Underestimated fracture probability in patients with unilateral hip osteoarthritis as calculated by FRAX

Reduced Awareness for Osteoporosis in Hip Fracture Patients Compared to Elderly Patients Undergoing Elective Hip Replacement

Background: Osteoporotic fractures are associated with a loss of quality of life, but only few patients receive an appropriate therapy. Therefore, the present study aims to investigate the awareness of musculoskeletal patients to participate in osteoporosis assessment and to evaluate whether there are significant differences between acute care patients treated for major fractures of the hip compared to elective patients treated for hip joint replacement.; Methods: From May 2015 to December 2016 patients who were undergoing surgical treatment for proximal femur fracture or total hip replacement due to osteoarthritis and were at risk for an underlying osteoporosis (female > 60 and male > 70 years) were included in the study and asked to complete a questionnaire assessing the awareness for an underlying osteoporosis. ASA Score, FRAX Score, and demographic information have also been examined. Results: In total 268 patients (female = 194 (72.0%)/male = 74 (28%)), mean age 77.7 years (±7.7) undergoing hip surgery were included. Of these, 118 were treated for fracture-related etiology and 150 underwent total hip arthroplasty in an elective care setting. Patients were interviewed about their need for osteoporosis examination during hospitalization. Overall, 76 of 150 patients receiving elective care (50.7%) considered that an examination was necessary, whereas in proximal femur fracture patients the awareness was lower, and the disease osteoporosis was assessed as threatening by significantly fewer newly fractured patients. By comparison, patients undergoing trauma surgery had a considerably greater risk of developing another osteoporotic fracture than patients undergoing elective surgery determined by the FRAX® Score (p ≤ 0.001).; Conclusions: The patients’ motivation to endure additional osteoporosis diagnostic testing is notoriously low and needs to be increased. Patients who underwent acute care surgery for a fragility proximal femur fracture, although acutely affected by the potential consequences of underlying osteoporosis, showed lower awareness than the elective comparison population that was also on average 6.1 years younger. Although elective patients were younger and at a lower risk, they seemed to be much more willing to undergo further osteoporosis assessment. In order to better identify and care for patients at risk, interventions such as effective screening, early initiation of osteoporosis therapy in the inpatient setting and a fracture liaison service are important measures.

Accounting for Surgical Confounding Factors Affecting Dual-Energy X-ray Absorptiometry in a Large Clinical Trial

Joint replacements are among the most common orthopedic procedures performed in the U.S. and will continue to increase with the aging population. It is therefore necessary to account for these and other confounding factors, such as breast implants, when performing dual-energy X-ray absorptiometry (DXA) measurements. Whole-body DXA scans were performed in 771 participants (men ≥50 yr and women ≥55 yr) to assess bone mineral density (BMD) and body composition (fat and lean mass). In the DXA scan analyses of participants with internal metal, these affected regions of interest were replaced with measures from the unaffected, contralateral side, consistent with recommendations of the International Society for Clinical Densitometry. T-scores and Z-scores were recalculated using default sex and ethnicity-matched databases. We also explored effects of breast implants on bone density and body composition analyses. Approximately 13.1% of participants had internal metal artifacts at baseline. Replacing metal artifacts with the unaffected, contralateral side decreased the whole-body BMD by an average of 8.1% (SEM 0.84%; n = 67). In participants with unilateral hip (n = 17) and knee replacements (n = 20), BMD was decreased by an average of 14.1% (SEM 1.7%) and 11.2% (SEM 1.1%), respectively. Fat and lean mass were not significantly affected by metal artifacts, as differences between values with and without metal were within 1%. Two participants had bilateral breast implants, and in a separate trial, one participant had a unilateral breast implant. Bone mineral content (BMC) in the region with the breast implant was 5.8 times higher than the contralateral side, and whole-body BMC was increased by 4.7%. Metal artifacts and breast implants can confound DXA whole-body bone but not fat and lean results. It is therefore important in clinical studies to account for these factors to detect physiologically relevant differences in bone measures.

How Good is Our Best Guess? Clinical Application of the WHO FRAX Tool in Osteoporotic Fracture Risk Determination and Treatment Decisions

Historically, treatment decisions for osteoporosis were based on bone mineral density. However, many fractures occur in patients with T-scores outside the osteoporotic range, emphasizing the importance of multi-factorial risk assessments. The World Health Organization Fracture Risk Assessment Tool (FRAX) predicts 10-year risk of osteoporotic fracture. We hypothesized that physicians' clinical estimates of osteoporotic fracture risk would differ significantly from that calculated by FRAX. Thus, treatment decisions would differ depending whether or not physicians used FRAX. A survey consisting of five clinical scenarios was administered to 76 endocrinologists, family physicians, internists, and internal medicine residents. They were asked to estimate the osteoporotic fracture risk and decide whether they would offer preventative treatment. Their estimates were compared to the risk predicted by FRAX and national treatment threshold guidelines. The primary outcome was the difference between the participant's estimate and the FRAX-based estimate of the 10-year risk of osteoporotic fracture for each scenario. In each scenario, physicians statistically significantly over-estimated fracture risk compared to that predicted by FRAX. Estimates for hip fracture risk were 2-4 times higher than FRAX estimates. The major osteoporotic fracture risk at which participants would offer treatment varied with physician group, with endocrinologists, family physicians, and residents requiring a 10-20 % 10-year risk, while internal medicine physician thresholds ranged from 2 to 20 %. Physicians greatly over-estimated the risk of hip fracture based on clinical information. FRAX is necessary to accurately quantify risk, but because physicians varied in the level of risk required before they would offer treatment, uniform approaches to risk estimation may still not result in uniform clinical treatment decisions.

Clinical characteristics influence in vitro action of 1,25-dihydroxyvitamin D(3) in human marrow stromal cells

Vitamin D is important for bone health, with low vitamin D levels being associated with skeletal fragility and fractures. Among its other biological activities, 1,25-dihydroxyvitamin D (1,25(OH)(2) D), stimulates the in vitro differentiation of human marrow stromal cells (hMSCs) to osteoblasts, which can be monitored by increases in alkaline phosphatase enzyme activity or osteocalcin gene expression. In this study, we tested the hypotheses that age and clinical attributes of subjects influence in vitro responsiveness of hMSCs to 1,25(OH)(2) D(3) . In a cohort of subjects whose hMSCs were isolated from bone marrow discarded during hip replacement surgery for osteoarthritis, there were significant inverse correlations with age for bone mineral density, renal function, body mass index, fat mass index, and lean mass index (n = 36-53). There were significant correlations with serum 25(OH)D for serum parathyroid hormone (PTH), body mass index, fat mass index, and lean mass index (n = 47-50). In vivo-in vitro correlation analyses indicated that there were significantly greater in vitro effects of 1,25(OH)(2) D(3) to stimulate osteoblast differentiation in hMSCs obtained from subjects who were younger than 65 years of age, or who had serum 25(OH)D ≤ 20 ng/mL, elevated serum PTH, or better renal function, assessed by estimated glomerular filtration rate. The greater in vitro stimulation of osteoblast differentiation by 1,25(OH)(2) D(3) in hMSCs from vitamin D-deficient subjects suggests that vitamin D replenishment may lead to more vigorous bone formation in subjects at risk.