RETRACTED ARTICLE: Changes in Bone and Calcium Metabolism Following Hip Fracture in Elderly Patients

Abstract

Although hip fracture is one of the most common causes of acute immobilization in elderly patients, little is known about the influence of immobilization on changes in bone and calcium metabolism following this event. We therefore compared serum biochemical indices of bone and calcium metabolism in 20 elderly subjects with hip fracture with those measured in 20 healthy age-matched controls. Rankin scores, a measure of functional dependence with 0 representing independence and 5 representing total dependence, were assigned. We also examined serial changes in these biochemical indices from shortly following the fracture to the early recovery period. Ionized calcium, intact parathyroid hormone (PTH), intact bone Gla protein (BGP), pyridinoline cross-linked carboxyterminal telopeptide of type I collagen (ICTP), 25-hydroxyvitamin D (25-OHD), and 1,25-dihydroxyvitamin D (1,25-[OH]2D) were measured. One week after the fracture, mean serum concentrations of calcium and ICTP were elevated in correspondence to degree of immobilization (mean Rankin score; 4.4), while serum concentrations of BGP, PTH, 25-OHD, and 1,25-[OH]2D were depressed. Rankin score (mean: 4.4) correlated positively with ICTP and negatively with BGP at this time. At 2 months, calcium and ICTP elevation decreased and BGP, PTH and 1,25-[OH]2D were less depressed, coinciding with a decline in Rankin score from 4.2 to 2.2. Indices were further improved at 3 months (mean Rankin score, 1.3), with calcium and BGP returning to normal. We concluded that increased bone resorption, and decreased bone formation, and hypercalcemia are present by 1 week following the hip fracture, and some resorption increase persists for at least 3 months. These changes could explain in part the high risk of another hip fracture.

Characteristics of Bone Turnover in the Long Bone Metaphysis Fractured Patients with Normal or Low Bone Mineral Density (BMD)

“…Previous studies showed increased levels of markers of bone resorption in patients with vertebral or hip fractures at an early stage of fracture healing [21], [22], although biochemical markers of bone formation increased at a later stage [23]. Our study showed interesting variations in the levels of the markers of bone metabolism that have not been described in the literature before.…”

Effect of Age-Related Chronic Immobility on Markers of Bone Turnover

“…(13) Rapid bone loss has also been reported in patients immobilized for prolapsed intervertebral disc, (14) after a stroke, (15) and in premenopausal women who are less physically active. (16) Most of these studies have measured BMD, not bone turnover, or used older, less specific markers of bone metabolism.…”

“…(16) Most of these studies have measured BMD, not bone turnover, or used older, less specific markers of bone metabolism. (9,10,(12)(13)(14)(15)(16)(17) The changes in bone turnover after acute immobilization are considered to be mediated through the local and systemic effects of cytokines and hormonal regulators of bone and calcium metabolism, which may be modulated through the activity of the mechanoreceptors in bone. (18)(19)(20)(21) The effects of more modest reductions in mobility on bone turnover have been less well studied.…”

Bone mineral density and bone markers in patients with a recent low-energy fracture: effect of 1 y of treatment with calcium and vitamin D

“…The changes in BMD correlated with the level of physical activity, ICTP, and age. Because frail patients older than 70 y of age are immobile, they are not able to decrease bone resorption and increase bone mass when treated with calcium and vitamin D. The importance of sufficient mechanical loading has been shown in clinical trials; the effect of intervention with calcium and vitamin D is reduced if patients are immobile (29,30).…”