Introduction: Proximal tibial bone quality is an important factor in implant mechanical stability following total knee arthroplasty. Quantitative computed tomography (CT) osteodensitometry has been used to measure the change in bone density post-operatively. We sought to validate the inter-observer reliability of these measurements.
Methods: Sixteen CT scans were obtained on cadaveric lower limbs. Two observers independently obtained cortical and cancellous bone mineral density measurements from these scans. Eight CT scans were performed with prosthesis in situ and eight without. Results were compared using correlation coefficient and Bland-Altman analysis.
Results: The study showed a high correlation coefficient of greater than 0.990 for all slices. The mean difference between observers falls within two standard deviations of the mean as seen on a Bland-Altman plot.
Interpretation: Quantitative CT-osteodensitometry is a reproducible method to measure bone mineral density changes about the knee and shows little variation between observers.