Should the lumbar or femoral neck young adult mean percentage be measured in patients with distal radius fractures? A case-control study.

Background: In the 2015 guidelines for the prevention and treatment of osteoporosis in Japan, the young adult mean percentage (%YAM) of the lumbar spine or femoral neck is required to diagnose osteoporosis in patients with distal radius fracture (DRF). When the %YAM of multiple locations is measured, the lower %YAM is adopted for the diagnosis. If the area with a lower %YAM is known, bone mineral densitometry tests may only need to be performed at one site. This study aimed to compare the lumbar and femoral neck %YAMs of patients with DRFs to find out the lower %YAM site.

Methods: We retrospectively compared the %YAM of the lumbar and femoral neck of patients with DRFs who underwent open reduction and internal fixation (ORIF) between April 2018 and March 2023. We also measured the lumbar and femoral neck %YAM of patients with hip fractures (HFs) treated by ORIF, bipolar hemiarthroplasty, or total hip arthroplasty.

Results: The %YAM of the femoral neck was significantly lower than that of the lumbar region in the DRF group. In the HF group, the lumbar %YAM was significantly higher than that of the femoral neck.

Conclusions: In patients with DRFs, the %YAM of the femoral neck was significantly lower than the lumbar %YAM. The lumbar %YAM appears to be less reliable than the %YAM of the femoral neck because of the lumbar degenerative changes. Therefore, we believe that the %YAM of the femoral neck should be measured first if osteoporosis is suspected in patients with DRF.

Level of evidence iii: Case-control study.