The inhibitory effect of alendronate-hydroxyapatite composite coating on wear debris-induced peri-implant high bone turnover

BackgroundBisphosphonate (BP) has been confirmed as the most potent drug for enhancing implant stability. There have been few studies focused on BP-hydroxyapatite (HA) composite coatings, and the mechanisms through which BPs inhibit wear debris-induced high bone turnover have not been comprehensively discussed.Materials and methodsThirty rabbits were divided into three groups. HA-coated implants were inserted into the proximal region of the medullary cavity of the left tibia. In groups II and III, particles were injected around the implant and into the knee joint during implantation. Low-dose alendronate (ALN) was combined with the HA coating in group III. The efficacy of the composite coating was evaluated using several parameters, including the intra-articular pressure, histology of the synovial membranes and bone-implant interfaces, bone histomorphometry and mineralization, implant stability, osteolysis-related cytokine levels, and the duration of ALN release in vitro.ResultsThe results indicate that the ALN-HA composite coating reduces peri-implant high bone turnover; improves bone-implant integration, bone quality, and implant stability; and inhibits particle migration. In vitro results suggest that the ALN-HA composite coating can afford long release duration.ConclusionsThis study may help us further realize the mechanisms through which BPs enhance bone-implant integration in a state of peri-implant high bone turnover. BP-HA composite coatings are promising materials, particularly in revision surgeries.