Analgesic effect of raloxifene on back and knee pain in postmenopausal women with osteoporosis and/or osteoarthritis

To assess the effect of raloxifene on bone and joint pain, 24 postmenopausal women with back or knee pain or both were randomly divided into two groups, based on the chronological sequence of consultation, to be treated with 60 mg raloxifene and 1 μg alfacalcidol (RA)/day (group RA) or 1 μg alfacalcidol alone (A)/day (group A), respectively, for 6 months. Pain following knee loading (KL) by standing up from a chair and bending the knee by squatting, knee and spine loading (KSL) by walking horizontally and ascending and descending stairs, and spine loading (SL) by lying down supine on a bed and leaving the bed to stand was evaluated by electroalgometry (EAM), based on measurement of the fall of skin impedance, and a visual rating scale (VRS), recording subjective pain on a scale of 0–100 between no pain and unbearable pain. The two groups showed no significant difference as to age, indices of mineral metabolism, back and knee pain, and bone status. RA gave a significantly greater analgesic effect than A by both EAM ( P = 0.0158) and VRS ( P = 0.0268) on overall comparison of the mean response to all modalities of exercise loading. Paired comparison between pretreatment and posttreatment indicated a significant effect of RA by both EAM ( P = 0.0045) and VRS ( P = 0.0017), but not that of A. The analgesic effect was more clearly noted on combined knee–spine loading (KSL) and spine loading (SL) than simple knee loading (KL). Monthly comparison of the analgesic effect indicated a significantly better analgesic effect in the fifth month by VRS. RA effect greater than A was more evident by EAM than VRS and during months 3–6 than during 1–2 months, suggesting a slowly progressive effect of RA. Pain evaluation by EAM and VRS mostly gave parallel results, except for a few occasions such as knee loading and spine loading by sitting up and leaving a bed, when EAM detected a positive effect but VRS failed to do so. RA appeared to be more effective on bone and joint pain than A in postmenopausal women according to both EAM and VRS measurements.