Correlation of bone density measurement and histopathologic results of femur resection material in patients undergoing total hip arthroplasty

The aim of this study is; firstly, to determine the differences in bone mineral density between the arthrosis side and the normal side in bilateral proximal femur Dexa results in patients with unilateral coxarthrosis. Secondly, to reveal which regions of the proximal femur are more affected in patients with coxarthrosis. Lastly, to make histomorphometric measurements of femoral head-neck and femoral ward specimens taken after Total Hip Arthroplasty (THA) and to correlate them with the Dexa results. Methodology: From June 2021 to January 2023, 30 patients who underwent THA at the Department of Orthopedics and Traumatology, Tekirdağ Namık Kemal University were included. Total and regional (femoral neck, trochanteric, intertrochanteric and ward triangle) Dexa measurements of the bilateral proximal femur were performed. Measurements were performed 2 weeks before arthroplasty surgery. After removal of the proximal femur including the head and neck during THA, 1 cm x 2 cm bone specimens were taken from the femoral head, femoral neck and femoral ward regions, with 3 specimens from each region, totaling 9 specimens. Histomorphometric examination was performed on the samples to determine trabecular thickness, trabecular distance, trabecular volume/bone volume (%) and trabecular number. Normality tests were used to determine whether there was a normal distribution. Dependent Sample T-Test was used for the evaluation of bilateral Dexa results. Pearson correlation test was used to correlate histomorphometric results with ipsilateral Dexa results. Results of the Study: In the first phase of the study, statistically significant differences were found between normal and arthritic hip Dexa results in the femoral neck and femoral ward region. Histomorphometric evaluation of the pathologic femur was performed to determine the reliability of these data and it was found that the increase in Bone Mineral Density (BMD) and Bone Mineral Content (BMI) in the femoral neck and femoral ward regions correlated with the measured parameters. Increased trabecular thickness, decreased inter-trabecular distance and decreased number of trabeculae were found in these regions. It was also found that the increase in trabecular thickness was greater in the femoral ward region and the decrease in inter-trabecular distance was greater in the femoral neck region. When histomorphometric measurements were evaluated in women with osteoarthritis compared to men, findings resulting in lower BMD, BMI and T score were obtained. Results of the Study: The changes in bone structure caused by osteoarthritis are a subject of continuous research. In this study, we found that BMI and BMD were significantly increased in the femoral neck and femoral ward region in coxarthrosis. Histomorphometric examination of these regions correlated with the same regions with osteoarthritis findings. It was also concluded that Dexa, a macroscopic bone quality assessment method, correlated with bone histomorphometry, a microscopic bone assessment criterion. Further studies with large case series are needed to fully reveal the effects of osteoarthritis in coxarthrosis.