ECTS2016 Poster Presentations Osteoporosis: evaluation and imaging (39 abstracts)
1Sun Yat-Sen Memorial Hospotal Sun Yat-Sen University, Guangzhou, China; 2The First Affiliated Hospital of Sun Yat-Sen University, Guangzhou, China; 3The Third Affiliated Hospital of Sun Yat-Sen University, Guangzhou, China; 4Peoples Hospital of Guangdong Province, Guangzhou, China; 5Zhujiang Hospital, Southern Medical University, Guangzhou, China.
Objective: To test the hypothesis that the cemented and uncemented implants had effect on the measurement of proximal femur BMD by DEXA.
Methods: 40 patients underwent unilateral THA using cemented (n=20) and uncemented (n=20) implants due to developmental dysplasia of the hip, femoral neck fracture or femoral head necrosis from January 2015 to July 2015 were included. Preoperative DEXA scans were acquired for the BMD of the posteroanterior lumbar spine (L1-L4) and the contralateral hip (total hip and Wards triangle). The periprosthetic BMD of the 7 regions of interests (Gruen zones) were measured preoperatively, 1 week and 3 months after the operation by DEXA.
Results: The periprosthetic BMD of uncemented group increased 1 week after the operation, especially in Gruen zone 6(+19.5%, P=0.028) and Gruen zone 7(+17.6%, P=0.054). The periprosthetic BMD of cemented group increased in all seven zones postoperative and the maximum was 33.8%(Gruen zone 1), but there is not statistical significance in all seven zones (P>0.05). The periprosthetic BMD began to fall down 3 months after THA and the greatest bone loss was found in Gruen zone 7 (−31.3%, P=0.023). Multivariate regression analysis showed that, for Gruen zone 1, Wards triangle BMD was a significant factor in predicting the effect of uncemeted prosthetic on periprosthetic BMD measurement (P=0.045).
Conclusion: BMD of proximal femur increased after the implantation of cemented and uncemented prosthetics. We recommend the periprosthetic BMD of the involved side measured 1 day before the THA as the best reference for follow-up to avoid the influence of the implants. Wards triangle may predict the effect of uncemeted prosthetic on periprosthetic BMD measurement.