Björn E. Rosengren

A Meta‐Analysis of Trabecular Bone Score in Fracture Risk Prediction and Its Relationship to FRAX

Trabecular bone score (TBS) is a gray‐level textural index of bone microarchitecture derived from lumbar spine dual‐energy X‐ray absorptiometry (DXA) images. TBS is a bone mineral density (BMD)‐independent predictor of fracture risk. The objective of this meta‐analysis was to determine whether TBS predicted fracture risk independently of FRAX probability and to examine their combined performance by adjusting the FRAX probability for TBS. We utilized individual‐level data from 17,809 men and women in 14 prospective population‐based cohorts. Baseline evaluation included TBS and the FRAX risk variables, and outcomes during follow‐up (mean 6.7 years) comprised major osteoporotic fractures. The association between TBS, FRAX probabilities, and the risk of fracture was examined using an extension of the Poisson regression model in each cohort and for each sex and expressed as the gradient of risk (GR; hazard ratio per 1 SD change in risk variable in direction of increased risk). FRAX probabilities were adjusted for TBS using an adjustment factor derived from an independent cohort (the Manitoba Bone Density Cohort). Overall, the GR of TBS for major osteoporotic fracture was 1.44 (95% confidence interval [CI] 1.35–1.53) when adjusted for age and time since baseline and was similar in men and women (p > 0.10). When additionally adjusted for FRAX 10‐year probability of major osteoporotic fracture, TBS remained a significant, independent predictor for fracture (GR = 1.32, 95% CI 1.24–1.41). The adjustment of FRAX probability for TBS resulted in a small increase in the GR (1.76, 95% CI 1.65–1.87 versus 1.70, 95% CI 1.60–1.81). A smaller change in GR for hip fracture was observed (FRAX hip fracture probability GR 2.25 vs. 2.22). TBS is a significant predictor of fracture risk independently of FRAX. The findings support the use of TBS as a potential adjustment for FRAX probability, though the impact of the adjustment remains to be determined in the context of clinical assessment guidelines.

Former Male Elite Athletes Have a Higher Prevalence of Osteoarthritis and Arthroplasty in the Hip and Knee Than Expected

Background: Intense exercise has been reported as one risk factor for hip and knee osteoarthritis (OA). Purpose: This study aimed to evaluate (1) whether this is true for both former impact and nonimpact athletes, (2) if the risk of a hip or knee arthroplasty due to OA is higher than expected, and (3) if joint deterioration is associated with knee injuries. Study Design: Cohort study; Level of evidence, 3. Methods: The prevalence of OA and arthroplasty in the hip and knee were registered in 709 former male elite athletes with a median age of 70 years (range, 50-93 years), retired from sports for a median 35 years (range, 1-63 years), and compared with 1368 matched controls. Odds ratios (ORs) are presented as means with 95% confidence intervals (95% CIs). Results: The risk of hip or knee OA was higher in former athletes (OR, 1.9; 95% CI, 1.5-2.3), as was arthroplasty based on OA in either of these joints (OR, 2.2; 95% CI, 1.6-3.1). The risk of hip OA was doubled (OR, 2.0; 95% CI, 1.5-2.8) and hip arthroplasty was 2.5 times higher (OR, 2.5; 95% CI, 1.6-3.7) in former athletes than in controls, predominantly driven by a higher risk in former impact athletes. Also, the risk of knee OA was higher (OR, 1.6; 95% CI, 1.3-2.1), as was knee arthroplasty (OR, 1.6; 95% CI, 0.9-2.7), driven by a higher risk in both former impact and nonimpact athletes. Knee OA in impact athletes was associated with knee injury. Conclusion: Hip and knee OA and hip and knee arthroplasty are more commonly found in former male elite athletes than expected. A previous knee injury is associated with knee OA in former impact athletes but not in nonimpact athletes.

Secular trends in Swedish hip fractures 1987-2002: birth cohort and period effects.

Background: Recently, a leveling off in hip-fracture incidence has been reported in several settings, but the annual number is nonetheless predicted to increase due to the growing elderly population. Methods: Using Swedish national data for 1987–2002 for all inpatients 50 years or older, we examined the annual number and incidence of hip fractures and explored age, period, and cohort effects. Age adjustment was done by direct standardization, time-trend analysis by linear regression, changes in linear trends by joinpoint regression, and age-period-cohort effects by log-likelihood estimates in Poisson regression models. Results: Before 1996, the age-standardized hip fracture incidence was stable (0.1% per year [95% confidence interval = −0.2% to 0.5%]), and the annual number of hip fractures increased (2.1% per year [1.8% to 2.4%]). After 1996, both the age-standardized hip fracture incidence (−2.2% per year [−2.8% to −1.6%]) and the number of hip fractures (−0.9% per year [−1.5% to −0.4%]) decreased. The period + cohort effects were more marked among women than men, with a major reduction in hip fracture incidence in subsequent birth cohorts (estimated incidence rate ratio = 2.2 comparing women born 1889–1896 with 1945–1952) or periods (estimated incidence rate ratio = 1.1 comparing women living 1987–1990 with 1999–2002). Conclusion: The age-standardized hip fracture incidence has decreased since 1996, more than counteracting the effects of the aging population and resulting in a decline in the annual number of hip fractures through 2002. The magnitude of the combined period and cohort effects in women seems to be of biologic importance. If this persists into older age, the annual number of hip fractures will be lower than has been projected.

A Six-Year Exercise Program Improves Skeletal Traits without Affecting Fracture Risk - a Prospective Controlled Study in 2621 Children.

Most pediatric exercise intervention studies that evaluate the effect on skeletal traits include volunteers and follow bone mass for less than 3 years. We present a population‐based 6‐year controlled exercise intervention study in children with bone structure and incident fractures as endpoints. Fractures were registered in 417 girls and 500 boys in the intervention group (3969 person‐years) and 835 girls and 869 boys in the control group (8245 person‐years), all aged 6 to 9 years at study start, during the 6‐year study period. Children in the intervention group had 40 minutes daily school physical education (PE) and the control group 60 minutes per week. In a subcohort with 78 girls and 111 boys in the intervention group and 52 girls and 54 boys in the control group, bone mineral density (BMD; g/cm2) and bone area (mm2) were measured repeatedly by dual‐energy X‐ray absorptiometry (DXA). Peripheral quantitative computed tomography (pQCT) measured bone mass and bone structure at follow‐up. There were 21.7 low and moderate energy‐related fractures per 1000 person‐years in the intervention group and 19.3 fractures in the control group, leading to a rate ratio (RR) of 1.12 (0.85, 1.46). Girls in the intervention group, compared with girls in the control group, had 0.009 g/cm2 (0.003, 0.015) larger gain annually in spine BMD, 0.07 g (0.014, 0.123) larger gain in femoral neck bone mineral content (BMC), and 4.1 mm2 (0.5, 7.8) larger gain in femoral neck area, and at follow‐up 24.1 g (7.6, 40.6) higher tibial cortical BMC (g) and 23.9 mm2 (5.27, 42.6) larger tibial cross‐sectional area. Boys with daily PE had 0.006 g/cm2 (0.002, 0.010) larger gain annually in spine BMD than control boys but at follow‐up no higher pQCT values than boys in the control group. Daily PE for 6 years in at study start 6‐ to 9‐year‐olds improves bone mass and bone size in girls and bone mass in boys, without affecting the fracture risk.

Validity, reliability, and responsiveness of the Self-reported Foot and Ankle Score (SEFAS) in forefoot, hindfoot, and ankle disorders

Background and purpose — The self-reported foot and ankle score (SEFAS) is a questionnaire designed to evaluate disorders of the foot and ankle, but it is only validated for arthritis in the ankle. We validated SEFAS in patients with forefoot, midfoot, hindfoot, and ankle disorders. Patients and methods — 118 patients with forefoot disorders and 106 patients with hindfoot or ankle disorders completed the SEFAS, the foot and ankle outcome score (FAOS), SF-36, and EQ-5D before surgery. We evaluated construct validity for SEFAS versus FAOS, SF-36, and EQ-5D; floor and ceiling effects; test-retest reliability (ICC); internal consistency; and agreement. Responsiveness was evaluated by effect size (ES) and standardized response mean (SRM) 6 months after surgery. The analyses were done separately in patients with forefoot disorders and hindfoot/ankle disorders. Results — Comparing SEFAS to the other scores, convergent validity (when correlating foot-specific questions) and divergent validity (when correlating foot-specific and general questions) were confirmed. SEFAS had no floor and ceiling effects. In patients with forefoot disorders, ICC was 0.92 (CI: 0.85–0.96), Cronbachs α was 0.84, ES was 1.29, and SRM was 1.27. In patients with hindfoot or ankle disorders, ICC was 0.93 (CI: 0.88-0.96), Cronbachs α was 0.86, ES was 1.05, and SRM was 0.99. Interpretation — SEFAS has acceptable validity, reliability, and responsiveness in patients with various forefoot, hindfoot, and ankle disorders. SEFAS is therefore an appropriate patient- reported outcome measure (PROM) for these patients, even in national registries.

The annual number of hip fractures in Sweden will double from year 2002 to 2050

Background and purpose — The incidence and annual number of hip fractures have increased worldwide during the past 50 years, and projections have indicated a further increase. During the last decade, however, a down-turn in the incidence of hip fracture has been seen in the western world. We predicted the development of hip fractures in Sweden until the year 2050. Methods — We reviewed surgical records for the period 2002–2012 in the city of Malmö, Sweden, and identified patients aged 50 years or more with a hip fracture. We estimated incidence rates by using official population figures as denominator and applied the rates to population projections each year until 2050. We also made projections based on our previously published nationwide Swedish hip fracture rates for the period 1987–2002. Since the projections are based on estimates, no confidence limits are given. Results — During the period 2002–2012, there were 7,385 hip fractures in Malmö. Based on these data, we predicted that there would be approximately 30,000 hip fractures in Sweden in the year 2050. Use of nationwide rates for 2002 in the predictive model gave similar results, which correspond to an increase in the number of hip fractures by a factor of 1.9 (1.7 for women and 2.3 for men) compared to 2002. Interpretation — The annual number of hip fractures will almost double during the first half of the century. Time trends in hip fractures and also changes in population size and age distribution should be continuously monitored, as such changes will influence the number of hip fractures in the future. Our results indicate that we must optimize preventive measures for hip fractures and prepare for major demands in resources.

Comparison of the Self-Reported Foot and Ankle Score (SEFAS) and the American Orthopedic Foot and Ankle Society Score (AOFAS)

Background: The Self-reported Foot and Ankle Score (SEFAS) is a patient-reported outcome measure, while the American Orthopedic Foot and Ankle Society Score (AOFAS) is a clinician-based score, both used for evaluation of foot and ankle disorders. The purpose of this study was to compare the psychometric properties of these 2 scoring systems. Methods: A total of 95 patients with great toe disorders and 111 patients with ankle or hindfoot disorders completed the 2 scores before and after surgery. We evaluated time to complete the scores in seconds, correlations between scores with Spearman’s correlation coefficient (rs), floor and ceiling effects by proportion of individuals who reached the minimum or maximum values, test–retest reliability and interobserver reliability by intraclass correlation coefficient (ICC), internal consistency by Cronbach’s coefficient alpha (CA), and responsiveness by effect size (ES). Data are provided as correlation coefficients, means, and standard deviations. Results: SEFAS was completed 3 times faster than AOFAS. The scores correlated with an rs of .49 for great toe disorders and .67 for ankle/hindfoot disorders (both P < .001). None of the scores had any floor or ceiling effect. SEFAS test–retest ICC values measured 1 week apart were .89 for great toe and .92 for ankle/hindfoot disorders, while the corresponding ICC values for AOFAS were .57 and .75. AOFAS interobserver reliability ICC values were .70 for great toe and .81 for ankle/hindfoot disorders. SEFAS CA values were .85 for great toe and .86 for ankle/hindfoot disorders, while the corresponding CA values for AOFAS were .15 and .42. SEFAS ES values were 1.15 for great toe and 1.39 for ankle/hindfoot disorders, while the corresponding ES values for AOFAS were 1.05 and 1.73. Conclusion: As SEFAS showed similar or better outcome in our tests and was completed 3 times faster than AOFAS, we recommend SEFAS for evaluation of patients with foot and ankle disorders. Level of Evidence: Level II, prospective comparative study.

The 21st century landscape of adult fractures - Cohort study of a complete adult regional population.

Recent reports on adult fracture epidemiology have focused mainly on the hip in the elderly, in whom increasing rates lately have changed to a decline. New reports of the preponderance of nonhip fractures in health expenditure call for a wider scope. We therefore examined current overall and site‐specific fracture epidemiology in adults. We ascertained all fractures diagnosed in inpatient and outpatient care in all men and women aged 20 years or older in Skåne County, Sweden, from 1999 to 2010 (10 million person‐years). For each fracture type, we estimated age‐specific and sex‐specific rates and evaluated potential time trends. We found 205,908 fractures yielding an overall fracture rate of 192 per 10,000 person‐years. The age‐standardized overall fracture rate increased by 1.2 per 10,000 and year (95% confidence interval, 0.8 to 1.5), but time trends were different for different fracture types, age strata, and for men and women. For example, in both women and men aged ≥50 years the rates of proximal humerus fracture increased (0.6 and 0.2 per 10,000 and year, respectively) while hip fracture rates declined (−1.0 and −0.3 per 10,000/year, respectively). Overall age‐specific number of fractures increased with age in women but was stable in men. The increasing overall fracture rate is a major concern in the context of a growing and aging population. Effective and affordable preventive strategies and treatments should be an urgent priority to meet the challenges, especially in older women in whom most fractures occur. Comprehensive current detailed data, as provided in this study, may serve as reference for projections and for cost calculations of fracture care in other settings before results of similar examinations are available there.

Does a childhood fracture predict low bone mass in young adulthood?—A 27-year prospective controlled study

A fracture in childhood is associated with low bone mineral density (BMD), but it is debated whether a fracture at growth also predicts low BMD in young adulthood. The purpose of this work was to gender‐specifically evaluate whether children with a fracture are at increased risk of low BMD in young adulthood. Distal forearm BMD (g/cm2) was measured with single‐photon absorptiometry (SPA) in 47 boys and 26 girls (mean age 10 years, range 3–16 years) with an index fracture and in 41 boys and 43 girls (mean age 10 years, range 4–16 years) with no fracture. BMD was re‐measured mean 27 years later with the same SPA apparatus and with dual‐energy absorptiometry (DXA), quantitative ultrasound (QUS), and peripheral computed tomography (pQCT). Individual Z‐scores were calculated using the control cohort as reference population. Data are presented as means with 95% confidence intervals (95% CI) within brackets and correlation with Pearsons correlation coefficient. Boys with an index fracture had at fracture event a distal forearm BMD Z‐score of −0.4 (95% CI, −0.7 to −0.1) and at follow‐up −0.4 (95% CI, −0.7 to −0.1). Corresponding values in girls were −0.2 (95% CI, −0.5 to 0.1) and −0.3 (95% CI, −0.7 to 0.1). The deficit in absolute bone mass was driven by men with index fractures in childhood due to low energy rather than moderate or high energy. There were no changes in BMD Z‐score during the follow‐up period. The BMD deficit at follow‐up was in boys with an index fracture verified with all advocated techniques. A childhood fracture in men was associated with low BMD and smaller bone size in young adulthood whereas the deficit in women did not reach statistical significance.

Bone mineral density and incidence of hip fracture in Swedish urban and rural women 1987-2002.

Background and purpose Although the incidence of hip fracture during the past 50 years has increased, a break in this trend has been reported in the last decade. Whether this change is attributable to changes in bone mineral density (BMD) or whether it varies between urban and rural regions is unknown. Methods We evaluated changes in annual hip fracture incidence in women aged ≥ 50 years in one urban population (n = 51,757) and one rural population (n = 26,446) from 1987 to 2002. We also examined secular differences in BMD (mg/cm2), evaluated by single-photon absorptiometry at the distal radius, prevalence of osteoporosis, and several other risk factors for hip fracture in one population-based sample of urban women and one sample of rural women aged 50–80 years at two time points: 1988/89 (n = 257 and n = 180, respectively) and 1998/99 (n = 171 and n = 118, respectively). Results No statistically significant changes were evident in annual age-adjusted hip fracture incidence per 104 when analyzing all women (–0.01 per year (95% CI: –0.37, 0.35)), rural women (–0.38 per year (-1.05, 0.28)), or urban women (0.19 per year (–0.28, 0.67)). BMD (expressed as T-score) was similar in 1988/99 and 1998/99 when analyzing all women (–0.09 (–0.26, 0.09)), urban women (–0.04 (–0.27, 0.19)), or rural women (–0.15 (–0.42, 0.13)) women. Interpretation Since no changes in age-adjusted hip fracture incidence and no differences in BMD were found during the study period, changes evident in the other risk factors for hip fracture that we investigated (such as gait velocity and balance) are either of minor importance or are counteracted by changes in other risk factors.