Stro-1-positive BMSCs predict postoperative periprosthetic bone mineral density outcomes in uncemented total hip arthroplasty patients

Bone marrow cell profiles are variable after total hip arthroplasty (THA), including variable levels of Stro-1+ and bone morphogenetic protein receptor (BMPRs)+ cells. We investigated the impact of bone marrow cell profiles on changes in periprosthetic bone mineral density (BMD) in uncemented THA patients. Bone marrow aspirates were collected from the metaphyseal region of discarded femoral heads from 24 consecutive THA patients (12 men and 12 women; mean age 66.7 ± 11.0 years; range 52-87 years) treated from March 2009 to March 2011 at a single facility. Perioperative proportions of Stro-1+ and BMPR+ cells in femoral heads were assessed by flow cytometry. Follow-up examined the proximal femur Gruen zones R1 and R7 at 1 week and at 3, 6, and 12 months after THA, using dual-energy X-ray absorptiometry. Associations between BMD loss and age, gender, BMPRs+, and Stro-1+ were analyzed. At 3 months, R1 and R7 BMD decreased by 4.4% and 6.4%, respectively (P