A Micro-CT Based Cadaveric Study Investigating Bone Density Changes During Hip Arthroplasty Surgery

The impact of broaching and uncemented implantation on bone density during total hip arthroplasty (THA) remains unclear. Previous studies have typically examined extracted bone sections, which may not directly correlate with outcomes in human hip systems. This study aimed to evaluate bone density changes resulting from broaching and uncemented implantation using micro-computed tomography (μCT) on cadaveric samples. An in-house density calibration phantom (DCP) was developed by validating the densities of polymer inserts through mass and volume measurements. Its performance was then evaluated using lamb bone in comparison with a commercial DCP (QRM-50124). The sensitivity of density predictions to μCT scan parameters was also evaluated with the lamb bone. Additionally, density predictions from medical-CT and μCT scans were compared using the in-house DCP. Finally, uncemented THA procedures were performed on three cadaveric femurs, each undergoing three μCT scans at various surgical stages to assess changes in bone density. The density predictions obtained using the in-house DCP achieved an accuracy of ±0.097 g/cc compared to QRM-50124, with a precision of ±0.052 g/cc. The sensitivity to changes in μCT scan parameters was ±0.022 g/cc. Notably, density predictions from medical-CT and μCT scans were similar, particularly in cortical bone. Broaching and implantation led to an average increase in bone density of 0.137 g/cc, which was attributed to the accumulation of bone debris around the bone-implant interface. This accumulation raised the bone volume fraction, ranging from 3.31% to 20.69%, which acts as an autograft. These measurements have been made for the first time using a µCT and an in-house DCP.