Aims. There is evidence that morbidly obese patients have more intra- and postoperative complications and poorer outcomes when undergoing total hip arthroplasty (THA) with the direct anterior approach (DAA). The aim of this study was to determine the efficacy of DAA for THA, and compare the complications and outcomes of morbidly obese patients with nonobese patients. Methods. Morbidly obese patients (n = 86), with BMI ≥ 40 kg/m. 2. who underwent DAA THA at our institution between September 2010 and December 2017, were matched to 172 patients with BMI < 30 kg/m. 2. Data regarding demographics, set-up and operating time, blood loss, radiological assessment, Harris Hip Score (HHS), International Hip Outcome Tool (12-items), reoperation rate, and complications at two years postoperatively were retrospectively analyzed. Results. No significant differences in blood loss, intra- and postoperative complications, or implant position were observed between the two groups. Superficial wound infection rate was higher in the obese group (8.1%) compared to the nonobese group (1.2%) (p = 0.007) and relative risk of reoperation was 2.59 (95% confidence interval 0.68 to 9.91). One periprosthetic joint infection was reported in the obese group. Set-up time in the operating table and mean operating time were higher in morbidly obese patients. Functional outcomes and patient-related outcome measurements were superior in the obese group (mean increase of HHS was 52.19 (SD 5.95) vs 45.1 (SD 4.42); p < 0.001), and mean increase of International Hip Outcome Tool (12-items) was 56.8 (SD 8.88) versus 55.2 (SD 5.85); p = 0.041). Conclusion. Our results suggest that THA in morbidly obese patients can be safely and effectively performed via the DAA by experienced surgeons. Cite this article: Bone Jt Open 2022;3(1):4–11

Aims. The aim of this study was to investigate the global and local impact of fat on bone in obesity by using the diet-induced obese (DIO) mouse model. Methods. In this study, we generated a diet-induced mouse model of obesity to conduct lipidomic and 3D imaging assessments of bone marrow fat, and evaluated the correlated bone adaptation indices and bone mechanical properties. Results. Our results indicated that bone mass was reduced and bone mechanical properties were impaired in DIO mice. Lipidomic sequencing and bioinformatic analysis identified 373 differential lipids, 176 of which were upregulated and 197 downregulated. Functional enrichment analysis revealed a significant downregulation of the pathways: fat digestion and absorption (ko04975) and lipolysis regulation in adipocytes (ko04923) in DIO mice, leading to local fat accumulation. The use of 3D imaging confirmed the increase in fat accumulation within the bone marrow cavity of obese mice. Conclusion. Our study sheds light on the intricate interplay between fat and bone, and provides a non-toxic and non-invasive method for measuring marrow adipose tissue. Cite this article: Bone Joint Res 2023;12(9):580–589

Aims. The purpose of this study was to assess total knee arthroplasty (TKA) volume and rates of early complications in morbidly obese patients over the last decade, where the introduction of quality models influencing perioperative care pathways occurred. Methods. Patients undergoing TKA between 2011 to 2018 were identified in the American College of Surgeons National Surgical Quality Improvement Program database. Patients were stratified by BMI < 40 kg/m. 2. and ≥ 40 kg/m. 2. and evaluated by the number of cases per year. The 30-day rates of any complication, wound complications, readmissions, and reoperation were assessed. Trends in these endpoints over the study period were compared between groups using odds ratios (ORs) and multivariate analyses. Results. In total, 314,695 patients underwent TKA and 46,362 (15%) had BMI ≥ 40 kg/m. 2. The prevalence of morbid obesity among TKA patients did not change greatly, ranging between 14% and 16%. Reoperation rate decreased from 1.16% to 0.96% (odds ratio (OR) 0.81 (95% confidence interval (CI) 0.66 to 0.99)) for patients with BMI < 40 kg/m. 2. , as did rates of readmission (4.46% to 2.87%; OR 0.61 (0.55 to 0.69)). Patients with BMI ≥ 40 kg/m. 2. also had fewer readmissions over the study period (4.87% to 3.34%; OR 0.64 (0.49 to 0.83)); however, the rate of reoperation did not change (1.37% to 1.41%; OR 0.99 (0.62 to 1.56)). Significant improvements were not observed for infective complications over time for either group; patients with BMI ≥ 40 kg/m. 2. had increased risk of both deep infection and wound complications compared to non-morbidly obese patients. Rate of any complication decreased for all patients. Conclusion. The proportion of TKAs in morbidly obese patients has not significantly changed over the past decade. Although readmission rates improved for all patients, reductions in reoperation in non-morbidly obese patients were not experienced by the morbidly obese, resulting in a widening of the complication gap between these cohorts. Care improvements have not lowered the differential risk of infective complications in the morbidly obese. Cite this article: Bone Joint J 2021;103-B(6 Supple A):38–44

Aims. Access to total knee arthroplasty (TKA) is sometimes restricted for patients with severe obesity (BMI ≥ 40 kg/m. 2. ). This study compares the cost per quality-adjusted life year (QALY) associated with TKA in patients with a BMI above and below 40 kg/m. 2. to examine whether this is supported. Methods. This single-centre study compared 169 consecutive patients with severe obesity (BMI ≥ 40 kg/m. 2. ) (mean age 65.2 years (40 to 87); mean BMI 44.2 kg/m. 2. (40 to 66); 129/169 female) undergoing unilateral TKA to a propensity score matched (age, sex, preoperative Oxford Knee Score (OKS)) cohort with a BMI < 40 kg/m. 2. in a 1:1 ratio. Demographic data, comorbidities, and complications to one year were recorded. Preoperative and one-year patient-reported outcome measures (PROMs) were completed: EuroQol five-dimension three-level questionnaire (EQ-5D-3L), OKS, pain, and satisfaction. Using national life expectancy data with obesity correction and the 2020 NHS National Tariff, QALYs (discounted at 3.5%), and direct medical costs accrued over a patient’s lifetime, were calculated. Probabilistic sensitivity analysis (PSA) was used to model variation in cost/QALY for each cohort across 1,000 simulations. Results. All PROMs improved significantly (p < 0.05) in both groups without differences between groups. Early complications were higher in BMI ≥ 40 kg/m. 2. : 34/169 versus 52/169 (p = 0.050). A total of 16 (9.5%) patients with a BMI ≥ 40 kg/m. 2. were readmitted within one year with six reoperations (3.6%) including three (1.2%) revisions for infection. Assuming reduced life expectancy in severe obesity and revision costs, TKA in patients with a BMI ≥ 40 kg/m. 2. costs a mean of £1,013/QALY (95% confidence interval £678 to 1,409) more over a lifetime than TKA in patients with BMI < 40 kg/m. 2. In PSA replicates, the maximum cost/QALY was £3,921 in patients with a BMI < 40 kg/m. 2. and £5,275 in patients with a BMI ≥ 40 kg/m. 2. . Conclusion. Higher complication rates following TKA in severely obese patients result in a lifetime cost/QALY that is £1,013 greater than that for patients with BMI < 40 kg/m. 2. , suggesting that TKA remains a cost-effective use of healthcare resources in severely obese patients where the surgeon considers it appropriate. Cite this article: Bone Joint J 2022;104-B(4):452–463

Aims. 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/m. 2. ) compared to healthy weight (HW) patients (BMI 18.5 to < 25 kg/m. 2. ) who underwent a THA using the anterior-based muscle-sparing (ABMS) approach. Methods. 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. Results. 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. Conclusion. 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. Cite this article: Bone Jt Open 2023;4(5):299–305

Aims. It has been shown that the preoperative modification of risk factors associated with obesity may reduce complications after total knee arthroplasty (TKA). However, the optimal method of doing so remains unclear. The aim of this study was to investigate whether a preoperative Risk Stratification Tool (RST) devised in our institution could reduce unexpected intensive care unit (ICU) transfers and 90-day emergency department (ED) visits, readmissions, and reoperations after TKA in obese patients. Methods. We retrospectively reviewed 1,614 consecutive patients undergoing primary unilateral TKA. Their mean age was 65.1 years (17.9 to 87.7) and the mean BMI was 34.2 kg/m. 2. (SD 7.7). All patients underwent perioperative optimization and monitoring using the RST, which is a validated calculation tool that provides a recommendation for postoperative ICU care or increased nursing support. Patients were divided into three groups: non-obese (BMI < 30 kg/m. 2. , n = 512); obese (BMI 30 kg/m. 2. to 39.9 kg/m. 2. , n = 748); and morbidly obese (BMI > 40 kg/m. 2. , n = 354). Logistic regression analysis was used to evaluate the outcomes among the groups adjusted for age, sex, smoking, and diabetes. Results. Obese patients had a significantly increased rate of discharge to a rehabilitation facility compared with non-obese patients (38.7% (426/1,102) vs 26.0% (133/512), respectively; p < 0.001). When stratified by BMI, discharge to a rehabilitation facility remained significantly higher compared with non-obese (26.0% (133)) in both obese (34.2% (256), odds ratio (OR) 1.6) and morbidly obese (48.0% (170), OR 3.1) patients (p < 0.001). However, there was no significant difference in unexpected ICU transfer (0.4% (two) non-obese vs 0.9% (seven) obese (OR 2.5) vs 1.7% (six) morbidly obese (OR 5.4); p = 0.054), visits to the ED (8.6% (44) vs 10.3% (77) (OR 1.3) vs 10.5% (37) (OR 1.2); p = 0.379), readmissions (4.5% (23) vs 4.0% (30) (OR 1.0) vs 5.1% (18) (OR 1.4); p = 0.322), or reoperations (2.5% (13) vs 3.3% (25) (OR 1.2) vs 3.1% (11) (OR 0.9); p = 0.939). Conclusion. With the use of a preoperative RST, morbidly obese patients had similar rates of short-term postoperative adverse outcomes after primary TKA as non-obese patients. This supports the assertion that morbidly obese patients can safely undergo TKA with appropriate perioperative optimization and monitoring. Cite this article: Bone Joint J 2021;103-B(6 Supple A):45–50

Aims. The aim of this study was to assess the influence of obesity on the clinical outcomes and survivorship ten years postoperatively in patients who underwent a fixed-bearing unicompartmental knee arthroplasty (UKA). Patients and Methods. We prospectively followed 184 patients who underwent UKA between 2003 and 2007 for a minimum of ten years. A total of 142 patients with preoperative body mass index (BMI) of < 30 kg/m. 2. were in the control group (32 male, 110 female) and 42 patients with BMI of ≥ 30 kg/m. 2. were in the obese group (five male, 37 female). Pre- and postoperative range of movement (ROM), Knee Society Score (KSS), Oxford Knee Score (OKS), 36-Item Short-Form Health Survey (SF-36), and survivorship were analyzed. Results. Patients in the obese group underwent UKA at a significantly younger mean age (56.5 years (. sd. 6.4)) than those in the control group (62.4 years (. sd. 7.8); p < 0.001). There was no significant difference in preoperative functional scores. However, those in the obese group had a significantly lower ROM (116° (. sd. 15°) vs 123° (. sd. 17°); p = 0.003). Both groups achieved significant improvement in outcome scores regardless of BMI, ten years postoperatively. All patients achieved the minimal clinically important difference (MCID) for OKS and KSS. Both groups also had high rates of satisfaction (96.3% in the control group and 97.5% in the obese group) and the fulfilment of expectations (94.9% in the control group and 95.0% in the obese group). Multiple linear regression showed a clear association between obesity and a lower OKS two years postoperatively and Knee Society Function Score (KSFS) ten years postoperatively. After applying propensity matching, obese patients had a significantly lower KSFS, OKS, and physical component score (PCS) ten years postoperatively. Seven patients underwent revision to total knee arthroplasty (TKA), two in the control group and five in the obese group, resulting in a mean rate of survival at ten years of 98.6% and 88.1%, respectively (p = 0.012). Conclusion. Both groups had significant improvements in functional and quality-of-life scores postoperatively. However, obesity was a significant predictor of poorer improvement in clinical outcome and an increased rate of revision ten years postoperatively

Aims. The purpose of our study is to summarise the current scientific findings regarding the impact of obesity on total hip arthroplasty (THA); specifically the influence of obesity on the timing of THA, incidence of complications, and effect on clinical and functional outcomes. Materials and Methods. We performed a systematic review that was compliant with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines to identify prospective studies from the PubMed/Medline, Embase, and Cochrane Library databases that evaluated primary THA in obese (body mass index (BMI) ≥ 30 kg/m. 2. ) patients. Results. There were 17 articles included in the review, which encompassed 13 722 THA patients. Analysis of the included studies showed that, when compared with non-obese patients, obesity was associated with younger age at time of primary THA, and an increased incidence of complications (up to four-fold). Results were mixed on the influence of obesity on the outcomes of primary THA, with three studies showing a detrimental effect on outcomes of a BMI ≥ 30 kg/m. 2. , while eight studies showed no effect. Conclusion. Obesity is associated with significantly younger age at time of primary THA and obese patients are likely to experience a higher rate of peri-operative complications. More investigation is needed into the effect of obesity on clinical outcomes, as the current literature is mixed. Cite this article: Bone Joint J 2017;99-B(1 Supple A):31–6

Aims. Rates of readmission and reoperation following primary total knee arthroplasty (TKA) are under scrutiny due to new payment models, which penalize these negative outcomes. Some risk factors are more modifiable than others, and some conditions considered modifiable such as obesity may not be as modifiable in the setting of advanced arthritis as many propose. We sought to determine whether controlling for hypoalbuminaemia would mitigate the effect that prior authors had identified in patients with obesity. Methods. We reviewed the American College of Surgeons National Surgical Quality Improvement Program (ACS-NSQIP) database for the period of January 2008 to December 2016 to evaluate the rates of reoperation and readmission within 30 days following primary TKA. Multivariate logistic regression modelling controlled for preoperative albumin, age, sex, and comorbidity status. Results. Readmission rates only differed significantly between patients with Normal Weight and Obesity Class II, with a decreased rate of readmission in this group (odds ratio (OR) 0.82; 95% confidence interval (CI) 0.71 to 0.96; p = 0.010). The only group demonstrating association with increased risk of reoperation within 30 days was the Obesity Class III group (OR 1.38; 95% CI 1.05 to 1.82; p = 0.022). Hypoalbuminaemia (preoperative albumin < 35 g/L) was significantly associated with readmission (OR 1.62; 95% CI 1.41 to 1.86; p < 0.001) and reoperation (OR 1.52; 95% CI 1.18 to 1.96; p = 0.001) within 30 days. Conclusion. In this study, hypoalbuminaemia appears to be a more significant risk factor for readmission and reoperation than even the highest obesity categories. Future studies may assess whether preoperative albumin restoration or weight loss may improve outcomes for patients with hypoalbuminaemia. The implications of this study may allow surgeons to discuss risk of surgery with obese patients planning to undergo primary TKA procedures if other comorbidities are adequately controlled. Cite this article: Bone Joint J 2020;102-B(6 Supple A):31–35

Aims. The aim of this study was to observe the implications of withholding total joint arthroplasty (TJA) in morbidly obese patients. Patients and Methods. A total of 289 morbidly obese patients with end-stage osteoarthritis were prospectively followed. There were 218 women and 71 men, with a mean age of 56.3 years (26.7 to 79.1). At initial visit, patients were given information about the risks of TJA in the morbidly obese and were given referral information to a bariatric clinic. Patients were contacted at six, 12, 18, and 24 months from initial visit. Results. The median body mass index (BMI) at initial visit was 46.9 kg/m. 2. (interquartile range (IQR) 44.6 to 51.3). A total of 82 patients (28.4%) refused to follow-up or answer phone surveys, and 149 of the remaining 207 (72.0%) did not have surgery. Initial median BMI of those 149 was 47.5 kg/m. 2. (IQR 44.6 to 52.5) and at last follow-up was 46.7 kg/m. 2. (IQR 43.4 to 51.2). Only 67 patients (23.2%) went to the bariatric clinic, of whom 14 (20.9%) had bariatric surgery. A total of 58 patients (20.1%) underwent TJA. For those 58, BMI at initial visit was 45.3 kg/m. 2. (IQR 43.7 to 47.2), and at surgery was 42.3 kg/m. 2. (IQR 38.1 to 46.5). Only 23 patients (39.7%) of those who had TJA successfully achieved BMI < 40 kg/m. 2. at surgery. Conclusion. Restricting TJA for morbidly obese patients does not incentivize weight loss prior to arthroplasty. Only 20.1% of patients ultimately underwent TJA and the majority of those remained morbidly obese. Better resources and coordinated care are required to optimize patients prior to surgery. Cite this article: Bone Joint J 2019;101-B(7 Supple C):28–32

Obesity is a global epidemic of 2.1 billion people and a well known cause of osteoarthritis. Joint replacement in the obese attracts more complications, poorer outcomes and higher revision rates. It is a reversible condition and the fundamental principles of dealing with reversible medical conditions prior to elective total joint replacement should apply to obesity. The dilemma for orthopaedic surgeons is when to offer surgery in the face of a reversible condition, which if treated may obviate joint replacement and reduce the risk and severity of obesity related disease in both the medical arena and the field of orthopaedics

Aims. This study investigated the influence of body mass index (BMI) on patients’ function and quality of life ten years after total knee arthroplasty (TKA). Patients and Methods. A total of 126 patients who underwent unilateral TKA in 2006 were prospectively included in this retrospective study. They were categorized into two groups based on BMI: < 30 kg/m. 2. (control) and ≥ 30 kg/m. 2. (obese). Functional outcome was assessed using the Knee Society Function Score (KSFS), Knee Society Knee Score (KSKS), and Oxford Knee Score (OKS). Quality of life was assessed using the Physical (PCS) and Mental Component Scores (MCS) of the 36-Item Short-Form Health Survey. Results. Patients in the obese group underwent TKA at a younger age (mean, 63.0 years, . sd. 8.0) compared with the control group (mean, 65.6 years, . sd. 7.6; p = 0.03). Preoperatively, both groups had comparable functional and quality-of-life scores. Ten years postoperatively, the control group had significantly higher OKS and MCS compared with the obese group (OKS, mean 18 (. sd. 5) vs mean 22 (. sd. 10), p = 0.03; MCS, mean 56 (. sd. 10) vs mean 50 (. sd. 11), p = 0.01). After applying multiple linear regression with the various outcomes scores as dependent variables and age, gender, and Charlson Comorbidity Index as independent variables, there was a clear association between obesity and poorer outcome in KSFS, OKS, and MCS at ten years postoperatively (p < 0.01 in both KSFS and OKS, and p = 0.03 in MCS). Both groups had a high satisfaction rate (97.8% in the control groupvs 87.9% in the obese group, p = 0.11) and fulfillment of expectations at ten years (98.9% in the control group vs 100% in the obese group, p = 0.32). Conclusion. Although both obese and non-obese patients have significant improvements in function and quality of life postoperatively, obese patients tend to have smaller improvements in the OKS and MCS ten years postoperatively. It is important to counsel patients on the importance of weight management to achieve a more sustained outcome after TKA. Cite this article: Bone Joint J 2018;100-B:579–83

Aims. The aim of this study was to utilize a national paediatric inpatient database to determine whether obesity influences the operative management and inpatient outcomes of paediatric limb fractures. Patients and Methods. The Kids’ Inpatient Database (KID) was used to evaluate children between birth and 17 years of age, from 1997 and 2012, who had undergone open and closed treatment of humeral, radial and ulna, femoral, tibial, and ankle fractures. Demographics, hospital charges, lengths of stay (LOS), and complications were analyzed. Results. Obesity was significantly associated with increased rates of open reduction and internal fixation (ORIF) for: distal humeral (odds ratio (OR) = 2.139, 95% confidence interval (CI) 1.92 to 3.44; p < 0.001); distal radius and ulna fractures (OR = 1.436, 95% CI 1.14 to 2.16; p < 0.05); distal femoral (OR = 2.051, 95% CI 1.69 to 3.60; p < 0.05); tibial and fibula shaft (OR = 2.101, 95% CI 2.10 to 3.50; p < 0.001); and ankle (OR = 1.733, 95% CI 1.70 to 2.39; p < 0.001). Older age was significantly associated with ORIF for all fractures (p < 0.05). LOS, hospital charges, and complications were significantly increased in obese patients following ORIF for upper and lower limb fractures (p < 0.05). Conclusion. Obese paediatric patients are more likely to undergo ORIF in both upper and lower limb fractures and have more inpatient complications. These findings may assist in informing obese paediatric fracture patients and their families regarding the increased risk for open operative fixation and associated outcomes. Cite this article: Bone Joint J 2019;101-B:491–496

Given the growing prevalence of obesity around the world and its association with osteoarthritis of the knee, orthopaedic surgeons need to be familiar with the management of the obese patient with degenerative knee pain. The precise mechanism by which obesity leads to osteoarthritis remains unknown, but is likely to be due to a combination of mechanical, humoral and genetic factors. . Weight loss has clear medical benefits for the obese patient and seems to be a logical way of relieving joint pain associated with degenerative arthritis. There are a variety of ways in which this may be done including diet and exercise, and treatment with drugs and bariatric surgery. Whether substantial weight loss can delay or even reverse the symptoms associated with osteoarthritis remains to be seen. . Surgery for osteoarthritis in the obese patient can be technically more challenging and carries a risk of additional complications. Substantial weight loss before undertaking total knee replacement is advisable. More prospective studies that evaluate the effect of significant weight loss on the evolution of symptomatic osteoarthritis of the knee are needed so that orthopaedic surgeons can treat this patient group appropriately.

Obesity is a risk factor for complications following many orthopaedic procedures. The purpose of this study was to investigate whether obesity was an independent risk factor increasing the rate of complications following periacetabular osteotomy (PAO) and to determine whether radiographic correction after PAO was affected by obesity. . We retrospectively collected demographic, clinical and radiographic data on 280 patients (231 women; 82.5% and 49 men; 17.5%) who were followed for a mean of 48 months (12 to 60) after PAO. A total of 65 patients (23.2%) were obese (body mass index (BMI) > 30 kg/m. 2. ). Univariate and multivariate analysis demonstrated that BMI was an independent risk factor associated with the severity of the complications. The average probability of a patient developing a major complication was 22% (95% confidence interval (CI) 11.78 to 38.21) for an obese patient compared with 3% (95% CI 1.39 to 6.58) for a non-obese patient The odds of a patient developing a major complication were 11 times higher (95% CI 4.71 to 17.60, p <  0.0001) for an obese compared with a non-obese patient. . Following PAO surgery, there was no difference in radiographic correction between obese and non-obese patients. PAO procedures in obese patients correct the deformity effectively but are associated with an increased rate of complications. Cite this article: Bone Joint J 2015;97-B:29–34

Objectives. The objective of this study was to investigate the association of four single-nucleotide polymorphisms (SNPs) of the cannabinoid receptor 2 (CNR2) gene, gene-obesity interaction, and haplotype combination with osteoporosis (OP) susceptibility. Methods. Chinese patients with OP were recruited between March 2011 and December 2015 from our hospital. In this study, a total of 1267 post-menopausal female patients (631 OP patients and 636 control patients) were selected. The mean age of all subjects was 69.2 years (sd 15.8). A generalized multifactor dimensionality reduction (GMDR) model and logistic regression model were used to examine the interaction between SNP and obesity on OP. For OP patient-control haplotype analyses, the SHEsis online haplotype analysis software (. http://analysis.bio-x.cn/. ) was employed. Results. The logistic regression model revealed that the C allele of rs2501431 and the G allele of rs3003336 were associated with increased OP risk, compared with those with wild genotype. However, no significant correlations were found when analyzing the association of rs4237 and rs2229579 with OP risk. The GMDR analysis suggested that the interaction model composed of two factors, rs3003336 and abdominal obesity (AO), was the best model with statistical significance (p-value from sign test (P. sign. ) = 0.012), indicating a potential gene-environment interaction between rs3003336 and AO. Overall, the two-locus models had a cross-validation consistency of 10/10 and had a testing accuracy of 0.641. Abdominally obese subjects with the AG or GG genotype have the highest OP risk, compared with subjects with the AA genotype and normal waist circumference (WC) (odds ratio (OR) 2.23, 95% confidence interval (CI) 1.54 to 3.51). Haplotype analysis also indicated that the haplotype containing the rs3003336-G and rs2501431-C alleles was associated with a statistically increased OP risk. Conclusion. Our results suggested that the C allele of rs2501431 and the G allele of rs3003336 of the CNR2 gene, interaction between rs3003336 and AO, and the haplotype containing the rs3003336-G and rs2501431-C alleles were all associated with increased OP risk. Cite this article: Bone Joint Res 2019;8:544–549

A total of 445 consecutive primary total knee replacements (TKRs) were followed up prospectively at six and 18 months and three, six and nine years. Patients were divided into two groups: non-obese (body mass index (BMI) < 30 kg/m. 2. ) and obese (BMI ≥ 30 kg/m. 2. ). The obese group was subdivided into mildly obese (BMI 30 to 35 kg/m. 2. ) and highly obese (BMI ≥ 35 kg/m. 2. ) in order to determine the effects of increasing obesity on outcome. The clinical data analysed included the Knee Society score, peri-operative complications and implant survival. There was no difference in the overall complication rates or implant survival between the two groups. Obesity appears to have a small but significant adverse effect on clinical outcome, with highly obese patients showing lower function scores than non-obese patients. However, significant improvements in outcome are sustained in all groups nine years after TKR. Given the substantial, sustainable relief of symptoms after TKR and the low peri-operative complication and revision rates in these two groups, we have found no reason to limit access to TKR in obese patients

Obesity is a worldwide epidemic that has both economic and health implications of enormous consequence. The obese patients tend to have earlier symptoms related to osteoarthritis, more peri-operative medical problems, higher rates of infection and more technical difficulties intra-operatively following hip and knee arthroplasty. Nevertheless, these patients have good long-term clinical outcomes and implant survival rates and are often some of the most satisfied patients after joint arthroplasty. Therefore, obese patients should not be denied surgery based on their weight alone. Cite this article: Bone Joint J 2016;98-B(1 Suppl A):3–5

Introduction: This observational study assessed the influence of obesity on operating time and duration of hospital admission following Total Knee Arthroplasty (TKA). Materials and Methods: 263 patients who underwent 276 TKAs between 1st January and December 31st 2005 at the Glenfield General Hospital were identified from the Trent (and Wales) Arthoplasty Audit Group. Patients were grouped into three weight categories based upon BMI. We examined hospital records for 265 of the 276 procedures and compared operating time, length of hospital admission and complication rates between the three BMI groups. Patient perceived outcomes including patient satisfaction, post-operative pain and frequency of walking were compared at 1-year post TKA. Results: Obesity did not adversely influence operating time and duration of hospital stay. The mean operating time was 82 minutes in patients with a BMI ≤ 25.0, 84 min in those with a BMI 25.1–30.0 and 88 minutes for those with a BMI> 30.0 (p=0.2). The mean hospital stay was 7.7 days in patients with a BMI ≤ 25.0, 7.2 days in the BMI 25.1–30.0 group, and 6.7 days in those with a BMI > 30.0 (p=0.8). There were no significant differences between the three BMI groups and post-operative complications (p = 0.7), patient satisfaction (p=0.1) or pain levels (p=0.7) at 1-year post-TKA. As has been demonstrated previously, increasing BMI negatively influenced post operative walking frequency (p=0.02). Conclusion: BMI did not influence operating time, length of stay, complication rates, post operative pain and patient satisfaction post Total Knee Arthroplasty, but was associated with decreased post operative mobility

This study evaluated whether obese patients who lost weight before their total joint replacement and kept it off post-operatively were at lower risk of surgical site infection (SSI) and re-admission compared with those who remained the same weight. We reviewed 444 patients who underwent a total hip replacement and 937 with a total knee replacement who lost weight pre-operatively and sustained their weight loss after surgery. After adjustments, patients who lost weight before a total hip replacement and kept it off post-operatively had a 3.77 (95% confidence interval (CI) 1.59 to 8.95) greater likelihood of deep SSIs and those who lost weight before a total knee replacement had a 1.63 (95% CI 1.16 to 2.28) greater likelihood of re-admission compared with the reference group. These findings raise questions about the safety of weight management before total replacement of the hip and knee joints. Cite this article: Bone Joint J 2014;96-B:629–35

Introduction. The purpose of this study is to estimate the cost-effectiveness of performing total hip arthroplasty (THA) versus nonoperative management (NM) in non-obese (BMI 18.5–24.9), overweight (25–29.9), obese (30–34.9), severely-obese (35–39.9), morbidly-obese (40–49.9), and super-obese (50+) patients. Methods. We constructed a state-transition Markov model to compare the cost-utility of THA and NM in the six above-mentioned BMI groups over a 15-year time period. Model parameters for transition probability (i.e. risk of revision, re-revision, death), utility, and costs (inflation adjusted to 2017 US dollars) were estimated from the literature. Direct medical costs of managing hip arthritis were accounted in the model. Indirect societal costs were not included. A 3% annual discount rate was used for costs and utilities. The primary outcome was the incremental cost-effectiveness ratio (ICER) of THA versus NM. One-way and Monte Carlo probabilistic sensitivity analysis of the model parameters were performed to determine the robustness of the model. Results. Over the 15-year time period, the ICERs for THA versus NM were: normal-weight ($6,043/QALY), overweight ($5,770/QALY), obese ($5,425/QALY), severely-obese ($7,382/QALY), morbidly-obese ($8,338/QALY), and super-obese ($16,651/QALY). The two highest BMI groups had higher incremental QALYs and incremental costs. The probabilistic sensitivity analysis suggests that THA would be cost-effective in 100% of the normal, overweight, obese, severely-obese, and morbidly-obese simulations, and 99.95% of super-obese simulations at an ICER threshold of $50,000/QALY. Conclusion. Even at a willingness-to-pay threshold of $50,000/QALY, which is considered low for the United States, our model showed that THA would be cost effective for all obesity levels. Therefore, invoking BMI cut-offs for THA may lead to unjustifiable loss of healthcare access for obese patients with end-stage hip osteoarthritis

Total Knee Arthroplasty (TKA) in obese patients has been under rigorous scrutiny due concerns of less satisfying results and increased risk of perioperative complications. We conducted a prospective study to observe functional scores between obese and non obese patients at two years after mini-robot computer assisted TKA. Average stay, time for wound to be dry and perioperative complications were also compared. A prospective study was conducted between February 2007 and February 2008 involving 50 patients. Two different groups of 25 each were made on the basis of body mass index (BMI). Oxford and Knee society scores were obtained at two years to observe difference in functional scores between these groups. Rate of post operative complications or hospital stay was comparable between the two groups. Oxford and Knee society scores improved significantly in both the groups postoperatively. Obese patients had better Oxford and Knee society scores, which were not statistically significant. There is no difference in early functional outcome and complications between obese and non obese patients after navigated TKA. Navigated TKA in obese patients help precise component placement with appropriate soft tissue balancing leading to improved results

Background. While tranexamic acid (TXA) has been well shown to reduce blood loss after joint replacement surgery, little is known regarding its effectiveness in obese patients. The aim of this study was to evaluate the effect of TXA changes in hematocrit and hemoglobin levels as well as incidence of packed red blood cell (pRBC) transfusions in obese patients undergoing total joint arthroplasty (TJA). Material and Methods. Between January 2014 and May 2015, 420 consecutive primary joint replacements were performed by two surgeons at our institution. 157 patients (THA=29; TKA=128) were obese with a body mass index (BMI) greater than or equal to 30 kg/m. 2. Medical records were reviewed and identified that TXA was utilized in 85 (54.1%) arthroplasties [study group] and was compared to a consecutive series of 72 (45.9%) TJAs [control group]. TXA was given intravenously(IV) in two doses: (1) one gram prior to incision and (2) one gram at the time of femoral preparation in THA or prior to cementation in TKA. Changes in hemoglobin and hematocrit levels, number of pRBC transfusions, and occurrence of thrombolytic events were recorded. Results. The changes in hematocrit (7.2% vs. 8.1%) and hemoglobin levels (3.0 g/dl vs. 3.3 g/dl) were less for group that received TXA than the control group, albeit not significantly (p=0.100 and p=0.278, respectively). Within the control group 26 (36.1%) patients required a pRBC transfusion with a mean of 2.0 units per patient (range:1–5); whereas, only 8 (9.4%) patients with TXA required a mean of 1.6 units per patient (range:1–2 units). The use of TXA significantly reduced the incidence of pRBC transfusions, especially in TKA (p<0.001). Sub-analyses revealed that transfusion rates were even more significantly reduced by TXA in obesity type II and III. Two pulmonary emboli were reported in the group that did not receive TXA, whereas no thrombolytic events were reported in the group that did receive TXA. Conclusion. Utilization of TXA significantly reduced the rate of pRBC transfusions in obese patients

The significance of weight in the indications for unicompartmental knee replacement (UKR) is unclear. Our hypothesis was that weight does not affect the long-term rate of survival of UKRs.

We undertook a retrospective study of 212 UKRs at a mean follow-up of 12 years (7 to 22). The patients were distributed according to body mass index (BMI; < vs ≥ 30 kg/m²) and weight (< vs ≥ 82 kg). Kaplan-Meier survivorship analysis was performed and ten-year survival rates were compared between the sub-groups. Multimodal regression analysis determined the impact of the various theoretical contraindications on the long-term rate of survival of UKR.

The ten-year rates of survival were similar in the two weight subgroups (≥ 82 kg: 93.5% (95% confidence interval (CI) 66.5 to 96.3); < 82 kg: 92.5% (95% CI 82.5 to 94.1)) and also in the two BMI subgroups (≥ 30 kg/m²: 92% (95% CI 82.5 to 95.3); < 30 kg/m²: 94% (95% CI 78.4 to 95.9)). Multimodal regression analysis revealed that weight plays a part in reducing the risk of revision with a relative risk of 0.387, although this did not reach statistical significance (p = 0.662). The results relating weight and BMI to the clinical outcome were not statistically significant. Thus, this study confirms that weight does not influence the long-term rate of survival of UKR.

Cite this article: Bone Joint J 2013;95-B:1064–8.

The aim of this study was to examine the incidence of obesity in patients undergoing primary total shoulder replacement (TSR) (stemmed and reverse) for osteoarthritis (OA) in Australia compared to the incidence of obesity in the general population. A 2017–18 cohort of 2,621 patients from the Australian Orthopaedic Association National Joint Replacement Registry (AOANJRR) who underwent TSR, were compared with matched controls from the Australian Bureau of Statistics (ABS) National Health Survey from the same period. The two groups were analysed according to BMI category, sex and age. According to the 2017–18 National Health Survey, 35.6% of Australian adults are overweight and 31.3% are obese. Of the primary TSR cases performed, 34.2% were overweight and 28.6% were obese. The relative risk of requiring TSR for OA increased with increasing BMI category. Class-3 obese females, aged 55–64, were 8.9 times more likely to require TSR compared to normal weight counterparts. Males in the same age and BMI category were 2.5 times more likely. Class-3 obese patients underwent TSR 4 years (female) and 7 years (male) sooner than their normal weight counterparts. Our findings suggest that the obese population is at risk for early and more frequent TSR for OA. Previous studies demonstrate that obese patients undergoing TSR also exhibit increased risks of longer operative times, higher superficial infection rates, higher periprosthetic fracture rates, significantly reduced post-operative forward flexion range and greater revision rates. Obesity significantly increases the risk of requiring TSR. To our knowledge this is the first study to publish data pertaining to age and BMI stratification of TSR Societal efforts are vital to diminish the prevalence and burden of obesity related TSR. There may well be reversible pathophysiology in the obese population to address prior to surgery (adipokines, leptin, NMDA receptor upregulation). Surgery occurs due to recalcitrant or increased pain despite non-op Mx

Spinal surgery in obese and morbidly obese patients can be challenging to the operating surgeon. One of the major problems is obtaining a good surgical access. We have used the synframe retractor system in patients undergoing spinal fusion and have found it especially useful in obese and morbidly obese patients. This study reports our experience. Seventy-seven consecutive obese and morbidly obese patients that underwent spinal decompression and fusion were reviewed. Patient selection was based on BMI values. Those with a BMI of more than thirty were included in the study. There were thirty-eight females and twenty-five males with an age of twenty-one to eighty-one years. Patient charts were used to acquire information regarding age,weight,height,gender,time in surgery, procedure start and end time,and departure. Postoperative complications and length of hospital stay were also recorded. Anesthesia notes were used to determine ASA scores,number of preoperative morbidities,and intraoperative blood loss. The synframe was used on all the patients. It is a retractor system which consists of a ring placed around the surgical site. It is fixed to both sides of the operating table with arms. Using retractor blades, the ring allows 360 degree access to the surgical exposure from any side. The set up tme for obese patients was 59.8 minutes and 73.5 minutes for morbidly obese patients. The surgical time and blood loss was only marginally higher in these two groups than in normal weighted patients. The average postoperative length of hospitalisation was 5.8 days. The surgical incision length averaged 7.8 cms for single level and 11.5 for two level fusions. 44% patients suffered a complication. These included cage migration due to a fall, wound infection, dural leak,pulmonary embolism, deep vein thrombosis etc. No significant weight loss was recorded following the surgery. Obese patients are a surgical challenge due to the comorbidities and difficulty in positioning and gaining good surgical access. The use of synframe retractor system improves surgical access, thereby reducing surgical time and blood loss. The surgical incision length was also comparable to normal weighted patients using this system. No significant weight loss was recorded following surgery. The high complication rate can be attributed to the associated comorbidities

Obesity is a common in individuals undergoing arthroplasty, and the potential for weight loss with improved mobility may be expected by some. The aim of this study was 1. determine the proportion that achieved weight loss after hip or knee arthroplasty, and 2. examine the effect of obesity on patient reported outcomes (PROMS) and satisfaction with surgery. Participants underwent primary TKA or THA between July 2015 and December 2020 and consented to participation in a research database with baseline PROMS, including weight, BMI, Oxford Knee, or Hip Score, and EQ5D. Participants repeated PROMS at 12 months after surgery with additional questions regarding satisfaction with surgery. 3449 patients completed PROMS 1 year after arthroplasty with weight and BMI. There were 1810 THA and 1639 TKA procedures. The mean baseline BMI was higher in TKA (29.8, SD 5.2) compared to THA (27.7, SD 5.0), p=0.001. A higher proportion of TKA were classified as obese class 1 (29% TKA, 19% THA), obese class 2 (11% TKA and 6% THA), and obese class 3 (5% TKA and 2% THA), p=0.001. The mean weight loss after 1 year was 0.4kg and 0.9kg in obese THA subjects and TKA subjects respectively. In the obese >5kg weight loss was achieved in 13% of TKA and 7% of THA (p=0.001). Obese experienced equivalent improvement in Oxford scores, compared to non-obese subjects. Satisfaction with surgery was reported by 95% of THA and 91% of TKA subjects with no significant differences between BMI group grades (p=0.491 THA and p=0.473 TKA). Preoperative obesity was observed in 44% of TKA and 27% of THA subjects. In the obese only 1 in 10 subjects lost 5kg or more over 12 months. Obese patients experienced equivalent improvements in outcome after arthroplasty and rates of satisfaction with surgery to the non-obese

Obesity is a known risk factor for hip osteoarthritis. The aim of this study was to compare the incidence of obesity in Australians undergoing hip replacements (HR) for osteoarthritis to the general population. A cohort study was conducted comparing data from the Australian Bureau of Statistics and the Australian Orthopaedic Association National Joint Replacement Registry (AOANJRR) from 2017-18. Body mass index (BMI) data for patients undergoing primary total hip replacement and resurfacing for osteoarthritis were obtained from the AOANJRR. The distribution of HR patients by BMI category was compared to the general population, in age and sex sub-groups. During the study period, 32,495 primary HR were performed for osteoarthritis in Australia. Compared to the general population, there was a higher incidence of Class I, II, and III obesity in patients undergoing HR in both sexes aged 35 to 74 years old. Class III obese females and males undergoing HR were on average 6 to 7 years younger than their normal weight counterparts. Class III obese females and males aged 55-64 years old were 2.9 and 1.7 times more likely to undergo HR, respectively (p<0.001). There is a strong association between increased BMI and relative risk of undergoing HR. Similar findings have been noted in the United States of America, Canada, United Kingdom, Sweden and Spain. A New Zealand Registry study and recent meta-analysis have also found a concerning trend of Class III obese patients undergoing HR at a younger age. Obese Australians are at increased risk of undergoing HR at a younger age. A national approach to address the prevalence of obesity is needed

Due to shorter hospital stays and faster patient rehabilitation Unicompartmental Knee Replacements (UKR) are now considered more cost effective than Total Knee Joint Replacements (TKJR). Obesity however, has long been thought of as a relative contraindication to UKR due to an unproven theoretical concern of early loosening. This study is a retrospective review of patient reported outcome scores and revision rates of all UKR with recorded BMI performed by the Canterbury District Health Board (CDHB) from January 2011 and September 2021. Patient reported outcome scores were taken preoperatively, at 6 months, 1 year, 5 years and 10 years post operatively. These included WOMAC, Oxford, HAAS, UCLA, WHOQOL, normality, pain and patient satisfaction. 873 patients had functional scores recorded at 5 years and 164 patients had scores recorded at 10 years. Further sub-group analysis was performed based on patient BMI of <25, 25–30, 30–35 and >35. Revision data was available for 2377 UKRs performed in Christchurch during this period. Both obese (BMI >30) and non-obese (BMI <30) patients had significantly improved post-operative scores compared to preoperative. Pre-operatively obese patients had significantly lower functional scores except for pain and UCLA. All functional scores were lower in obese patients at 5 years but this did not meet minimum clinical difference. At 10 years, there was significantly lower HAAS, satisfaction and WOMAC scores for obese patients but no difference in Oxford, normality, WHOQOL, UCLA and pain scores. There was no significant difference in the improvement from pre-operative scores between obese and non-obese patients. All cause revision rate for obese patients at 10 years was 0.69 per 100 observed component years compared to 0.76 in non-obese. This was not statistically significant. Our study proves that UKR is an excellent option in obese patients with post-operative improvement in functional scores and 10 year survivorship equivalent to non-obese patients

Osteoarthritis (OA) of the hip is the most common indication for total hip replacement (THR). Obesity is a risk factor for the development of OA and has recently resulted in patients requiring THRs at much younger ages to relieve pain at the joint capsule and restore mobility. However, the impact of obesity on THR mortality is not well understood. An updated systematic review was performed to identify whether an obese BMI should influence patient selection for surgery. Specifically, the impact of obesity on short-term mortality, long-term mortality, and peri- and post-operative complications was assessed with a particular focus on BMI classes. A comprehensive literature search of Ovid Medline and EMBASE in November 2022 identified relevant papers in accordance with PRISMA methodology. After removing duplicates, 2988 articles underwent strict inclusion and exclusion criteria, resulting in 12 papers for analysis. There was no statistically significant difference in mortality risk between obese and non-obese populations. Obesity was associated with a lower risk of short-term mortality than in the normal weight control group, however there was an increased mortality risk in obese patients long-term likely due to comorbidities. Obese patients were significantly younger than normal BMI and underweight patients. However, the paper found increased mortality risk in underweight and morbidly obese patients. Obese patients did not have an increased risk of mortality when compared to non-obese patients following THR. Obesity may have a protective effect on mortality up to a BMI of 40kg/m2, although this may be influenced by the obesity paradox which states only the healthiest obese individuals are selected for surgery, which could attribute to a lower mortality risk. The greatest risk of mortality and complication was associated with underweight patients. As a result, a BMI greater than 30kg/m2 may not necessitate a hip replacement contraindication. It is important surgeons apply careful consideration and comprehensive risk assessment on patients who require a THR, especially at the BMI extremes

To determine the risk of total knee replacement (TKR) for primary osteoarthritis (OA) associated with overweight/obesity in the Australian population. This population-based study analyzed 191,723 cases of TKR collected by the Australian Orthopaedic Association National Joint Registry and population data from the Australian Bureau of Statistics. The time-trend change in incidence of TKR relating to BMI was assessed between 2015-2018. The influence of obesity on the incidence of TKR in different age and gender groups was determined. The population attributable fraction (PAF) was then calculated to estimate the effect of obesity reduction on TKR incidence. The greatest increase in incidence of TKR was seen in patients from obese class III. The incidence rate ratio for having a TKR for obesity class III was 28.683 at those aged 18-54 years but was 2.029 at those aged >75 years. Females in obesity class III were 1.7 times more likely to undergo TKR compared to similarly classified males. The PAFs of TKR associated with overweight or obesity was 35%, estimating 12,156 cases of TKR attributable to obesity in 2018. The proportion of TKRs could be reduced by 20% if overweight and obese population move down one category. Obesity has resulted in a significant increase in the incidence of TKR in the youngest population in Australia. The impact of obesity is greatest in the young and the female population. Effective strategies to reduce the national obese population could potentially reduce 35% of the TKR, with over 10,000 cases being avoided

Literature has suggested that obese (BMI >30) and morbidly obese (BMI > 35) patients should not be offered surgery as a day case due to increases in complication and readmission rates. At Torbay hospital, patients are routinely offered day case surgery, in a specialist day case unit, regardless of BMI. This is done with minimal complications and enables a higher throughput of patients and at least 75% of surgical procedures to be performed as a day case, as per NHS guidelines. We present 12 year data of day case knee arthroscopy surgery performed at Torbay hospital. Over 12 years, 3421 knee arthroscopies were performed. 649 were performed on obese patients and 222 on morbidly obese patients. No anaesthetic complications were observed in any of the obese patient groups and readmissions rates (up to 28 days) were 0.8% in the morbidly obese group and 0.9% in the Obese group, compared to 0.9% for patients with BMI <30. Our data shows that day case surgery can be performed on all patients regardless of BMI and patient obesity. We believe that other units should offer surgery to obese and morbidly obese patients to allow increased efficiency and achievement of NHS day case guidelines

Background. Obesity has been linked with increased rates of knee osteoarthritis. Limited information is available on the survival and functional outcome results of rTKR in the obese patients. This registry-based study aimed to identify whether BMI is an independent risk factor for poorer functional outcomes and /or implant survival in rTKA. Methods. New Zealand Joint Registry (NZJR) data of patients who underwent rTKA from 1st January 2010 to January 2023 was performed. Demographics, American Society of Anesthesiologists (ASA), BMI, Operative time, indications for revision and components revised of the patients undergoing rTKA was collected. Oxford knee score (OKS) at 6 months and rates of second revision (re- revision) were stratified based on standardised BMI categories. Results. Of the 2687 revisions, functional outcome scores were available for 1261 patients. Oxford knee scores following rTKA are significantly inferior in higher BMI patients (36.5 vs 31.5 p<0.001). This held true when adjusted for age (35.7 vs 30.9 p<0.001). Tibial component loosening was a more common indication for revision in patients with BMI >40 (31.1% vs 21% for BMI <25), whereas periprosthetic femoral fracture was significantly more commonly seen in patients with BMI <25. Re-revision rates displayed no significant differences between any pairs of BMI groups (2.18/100 component years) and adjusting for age and sex did not alter this (p= 0.462). Indications for re-revision were also not different between BMI categories. Over 50% of the rTKA patients were obese. Significantly more obese patients were ASA grade 3,4 and more were <75 years. Operative time was longer in the obese patients (p<0.001). Conclusions. Although overall re-revision rates are similar between all BMI categories, the functional outcomes favour those with lower BMI. Patients with higher BMI are younger, more comorbid and carry potentially higher perioperative risks. The registry data provides valuable information when providing counsel to patients undergoing rTKA and lends further support to optimising patients prior to pTKA

Abstract. Objectives. Obesity is prevalent with nearly one third of the world's population being classified as obese. Total knee arthroplasty (TKA) is an effective treatment option for high BMI patients achieving similar outcomes to non-obese patients. However, increased rates of aseptic loosening in patients with a high BMI have been reported. In patients with high BMI/body mass there is an increase in strain placed on the implant fixation interfaces. As such component fixation is a potential concern when performing TKA in the obese patient. To address this concern the use of extended tibial stems in cemented implants or cementless fixation have been advocated. Extend tibial stems are thought to improve implant stability reducing the micromotion between interfaces and consequently the risk of aseptic loosening. Cementless implants, once biologic fixation is achieved, effectively integrate into bone eliminating an interface. This retrospective study compared the use of extended tibial stems and cementless implants to conventional cemented implants in high BMI patients. Methods. From a prospectively maintained database of 3239 primary Attune TKA (Depuy, Warsaw, Indiana), obese patients (body mass index (BMI) >30 kg/m²) were retrospectively reviewed. Two groups of patients 1) using a tibial stem extension [n=162] and 2) cementless fixation [n=163] were compared to 3) a control group (n=1426) with a standard tibial stem cemented implant. All operations were performed by or under the direct supervision of specialist arthroplasty surgeons. Analysis compared the groups with respect to class I, II, and III (BMI >30kg/m², >35 kg/m², >40 kg/m²) obesity. The primary outcome measures were all-cause revision, revision for aseptic loosening, and revision for tibial loosening. Kaplan-Meier survival analysis and Cox regression models were used to compare the primary outcomes between groups. Where radiographic images at greater than 3 months post-operatively were available, radiographs were examined to compare the presence of peri-implant radiolucent lines. Results. The mean follow-up of 4.8, 3.4, and 2.5 years for cemented, stemmed, and cementless groups respectively. In total there were 34 all-cause revisions across all the groups with revision rates of 4.55, 5.50, and 0.00 per 1000-implant-years for cemented, stemmed, and cementless groups respectively. Survival Analysis did not show any significant differences between the three groups for all-all cause revision. There were 6 revisions for aseptic loosening (5 tibial and 1 femoral); all of which were in the standard cemented implant group. In contrast there were no revisions in the stemmed or cementless implant groups, however, this was not significant on survival analysis. Analysis looking at class I, II, and III obesity also did not show any significant differences in survival for all cause revision or aseptic loosening. Conclusion. This retrospective analysis showed that there were no revisions required for aseptic loosening when either a cemented stemmed or cementless implant were used in obese patients. These findings are in line with other studies showing that cementless fixation or extended stem implants are a reasonable option in obese patients who represent an increasing cohort of patients requiring TKR. Declaration of Interest. (b) declare that there is no conflict of interest that could be perceived as prejudicing the impartiality of the research reported:I declare that there is no conflict of interest that could be perceived as prejudicing the impartiality of the research project

Aims. We studied the outcomes of hip and knee arthroplasties in a high-volume arthroplasty centre to determine if patients with morbid obesity (BMI ≥ 40 kg/m. 2. ) had unacceptably worse outcomes as compared to those with BMI < 40 kg/m. 2. . Methods. In a two-year period, 4,711 patients had either total hip arthroplasty (THA; n = 2,370), total knee arthroplasty (TKA; n = 2,109), or unicompartmental knee arthroplasty (UKA; n = 232). Of these patients, 392 (8.3%) had morbid obesity. We compared duration of operation, anaesthetic time, length of stay (LOS), LOS > three days, out of hours attendance, emergency department attendance, readmission to hospital, return to theatre, and venous thromboembolism up to 90 days. Readmission for wound infection was recorded to one year. Oxford scores were recorded preoperatively and at one year postoperatively. Results. On average, the morbidly obese had longer operating times (63 vs 58 minutes), longer anaesthetic times (31 vs 28 minutes), increased LOS (3.7 vs 3.5 days), and significantly more readmissions for wound infection (1.0% vs 0.3%). There were no statistically significant differences in either suspected or confirmed venous thromboembolism. Improvement in Oxford scores were equivalent. Conclusion. Although morbidly obese patients had less favourable outcomes, we do not feel that the magnitude of difference is clinically significant when applied to an individual, particularly when improvement in Oxford scores were unrelated to BMI. Cite this article: Bone Jt Open 2021;2(7):515–521

Direct anterior approach (DAA) arthroplasty has generated great interest because of its minimally invasive and muscle sparing nature. Obese patients are reported to be associated with greater incidence of complications in primary joint replacement. The purpose of this study was to compare patient outcomes and complication rates between obese and non-obese patients undergoing primary total hip arthroplasty (THA) through a Bikini direct anterior incision. This retrospective, single surgeon study compared the outcome of 258 obese patients and 200 non-obese patients undergoing DAA THA using a Bikini incision, over a 7-year period. The average follow-up was 4.2 years (range 2.6-7.6 years). There were no statistically significant differences in the complication rate between the two groups. The obese group recorded 2 major (venous thromboembolism and peri-prosthetic fracture) and 2 minor complications (superficial wound infection), compared with the non-obese group, which recorded 2 major (deep-wound infection and peri-prosthetic fracture) and 1 minor complication (superficial wound infection). Patient-reported outcomes (WOMAC and Harris Hip Scores) showed significant post-operative improvements (p < 0.001) and did not differ between the two groups. Bikini DDA THA does not increase the complication rate in obese patients and offers similar clinical improvements compared to non-obese patients. (200 words)

Obesity is associated with poor outcomes and increased risk of failure after rotator cuff (RC) repair surgery. The effect of diet-induced obesity (DIO) on enthesis healing has not been well characterised and whether its effects can be reversed with dietary intervention is unknown. We hypothesised that DIO would result in inferior enthesis healing in a rat model of RC repair and that dietary intervention in the peri-operative period would improve enthesis healing. A total of 78 male Sprague-Dawley rats were divided into three weight-matched groups from weaning and fed either: control diet (CD), high-fat diet (HFD), or HFD until surgery, then CD thereafter (HF-CD). After 12 weeks the left supraspinatus tendon was detached, followed by immediate surgical repair. At 2 and 12 weeks post-surgery, animals were cullers and RCs harvested for biomechanical and histological evaluation. Body composition and metabolic markers were assessed via DEXA and plasma analyses, respectively. DIO was established in the HFD and HF-CD groups prior to surgery, and subsequently reversed in the HF-CD group after surgery. At 12 weeks post-surgery, plasma leptin concentrations were higher in the HFD group compared to the CD group (5.28 vs. 2.91ng/ml, P=0.003). Histologically, the appearance of the repaired entheses was poorer in both the HFD and HF-CD compared to the CD group at 12 weeks (overall histological score 6.20 (P=0.008), 4.98 (P=0.001) and 8.68 out of 15, respectively). The repaired entheses in the HF-CD group had significantly lower (26.4 N, P=0.028) load-at-failure 12 weeks post-surgery compared to the CD group (34.4 N); while the HFD group was low, but not significantly different (28.1 N, P=0.096). Body mass at the time of surgery, plasma leptin and body fat percentage were negatively correlated with histological scores and plasma leptin with load-at-failure 12 weeks post-surgery. DIO impaired enthesis healing in this rat RC repair model, with inferior biomechanical and histological outcomes. Restoring normal weight with dietary change after surgery did not improve healing outcomes. Exploring interventions that improve the metabolic state of obese patients and counselling patients appropriately about their modest expectations after repair should be considered

To describe the longitudinal trends in patients with obesity and Metabolic Syndrome (MetS) undergoing TKA and the associated impact on complications and lengths of hospital stay. We identified patients who underwent primary TKA between 2006 – 2017 within the American College of Surgeons National Surgical Quality Improvement Program (NSQIP) database. We recorded patient demographics, length of stay (LOS), and 30-day major and minor complications. We labelled those with an obese Body Mass Index (BMI ≥ 30), hypertension, and diabetes as having MetS. We evaluated mean BMI, LOS, and 30-day complication rates in all patients, obese patients, and those with MetS from 2006-2017. We used multivariable regression to evaluate the trends in BMI, complications, and LOS over time in all patients and those with MetS, and the effect of BMI and MetS on complication rates and LOS, stratified by year. 270,846 patients underwent primary TKA at hospitals participating in the NSQIP database. 63.71% of patients were obese (n = 172,333), 15.21% were morbidly obese (n = 41,130), and 12.37% met criteria for MetS (n = 33,470). Mean BMI in TKA patients increased at a rate of 0.03 per year (0.02-0.05; p < 0 .0001). Despite this, the rate of adverse events in obese patients decreased: major complications by an odds ratio (OR) of 0.94 (0.93-0.96; p < 0 .0001) and minor complications by 0.94 (0.93-0.95; p < 0 .001). LOS also decreased over time at an average rate of −0.058 days per year (-0.059 to −0.057; p < 0 .0001). The proportion of patients with MetS did not increase, however similar improvements in major complications (OR 0.94 [0.91-0.97] p < 0 .0001), minor complications (OR 0.97 [0.94-1.00]; p < 0 .0330), and LOS (mean −0.055 [-0.056 to −0.054] p < 0 .0001) were found. In morbidly obese patients (BMI ≥ 40), there was a decreased proportion per year (OR 0.989 [0.98-0.994] p < 0 .0001). Factors specifically associated with major complications in obese patients included COPD (OR 1.75 [1.55-2.00] p < 0.0001) and diabetes (OR 1.10 [1.02-1.1] p = 0.017). Hypertension (OR 1.12 [1.03-1.21] p = 0.0079) was associated with minor complications. Similarly, in patients with MetS, major complications were associated with COPD (OR 1.72 [1.35-2.18] p < 0.0001). Neuraxial anesthesia was associated with a lower risk for major complications in the obese cohort (OR 0.87 [0.81-0.92] p < 0.0001). BMI ≥ 40 was associated with a greater risk for minor complications (OR 1.37 [1.26-1.50] p < 0.0001), major complications (1.11 [1.02-1.21] p = 0.015), and increased LOS (+0.08 days [0.07-0.09] p < 0.0001). Mean BMI in patients undergoing primary TKA increased from 2006 - 2017. MetS comorbidities such as diabetes and hypertension elevated the risk for complications in obese patients. COPD contributed to higher rates of major complications. The obesity-specific risk reduction with spinal anesthesia suggests an improved post-anesthetic clinical course in obese patients with pre-existing pulmonary pathology. Encouragingly, the overall rates of complications and LOS in patients with obesity and MetS exhibited a longitudinal decline. This finding may be related to the decreased proportion of patients with BMI ≥ 40 treated over the same period, possibly the result of quality improvement initiatives aimed at delaying high-risk surgery in morbidly obese patients until healthy weight loss is achieved. These findings may also reflect increased awareness and improved management of these patients and their elevated risk profiles

In a recent study, 54.5% of patients reporting to arthroplasty clinics in the US were obese. We performed a recent literature review to determine how obesity impacts outcomes in total hip and knee arthroplasty and what must be done to improve outcomes in the obese arthroplasty patient. Specifically, obese patients have shown increased rates of infection, dislocation, need for revision, wound dehiscence, increased operative time and prolonged hospital stay. Additionally, obese TKA patients have been shown to have increased rates of aseptic loosening, thromboembolic events, wound complications, and cardiopulmonary events. Worsening severity of obesity seems to correlate with worsening outcomes and super obesity (BMI>50) has been identified as an independent risk factor for complications. Patients with BMI>35 have shown to be 6.7 times more likely to develop infection after TKA. Patients with BMI>40 have a 3.35 times higher rate of revision for deep infection than those with BMI<35. The odds ratio for major complications increases dramatically beyond BMI>45. How can we improve outcomes in the obese patient? Preoperative care for the obese patient involves nutritional counseling, incorporating weight loss methods, physical therapy, metabolic workup and diagnosis and management of frequent comorbid conditions (OSA, DM2, HTN, HLD, malnutrition, renal failure). Identifying and managing comorbidities is especially important given that some comorbidities such as malnutrition have been shown to be as strong or even stronger an independent risk factor for postoperative TJA complications than obesity. In some cases higher complications were seen which some authors attribute to bariatric patients remaining in a catabolic state after weight loss.  . We know that obesity and its associated comorbid conditions do have worse outcomes and increased complications in TJA patients. We also know that complications proportionately increase with increasing severity of obesity. The super-obese population is at the greatest risk of complication following TJA and preoperative screening and management is essential in reducing complications. Although weight loss is important, bariatric data has shown that it does not solve the problem of obesity in itself and the patient's metabolic state is likely a more important issue. Implant selection is important and strong consideration should be given to avoiding direct anterior approach in the THA obese patient. Understanding of obesity specific complications and treatment options is crucial for patient counseling and optimization to ensure successful treatment in obese TJA patients

Over the last decade, the number of total knee arthroplasty (TKA) has risen over 125%. Numerous studies have established a relationship between obesity and complications in primary TKA. Interestingly, few studies have investigated medical and orthopaedic complications in obese patients undergoing revision TKA (RTKA). With the increasing number of RTKA and with the prevalence of obesity still on the rise, the study of obesity on complications following RTKA is indicated. We retrospectively reviewed 180 RTKA performed by a single surgeon done between August 2008 and June 2017. All patients who underwent RTKA were included, but revisions done with simultaneous extensor mechanism reconstruction and/or distal femur replacement were excluded since these procedures are technically more demanding. 154 revisions met our inclusion/exclusion criteriaes and were included in the final analysis. 81 patients were included in the non-obese group (BMI . The total number of orthopaedic complications in the obese group (46.6%) was significantly higher than in the non-obese group (27.2%) (OR=1.71) (p = 0.01). The number of infection was higher in the obese group (11%) than in the non-obese (6.2%) but this was not statistically significant (OR=1.77) (p = 0.28). Reoperation rate was also higher in the obese group (23.3%) than in the non-obese group (16%) but this did not reach statistical significance (OR=1.46) (p = 0.26) (Table 3). Medical complications were higher in the obese group (31.5% vs 19.8%) (OR=1.59) (p=0.09). According to the Dindo-Clavien classification, the obese group demonstrated a significantly higher rate of grade 3 or higher complications (p = 0.01). Obesity significantly increases the occurrence of orthopaedic complications following RTKA. Obesity also seems to increase the number of medical complications following RTKA. The obese patient should be informed prior to revision TKA that there is an increased risk of complications when compared with the non-obese patient. Further research with higher power would seem advisable to confirm this trend. For any figures or tables, please contact the authors directly

We hypothesised that diet-induced obesity (DIO) would result in inferior enthesis healing in a rat model of rotator cuff (RC) repair and that dietary intervention in the peri-operative period would improve enthesis healing. A total of 78 male Sprague-Dawley rats were divided into three weight-matched groups from weaning and fed either: control diet (CD), high-fat diet (HFD), or HFD until surgery, then CD thereafter (HF-CD). After 12 weeks, the left supraspinatus tendon was detached, followed by immediate surgical repair. At 2 and 12 weeks post-surgery, animals were culled, and RCs harvested for biomechanical and histological evaluation. Body composition and metabolic markers were assessed via DEXA and plasma analyses, respectively. DIO was established in the HFD and HF-CD groups before surgery and subsequently reversed in the HF-CD group after surgery. Histologically, the appearance of the repaired entheses was poorer in both the HFD and HF-CD groups compared with the CD group at 12 weeks after surgery, with semiquantitative scores of 6.2 (P<0.01), 4.98 (P<0.01), and 8.7 of 15, respectively. The repaired entheses in the HF-CD group had a significantly lower load to failure (P=0.03) at 12 weeks after surgery compared with the CD group, while the load to failure in the HFD group was low but not significantly different (P=0.10). Plasma leptin were negatively correlated with histology scores and load to failure at 12 weeks after surgery. DIO impaired enthesis healing in this rat RC repair model, with inferior biomechanical and histological outcomes. Restoring normal weight with dietary change after surgery did not improve healing outcomes. Circulating levels of leptin significantly correlated with poor healing outcomes. This pre-clinical rodent model demonstrates that obesity is a potentially modifiable factor that impairs RC healing and increases the risk of failure after RC surgery

Obese patients show a higher incidence of tendon-related pathologies. These patients present a low inflammatory systemic environment and a higher mechanical demand which can affect the tendons. In addition, inflammation might have a role in the progression of the disease as well as in the healing process. A systematic review was performed by searching PubMed, Embase and Cochrane Library databases. Inclusion criteria were studies of any level of evidence published in peer-reviewed journals reporting clinical or preclinical results. Evaluated data were extracted and critically analysed. PRISMA guidelines were applied, and risk of bias was assessed, as well as the methodological quality of the included studies. We excluded all the articles with high risk of bias and/or low quality after the assessment. Due to the high heterogeneity present among the studies, a metanalysis could not be done. Thus, a descriptive analysis was performed. After applying the previously described criteria, thirty articles were included, assessed as medium or high quality. We analysed the data of 50865 subjects, 6096 of which were obese (BMI over 30 accordingly to the WHO criteria). The overall risk of re-tear after surgery is about the 10% more than normal BMI subjects. The rupture risk fluctuates in the studies without showing a significant trend. Obese subjects have a higher risk to develop tendinopathy and a worse outcome after surgery as confirmed in several human studies. The obesity influence on tendon structure and mechanical properties may rely on the fat tissue endocrine proprieties and on hormonal imbalance. Clinicians should consider obesity as a predisposing factor for the development of tendinopathies and for a higher risk of complications in patients who underwent surgical repair of tendons

Osteoarthritis is one of the major causes of immobility. Most commonly, osteoarthritis manifests at the knee joint. Prevalence of knee osteoarthritis (KNOA) increases with age. Another important risk factor for KNOA is obesity. Research has shown that obese subjects have almost four times the risk of developing KNOA, which may be explained by both an increased knee loading. In medial compartment KNOA, the knee adduction moment (KAM) during gait is considered a marker for disease severity. KAM is dependent of the magnitude of the ground reaction force and its moment arm relative to the knee joint centre. In addition, obesity has been reported to augment KAM during gait. However, after removal of the direct contributions of body weight, KAM parameters may be different due to obesity-related gait adaptations to limit knee loading. While KAM has been thoroughly investigated during gait, little is known about KAM during stair negotiation, during which knee loads are higher compared to gait. The aim of the current study is therefore to compare normalized KAM during the stance phase of stair negotiation between lean KNOA patients, obese KNOA patients, and healthy controls. This case control study included 20 lean controls, 14 lean KNOA patients, and 16 obese KNOA patients. All subjects ascended and descended a two-step staircase at a self-selected, comfortable speed. Radiographic imaging and MRI were used to evaluate knee cartilage and KNOA status. Motion analysis was performed with a three-dimensional motion capture system. Kinetic data were obtained by one force platform. The parameters of study included: stance phase duration, toe-out angle, KAM peaks and KAM impulse. During stair ascent obese KNOA patients showed a longer stance phase than healthy controls (P 0.050). Despite high between-subject variability, KAM impulse was found 45% higher in the obese KNOA group during stair descent, when compared to healthy controls (P =0.012). The absence of a significant effect of groups on the normalized KAM during stair negotiation may be explained by a lower ambulatory speed in the obese KNOA group, that effectively lowers GRFz. Decreasing ambulatory speed may be an effective strategy to lower KAM during stair negotiation

Introduction. Previous research has indicated that preoperative modification of risk factors associated with obesity may reduce complications after TKA. However, the optimal method is still debated. This study aims to investigate whether a preoperative Risk Stratification Tool (RST) devised by our institution to optimize obese patients can reduce unexpected ICU transfers, and 90-day ED visits, readmissions, and reoperations. Methods. We retrospectively reviewed 1,724 consecutive risk stratified patients undergoing primary unilateral TKA. The mean age was 64.8 years and average body mass index (BMI) was 34.2 kg/m2. All patients underwent preoperative optimization using the RST. We first compared our primary variables of interest between obese (BMI>30, n=1,189) and non-obese patients (n=535). Patients were then divided into 3 groups (I-non-obese, II-obese (30–39.9 kg/m2) and III-morbidly obese ((>40 kg/m2)) and logistic regression was used to evaluate outcomes among the groups adjusted for age, sex, smoking history and diabetes. Results. Overall, obese patients had an increased rate of discharge to facility compared to non-obese patients (38.0% vs 25.9%, p<0.001). After stratifying by BMI (group I (n=535), II (n=793), III (n=396)), discharge to facility remained higher relative to non-obese (25.9%) in both obese (34.0%, OR 1.6, CI 1.3–2.1) and morbidly obese (45.8%, OR 3.0, CI 2.2–4.1) patients. However, there was no difference in unexpected ICU transfer (0.6% non-obese vs 1.0% obese [OR 1.9, CI 0.5–7.3] vs 1.8% morbidly obese [OR 4.1, CI 1.0–17.2]), ED visits (8.6% vs 10.5% [OR 1.3, CI 0.9–1.9] vs 10.3% [OR 1.2, CI 0.7–1.9]), readmissions (4.7% vs 4.3% [OR 1.0, CI 0.6–1.8] vs 4.8% [OR 1.3, CI 0.7–2.6]), or reoperations (2.4% vs 3.3% [OR 1.3, CI 0.6–2.5] vs 3.0% [OR 1.0, CI 0.7–2.2]). Conclusion. Use of a preoperative risk stratification tool is effective at lowering the risk of short-term complications after TKA in obese patients to similar levels as non-obese patients. For any figures or tables, please contact the authors directly

Aim. The aim of this study is to evaluate if obesity negatively affects: (1) complication rate, (2) reoperation and revision rate and (3) functional outcome (based on patient reported outcome measures, PROMs) in revision total hip arthroplasty (rTHA). To our knowledge this is the only recent study to prospectively review these three aspects in what might be considered challenging rTHA. Methods. 444 rTHAs (cup, stem, both, n= 265, 57, 122 respectively), performed in a specialized high-volume orthopaedic center from 2013 to 2015, were prospectively followed. Complications and Oxford Hip Score (OHS) were evaluated at 4 months, 1 year and 2 years. Thirtyfour patients had a BMI >35 kg/m2 (obese), of which thirteen patients with a BMI >40 kg/m2 (morbidly obese). Results. Infection following rTHA was more common in obese patients (8/34: 24%) and in morbidly obese patients (5/13: 38%) than in non-obese patients (15/410: 4%; p's < 0.001). No differences between obese and non-obese groups for other complications were observed (aseptic loosening, dislocation, periprosthetic fractures, thromboembolic events). Reoperation and revision rates were similar overall (p = 0.067 / 0.303 respectively) and due to infection (p = 0.469 / 0.879 respectively) for obese and non-obese groups. Scores on the OHS improved from 42 ±13 at baseline to 27±12 at 1 and 2 year follow-up (p < 0.001). Obese patients had overall poorer OHS scores than non-obese patients (p < 0.001), but improvement of OHS did not differ between obese and non-obese patients (p = 0.198). Conclusion. Obesity is associated with an increased risk of infection following revision THA. Patients with high BMI should be counselled appropriately before surgery

Introduction. Rates of readmission and reoperation following primary total knee arthroplasty (TKA) are under scrutiny due to new payment models, which penalize these negative outcomes. Many prior studies have demonstrated the risk of perioperative complications among patients with obesity. However, an elevated complication rate among patients with poor nutrition, as measured by hypoalbuminemia, has also been reported. We sought to determine whether controlling for hypoalbuminemia would mitigate the effect that prior authors had identified in patients with obesity. In addition, we hoped to identify an albumin threshold above which risk of readmission and reoperation would be minimized. Materials and Methods. We reviewed the American College of Surgeons National Surgical Quality Improvement Program (ACS-NSQIP) database for the period of 2008–2016 to evaluate the rates of perioperative complications among primary TKA patients by obesity category and albumin level. Patients were divided into groups according to World Health Organization obesity category and continuous as well as dichotomous albumin level. The primary outcomes were readmission and reoperation within 30 days of surgery. Patients without BMI or albumin data were excluded, as were patients undergoing surgery for the treatment of fracture or bone tumor. Univariate logistic regression compared predictive value of body mass index and albumin on incidence of these outcomes, using the normal weight and albumin > 3.5 g/dL groups as controls. Multivariate logistic regression modeling controlled for age, gender, and comorbidity status. Receiver operator curves (ROC) were generated to determine if an albumin threshold could be determined, above which risk for these complications would be minimized. Results. Outcome data was available 108,601 patients. Overall, 3,508 patients (3.46%) were readmitted and 1,219 patients (1.19%) underwent reoperation within 30 days. Hypoalbuminemia was present in 4,327 patients (4.11%), lowest in the Overweight group (3.16%) and highest in the Obese Type III (6.72%) and Underweight (12.62%) groups (p <0.001). Readmission and reoperation rates were highest among patients categorized as Obesity Class III (4.15 and 1.73%, respectively) compared with Normal Weight (3.59 and 1.14%, respectively, p <0.001). Readmission and reoperation rates were higher among patients with hypoalbuminemia (6.10 and 1.96%, respectively) compared with normal albumin (3.34 and 1.16%, respectively, p <0.001). After controlling for covariates of interest using multivariate regression including continuous albumin, odds ratio of readmission among the highest obesity category no longer differed from the Normal Weight control group. Odds ratio of reoperation among the highest obesity category declined from 1.52 to 1.38 after controlling for albumin and other covariates (p = 0.022). A subanalysis was performed excluding all patients with albumin < 3.5 g/dL, but results did not differ significantly from the multivariate model. ROC modeling was unable to identify a threshold for continuous BMI or albumin that would adequately mitigate risk for readmission or reoperation. Discussion. Albumin and obesity remain significant independent risk factors for reoperation following primary TKA procedures. However, after controlling for hypoalbuminemia and other important covariates, readmission rates did not significantly differ between patients with Normal Weight and any other obesity category. Controlling for albumin alone does not mitigate all risk imposed by obesity on perioperative outcomes. Future studies may assess whether preoperative albumin repletion or weight loss may improve outcomes for patients with hypoalbuminemia and obesity. For figures, tables, or references, please contact authors directly

The purpose of this population-based study was to determine the association between morbid obesity and 10-year mortality and complications in patients undergoing primary THA. A cohort study of 22,251 patients, aged 45–74 years old, treated with primary THA between 2002 and 2007 for osteoarthritis, was conducted using Ontario administrative healthcare databases. Patients were followed for 10 years. Risk ratios (RRs) of mortality, reoperation, revision, and dislocation in patients with body mass index (BMI) > 45 kg/m2(morbidly obese patients) compared with BMI ≤45 kg/m2 (non-morbidly obese) were estimated. 3.3% of the cohort (726) was morbidly obese. Morbidly obese patients were younger (mean age 60.6 vs. 63.3, P-value < 0 .001) and more likely to be female (63.9% vs. 52.2%, P-value < 0 .001), compared with non-morbidly obese patients. Morbid obesity was associated with higher 10-year risk of death (RR 1.38, 95% CI 1.18, 1.62). Risks of revision (RR 1.43, 95% CI 0.96, 2.13) and dislocation (RR 2.38, 95% CI 1.38, 4.10) were higher in morbidly obese men, compared with non-morbidly obese men, there were no associations between obesity and revision or dislocation in women. Risk of reoperation was higher in morbidly obese women, compared to non-morbidly obese women (RR 1.60, 95% CI 1.05, 2.40), there was no association between obesity and reoperation in men. Morbidly obese patients undergoing primary THA are at higher risks of long-term mortality and complications. There were differences in complication risk by sex. Results should inform evidence-based perioperative counseling of morbidly obese patients considering THA

Introduction. Perioperative optimization efforts have improved outcomes following primary total knee arthroplasty (TKA). However, morbidly obese patients continue to have increased rates of complications. The purpose of this study was to assess if rates of early complications after TKA have similarly improved for both morbidly obese and non-morbidly obese patients. Methods. Elective, primary TKA patients from 2011–2018 were identified in the National Surgical Quality Improvement Program database. Patients were stratified by body mass index (BMI) <40 kg/m. 2. and ≥40 kg/m. 2. Thirty-day rates of infectious complications, readmissions, and reoperation were assessed. Trends in these endpoints over the study period were compared between BMI groups utilizing odds ratios (OR) and multivariate analyses. Results. In total, 314,719 patients underwent TKA and 46,386 (15%) had BMI ≥40 kg/m. 2. From 2011–2018, the reoperation rate significantly improved from 1.2% to 1.0% (OR: 0.6 [0.6–0.7]) for patients with BMI <40 kg/m. 2. , as did rates of readmission (4.5% to 2.9%, OR: 0.8 [0.7–0.99]). Patients with BMI ≥40 kg/m. 2. also had a significant decrease in the rate of readmission over the study period (4.9% to 3.3%, OR: 0.6 [0.5–0.8]); however, the rate of reoperation did not significantly change (1.4% to 1.4%, OR: 1.0 [0.6–1.6]). Significant improvements were not observed for infectious complications over time for either group. However, patients with BMI ≥40 kg/m. 2. consistently had increased risk of both deep infection from 2014–2018 (2014 OR: 2.2 [1.4–3.4], 2018: 2.2 [1.6–3.0]) and wound complications from 2011–2018 (2011 OR: 1.7 [1.2–2.6], 2018 OR: 2.0 [1.7–2.4]) compared to non-morbidly obese patients. Conclusion. Although readmission rates significantly decreased for all patients, improvements in reoperation rates observed in non-morbidly obese patients were not experienced by the morbidly obese – resulting in a widening of the complication gap between these cohorts. Care improvements have not lowered the differential risk of infectious complications compared to non-morbidly obese

As the American population ages and a trend toward performing total hip arthroplasty (THA) in younger patients continues, the number of Americans undergoing THA is projected to increase over time. The advent of the bundled payment system combined with the current medical utilization climate has placed considerable pressure on surgeons to produce excellent results with early functional recovery and short hospital stays. The US obesity epidemic has transcended into the arthroplasty patient population and surgeons must assess whether obesity is a risk factor for poor outcomes in THA and determine how it should be managed. We performed a recent literature review to determine how obesity impacts outcomes in total hip arthroplasty and what must be done to improve outcomes in the obese arthroplasty patient. Our goal is to answer 3 questions: does obesity increase the complication rate in THA, if obesity matters how obese is too obese, and what must be done to improve outcomes in the obese patient?. Ultimately, obesity has been shown to correlate with increased post-operative complications in THA. The arthroplasty surgeon must optimise the obese patient prior to surgery by identifying associated comorbidities and consider malnutrition screening with counseling. Notice should be taken of the degree of obesity as patients with BMI > 40 have demonstrated much higher complication rates. Strong consideration should be given to avoiding direct anterior approach in the obese patient. Healthy weight loss must be encouraged with appropriate patient counseling and treatment in order to achieve success with THA in obese patients.  

A prospective, multi-centre study was carried out on 1421 total hip replacements between January 1999 and July 2007 to examine if obesity has an effect on clinical outcomes. The patients were categorised into three groups: non-obese (body mass index (BMI) < 30 kg/m. 2. ), obese (BMI 30 to 40 kg/m. 2. ) and morbidly obese (BMI > 40 kg/m. 2. ). The primary outcome measure was the change in Oxford hip score at five years. Secondary outcome measures included dislocation and revision rates, increased haemorrhage, deep infection, deep-vein thrombosis and pulmonary embolism, mean operating time and length of hospital stay. Radiological analysis assessing heterotopic ossification, femoral osteolysis and femoral stem positioning was performed. Data were incomplete for 362 hips (25.5%). There was no difference in the change in the Oxford hip score, complication rates or radiological changes at five years between the groups. The morbidly obese group was significantly younger and required a significantly longer operating time. Obese and morbidly obese patients have as much to gain from total hip replacement as non-obese patients