Koppens D, et al. - In the present study, the researchers analyzed the impact of systemic and peri-prosthetic bone mineral density (BMD) of the proximal tibia on migration of the tibial component of cemented medial unicompartmental knee arthroplasty (UKA). According to WHO criteria, the cohort was dichotomized in a normal BMD group (T-score ≥ -1; n = 37) and a low BMD group (T-score < -1; n = 28). Compared with patients with low systemic BMD throughout follow-up, patients with normal systemic BMD had an 11-15% higher BMD in all regions of interest (ROIs). Over time, a reduction in periprosthetic BMD in ROI 1-3 was observed for both groups. The normal BMD group migrated 0.03 mm and the low BMD group migrated 0.02 mm between 12 and 24 months. According to findings, migration of cemented medial tibial UKA was low up to 24 months and was not affected by systemic BMD preoperative or postoperative change in periprosthetic BMD. This indicates good long-term fixation in the proximal tibial BMD despite an index difference.