Morita A, Kobayashi N, Choe H, et al. - Stress shielding following total hip arthroplasty (THA) results in loss of bone mineral density (BMD) around the femoral implants, especially in the proximal area. Loss of BMD around the implant is likely to occur within 1 year after THA; however, patient characteristics were identified influencing its severity. Researchers herein conducted a retrospective cohort study of 48 patients who underwent primary THA in order to determine preoperative factors that linked with the severity of zone 7 BMD loss after THA. Implantation of a Zweymüller-type femoral component was performed in all patients without any postoperative osteoporosis medications. Zone 7 BMD loss was observed after THA in correlation with lower preoperative lumbar BMD on the lateral side and lower CFI. Careful monitoring of patients with these characteristics is recommended for severe BMD loss after THA.