Abstract
Background: Previous study has shown that a short-term use of zoledronic acid (ZA) after cementless total hip arthroplasty (THA) significantly increases bone mineral density (BMD) over the proximal femur and inhibits bone turnover markers (BTMs) after two years. However, could the discontinuation of ZA have a lasting effect is of interest.Method: This is an extension study of a two-year prospective randomized controlled trial on 54 cementless THA treated with either two doses of ZA or placebo. We compared BTMs [alkaline phosphatase (ALP); osteocalcin (OC); procollagen 1 intact N-terminal propeptide (P1NP)], serum calcium, renal function, radiological findings, and functional outcomes (Harris hip score and UCLA activity score) from baseline to 5 years post-THA in 49 patients, and periprosthetic BMD of the seven Gruen zones in 19 patients.Result: All patients had well-functioning hip prostheses, normal renal function, and normal serum calcium levels at 5-year follow-up. At the fifth year, the BMD levels were not statistically different between the two groups, but the change in BMD from baseline (BMD change ratios) in ZA group were significantly increased in zone 2, 4, and 6 as compared with control group. Parallel to that, in ZA group, levels of ALP were significantly lower at the fifth year; OC were significantly lower at the second and the fifth year; P1NP were significantly lower from 6 weeks to 2 years as compared with those in control group.Conclusion: This study demonstrates the lasting effect of a two-dose ZA given within one year after THA on bone metabolism and periprosthetic BMD at five years. The short-term dosing of ZA followed by a 4-year drug holiday had no adverse events and resulted in significant inhibition of periprosthetic bone loss and BTMs.Trial Registration:This extension study on a randomized, open label, single-center clinical trial was conducted under Institutional Review Board of Chang Gung Memorial Hospital Protocol Records 98-1150A3; 105-1296C1; 105-7004D, and was registered July 19th, 2016 on public registry ClinicalTrials.gov trial registration number NCT02838121.
The lasting effect of words on feelings: Words may facilitate exposure effects to threatening images.