.8%, 21.6%, 23.9% and 35.0% for women, respectively. The prevalence of VFx in patients with OA undergoing TKA for the same age groups were 0%, 0%, 0%, 0% and 16.7% for men, and 0%, 0%, 5.9%, 10.4% and 11.8% for women, respectively. The prevalence of OP of the lumbar spine in patients with OA undergoing THA in the same age groups were 0%, 0%, 0%, 11.0% and 0% for men, and 0%, 3.3%, 6.0%, 7.3% and 11.8% for women, respectively. The prevalence of OP of the lumbar spine in patients with OA undergoing TKA in the same age groups were 0%, 0%, 25.0%, 0% and 0% for men, and 0%, 0%, 0%, 6.1% and 9.1% for women, respectively. The prevalence of OP at femoral neck in patients with OA undergoing THA in the same age groups were 0%, 0%, 0%, 11.0% and 0% for men, and 0%, 1.9%, 10.5%, 25.6% and 46.2% for women, respectively. The prevalence of OP at femoral neck in patients with OA undergoing TKA in the same age groups were 0%, 0%, 0%, 0% and 25.0% for men, and 0%, 0%, 0%, 18.8% and 22.2% for women, respectively.
Conclusion: The following pattern was observed in patients with OA undergoing TKA or THA: Firstly, the prevalence of VFx tended to be higher in women than in men. Secondly, the prevalence of VFx tended to be higher with increasing age in both genders. Lastly, the prevalence of OP tended to be greater in BMD at the femoral neck than at the lumbar spine.
