Relationship of height, weight and body mass index to the risk of hip and knee replacements in middle-aged women

Did the Comprehensive Care for Joint Replacement Bundled Payment Program Impact Sex Disparities in Total Hip and Knee Arthroplasties?

BACKGROUND

Sex disparities have been noted across various aspects of total hip/knee arthroplasty (THA/TKA). Given incentives to standardize care, bundled payment initiatives including the Comprehensive Care for Joint Replacement (CJR) program may reduce disparities. This study aimed to assess the CJR program's impact on sex disparities in THA/TKA care and outcomes.

METHODS

This retrospective cohort study included 259,673 THAs (61.7% women) and 506,311 TKAs (64.0% women) from a large national database (2013 to 2017). Sex disparities were assessed for care and outcomes related to the period (1) before surgery, (2) during hospitalization for THA/TKA, and (3) after discharge. Disparities were reported as women:men ratios. Difference-in-differences analyses estimated the impact of the CJR program on pre-existing sex disparities.

RESULTS

For both THA and TKA, women were less likely than men to present with a Charlson-Deyo comorbidity index >0 (women:men ratio 0.88 to 0.92), but were more likely to require blood transfusions (women:men ratio 1.48 to 1.79) and be discharged to institutional postacute care (women:men ratio 1.50 to 1.66). Difference-in-differences models demonstrated that the CJR bundled payment program reduced sex disparities in institutional postacute care discharges (THA: -2.28%; 95% confidence interval [CI] -4.20 to -0.35%, P = .02; TKA: -2.07%; 95% CI -3.93 to -0.20%; P = .03) and THA 90-day readmissions (-1.00%, 95% CI -1.88 to -0.13%, P = .02), indicating a differential impact of CJR in women versus men for some outcomes.

CONCLUSIONS

While sex disparities in THA/TKA persist, the CJR program demonstrates potential to impact such differences. Future research should focus on how potential mechanisms could be leveraged to reduce disparities.

Decreased Risk of Knee Osteoarthritis with Taller Height in an East Asian Population: A Nationwide Cohort Study

BACKGROUND

Numerous studies have explored factors impacting osteoarthritis (OA), but its relationship with height remains uncertain. This study investigates the relationship between height and osteoarthritis risk in South Korea.

METHODS

Participants aged 50 or older who underwent health screenings in 2009 were selected from the National Health Insurance System database. A total of 1,138,904 subjects were divided into height quartiles (Q1-Q4) based on age and gender. Cox proportional hazard models were used to assess knee osteoarthritis incidence risk, with the shortest quartile (Q1) as the reference.

RESULTS

After adjusting for age, sex, income, smoking, drinking, exercise, hypertension, diabetes mellitus, dyslipidemia, and body mass index (BMI), no significant difference in OA incidence risk based on height was observed. However, when adjusted for weight instead of BMI, we observed a gradual decrease in hazard ratio with increasing height. The hazard ratio for the tallest group was 0.787 (95% CI, 0.781~0.795). Similar results were obtained in all subgroups.

CONCLUSIONS

Compared to previous studies, our findings present a clear distinction. Therefore, there may be racial differences in the association between height and knee OA risk, and our study provides evidence that, in East Asian populations, taller individuals have a reduced risk of knee OA.

Impact of wound complications in obese versus non-obese patients undergoing total hip arthroplasty: A meta-analysis

This meta-analysis examined the post-operative wound effect of both obese and non-obese in total hip arthroplasty (THA) patients. To gather as complete an overview as possible, the researchers took advantage of 4 databases-PubMed, Embase, Cochrane Library and Web of Science-to conduct a critical assessment. Following the development of inclusion and exclusion criteria, the researchers evaluated the quality of each document. A total of 9 related trials were conducted to determine the 95% CI (CI) and OR using a fixed-effect model. The final meta-analyses were conducted with RevMan 5.3. Our findings indicate that there is no statistically significant benefit in terms of post-operative wound complications among obese and non-obese patients. Obese subjects had a significantly higher risk of injury than those without obesity (OR, 1.43; 95% CI, 1.04, 1.95, p = 0.03); obesity was also associated with a significantly higher risk of operative site infection than in non-obese subjects (OR, 1.96; 95% CI, 1.76, 2.18, p < 0.0001); and after surgery, there was also a significant increase in the risk of post-operative wound infections among obese subjects than in non-obese subjects (OR, 1.57; 95% CI, 1.34, 1.84, p < 0.0001). However, due to the small size of the cohort study in this meta-study, caution is required in the analysis. More randomized, controlled studies will be needed to validate these results.

The identification of distinct protective and susceptibility mechanisms for hip osteoarthritis: findings from a genome-wide association study meta-analysis of minimum joint space width and Mendelian randomisation cluster analyses

BACKGROUND

Hip minimum joint space width (mJSW) provides a proxy for cartilage thickness. This study aimed to conduct a genome-wide association study (GWAS) of mJSW to (i) identify new genetic determinants of mJSW and (ii) identify which mJSW loci convey hip osteoarthritis (HOA) risk and would therefore be of therapeutic interest.

METHODS

GWAS meta-analysis of hip mJSW derived from plain X-rays and DXA was performed, stratified by sex and adjusted for age and ancestry principal components. Mendelian randomisation (MR) and cluster analyses were used to examine causal effect of mJSW on HOA.

FINDINGS

50,745 individuals were included in the meta-analysis. 42 SNPs, which mapped to 39 loci, were identified. Mendelian randomisation (MR) revealed little evidence of a causal effect of mJSW on HOA (ORIVW 0.98 [95% CI 0.82-1.18]). However, MR-Clust analysis suggested the null MR estimates reflected the net effect of two distinct causal mechanisms cancelling each other out, one of which was protective, whereas the other increased HOA susceptibility. For the latter mechanism, all loci were positively associated with height, suggesting mechanisms leading to greater height and mJSW increase the risk of HOA in later life.

INTERPRETATIONS

One group of mJSW loci reduce HOA risk via increased mJSW, suggesting possible utility as targets for chondroprotective therapies. The second group of mJSW loci increased HOA risk, despite increasing mJSW, but were also positively related to height, suggesting they contribute to HOA risk via a growth-related mechanism.

FUNDING

Primarily funded by the Medical Research Council and Wellcome Trust.

Obesity is associated with an increased risk of undergoing hip replacement in Australia

BACKGROUND

Obesity is a known risk factor for the development of hip osteoarthritis. The aim of this study was to investigate whether obesity is associated with the risk of undergoing total hip replacement (THR) in Australia.

METHODS

A cohort study was conducted comparing data from the Australian Bureau of Statistics and the Australian Orthopaedic Association National Joint Replacement Registry (AOANJRR) from 2017 to 2018. Body mass index (BMI) data for patients undergoing primary total hip replacement and resurfacing for osteoarthritis were obtained from the AOANJRR. The distribution of THR patients by BMI category was compared to the general population, in age and sex sub-groups.

RESULTS

During the study period, 32 495 primary THR were performed for osteoarthritis in Australia. Compared to the general population, there was a higher prevalence of Class I, II and III obesity in patients undergoing THR in both sexes aged 35-74 years. Class III obese females and males aged 55-64 years were 2.9 and 1.7 times more likely to undergo THR, respectively (P < 0.001). Class III obese females and males underwent THR on average 5.7 and 7.0 years younger than their normal weight counterparts, respectively.

CONCLUSION

Obese Australians are at increased risk of undergoing THR, and at a younger age.

Outcomes of morbidly obese patients undergoing total hip arthroplasty with the anterior-based muscle-sparing approach

Obesity is associated with an increased risk of hip osteoarthritis, resulting in an increased number of total hip arthroplasties (THAs) performed annually. This study examines the peri- and postoperative outcomes of morbidly obese (MO) patients (BMI ≥ 40 kg/m²) compared to healthy weight (HW) patients (BMI 18.5 to < 25 kg/m²) who underwent a THA using the anterior-based muscle-sparing (ABMS) approach. This retrospective cohort study observes peri- and postoperative outcomes of MO and HW patients who underwent a primary, unilateral THA with the ABMS approach. Data from surgeries performed by three surgeons at a single institution was collected from January 2013 to August 2020 and analyzed using Microsoft Excel and Stata 17.0. This study compares 341 MO to 1,140 HW patients. Anaesthesia, surgery duration, and length of hospital stay was significantly lower in HW patients compared to MO. There was no difference in incidence of pulmonary embolism, periprosthetic fracture, or dislocation between the two groups. The rate of infection in MO patients (1.47%) was significantly higher than HW patients (0.14%). Preoperative patient-reported outcome measures (PROMs) show a significantly higher pain level in MO patients and a significantly lower score in functional abilities. Overall, six-week and one-year postoperative data show higher levels of pain, lower levels of functional improvement, and lower satisfaction scores in the MO group. The comorbidities of obesity are well studied; however, the implications of THA using the ABMS approach have not been studied. Our peri- and postoperative results demonstrate significant improvements in PROMs in MO patients undergoing THA. However, the incidence of deep infection was significantly higher in this group compared with HW patients.

Causal associations of anthropometric measurements with osteoarthritis: A Mendelian randomization study

OBJECTIVE

We believe that there is a causal relationship between waist circumference and knee osteoarthritis. To confirm the hypothesis, we have conducted this study.

METHODS

Genetic variants associated with the five anthropometric variables were obtained from previous large-scale genomewide association studies. Summary-level data on osteoarthritis were obtained from the UK Biobank. The univariable and multivariable MR framework were used to evaluate the associations. The two-sided p value was considered to be statistically significant at 0.01 (where p = 0.05/5) after Bonferroni correction for the five exposure variables.

RESULTS

In the univariable MR, there was evidence of a detrimental effect of height, weight, BMI, waist circumference, and hip circumference on osteoarthritis risk in the main IVW analyses (height: OR 1.115, 95% CI 1.054-1.180; weight: OR 1.765, 95% CI 1.650-1.889; BMI: OR 1.952, 95%CI 1.841-2.068; waist circumference: OR 2.140, 95% CI 1.994-2.296; hip circumference: OR 1.719, 95% CI 1.600-1.846). And the analyses on knee osteoarthritis and hip osteoarthritis yielded similar results. However, the multivariable MR showed that only waist circumference was causally associated with osteoarthritis, after adjusting for the confounding exposure effects (waist circumference: OR 1.877, 95% CI 1.286-2.739). Such association was also repeated in the analyses on knee osteoarthritis but not hip osteoarthritis.

CONCLUSION

Our study highlighted the causal associations between waist circumference and knee osteoarthritis risk.

Multidisciplinary patient-centred model of care for osteoarthritis: scoping review protocol—an initiative by the Egyptian Academy of Bone Health

Background

There is an evidence-practice gap in osteoarthritis (OA) management which has caused several patients living with the disease are receiving suboptimal medical care. Though there are several guidelines and treatment recommendations published, there is a real need to operationalise such evidence-based guidelines and facilitate their implementation by healthcare professionals in their local health systems

Main text

This work was carried out to outline a patient-centred multidisciplinary osteoarthritis care programme for knee and hip joint osteoarthritis that is applicable in standard clinical practice. A scoping review was conducted to identify an evidence-informed osteoarthritis management strategy, which outlines the optimal manner to treat patients living with osteoarthritis and can be implemented by healthcare professionals. The Preferred Reporting Items for Systematic reviews and Meta-Analyses (PRISMA) extension for Scoping Reviews (PRISMA-ScR) checklist was used to guide the reporting of this review. Based on this, a “Model of Care” based on a patient-centred approach with shared decision-making to enhance the timely consideration of all treatment options (including non-pharmacological, pharmacological therapies, psychotherapy, rehabilitation as well as surgery) has been developed aiming to optimise the outcomes. The goals and principles have been identified as well as the key performance indices. An algorithm for the multidisciplinary management of osteoarthritis has been developed.

Conclusion

The developed osteoarthritis care programme (OACP) provided a “Model of Care” for people living with OA which can be implemented in standard practice. The results will give insight into the features, performance, results, and outcome measures assessed. It will also guide future research towards how “Model of Care” can be patient-centred and tailored to the individual medical status.

Relationship of early postoperative perceived leg length discrepancy to the progression of osteoarthritis in the contralateral hip after unilateral total hip arthroplasty—a retrospective cohort study using propensity score matching

[Purpose] This study aimed to identify the relationship between the early postoperative perceived leg length discrepancy after unilateral total hip arthroplasty and the progression of osteoarthritis in the contralateral hip. [Participants and Methods] This was a retrospective cohort study of 65 patients who underwent primary unilateral total hip arthroplasty for bilateral hip osteoarthritis. The minimum joint space width of the contralateral hip was measured preoperatively. The change in minimum joint space width one year postoperatively compared with preoperatively was measured. At three weeks postoperatively, patients were divided into the perceived and non-perceived leg length discrepancy groups using the block test. Patients with a perceived leg length discrepancy of 2 mm or more and less than 2 mm were grouped into the perceived and non-perceived leg length discrepancy groups, respectively. Before and after propensity score matching, the change in minimum joint space width between the two groups from the preoperative period to one year postoperatively was compared. [Results] In the pre-propensity matching sample, there was no significant difference in the change in minimum joint space width between the two groups. In the post-propensity matching sample, the change in minimum joint space width in the perceived leg length discrepancy group was significantly larger than that in the non-perceived leg length discrepancy group. [Conclusion] The early postoperative perceived leg length discrepancy after unilateral total hip arthroplasty may affect the progression of osteoarthritis in the contralateral hip.

Obesity is associated with an increased risk of undergoing knee replacement in Australia

Background

Obesity is associated with the development of knee osteoarthritis (OA). The aim of this study was to examine the incidence of obesity in patients undergoing knee replacement (KR) for OA in Australia compared to the incidence of obesity in the general population.

Methods

A cohort study was conducted, comparing data from the Australian Bureau of Statistics (ABS) 2017–2018 National Health Survey with data from the National Joint Replacement Registry. The distribution of patients who underwent KR from July 2017 to June 2018 by BMI category was compared to the distribution of the general population, in age and gender sub‐groups.

Results

During the study period, 35.6% of Australian adults were overweight and 31.3% were obese. Of the 56 217 patients who underwent primary KR for OA, 31.9% were overweight and 57.7% were obese. The relative risk of undergoing KR for OA increased with increasing BMI category. Class 1, 2 and 3 obese females aged 55–64 years were 4.7, 8.4 and 17.3 times more likely to undergo KR than their normal weight counterparts, respectively. Males in the same age and BMI categories were 3.4, 4.5 and 5.8 times more likely to undergo KR, respectively. Class 3 obese patients underwent KR 7 years younger, on average, than normal weight individuals.

Conclusion

Obesity is associated with an increased risk of undergoing KR, and at a younger age, particularly for females. There is an urgent need for a societal level approach to address the prevalence of obesity, to reduce the burden of obesity related KR.

A community-centric multi-disciplinary education program with the 8-section brocade Tai Chi therapy for patients with osteoarthritis of the knee - a pilot study

Background

Osteoarthritis (OA) of the knee is one of the most common chronic degenerative joint diseases, and a multi-disciplinary approach to educating patients with OA knee are effective in symptoms management. Tai Chi exercise is a novel approach to relieving knee OA symptoms. Combining both educational program and Tai Chi has not yet been explored.

Methods

Multi-disciplinary education program included a total of 4-week 2-h weekly talks delivered by different health professionals with live demonstrations. This was then followed by a 1-h Tai Chi class (Baduanjin). Results from IPAQ (Physical activity level), WOMAC (evaluate knee OA conditions), and SF-36v2 (quality of life) were collected at the first class of education program, 3 and 6 months after the end of Tai Chi class. CSQ-8 (program effectiveness) was administered on the last day of Tai Chi class.

Results

One hundred and twelve patients joined the program. The overall attendance was over 90% with close-to-zero dropout rate. Satisfaction scored high in 85% of patients. WOMAC pain scores (p = 0.04) and SF-36v2 emotional role (p = 0.02) were statistically decreasing (improving) at 6 months after the program. SF-36v2 physical role and mental health tended to improve with time.

Conclusions

Combining both multidisciplinary education program program and Tai Chi exercise for knee OA patients was proven feasible. This program received high satisfaction, high attendance and very low dropout rates without any adverse event. Patients’ pain and emotion were significantly improved. A large-scale randomized trial introducing a control group is recommended.

Trial registration

Registry: ClinicalTrials.gov

Registration number: NCT04204213

Date of registration: 18/12/2019 (Retrospectively registered)

The relationship between obesity and primary Total Knee Replacement: A scoping review of the literature

BACKGROUND

Primary Total Knee Replacement (TKR) is one of the most commonly performed elective orthopaedic procedures globally. Many patients undergoing this type of surgery are overweight or obese. In the UK, clinical commissioning groups have imposed arbitrary Body Mass Index (BMI) thresholds for TKR surgery. Many obese patients undergoing TKR believe they will lose weight following the procedure because of increased mobility.

AIM

This paper aims to present the findings of a scoping literature review about the relationship between obesity and primary TKR and to make recommendations for clinical practice, education and policy.

METHODS

A scoping literature review investigated the impact of BMI/body weight on the need for TKR, the impact of body weight and or BMI on patient outcomes following TKR, weight loss/gain following TKR and the implications of obesity on cost of TKR.

FINDINGS

Seventy-one papers were included in the review. Seven studies reported statistically significant associations between increased BMI/obesity with the need for TKR. Thirty of the studies reported worse outcomes for obese patients compared to non-obese comparisons. Forty of the studies reported no difference between obese and non-obese participants, including some where outcomes of obese patients were better than non-obese comparisons. Eight studies reported on changes to weight before and after TKR, three of the studies reporting a higher percentage losing weight than gaining weight and four studies reporting that obese patients gained weight. The 8th study reported that morbidly obese patients largely returned to their baseline BMI postoperatively.

CONCLUSION

The findings of the review challenge the legitimacy of setting BMI thresholds to control access to TKR surgery. There is an urgent need to develop evidence based approaches to support weight loss and weight management for this group of patients. Obese patients undergoing TKR should receive specific information regarding potential additional risks of complications and poorer outcomes. There is a need for health promotion regarding the association of being overweight/obese in young adulthood and developing osteoarthritis of the knee joints requiring TKR in middle and older age.

Comorbid conditions and the transition among states of hip osteoarthritis and symptoms in a community-based study: a multi-state time-to-event model approach

Background

We examined the association of three common chronic conditions (obesity, diabetes mellitus [DM], and cardiovascular disease [CVD]) with transitions among states of hip osteoarthritis (HOA).

Methods

This longitudinal analysis used data from the Johnston County Osteoarthritis Project (JoCo OA, n = 3857), a community-based study in North Carolina, USA, with 18.4 ± 1.5 years of follow-up. Transitions across the following states were modeled: development of radiographic HOA (rHOA; Kellgren-Lawrence grade [KLG] of< 2); development of hip symptoms (self-reported hip pain, aching, or stiffness on most days) or symptomatic HOA (sxHOA; rHOA and symptoms in the same hip), and resolution of symptoms. Obesity (body mass index ≥ 30 kg/m²) and self-reported DM and CVD were the time-dependent comorbid conditions of interest. Markov multi-state models were used to estimate adjusted hazard ratios and 95% confidence intervals to describe the associations between the conditions and HOA states.

Results

The sample included 33% African Americans, 39% men, with a mean (SD) age of 62.2 (9.8) years; the frequencies of the comorbidities increased substantially over time. When considered individually, obesity was associated with incident hip symptoms, while CVD and DM were associated with reduced symptom resolution. For those with > 1 comorbidity, the likelihood of incident sxHOA increased, while that of symptom resolution significantly decreased. When stratified by sex, the association between obesity and incident symptoms was only seen in women; among men with DM versus men without, there was a significant (~ 75%) reduction in symptom resolution in those with rHOA. When stratified by race, African Americans with DM, versus those without, were much more likely to develop sxHOA.

Conclusions

Comorbid chronic conditions are common in individuals with OA, and these conditions have a significant impact on the persistence and progression of HOA. OA management decisions, both pharmacologic and non-pharmacologic, should include considerations of the inter-relationships between OA and common comorbidities such as DM and CVD.

Greater risks of complications, infections, and revisions in the obese versus non-obese total hip arthroplasty population of 2,190,824 patients: a meta-analysis and systematic review

BACKGROUND

Obesity is an epidemic, especially in developed countries. This affects the general health of these patients, especially when they are having a major surgical procedure such as total hip arthroplasty (THA). Several articles have described the effects of obesity on THA with varying conclusions. This meta-analysis aims to compare the outcomes, complications, and peri-operative parameters of THA in the obese (BMI≥30 kg/m²) vs non-obese (BMI<30 kg/m²) population as well as a subgroup analysis of morbidly obese (BMI≥40 kg/m²) vs non-obese population.

METHODS

A multi-database search was performed according to PRISMA guidelines. Data from studies assessing the outcomes and complications of THA in the obese and non-obese population were extracted and analyzed.

RESULTS

Sixty-seven studies were included in this meta-analysis, consisting of 581,012 obese and 1,609,812 non-obese patients. Meta-analysis could not be performed on patient reported outcome measures due to heterogeneous reporting methods. Obese patients had a higher risk of all complications (OR = 1.53, 95%CI: 1.30-1.80, P < 0.001), deep infections (OR = 2.71, 95%CI: 2.08-3.53, P < 0.001), superficial infections (OR = 1.99, 95%CI: 1.55-2.55, P < 0.001), dislocations (OR = 1.72, 95%CI: 1.66-1.79, P < 0.001), reoperations (OR = 1.61, 95%CI: 1.40-1.85, P < 0.001), revisions (OR = 1.44, 95%CI: 1.32-1.57, P < 0.001), and readmissions (OR = 1.37, 95%CI: 1.15-1.63, P < 0.001). When sub-group analysis of morbidly obese (BMI≥40 kg/m²) patients was performed, the risks of all these parameters were even greater.

CONCLUSION

Obese and morbidly obese patients are at higher risks of complications post THA than non-obese patients. Surgeons should be aware of these risks in order to counsel patients and adopt prophylactic strategies to reduce these risks where applicable.

Identification of Novel Loci Associated With Hip Shape: A Meta-Analysis of Genomewide Association Studies

We aimed to report the first genomewide association study (GWAS) meta-analysis of dual-energy X-ray absorptiometry (DXA)-derived hip shape, which is thought to be related to the risk of both hip osteoarthritis and hip fracture. Ten hip shape modes (HSMs) were derived by statistical shape modeling using SHAPE software, from hip DXA scans in the Avon Longitudinal Study of Parents and Children (ALSPAC; adult females), TwinsUK (mixed sex), Framingham Osteoporosis Study (FOS; mixed), Osteoporotic Fractures in Men study (MrOS), and Study of Osteoporotic Fractures (SOF; females) (total N = 15,934). Associations were adjusted for age, sex, and ancestry. Five genomewide significant (p < 5 × 10-9 , adjusted for 10 independent outcomes) single-nucleotide polymorphisms (SNPs) were associated with HSM1, and three SNPs with HSM2. One SNP, in high linkage disequilibrium with rs2158915 associated with HSM1, was associated with HSM5 at genomewide significance. In a look-up of previous GWASs, three of the identified SNPs were associated with hip osteoarthritis, one with hip fracture, and five with height. Seven SNPs were within 200 kb of genes involved in endochondral bone formation, namely SOX9, PTHrP, RUNX1, NKX3-2, FGFR4, DICER1, and HHIP. The SNP adjacent to DICER1 also showed osteoblast cis-regulatory activity of GSC, in which mutations have previously been reported to cause hip dysplasia. For three of the lead SNPs, SNPs in high LD (r2  > 0.5) were identified, which intersected with open chromatin sites as detected by ATAC-seq performed on embryonic mouse proximal femora. In conclusion, we identified eight SNPs independently associated with hip shape, most of which were associated with height and/or mapped close to endochondral bone formation genes, consistent with a contribution of processes involved in limb growth to hip shape and pathological sequelae. These findings raise the possibility that genetic studies of hip shape might help in understanding potential pathways involved in hip osteoarthritis and hip fracture. © 2018 The Authors. Journal of Bone and Mineral Research Published by Wiley Periodicals, Inc.

Relationship between height and outcomes among critically ill adults: a cohort study

PURPOSE

Many diagnostic and therapeutic interventions for critically ill adult patients are not performed according to patient size, but are standardized for an idealized 174-cm man (ideal body weight 70 kg). This study aims to determine whether critically ill patients with heights significantly different from a standardized patient have higher hospital mortality or greater resource utilization.

METHODS

Retrospective cohort study of consecutive patients admitted to 210 intensive care units (ICUs) in the United Kingdom participating in the Intensive Care National Audit and Research Centre's Case Mix Programme Database from April 1, 2009, to March 31, 2015. Primary outcome was hospital mortality, adjusted for age, comorbid disease, severity of illness, socioeconomic status and body mass index, using hierarchical modeling to account for clustering by ICU. Data were stratified by sex, and the effect of height was modeled continuously using restricted cubic splines.

RESULTS

The cohort included 233,308 men and 184,070 women, with overall hospital mortality of 22.5% and 20.6%, respectively. After adjustment for potential confounders, hospital mortality decreased with increasing height; predicted mortality (holding all other covariates at their mean value) decreased from 24.1 to 17.1% for women and from 29.2 to 21.0% for men across the range of heights. Similar patterns were observed for ICU mortality and several additional secondary outcomes.

CONCLUSIONS

Short stature may be a risk factor for mortality in critically ill patients. Further work is needed to determine which unmeasured patient characteristics and processes of care may contribute to the increased risk observed.

Meta-analysis of Icelandic and UK data sets identifies missense variants in SMO, IL11, COL11A1 and 13 more new loci associated with osteoarthritis

Osteoarthritis has a highly negative impact on quality of life because of the associated pain and loss of joint function. Here we describe the largest meta-analysis so far of osteoarthritis of the hip and the knee in samples from Iceland and the UK Biobank (including 17,151 hip osteoarthritis patients, 23,877 knee osteoarthritis patients, and more than 562,000 controls). We found 23 independent associations at 22 loci in the additive meta-analyses, of which 16 of the loci were novel: 12 for hip and 4 for knee osteoarthritis. Two associations are between rare or low-frequency missense variants and hip osteoarthritis, affecting the genes SMO (rs143083812, frequency 0.11%, odds ratio (OR) = 2.8, P = 7.9 × 10^-12, p.Arg173Cys) and IL11 (rs4252548, frequency 2.08%, OR = 1.30, P = 2.1 × 10^-11, p.Arg112His). A common missense variant in the COL11A1 gene also associates with hip osteoarthritis (rs3753841, frequency 61%, P = 5.2 × 10^-10, OR = 1.08, p.Pro1284Leu). In addition, using a recessive model, we confirm an association between hip osteoarthritis and a variant of CHADL¹ (rs117018441, P = 1.8 × 10^-25, OR = 5.9). Furthermore, we observe a complex relationship between height and risk of osteoarthritis.

Risk of Subsequent Joint Arthroplasty in Contralateral or Different Joint After Index Shoulder, Hip, or Knee Arthroplasty: Association with Index Joint, Demographics, and Patient-Specific Factors

BACKGROUND

The risk of subsequent joint replacement following an index joint replacement for osteoarthritis and the association of this risk with demographic and patient-specific factors are not well understood. The purpose of this study was to determine how demographic and other patient-specific factors are associated with the risk of subsequent joint replacement in the contralateral or a different joint following an index joint replacement for osteoarthritis.

METHODS

The Healthcare Cost and Utilization Project (HCUP) State Inpatient Database (SID) of New York was used to identify the first (primary) total hip arthroplasty (THA), total knee arthroplasty (TKA), or total shoulder arthroplasty (TSA) and the risk of subsequent joint replacement in the contralateral or a different joint over 5 to 8 years. The association of demographic and other patient-specific factors with subsequent joint replacement was assessed via multivariable Cox proportional hazards modeling. We also investigated the time between the index and subsequent joint replacement.

RESULTS

Of 85,616 patients, 20,223 (23.6%) underwent a subsequent replacement of the contralateral joint within 5 to 8 years (median, 343 days) after the index joint replacement. The strongest predictors were obesity (adjusted hazard ratio [HR] = 1.28; p < 0.001) and index TKA compared with THA (1.72; p < 0.001). A total of 3,197 patients (3.7%) underwent a subsequent replacement of a different joint within 5 to 8 years (median, 876 days) after the index joint replacement. The strongest predictors were obesity (adjusted HR = 1.41; p < 0.001) and index TSA compared with THA (adjusted HR = 2.52; p < 0.001).

CONCLUSIONS

There is a relatively high risk of subsequent replacement of the contralateral joint and a relatively low risk of subsequent replacement of a different joint within 5 to 8 years after an index THA, TKA, or TSA. Obesity was associated with a higher risk of subsequent replacement of the contralateral joint or a different joint.

LEVEL OF EVIDENCE

Prognostic Level IV. See Instructions for Authors for a complete description of levels of evidence.

Association of Metabolic Markers with self-reported osteoarthritis among middle-aged BMI-defined non-obese individuals: a cross-sectional study

BACKGROUND

Osteoarthritis (OA) is a chronic degenerative joint disease. While it is well-established that obesity affects OA through increased axial loading on the joint cartilage, the indirect effect of obesity through metabolic processes among the body mass index (BMI)-defined non-obese population, i.e., BMI < 30 kg/m2, is less known. Our goal was to evaluate the association of metabolic markers including body fat percentage (BF%), waist circumference, maximum weight gain during adulthood and serum creatinine with self-reported OA to establish if such measures offer additional information over BMI among the non-obese population between 40 and 65 years of age.

METHODS

Cross-sectional data from two cycles of the Canadian Health Measures Survey (CHMS) in 2007-2009 and 2009-2011 were analyzed. Sex-specific logistic regression models were developed to evaluate the association of self-reported OA with metabolic markers. Models were separately adjusted for age, BMI categories and serum creatinine, and a stratified analysis across BM categories was performed. In a secondary analysis, we evaluated the association of self-reported OA, cardiovascular diseases and hypertension across BF% categories.

RESULTS

Of 2462 individuals, 217 (8.8%) self-reported OA. After adjusting for age and BMI, those within BF%-defined overweight/obese category had 2.67 (95% CI: 1.32-3.51) and 2.11(95% CI: 1.38-3.21) times higher odds of reporting self-reported OA compared to those within BF%-defined athletic/acceptable category for females and males, respectively. BF% was also significantly associated with self-reported OA after adjusting for age and serum creatinine only among females (OR: 1.47, 95%CI: 1.12-1.84). Furthermore, among the BMI-defined overweight group, the age-adjusted odds of self-reported OA was significantly higher for overweight/obese BF% compared to athletic/acceptable BF% in both females and males. In a secondary analysis, we showed that the association of self-reported OA and hypertension/cardiovascular diseases is significantly higher among BF% overweight/obese (OR: 1.37, 95%CI: 1.19-3.09) compared to BF% athletic/acceptable (OR: 1.13, 95%CI: 0.87-2.82).

CONCLUSION

Our results provide corroborating evidence for a relationship between body fat and OA in a population-based study, while no significant independent correlates were found between other metabolic markers and OA prevalence. Future investigation on the longitudinal relationship between BF and OA among this sub-population may inform targeted prevention opportunities.

Bariatric Surgery Improves Outcomes After Lower Extremity Arthroplasty in the Morbidly Obese: A Propensity Score-Matched Analysis of a New York Statewide Database

BACKGROUND

The purpose of this study was to compare risks for revision and short-term complications after total joint arthroplasty (TJA) in matched cohorts of morbidly obese patients, receiving and not receiving prior bariatric surgery.

METHODS

Patients undergoing elective TJA between 1997 and 2011 were identified in a New York Statewide database, analyzing total knee arthroplasty (TKA) and total hip arthroplasty (THA) separately. Propensity scores were used to match morbidly obese patients receiving and not receiving bariatric surgery prior to TJA. Cox proportional hazard modeling assessed revision risk. Logistic regression evaluated odds for complications.

RESULTS

For TKA, 2636 bariatric surgery patients were matched to 2636 morbidly obese patients. For THA, 792 bariatric surgery patients were matched to 792 morbidly obese patients. Matching balanced all covariates. Bariatric surgery reduced co-morbidities prior to TJA (TKA P < .0001; THA P < .005). Risks for in-hospital complications were lower for THA and TKA patients receiving prior bariatric surgery (odds ratio [OR] 0.25, P < .001; and OR = 0.69, P = .021, respectively). Risks for 90-day complications were lower for TKA (OR 0.61, P = .002). Revision risks were not different for either THA (P = .634) or TKA (P = .431), nor was THA dislocation risk (P = 1.000).

CONCLUSION

After accounting for relevant selection biases, bariatric surgery prior to TJA was associated with reduced co-morbidity burden at the time of TJA and with reduced post-TJA complications. However, bariatric surgery did not reduce the risk for revision surgery for either TKA or THA.

The gait speed advantage of taller stature is lost with age

Taller individuals walk faster but it is unknown whether this advantage persists at older ages. We examined the cross-sectional/longitudinal associations of height with gait speed (GS) in participants from the Dijon-Three-City cohort study (France) over 11 years. In 4011 participants (65–85 y), we measured usual/fast GS (6 m) up to five times. We examined whether the baseline height-GS association varied with age using linear regression, and whether height influenced GS change using linear mixed models. Taller participants 65 y at baseline walked faster than shorter ones (fast GS difference between top/bottom height quartiles, 0.100 m/s, P < 0.001); this association weakened with age (P-interaction = 0.02), with a 0.012 m/s (P = 0.57) difference at 80 y. Ten-year fast GS decline was 51% greater (P < 0.001) in younger participants in the top height quartile (−0.183 m/s) compared to those in the bottom quartile (−0.121 m/s), leading the GS difference between the two groups to be attenuated by 50% over the follow-up. The height-related difference in fast GS decline was not explained by time-dependent comorbidities or height shrinkage. Analyses for usual GS yielded consistent findings. The height-GS relation is more complex than previously thought, as the height related advantage in GS disappears as persons grow older due to faster decline in taller compared to shorter persons.

Maximum lifetime body mass index is the appropriate predictor of knee and hip osteoarthritis

INTRODUCTION

In light of inconsistencies in the literature, this study aimed to investigate the relationship between obesity (current and historic) and osteoarthritis (OA) of the knee or hip.

MATERIALS AND METHODS

We examined 99 people (knee OA, hip OA and controls), age > 50 years, in a case-control study. The current weight, height and waist circumference were measured on site, and detailed weight changes over their lifetime were based on questionnaires and standardized interviews. We used binomial logistic regression to determine the predictive value for an osteoarthritis group membership of each derived indicator.

RESULTS

An increase in 'maximum-BMI' increased the odds ratio for both knee OA (OR 1.2; CI 1.1-1.4; p = 0.005; R ² = 0.36) and hip OA (OR 1.2; CI 1.0-1.3; p = 0.027; R ² = 0.16). Current BMI was significantly associated with knee OA but not with hip OA. A high "minimum-BMI" (over the age of 18 years) had the highest odds ratio of all calculated indicators for both osteoarthritis groups.

CONCLUSIONS

Based on our findings, it is concluded that the maximum BMI over one's lifespan is a better predictor of OA of the hip or the knee than the current BMI. The knee joint seems to be more sensitive to obesity as current BMI was associated only with knee OA but not with hip OA.

Body Mass Index Class Is Independently Associated With Health-Related Quality of Life After Primary Total Hip Arthroplasty: An Institutional Registry-Based Study

BACKGROUND

The purpose of this study was to compare the health-related quality of life (HRQoL) of patients across World Health Organization (WHO) body mass index (BMI) classes before and after total hip arthroplasty (THA).

METHODS

Patients with end-stage hip osteoarthritis who received elective primary unilateral THA were identified through an institutional registry and categorized based on the World Health Organization BMI classification. Age, sex, laterality, year of surgery, and Charlson-Deyo comorbidity index were recorded. The primary outcome was the EQ-5D-3L index and visual analog scale (EQ-VAS) scores at 2 years postoperatively. Inferential statistics and regression analyses were performed to determine associations between BMI classes and HRQoL.

RESULTS

EQ-5D-3L scores at baseline and at 2 years were statistically different across BMI classes, with higher EQ-VAS and index scores in patients with lower BMI. There was no difference observed for the 2-year change in EQ-VAS scores, but there was a statistically greater increase in index scores for more obese patients. In the regression analyses, there were statistically significant negative effect estimates for EQ-VAS and index scores associated with increasing BMI class.

CONCLUSION

BMI class is independently associated with lower HRQoL scores 2 years after primary THA. While absolute scores in obese patients were lower than in nonobese patients, obese patients enjoyed more positive changes in EQ-5D index scores after THA. These results may provide the most detailed information on how BMI influences HRQoL before and after THA, and they are relevant to future economic decision analyses on the topic.

Factors associated with functional limitations in the daily living activities of Japanese hip osteoarthritis patients

AIM

As society ages, there is a vast number of elderly people with locomotive syndrome. In this study, the factors associated with functional limitations in daily living activities evaluated by female hip osteoarthritis (OA) patients were investigated.

METHODS

This study was a cross-sectional study. The subjects were 353 female patients who were newly diagnosed with hip OA at an orthopedic clinic with no history of hip joint surgery. Outcome indices were functional limitations in two daily living activities obtained from a questionnaire completed by the patients: (i) standing up (standing from a crouched position) and (ii) stair-climbing (climbing and/or descending stairs). The odds ratios (ORs) and 95% confidence intervals (CIs) were computed for explanatory variables using the proportional odds model in logistic regression to evaluate their associations with functional limitations.

RESULTS

Functional limitations in standing up were associated with heavy weight (third tertile vs. first tertile: 1.91, 1.11-3.27), participation in sports at school (0.62, 0.40-0.98), parity (vs. nullipara: 1.96, 1.08-3.56), old age and OA stage. Associations with functional limitations in stair-climbing were seen with short height (< 151.0 cm vs. ≥ 156.0 cm: 2.05, 1.02-4.12), bilateral involvement (vs. unilateral: 1.71, 1.01-2.88), old age and OA stage.

CONCLUSION

Old age, OA stage, heavy weight, parity, shorter height and bilateral OA were associated with functional limitations in standing up and/or stair-climbing, whereas participation in sports such as club activities in school maintained standing up.

No clinically meaningful weight changes in a young cohort following total joint arthroplasty at 3-year follow-up

BACKGROUND

Total joint arthroplasty (TJA) is one of the most successful operations. There is little in the literature regarding weight change following TJA, particularly in a young cohort.

METHODS

Retrospective analysis of 181 primary total hip arthroplasty (THA) and 185 primary total knee arthroplasty (TKA) patients was conducted. We reviewed preoperative and post-operative weights and post-operative body mass index at 3 and 6 months, 1 year, 2 and 3 years. We evaluated expected versus actual weight gain, and performed subgroup analyses of obese versus non-obese patients and active duty versus civilian patients. We used a minimal clinically meaningful weight change from baseline of ≥5%.

RESULTS

One hundred and fifty-one (41.3%) patients were active duty military service members with the mean age of 53 ± 11.1 years. In TKA patients, statistically significant differences were found in mean weights at 3 months (-1.8%, P ≤ 0.0001) and 2 years (+1.9%, P = 0.0006). In THA patients, statistically significant weight gains were found at 6 months (+1.1%, P = 0.006). For obese TKA patients, significant weight changes were observed at 3 months (-2.5%, P ≤ 0.0001), and none in the obese THA group. There were no statistical or clinically meaningful weight changes in the non-obese TKA or THA groups. There was a clinically meaningful weight gain in active duty TKA patients at 3 years (5.18%, P = 0.17).

CONCLUSION

Despite a theoretical ability to lose weight following TJA, patients maintain their preoperative weight following TJA. We found a clinically meaningful weight gain at 3 years post-operatively only in active duty TKA patients. Overall, however, we found no clinically significant weight changes following TJA at 3-year follow-up.

Morbid Obesity in Total Hip Arthroplasty: Redefining Outcomes for Operative Time, Length of Stay, and Readmission

BACKGROUND

The incidence of obesity among patients presenting for elective total hip arthroplasty (THA) has increased in the last decade, and the relationship between obesity and the need for joint arthroplasty has been demonstrated. This study evaluates the effects of morbid obesity on outcomes after primary THA by comparing short-term outcomes in THA between a morbidly obese (body mass index [BMI] ≥40) and a normal weight (BMI, 18.5 to <25) cohort at our institution between January 2003 and December 2010.

METHODS

Thirty-nine patients included in the morbidly obese group were compared with 186 in the normal weight group. Operative time, length of stay, complications, readmission, and length of readmission were compared.

RESULTS

Operative time was increased in the morbidly obese group at 122 minutes compared with 100 minutes (P = .002). Postoperatively, there was an increased 30-day readmission rate related to surgery of 12.8% associated with BMI ≥40 compared with 2.7% (P = .005) as well as a 5.1-fold increase in surgery-related readmitted bed days-0.32 bed days per patient for normal weight compared with 1.64 bed days per patient for the morbidly obese (P = .026).

CONCLUSION

Morbidly obese patients present a technical challenge and likely this, and the resultant complications are underestimated. More work needs to be performed to enable suitable allocation of resources.

Obesity and the Relative Risk of Knee Replacement Surgery in Patients With Knee Osteoarthritis: A Prospective Cohort Study

OBJECTIVE

It is unclear what impact obesity has on the progression of knee osteoarthritis (OA) from diagnosis to knee replacement surgery. This study was undertaken to examine the relative risk of knee replacement surgery in overweight and obese patients who were newly diagnosed as having knee OA in a community setting.

METHODS

Subjects were selected from the Information System for Development of Primary Care Research database, which compiles comprehensive clinical information collected by health care professionals for >5.5 million people in Catalonia, Spain (80% of the population). Patients newly diagnosed as having knee OA in primary care between 2006 and 2011 were included. Knee replacement was ascertained using International Classification of Diseases, Ninth Revision, Clinical Modification codes from linked hospital admissions data. Multivariable Cox regression models were fitted for knee replacement according to body mass index (BMI), and were adjusted for relevant confounders. Population proportional attributable risk was calculated.

RESULTS

A total of 105,189 participants were followed up for a median of 2.6 years (interquartile range 1.3-4.2). Of these patients, 7,512 (7.1%) underwent knee replacement. Adjusted hazard ratios and 95% confidence intervals (95% CIs) for knee replacement for the World Health Organization BMI categories were 1.41 (95% CI 1.27-1.57) for overweight, 1.97 (95% CI 1.78-2.18) for obese I, 2.39 (95% CI 2.15-2.67) for obese II, and 2.67 (95% CI 2.34-3.04) for obese III compared to normal weight. The effect of BMI on risk of knee replacement was stronger among younger participants. The population attributable risk of obesity for knee OA-related knee replacement was 31.0%.

CONCLUSION

Overweight and obese patients are at >40% and 100% increased risk of knee replacement surgery, respectively, compared to patients with normal weight. This association is even stronger in younger patients. Weight reduction strategies could potentially reduce the need for knee replacement surgery by 31% among patients with knee OA.

Factors associated with diagnostic stage of hip osteoarthritis due to acetabular dysplasia among Japanese female patients: a cross-sectional study

Background

In Japan, the majority of hip osteoarthritis (OA) was caused by acetabular dysplasia, and about 90 % of patients were female. The present study focused on Japanese female patients with hip OA due to acetabular dysplasia, and examined the associated factors with OA staging at diagnosis, in special reference to body weight.

Methods

Study subjects were 336 Japanese women who were newly diagnosed with hip OA caused by acetabular dysplasia at 15 hospitals in 2008. The self-administered questionnaire elicited patients’ body weight at age 20 and at OA diagnosis. Four ranked OA staging according to radiographic findings of the hip joint (pre-OA, initial stage, advanced stage or terminal stage) was regarded as the outcome index. Proportional odds models in logistic regression were used to calculate odds ratios (ORs) and 95 % confidence intervals (CIs) for severer stage of OA.

Results

At diagnosis, 45 % of patients suffered from terminal stage of OA, whereas 13 % and 14 % were categorized into pre-OA and initial stage, respectively. After adjustment for potential confounders, weight gain since age 20 revealed the increased ORs for severer OA stage at diagnosis (OR 2.02; 95 % CI, 1.07–3.80). Other significant characteristics were age (67+ vs. 20–49 years, OR 12.4), lower education (junior high school vs. junior college or higher, OR 4.00), parity (OR 2.19), lower acetabular head index (<60.0 vs. 71.1+, OR 2.36), and longer duration since symptom onset (6.0+ vs. <1.0 year, OR 2.94).

Conclusions

Weight gain since age 20 might be involved in mechanisms of OA development, which is independent of age or severity of acetabular dysplasia.

Improving patients’ experience and outcome of total joint replacement: the RESTORE programme

Background

Total hip replacements (THRs) and total knee replacements (TKRs) are common elective procedures. In the REsearch STudies into the ORthopaedic Experience (RESTORE) programme, we explored the care and experiences of patients with osteoarthritis after being listed for THR and TKR up to the time when an optimal outcome should be expected.

Objective

To undertake a programme of research studies to work towards improving patient outcomes after THR and TKR.

Methods

We used methodologies appropriate to research questions: systematic reviews, qualitative studies, randomised controlled trials (RCTs), feasibility studies, cohort studies and a survey. Research was supported by patient and public involvement.

Results

Systematic review of longitudinal studies showed that moderate to severe long-term pain affects about 7–23% of patients after THR and 10–34% after TKR. In our cohort study, 10% of patients with hip replacement and 30% with knee replacement showed no clinically or statistically significant functional improvement. In our review of pain assessment few research studies used measures to capture the incidence, character and impact of long-term pain. Qualitative studies highlighted the importance of support by health and social professionals for patients at different stages of the joint replacement pathway. Our review of longitudinal studies suggested that patients with poorer psychological health, physical function or pain before surgery had poorer long-term outcomes and may benefit from pre-surgical interventions. However, uptake of a pre-operative pain management intervention was low. Although evidence relating to patient outcomes was limited, comorbidities are common and may lead to an increased risk of adverse events, suggesting the possible value of optimising pre-operative management. The evidence base on clinical effectiveness of pre-surgical interventions, occupational therapy and physiotherapy-based rehabilitation relied on small RCTs but suggested short-term benefit. Our feasibility studies showed that definitive trials of occupational therapy before surgery and post-discharge group-based physiotherapy exercise are feasible and acceptable to patients. Randomised trial results and systematic review suggest that patients with THR should receive local anaesthetic infiltration for the management of long-term pain, but in patients receiving TKR it may not provide additional benefit to femoral nerve block. From a NHS and Personal Social Services perspective, local anaesthetic infiltration was a cost-effective treatment in primary THR. In qualitative interviews, patients and health-care professionals recognised the importance of participating in the RCTs. To support future interventions and their evaluation, we conducted a study comparing outcome measures and analysed the RCTs as cohort studies. Analyses highlighted the importance of different methods in treating and assessing hip and knee osteoarthritis. There was an inverse association between radiographic severity of osteoarthritis and pain and function in patients waiting for TKR but no association in THR. Different pain characteristics predicted long-term pain in THR and TKR. Outcomes after joint replacement should be assessed with a patient-reported outcome and a functional test.

Conclusions

The RESTORE programme provides important information to guide the development of interventions to improve long-term outcomes for patients with osteoarthritis receiving THR and TKR. Issues relating to their evaluation and the assessment of patient outcomes are highlighted. Potential interventions at key times in the patient pathway were identified and deserve further study, ultimately in the context of a complex intervention.

Study registration

Current Controlled Trials ISRCTN52305381.

Funding

This project was funded by the NIHR Programme Grants for Applied Research programme and will be published in full inProgramme Grants for Applied Research; Vol. 4, No. 12. See the NIHR Journals Library website for further project information.

Body size from birth to middle age and the risk of hip and knee replacement

BACKGROUND

Information regarding the effects of body size in childhood and early adulthood on the risk of hip and knee replacement in later life is inconsistent. We aimed to assess their effect, taking into account body mass index (BMI) in middle-age.

METHODS

Prospective cohort (Million Women Study) of 791,034 women with information on birth weight, body size at age 10 and age 20, and current BMI (at mean age 59.5 years) were followed for 6.82 million person-years. Adjusted relative risks (RRs) and absolute risks of hospitalisations for hip or knee replacement surgery for osteoarthritis were estimated.

RESULTS

After a mean of 8.6 years follow-up, 17,402 women had a hip replacement and 18,297 a knee replacement. Between the ages of 50 and 79 years, absolute risks for women with current BMIs of <22.5 kg/m(2) and 35 + kg/m(2) were respectively 5.6 and 13.2 % for hip replacement; and 2.6 and 35.1 % for knee replacement. Within each category of current BMI, increasing body size at age 10 and at age 20 had comparatively small effects; there were no significant associations with birth weight. We estimate that 40 % of UK women with a BMI 35 + kg/m(2) have either a hip or knee replacement between the ages of 50-79 years; this compares to just 10 % of UK women with a healthy BMI (<25 kg/m(2)).

CONCLUSIONS

The effects of body size in childhood and early adulthood on the absolute risks of either a hip or knee replacement are minimal compared to the effect of adiposity in middle age.

Addressing obesity in the management of knee and hip osteoarthritis - weighing in from an economic perspective

Background

Obesity is one of the only modifiable risk factors for both incidence and progression of Osteoarthritis (OA). So there is increasing interest from a public health perspective in addressing obesity in the management of OA. While evidence of the efficacy of intereventions designed to address obesity in OA populations continues to grow, little is known about their economic credentials.

The aim of this study is to conduct a scoping review of: (i) the published economic evidence assessing the economic impact of obesity in OA populations; (ii) economic evaluations of interventions designed to explicitly address obesity in the prevention and management of OA in order to determine which represent value for money. Besides describing the current state of the literature, the study highlights research gaps and identifies future research priorities.

Methods

In July 2014, a search of the peer reviewed literature, published in English, was undertaken for the period January 1975 – July 2014 using Medline Complete (Ebscohost), Embase, Econlit, Global Health, Health Economics Evaluation Database (HEED), all Cochrane Library databases as well as the grey literature using Google and reference lists of relevant studies. A combination of key search terms was used to identify papers assessing the economic impact of obesity in OA or economic evaluations conducted to assess the efficiency of obesity interventions for the prevention or management of OA.

Results

14 studes were identified; 13 were cost burden studies assessing the impact of obesity as a predictor for higher costs in Total Joint Arthroplasty (TJA) patients and one a cost-effectiveness study of an intervention designed to address obesity in the managment of mild to moderate OA patients.

Conclusion

The majority of the economic studies conducted are cost burden studies. While there is some evidence of the association between severe obesity and excess hospital costs for TJA patients, heterogeneity in studies precludes definitive statements about the strength of the association. With only one economic evaluation to inform policy and practice, there is a need for future research into the cost-effectiveness of obesity interventions designed both for prevention or management of OA along the disease spectrum and over the life course.

Patient-Reported Outcomes Following Total Hip Arthroplasty Stratified by Body Mass Index

Obese patients undergoing total hip arthroplasty have been shown to have less functional recovery. This study prospectively compared temporal trends in patient-reported outcomes and activity levels between patients with a body mass index (BMI) of less than 30, 30 to 35, and 35 to 40 kg/m(2) after total hip arthroplasty. Patients were evaluated via the Harris Hip Score, Lower Extremity Activity Scale, and Short Form-12 physical and mental components. The results suggest that patients with BMIs of 35 to 40 kg/m(2) might have poorer functional outcomes preoperatively, with function returning more slowly or poor function being sustained and their not reaching other cohorts' levels. Surgeons must counsel these patients regarding functional expectations and the potential for slower functional returns. [Orthopedics. 2016; 39(3):e572-e577.].

Body composition of women 20-49 years old as a predictor for noncommunicable diseases: a community-based study

BACKGROUND

Obesity increases a person's risk of developing a number of noncommunicable diseases (NCDs), including, type 2 diabetes, coronary heart disease, hypertension, and certain cancers. The bioelectrical impedance analysis (BIA) has been considered as a safe, noninvasive, simple, and least expensive portable method for the evaluation of body composition in clinical practice. However, there is not enough information about its use in community-based surveys to detect the optimal cutoff point for the body fat percent (BF%) that could predict NCDs.

OBJECTIVE

To identify the cutoff point for the BF%, at which NCD risk could be predicted compared with BMI and waist circumference (WC).

METHODS

A community-based study was conducted in a randomly selected cluster located within the catchment area of Cairo University Hospitals. All ever-married women 20-49 years old and not currently pregnant (n=373) in the selected cluster were included in the study. A questionnaire was used for recoding data during the household survey. Portable equipment that estimates body composition (water, fat, protein, and bone) through BIA was used.

RESULTS

Receiver operating characteristic curve analysis showed cutoff point for BF% of 37.5% (P=0.02) at the time of reporting hypertension, with 78% sensitivity and 40% specificity. For diagnosed diabetes, cutoff point for the BF% was 38.5% (P=0.005), with 71% sensitivity and 46% specificity. For diagnosed cardiovascular diseases, cutoff point for BF% was 38.5% (P=0.001) with 86% sensitivity and 47% specificity. For diagnosed joint diseases, cutoff point for BF% was 38.5% (P=0.005), with 67% sensitivity and 48% specificity.

CONCLUSION AND RECOMMENDATIONS

BIA was effective in predicting and suggesting the cutoff points for the BF% associated with four types of NCDs (hypertension, cardiovascular, diabetes, and joint diseases). The use of BIA for women before the age of 20 years could guide strategies for reducing body fat and its risk of NCDs.

Activity Level and Severity of Dysplasia Predict Age at Bernese Periacetabular Osteotomy for Symptomatic Hip Dysplasia

BACKGROUND

The age when patients present for treatment of symptomatic developmental dysplasia of the hip with periacetabular osteotomy (PAO) varies widely. Modifiable factors influencing age at surgery include preexisting activity level and body mass index (BMI). The severity of the hip dysplasia has also been implicated as a factor influencing the age at arthritis onset. The purpose of this study was to determine whether activity level, BMI, and severity of dysplasia are independent predictors of age of presentation for PAO.

METHODS

A retrospective, institutional review board-approved review of prospectively collected data from a multicenter study group identified 708 PAOs performed for developmental dysplasia of the hip. Demographic factors that were considered in the analysis included age at surgery, BMI, history of hip disorder or treatment, and duration of symptoms. The severity of the developmental dysplasia of the hip was assessed by radiographic measurement of the lateral and anterior center-edge angles and acetabular inclination. Activity level was assessed with the University of California, Los Angeles (UCLA) activity score. Spearman correlations and t tests were used for univariable analysis. Multivariable regression analysis using generalized estimating equations was applied to determine independent predictors of age at PAO.

RESULTS

Univariable analysis indicated that age at presentation for treatment of PAO correlated with the lateral and anterior center-edge angles (p < 0.001), UCLA score (p < 0.001), and BMI (p = 0.04). Since the lateral and anterior center-edge angles were similarly correlated (Spearman rho = 0.61, p < 0.001), the lateral center-edge angle alone was used to classify the severity of the developmental dysplasia of the hip. Multivariable linear regression confirmed that a high UCLA score and severe hip dysplasia were independent predictors of age at PAO (p < 0.001).

CONCLUSIONS

A high activity level and severe dysplasia lead to the development of symptoms and presentation for PAO at significantly younger ages. The combination of these two factors has an even greater effect on decreasing the age at presentation for hip-preserving surgery. An increased BMI was not independently associated with a younger age at surgery. Modifying activity level may be beneficial in terms of delaying the onset of symptoms from developmental dysplasia of the hip.

LEVEL OF EVIDENCE

Prognostic Level IV. See Instructions for Authors for a complete description of levels of evidence.

Association between direct and indirect smoking and osteoarthritis prevalence in Koreans: a cross-sectional study

OBJECTIVES

To assess the association between smoking patterns and knee and hip joint osteoarthritis (OA) prevalence in Koreans aged 50 years or older with focus on knee OA.

DESIGN

Cross-sectional study using nationally representative data.

SETTING

Data were collected at portable Health Examination Centres in Korea.

PARTICIPANTS

Data of 9064 participants of the 5th Korean National Health and Nutrition Examination Survey (2010-2012) aged 50 years or older who received knee or hip joint X-rays out of 31,596 total surveyees were analysed.

PRIMARY OUTCOME MEASURES

OA prevalence by smoking behaviour (current smoking, past smoking, indirect smoking and non-smoking).

SECONDARY OUTCOME MEASURES

Estimated risk of OA by smoking amount, period, pack-years and indirect smoking exposure time to assess the association between smoking-related factors and knee OA by calculating ORs and adjusting for covariates in a complex sampling design. A multinomial logistic regression analysis and backward elimination method was used.

RESULTS

OA prevalence in Koreans aged 50 years or older was 13.9%, with prevalence about 3.5 times higher in women (men 5.7%, women 20.1%). ORs for knee and hip joint OA prevalence by smoking behaviour in male indirect-smokers were lower than those in non-smokers in age and sex (OR 0.271; 95% CI 0.088 to 0.828), and selective adjustments (OR 0.314; 95% CI 0.102 to 0.966). All other analyses for smoking behaviour and total OA prevalence, and knee OA prevalence were not significantly different. Associations between smoking amount, period, pack-years and knee OA prevalence were non-significant in ever-smokers. Associations between indirect smoking exposure time and knee OA prevalence were also non-significant.

CONCLUSIONS

This study found that though direct and previous smoking and OA prevalence were not associated, there was a weak relationship between indirect smoking and OA.

Body mass index and risk of knee osteoarthritis: systematic review and meta-analysis of prospective studies

OBJECTIVES

Obesity is suggested to be a risk factor for knee osteoarthritis (OA). This meta-analysis aimed to examine the relationship between body mass index (BMI) and the risk of knee OA in published prospective studies.

DESIGN

Meta-analysis.

STUDIES REVIEWED

An extensive literature review was performed, and relevant studies published in English were retrieved from the computerised databases MEDLINE, EMBASE and Cochrane.

METHODS

The effect estimate (RR or HR) and its 95% CI are investigated on the basis of the evaluation of differences of knee OR risk in overweight or obesity versus those with normal weight. Category-specific risk estimates were further transformed into estimates of the RR in terms of per increase of 5 in BMI by using the generalised least-squares method for trend estimation. Studies were independently reviewed by two investigators. Subgroup analysis was performed. Heterogeneity and publication bias were assessed. Data from eligible studies were extracted, and the meta-analysis was performed by using the STATA software V.12.0.

RESULTS

14 studies were finally included in the analysis. The results showed that overweight and obesity were significantly associated with higher knee OA risks of 2.45 (95% CI 1.88 to 3.20, p<0.001) and 4.55 (95% CI 2.90 to 7.13, p<0.001), respectively. The risk of knee OA increases by 35% (95% CI 1.18 to 1.53, p<0.001) with a 5 kg/m(2) increase in BMI. Subgroup analysis showed that obesity was an independent predictor of knee OA risk regardless of the study country, sample size, gender proportion of participants, duration of follow-up, presence of adjusted knee injury and assessed study quality above or below an NOS score of 8. No publication bias was detected.

CONCLUSIONS

Obesity was a robust risk factor for knee OA. Professionals should take a possible weight reduction into account for the treatment of knee OA whenever a patient is significantly overweight.

Overweight and obesity in hip and knee arthroplasty: Evaluation of 6078 cases

AIM: To evaluate a possible association between the various levels of obesity and peri-operative charac-teristics of the procedure in patients who underwent endoprosthetic joint replacement in hip and knee joints.

METHODS: We hypothesized that obese patients were treated for later stage of osteoarthritis, that more conservative implants were used, and the intra-and perioperative complications increased for such patients. We evaluated all patients with body mass index (BMI) ≥ 25 who were treated in our institution from January 2011 to September 2013 for a primary total hip arthroplasty (THA) or total knee arthroplasty (TKA). Patients were split up by the levels of obesity according to the classification of the World Health Organization. Average age at the time of primary arthroplasty, preoperative Harris Hip Score (HHS), Hospital for Special Surgery score (HSS), gender, type of implanted prosthesis, and intra-and postoperative complications were evaluated.

RESULTS: Six thousand and seventy-eight patients with a BMI ≥ 25 were treated with a primary THA or TKA. Age decreased significantly (P < 0.001) by increasing obesity in both the THA and TKA. HHS and HSS were at significantly lower levels at the time of treatment in the super-obese population (P < 0.001). Distribution patterns of the type of endoprostheses used changed with an increasing BMI. Peri- and postoperative complications were similar in form and quantity to those of the normal population.

CONCLUSION: Higher BMI leads to endoprosthetic treat-ment in younger age, which is carried out at significantly lower levels of preoperative joint function.

Association between body mass index and risk of total knee replacement, the Singapore Chinese Health Study

PURPOSE

Data on the association between body mass index (BMI) and risk of knee osteoarthritis (KOA) are sparse for Asian populations who are leaner than Western populations. We evaluated the association between BMI and risk of total knee replacement (TKR) due to severe KOA among Chinese in Singapore.

METHODS

We used data from the Singapore Chinese Health Study (SCHS), a population-based prospective cohort of 63,257 Chinese men and women, aged 45-74 years at enrollment from 1993 to 1998. Information on height, weight, diet and lifestyle factors were obtained via in-person interviews. TKR cases for severe KOA were identified via linkage with the nationwide hospital discharge database through 2011. Cox regression and weighted least squares regression were used in the analysis.

RESULTS

The mean BMI among cohort participants was 23.1 kg/m(2), and more than two-thirds had BMI below 25 kg/m(2). A total of 1649 had TKR attributable to severe KOA. Risk of TKR increased in a strong dose-dependent manner with increasing BMI throughout the 15-32 kg/m(2) range and became less clear at BMI >32 kg/m(2). In the BMI range 16-27 kg/m(2), there was a 27% increase in TKR risk for each unit increase in BMI (P for trend < 0.001). Compared to BMI 19-20 kg/m(2), the risk estimates of TKR were all statistically significant with increasing unit of BMI ≥21 kg/m(2). Results were similar for men and women.

CONCLUSION

Our results provided evidence for a constant mechanical mechanism underlying BMI and KOA initiation and/or progression.

Influence of weight loss on the clinical manifestations of osteoarthritis of the knee-joints

Obesity consistently associated with the development of a number of chronic diseases, leading to a decrease in quality of life, disability and death. The article examines the connection between obesity and disease of the musculoskeletal system, describes the mechanisms by means of which obesity leads to the development of osteoarthritis. It is evident that reduction of body mass can slow the progression of osteoporosis. The own experience of non-pharmacological and pharmacological treatment of obesity with the use of orlistat in 50 obese patients with osteoarthritis of the knee II–III stage is presented. Treatment has resulted in a decrease in body weight, waist circumference, accompanied by a decrease in symptoms osteoarthritis among all the patients. Our results showed that the addition of orlistat to standard osteoarthritis scheme leads to significant reduction in weight and reduction of clinical manifestations of osteoarthritis. According to the above, the drugs that have impact on weight loss, should be included in the treatment regimen of patients with osteoarthritis and obesity.

Perceived health status of women with knee osteoarthritis: a cross-sectional study of the relationships of age, body mass, pain and walking limitations

Persons with knee osteoarthritis (OA) often experience considerable physical disability. Although some studies suggest women with this condition suffer more than men, few have attempted to characterize the magnitude and that impact of this condition specifically among women with moderate knee osteoarthritis as well as the relationships that exist between their perceived health status and well established physical, emotional and perceptual factors found in this disease. This exploratory study strove to better understand factors that underpin the perceived impact of the condition, and to describe the extent of pain and function among women with mild to moderate knee osteoarthritis, and how this impacts this condition. The records of 20 women with the condition who had undergone multiple tests using a standardized protocols and validated instruments were examined. The primary outcome measure was the perceived impact of the disease using the Arthritis Impact Measurement Scale. Secondary outcome measures included six minute walking distance, fastest walking velocity, self-reported pain, pain and functional self-efficacy, body mass, and depression. The variables were subjected to t-tests, and correlational analyses. Results demonstrated pain is the clinical factor most consistently impacting the disease experience, along with deficiencies in walking ability (p <0.05). Important mediating variables of ambulatory capacity were body mass and pain self-efficacy.

Percent body fat more associated with perioperative risks after total joint arthroplasty than body mass index

Understanding the impact of obesity on elective total joint arthroplasty (TJA) remains critical. Perioperative outcomes were reviewed in 316 patients undergoing primary TJA. Higher percent body fat (PBF) was associated with postoperative blood transfusion, increased hospital length of stay (LOS) >3 days, and discharge to an extended care facility while no significant differences existed for BMI. Additionally, PBF of 43.5 was associated with a 2.4× greater likelihood of blood transfusion, PBF of 36.5 with a 1.9× greater likelihood for LOS >3 days, and PBF of 36.0 with a 1.4× greater likelihood for discharge to an extended care facility. PBF may be a more effective measure than BMI to use in screening for perioperative risks and acute outcomes associated with obese total joint patients.

Determinants of MSK health and disability: lifestyle determinants of symptomatic osteoarthritis

It is frequently considered that, for many people, symptomatic osteoarthritis involving the lower limb joints is a largely preventable 'lifestyle disease'. The purpose of this review is to evaluate the most recent scientific evidence examining the effect of various lifestyle factors, such as physical activity, obesity, diet, smoking, alcohol and injury, on the development of symptomatic knee or hip osteoarthritis. The strengths and weaknesses of various studies are discussed, the magnitude of any demonstrated risks presented and current overall conclusions drawn.

Risk factors for knee replacement due to primary osteoarthritis, a population based, prospective cohort study of 315,495 individuals

BACKGROUND

Osteoarthritis (OA) of the knee is a common and disabling condition. We wanted to investigate the modifiable risk factors Body Mass Index (BMI) and physical activity, using knee replacement (KR) as a marker for severely symptomatic disease, focusing on the interaction between these risk factors.

METHODS

315,495 participants (mean age 43.0 years) from national health screenings were followed prospectively with respect to KR identified by linkage to the Norwegian Arthroplasty Register. Data were analysed by Cox proportional hazard regression.

RESULTS

During 12 years of follow up 1,323 individuals received KR for primary OA. There was a dose-response relationship between BMI and heavy labour, and later KR. Comparing the highest versus the lowest quarter of BMI, the relative risk was 6.2 (95% CI: 4.2-9.0) in men and 11.1 (95% CI: 7.8-15.6) in women. Men reporting intensive physical activity at work had a relative risk of 2.4 (95% CI: 1.8-3.2) versus men reporting sedentary activity at work, the corresponding figure in women being 2.3 (95% CI: 1.7-3.2). The effect of BMI and physical activity at work was additive. The heaviest men with the most strenuous work had a RR of 11.7 (95% CI: 5.9-23.1) compared to the ones with the lowest BMI and most sedentary work. For women the corresponding RR was 15.8 (95% CI: 8.2-30.3). There was no association between physical activity during leisure and KR.

CONCLUSION

We found that a high BMI and intensive physical activity at work both contribute strongly to the risk of having a KR. As the two risk factors seem to act independently, people with strenuous physical work with a high BMI are at particularly high risk for severely disabling OA of the knee, and should be targeted with effective preventive measures.

The Role of Overweight and Obesity in Relation to the More Rapid Growth of Total Knee Arthroplasty Volume Compared with Total Hip Arthroplasty Volume

BACKGROUND

The volume of primary joint replacements performed in the United States increased rapidly over the past twenty years, but the growth rate of total knee arthroplasties exceeded that of total hip arthroplasties. The aim of this study was to identify the key contributing factors behind this differential growth rate.

METHODS

We compiled longitudinal data on total hip arthroplasty and total knee arthroplasty volume, length of hospital stay, and in-hospital mortality from the Nationwide Inpatient Sample; we calculated reimbursement using information available in the Federal Register and Centers for Medicare & Medicaid Services databases; we determined trends in body mass index from Behavioral Risk Factor Surveillance System findings; and we estimated the size of the surgical workforce based on membership data from the American Academy of Orthopaedic Surgeons. These sources each contained at least ten years of data, ending in 2009. Data sources were analyzed and were compared to identify supply-side and demand-side factors contributing to the more rapid growth observed in total knee arthroplasty.

RESULTS

Of the factors examined, body mass index played the most substantial role in increasing demand for total knee arthroplasty above that of total hip arthroplasty, with younger individuals affected to a greater degree. More rapid growth in utilization of total knee arthroplasty over total hip arthroplasty in individuals with a body mass index of ≥25 kg/m² was responsible for 95% of the differential increase in total knee arthroplasty over total hip arthroplasty volumes. Hospital and physician reimbursement, length of stay, and in-hospital mortality did not improve more for total knee arthroplasty than total hip arthroplasty. The surgical community responded to additional demand primarily by increasing per-physician output.

CONCLUSIONS

Growth in total knee arthroplasty volume has far outpaced that of total hip arthroplasty among those with a body mass index of ≥25 kg/m² but not for those with a body mass index of <25 kg/m². The magnitude of this effect will continue to expand if the proportion of Americans with a body mass index of ≥25 kg/m² continues to increase. Changes in hospital and physician reimbursement, length of stay, and in-hospital mortality did not contribute to this differential growth rate.