Lumbar spine and proximal femur bone mineral density after contralateral total hip replacement

Abstract

Controversy persists regarding the eventual bone mineral density (BMD) variations in the contralateral hip and lumbar spine after unilateral primary total hip arthroplasty. Bone loss may occur if the operation requires a period of bed rest. The purpose of this study was to characterize BMD changes at these two sites after unilateral total hip replacement (THR). In this study, 52 male patients who underwent total hip arthroplasty with a cemented modular straight stem were included. BMD was assessed at the lumbar spine and the contralateral, nonoperated hip using the dual energy X-ray absorptiometry (DEXA) method. Measurements were done 1 month before the operation and at days 8, 90, 180, 365, and 710 postoperatively. No statistically significant BMD changes were present between the different measurements either in L2–L4 vertebrae or at any of the seven Gruen zones of the contralateral, nonoperated hip. Our results suggest that immediate full weightbearing permitted by cemented implants avoids bone loss from the proximal nonoperated femur and the lumbar spine and hence may prevent transformation of osteopenia to osteoporosis in older patients.