Teriparatide Administration Increases Periprosthetic Bone Mineral Density After Total Knee Arthroplasty: A Prospective Study

Teriparatide is a currently available therapeutic agent for osteoporosis. Previous studies have reported that teriparatide affects periprosthetic bone mineral density (BMD) after total knee arthroplasty (TKA). However, little agreement has been reached concerning the treatment of periprosthetic BMD after TKA with teriparatide. Moreover, BMD in the femoral and tibial sides of the joints together has never been examined. We investigated the efficacy of teriparatide to inhibit BMD loss in the femoral and tibial side and considered complications such as migration and periprosthetic fractures after TKA. Twenty-two knees in 17 patients were included in this study, and a control group of patients who underwent TKA was identified according to their medical records. Dual-energy X-ray absorptiometry was performed for different locations (knee, hip, and lumbar spine), and regions of interest were measured to estimate BMD at initiation of the study as a baseline reference, followed by subsequent measurements at 6 and 12 months. As a result of adjusting the difference between the BMDs of the 2 groups at initiation, there was a significant increase in R3 (posterior condyle) and R4 (lateral) at 6 months. Furthermore, there was a significant increase in R2 (anterior condyle), R3 (posterior condyle), and R6 (tibial diaphysis) at 12 months. The study group had a higher adjusted mean BMD in all regions than did the control group at 6 and 12 months. Teriparatide may be a reasonable treatment option for osteoporotic patients to preserve or improve periprosthetic BMD after TKA.