Low-energy fractures of the proximal humerus indicate osteoporosis and it is important to direct treatment to this group of patients who are at high risk of further fracture. Data were prospectively collected from 79 patients (11 men, 68 women) with a mean age of 69 years (55 to 86) with fractures of the proximal humerus in order to determine if current guidelines on the measurement of the bone mineral density at the hip and lumbar spine were adequate to stratify the risk and to guide the treatment of osteoporosis. Bone mineral density measurements were made by dual-energy x-ray absorptiometry at the proximal femur, lumbar spine (L2-4) and contralateral distal radius, and the T-scores were generated for comparison. Data were also collected on the use of steroids, smoking, the use of alcohol, hand dominance and comorbidity.

The mean T-score for the distal radius was −2.97 (sd 1.56) compared with −1.61 (sd 1.62) for the lumbar spine and −1.78 (sd 1.33) for the femur. There was a significant difference between the mean lumbar and radial T scores (1.36 (1.03 to 1.68); p < 0.001) and between the mean femoral and radial T-scores (1.18 (0.92 to 1.44); p < 0.001). The inclusion of all three sites in the determination of the T-score increased the sensitivity to 66% compared with that of 46% when only the proximal femur and lumbar spine were used. This difference between measurements in the upper limb compared with the axial skeleton and lower limb suggests that basing risk assessment and treatment on only the bone mineral density taken at the hip or lumbar spine may misrepresent the extent of osteoporosis in the upper limb and the subsequent risk of fracture at this site.

The assessment of osteoporosis must include measurement of the bone mineral density at the distal radius to avoid underestimation of osteoporosis in the upper limb.

Introduction The effect of hip rotation on the measurement of femoral offset is determined firstly using artificial bones in an anatomical study and then in a patient population. Its effect on the choice of femoral component in total hip arthroplasty is discussed

Methods Radiographs were taken of a series of saw bone models rotated through a range of angles. The resultant offset was then measured Standardised and Control (unstandardised) radiographs of the pelvis were taken of patients presenting to orthopaedic outpatients. Femoral offset was measured from each radiograph

Results In the anatomical study angles of rotation differed significantly with respect to measurement of offset (p< 0.0001 Friedman 2-way analysis of variance by ranks). The greatest measurement of offset was at 15 degrees internal rotation. Offset decreased with external rotation. The clinical study had power of 80%. Femoral offset was increased in all the standardised x-rays compared with their controls (n=108, mean=7.64, SD=5.55, 95% CI (6.58,8.70)). A one-sample t-test was performed to see if the standardised and control films were greater than 5mm different (t=14.30 (107df), p< 0.01).

Conclusions The clinical study confirmed the findings of the anatomical study. A standardised AP radiograph of the pelvis improves the measurement of femoral offset. For surgeons using the Exeter hip system failure to account for offset could lead to the selection of a stem two sizes too small with regards to offset. Lesser degrees of rotation, not readily identified by looking at the radiograph, could still lead to the selection of an incorrectly sized stem. Offset has been shown to increase the range of movement, abductor strength and stability of the hip joint whilst decreasing the rate of wear. It therefore benefits patients to account for offset, ensuring a correctly sized hip replacement.