Structural changes and artifacts that interfere with DXA proximal femoral BMD measurements occur less often than at the spine. Osteoarthritic change in the hip joint may cause thickening of the medial cortex and hypertrophy of the trabeculae in the femoral neck, which may increase the BMD in the femoral neck and Ward's area (36). The trochanteric region is not apparently affected by such change and has been recommended as the preferred site to evaluate in patients with osteoarthritis of the hip (37). Osteophytes in the proximal femur are apparently much less common than osteophytes in the lumbar spine (19). They also appear to have little effect on the bone densities measured in the proximal femur. In patients with scoliosis, however, lower bone densities have been reported on the side of the convexity (38). If a "worst-case" measurement is desired, the bone density in the proximal femur should be measured in the femur on the side of the convexity. Proximal femur fracture and surgically implanted prostheses will render measurements of bone density in the proximal femur inaccurate.
If osteoarthritis or some other process restricts the ability of the patient to rotate the femur properly, the study should not be done. An attempt should be made to scan the opposite proximal femur if possible. Similarly, if pain restricts the patient's range of motion such that the femur cannot be properly positioned, the study should not be done as the results will be not be valid.
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