Cost-Effectiveness of Bariatric Surgery Prior to Total Knee Arthroplasty in the Morbidly Obese: A Computer Model-Based Evaluation

The cost-effectiveness of guideline-recommended treatments for osteoarthritis: A systematic review

OBJECTIVE

To critically appraise the literature on the cost-effectiveness of guideline-recommended treatments for osteoarthritis (OA).

DESIGN

Electronic databases were searched for studies that provided incremental cost-effectiveness ratios (ICER) for treatments recommended by key international guidelines to manage OA in adults. Treatments were grouped as lifestyle and rehabilitative therapies, pharmacological, injection, or surgical. Primary outcome was ICERs, converted to 2023 US dollars for comparability across studies. Risk of bias was assessed using the Consensus on Health Economic Criteria checklist for trials and the Drummond checklist for modelling studies. Studies were deemed cost-effective based on established country-specific thresholds per quality-adjusted life-year.

RESULTS

There were 110 studies that included 33 lifestyle and rehabilitative therapies, 25 pharmacological, 11 injection and 42 surgical studies. Most studies (95%) were conducted in high-income countries. Time horizons varied from 8 weeks to a lifetime. Risk of bias domains were frequently scored poorly related to cost methods. Overall, the cost-effectiveness of lifestyle and rehabilitative therapies and non-steroidal anti-inflammatory drugs (NSAIDs) was mixed. Hyaluronic acid injection was cost-effective in knee OA compared to placebo, usual care and paracetamol but not to corticosteroid injections and NSAIDs. Total hip or knee replacement was cost-effective compared to usual care or no surgery, with early access to replacement cost-effective compared to delaying surgery.

CONCLUSIONS

There was a diversity of analytical perspectives and clinical heterogeneity of interventions. Policymakers should consider their local context when deciding clinical care and resource allocation.

Bariatric surgery prior to pancreas transplantation: a retrospective matched case-control study

BACKGROUND

The clinical impact of bariatric surgery (BS) prior to pancreas transplantation (PTx) is unclear.

SETTING

University of Minnesota Hospital, Minneapolis, MN.

METHODS

This was a single center retrospective case-controlled study of all patients January 1, 1998 and May 1, 2024 with a history of BS prior to PTx. Patients were matched (1:3) with control patients by recipient age, body mass index (BMI) at PTx, type of transplant, primary versus retransplant, and year of PTx.

RESULTS

Among 1542 transplants, 17 patients had a history of BS prior to PTx, with an overall incidence of 1.1%. Eleven patients underwent roux-en-y gastric bypass, 5 underwent sleeve gastrectomy (SG), and one underwent vertical-banded gastroplasty. Eleven underwent simultaneous pancreas kidney transplant, 5 underwent pancreas transplant alone, and one underwent pancreas after kidney transplant. The median time (interquartile range [IQR]) between BS and PTx was 2.9 yrs (4.6) and ranged from .7 to 20.6 yrs. Compared to the non-BS group, patients in the BS group had similar rates of graft thrombosis (5.9% versus 3.9%, P = .76) and rejection (29.4% versus 29.4%, P > .99). Length of stay following PTx (P = .22), number of 30-day readmissions (P = .24), and number of 1-year readmissions (P = .70) were not different between the two groups. Median death-censored graft survival (9.4 yrs versus median not reached, P = .23) and patient survival (9.4 yrs versus median not reached, P = .18) were similar between the BS and non-BS groups. Finally, six patients underwent BS with the specific intention of reaching the acceptable BMI threshold for PTx. Median BMI was reduced from 37.4 prior to BS to 26.4 at time of PTx. Median time from BS to PTx was 2.4 yrs. At 4 yr follow-up, graft and patient survival was 100%.

CONCLUSIONS

This represents the largest series of patients with BS prior to PTx. Perioperative complications are not increased in patients undergoing PTx with a history of prior BS and long-term outcomes are equivalent. Patients with a prohibitive BMI for PTx eligibility should be considered for BS without concern for detrimental effect on post-transplant outcomes.

Optimal timing of hip and knee arthroplasty after bariatric surgery: A systematic review

Background

Obesity is a risk factor for the development of osteoarthritis and contributes to the increasing demand for total joint arthroplasty (TJA). Because a lower preoperative weight decreases the risk of complications after TJA, and because bariatric surgery (BS) can reduce weight and comorbidity burden, orthopedic surgeons often recommend BS prior to TJA in patients with obesity. However, the optimal timing of TJA after BS in terms of complications, revisions and dislocations is unknown.

Methods

PubMed, Embase and Cochrane CENTRAL databases were systematically searched for any type of study reporting rates of complications, revisions and dislocations in patients who had TJA after BS. The included studies' quality was assessed using the Newcastle-Ottawa Scale.

Results

Out of the 16 studies eligible for review, eight registry-based retrospective studies of high to moderate quality compared different time periods between BS and TJA and overall their results suggest little differences in complication rates. The remaining eight retrospective studies evaluated only one time period and had moderate to poor quality. Overall, there were no clear differences in outcomes after TJA for the different time frames between BS and TJA.

Conclusion

The results of this systematic review suggest that there is limited and insufficient high-quality evidence to determine the optimal timing of TJA after BS in terms of the rates of complications, revisions and dislocations. Given this lack of evidence, timing of TJA after BS will have to be decided by weighing the individual patients' risk factors against the expected benefits of TJA.

Medical Weight Optimization for Arthroplasty Patients: A Primer of Emerging Therapies for the Joint Arthroplasty Surgeon

The obesity epidemic in the United States continues to grow with more than 40% of individuals now classified as obese (body mass index >30). Obesity has been readily demonstrated to increase the risk of developing hip and knee osteoarthritis and is known to increase the risk of complications following joint arthroplasty. Weight loss prior to arthroplasty may mitigate this risk of complications; however, the existing evidence remains mixed with no clear consensus on the optimal method of weight loss and timing prior to arthroplasty. Treatment options for weight loss have included nonsurgical lifestyle modifications consisting of structured diet, physical activity, and behavioral modification, as well as bariatric and metabolic surgery (ie, sleeve gastrectomy, Roux-en-Y gastric bypass, and the adjustable gastric band). Recently, glucagon-like peptide-1 receptor agonists have gained notable popularity within the scientific literature and media for their efficacy in weight loss. The aim of this review is to provide a foundational primer for joint arthroplasty surgeons regarding the current and emerging options for weight loss to aid surgeons in shared decision-making with patients prior to arthroplasty.

Cost-effectiveness of endoscopic, surgical and pharmacological obesity therapies: a microsimulation and threshold analyses

OBJECTIVE

Weight loss interventions to treat obesity include sleeve gastrectomy (SG), lifestyle intervention (LI), endoscopic sleeve gastroplasty (ESG) and semaglutide. We aimed to identify which treatments are cost-effective and identify requirements for semaglutide to be cost-effective.

DESIGN

We developed a semi-Markov microsimulation model to compare the effectiveness of SG, ESG, semaglutide and LI for weight loss in 40 years old with class I/II/III obesity. Extensive one-way sensitivity and threshold analysis were performed to vary cost of treatment strategies and semaglutide adherence rate. Outcome measures were incremental cost-effectiveness ratios (ICERs), with a willingness-to-pay threshold of US$100 000/quality-adjusted life-year (QALY).

RESULTS

When strategies were compared with each other, ESG was cost-effective in class I obesity (US$4105/QALY). SG was cost-effective in class II obesity (US$5883/QALY) and class III obesity (US$7821/QALY). In class I/II/III, obesity, SG and ESG were cost-effective compared with LI. However, semaglutide was not cost-effective compared with LI for class I/II/III obesity (ICER US$508 414/QALY, US$420 483/QALY and US$350 637/QALY). For semaglutide to be cost-effective compared with LI, it would have to cost less than US$7462 (class III), US$5847 (class II) or US$5149 (class I) annually. For semaglutide to be cost-effective when compared with ESG, it would have to cost less than US$1879 (class III), US$1204 (class II) or US$297 (class I) annually.

CONCLUSIONS

Cost-effective strategies were: ESG for class I obesity and SG for class II/III obesity. Semaglutide may be cost-effective with substantial cost reduction. Given potentially higher utilisation rates with pharmacotherapy, semaglutide may provide the largest reduction in obesity-related mortality.

Cost-Effectiveness of Weight-Loss Interventions Prior to Total Knee Replacement for Patients With Class III Obesity

OBJECTIVE

Class III obesity (body mass index >40 kg/m2 ) is associated with higher complications following total knee replacement (TKR), and weight loss is recommended. We aimed to establish the cost-effectiveness of Roux-en-Y gastric bypass (RYGB), laparoscopic sleeve gastrectomy (LSG), and lifestyle nonsurgical weight loss (LNSWL) interventions in knee osteoarthritis patients with class III obesity considering TKR.

METHODS

Using the Osteoarthritis Policy model and data from published literature to derive model inputs for RYGB, LSG, LNSWL, and TKR, we assessed the long-term clinical benefits, costs, and cost-effectiveness of weight-loss interventions for patients with class III obesity considering TKR. We assessed the following strategies with a health care sector perspective: 1) no weight loss/no TKR, 2) immediate TKR, 3) LNSWL, 4) LSG, and 5) RYGB. Each weight-loss strategy was followed by annual TKR reevaluation. Primary outcomes were cost, quality-adjusted life expectancy (QALE), and incremental cost-effectiveness ratios (ICERs), discounted at 3% per year. We conducted deterministic and probabilistic sensitivity analyses to examine the robustness of conclusions to input uncertainty.

RESULTS

LSG increased QALE by 1.64 quality-adjusted life-years (QALYs) and lifetime medical costs by $17,347 compared to no intervention, leading to an ICER of $10,600/QALY. RYGB increased QALE by 0.22 and costs by $4,607 beyond LSG, resulting in an ICER of $20,500/QALY. Relative to immediate TKR, LSG and RYGB delayed and decreased TKR utilization. In the probabilistic sensitivity analysis, RYGB was cost-effective in 67% of iterations at a willingness-to-pay threshold of $50,000/QALY.

CONCLUSION

For patients with class III obesity considering TKR, RYGB provides good value while immediate TKR without weight loss is not economically efficient.

Optimising the current model of care for knee osteoarthritis with the implementation of guideline recommended non-surgical treatments: a model-based health economic evaluation

AIMS OF THE STUDY

Structured exercise, education, weight management and painkiller prescription are guideline recommended non-surgical treatments for patients suffering from knee osteoarthritis. Despite its endorsement, uptake of guideline recommended non-surgical treatments remains low. It is unknown whether the implementation of these treatments into the current model of care for knee osteoarthritis would be cost-effective from a Swiss statutory healthcare perspective. We therefore aimed to (1) assess the incremental cost-effectiveness ratio of an optimised model of care incorporating guideline recommended non-surgical treatments in adults with knee osteoarthritis and (2) the effect of total knee replacement (TKR) delay with guideline recommended non-surgical treatments on the cost-effectiveness of the overall model of care.

METHODS

A Markov model from the Swiss statutory healthcare perspective was used to compare an optimised model of care incorporating guideline recommended non-surgical treatments versus the current model of care without standardised guideline recommended non-surgical treatments. Costs were derived from two Swiss health insurers, a national database, and a reimbursement catalogue. Utility values and transition probabilities were extracted from clinical trials and national population data. The main outcome was the incremental cost-effectiveness ratio for three scenarios: "base case" (current model of care vs optimised model of care with no delay of total knee replacement), "two-year delay" (current model of care vs optimised model of care + two-year delay of total knee replacement) and "five-year delay" (current model of care vs optimised model of care + five-year delay of total knee replacement). Costs and utilities were discounted at 3% per year and a time horizon of 70 years was chosen. Probabilistic sensitivity analyses were conducted.

RESULTS

The "base case" scenario led to 0.155 additional quality-adjusted life years (QALYs) per person at an additional cost per person of CHF 341 (ICER = CHF 2,203 / QALY gained). The "two-year delay" scenario led to 0.134 additional QALYs and CHF -14 cost per person. The "five-year delay" scenario led to 0.118 additional QALYs and CHF -501 cost per person. Delay of total knee replacement by two and five years led to an 18% and 36% reduction of revision surgeries, respectively, and had a cost-saving effect.

CONCLUSION

According to this Markov model, the optimisation of the current model of care by implementing guideline recommended non-surgical treatments would likely be cost-effective from a statutory healthcare perspective. If implementing guideline recommended non-surgical treatments delays total knee replacement by two or five years, the amount of revision surgeries may be reduced.

Cost-Effectiveness of Surgical Weight-Loss Interventions for Patients With Knee Osteoarthritis and Class III Obesity

OBJECTIVE

Class III obesity (body mass index [BMI] ≥40 kg/m2 ) is associated with worse knee pain and total knee replacement (TKR) outcomes. Because bariatric surgery yields sustainable weight loss for individuals with BMI ≥40 kg/m2 , our objective was to establish the value of Roux-en-Y gastric bypass (RYGB) and laparoscopic sleeve gastrectomy (LSG) in conjunction with usual care for knee osteoarthritis (OA) patients with BMI ≥40 kg/m2 .

METHODS

We used the Osteoarthritis Policy model to assess long-term clinical benefits, costs, and cost-effectiveness of RYGB and LSG. We derived model inputs for efficacy, costs, and complications associated with these treatments from published data. Primary outcomes included quality-adjusted life-years (QALYs), lifetime costs, and incremental cost-effectiveness ratios (ICERs), all discounted at 3%/year. This analysis was conducted from a health care sector perspective. We performed sensitivity analyses to evaluate uncertainty in input parameters.

RESULTS

The usual care + RYGB strategy increased the quality-adjusted life expectancy by 1.35 years and lifetime costs by $7,209, compared to usual care alone (ICER = $5,300/QALY). The usual care + LSG strategy yielded less benefit than usual care + RYGB and was dominated. Relative to usual care alone, both usual care + RYGB and usual care + LSG reduced opioid use from 13% to 4%, and increased TKR usage from 30% to 50% and 41%, respectively. For cohorts with BMI between 38 and 41 kg/m2 , usual care + LSG dominated usual care + RYGB. In the probabilistic sensitivity analysis, at a willingness-to-pay threshold of $50,000/QALY, usual care + RYGB and usual care + LSG were cost-effective in 70% and 30% of iterations, respectively.

CONCLUSION

RYGB offers good value among knee OA patients with BMI ≥40 kg/m2 , while LSG may provide good value among those with BMI between 35 and 41 kg/m2 .

Clinical Pathways of Patients Denied Total Knee Arthroplasty Due to an Institutional BMI Cutoff

Out of concern for the increased risk of complications with morbid obesity, institutional body mass index (BMI) cutoffs for total knee arthroplasty (TKA) have become commonplace. We sought to answer the questions: what percentage of morbidly obese patients with knee osteoarthritis who present to an arthroplasty clinic will, within 2 years, undergo TKA at (1) a BMI less than 40 kg/m² or (2) at a BMI greater than 40 kg/m²? Of those who do not undergo surgery, (3) what percentage lose enough weight to become TKA-eligible, and (4) what percentage do not? We performed an observational study of 288 patients, of which 256 had complete follow-up. Institutional electronic medical record review and patient follow-up by telephone were conducted to determine which patients underwent surgery, and at what BMI. For those that did not undergo TKA, BMI was examined to see if the patient ever lost enough weight to become TKA eligible. Twelve of 256 patients (4.7%) underwent TKA at a BMI less than 40 kg/m², 64 patients (25%) underwent TKA at a BMI greater than 40 kg/m², and 7 patients (2.7%) underwent surgery at an outside hospital. The average BMI at the time of surgery was 42.3 kg/m². Thirty-seven of 256 patients (14.4%) lost enough weight to become TKA-eligible within 2 years of the initial visit but did not undergo surgery, while 136 patients (53.1%) neither underwent TKA nor became eligible. Strict enforcement of a BMI cutoff for TKA is variable among surgeons. In the absence of weight loss protocols, 19.1% of morbidly obese patients may be expected to reach the sub-40 kg/m² BMI milestone.

Timing and Type of Bariatric Surgery Preceding Total Knee Arthroplasty Leads to Similar Complications and Outcomes

BACKGROUND

No consensus exists regarding the appropriate timing of bariatric surgery (BS) or the complication profiles between Roux-en-Y Gastric Bypass (RYGB) and sleeve gastrectomy (SG) prior to total knee arthroplasty (TKA). We sought to compare 90-day medical and up to two-year surgical complications and revisions among (1) BS performed 6 months and 1 year prior to TKA; (2) between BS types (RYGB and SG) prior to TKA; and (3) with comparison to 2 non-BS cohorts of morbidly and nonmorbidly obese patients.

METHODS

We queried a national database to identify patients undergoing BS (RYGB and SG) prior to TKA from 2010 to 2020. Timing (six-month and one-year intervals) and type of BS (RYGB and SG) were identified. Cohorts without prior BS served as comparators: BMI, kg/m² > 40 and 20-35. Ninety-day to two-year medical/surgical complications and revisions were assessed. Multivariate regression analyses examined the risk factors for prosthetic joint infections (PJIs) and revisions.

RESULTS

The timing of BS (6 months and 1 year) had similar incidences of medical/surgical complications and revisions, with both lower than the BMI > 40 cohort (P < .001). Differences between types of BS were also lower than the BMI > 40 cohort (P < .001). The BMI 20-35 had lower complications and revisions among all cohorts. No differences were observed between BS timing or type as risk-factors for PJIs and revisions.

CONCLUSION

Timing (6 months or 1 year prior to TKA) and type of BS shared similar complication profiles, lower than BMI > 40 and higher than BMI 20-35. These findings support a surgeon's decision to proceed with TKA at six months post-BS if indicated.

Understanding Health Economics in Joint Replacement Surgery

The number of arthroplasty procedures has been rising at a significant rate, contributing to a notable portion of the nation's health care spending. This growth has contributed to an increase in the number of health care economic studies in the field of adult reconstruction surgery. Although these articles are filled with important information, they can be difficult to understand without a background in business or economics. The goal of this review is to define the common terminology used in health care economic studies, assess their value and benefit in the context of total joint arthroplasty, and highlight shortcomings in the current literature. [Orthopedics. 2022;45(4):e174-e182.].

Estimation of Tibiofemoral Joint Contact Forces Using Foot Loads during Continuous Passive Motions

Continuous passive motion (CPM) machines are commonly used after various knee surgeries, but information on tibiofemoral forces (TFFs) during CPM cycles is limited. This study aimed to explore the changing trend of TFFs during CPM cycles under various ranges of motion (ROM) and body weights (BW) by establishing a two-dimensional mathematical model. TFFs were estimated by using joint angles, foot load, and leg−foot weight. Eleven healthy male participants were tested with ROM ranging from 0° to 120°. The values of the peak TFFs during knee flexion were higher than those during knee extension, varying nonlinearly with ROM. BW had a significant main effect on the peak TFFs and tibiofemoral shear forces, while ROM had a limited effect on the peak TFFs. No significant interaction effects were observed between BW and ROM for each peak TFF, whereas a strong linear correlation existed between the peak tibiofemoral compressive forces (TFCFs) and the peak resultant TFFs (R2 = 0.971, p < 0.01). The proposed method showed promise in serving as an input for optimizing rehabilitation devices.

Non-ischaemic cardiomyopathy associated with elevated serum cobalt and accelerated wear of a metal-on-metal hip resurfacing

A man in his late 30s developed non-ischaemic cardiomyopathy due to systemic cobalt toxicity associated with accelerated bearing surface wear from metal-on-metal hip resurfacing implanted in the previous 6 years. Following revision arthroplasty, the patient regained baseline cardiac function. Cobalt-induced cardiomyopathy is a grave condition that deserves early consideration due to potentially irreversible morbidity. We present this case to increase awareness, facilitate early detection and emphasise the need for research into the diagnosis and management of at-risk patients.

Bariatric surgery and total knee/hip arthroplasty: an analysis of the impact of sequence and timing on outcomes

BACKGROUND

Patients with morbid obesity may require both bariatric surgery and total knee/hip arthroplasty (TKA/THA). How to sequence these two procedures with better outcomes remains largely unstudied.

METHODS

This cohort study extracted claims data on patients with an obesity diagnosis that received both bariatric surgery and TKA/THA surgery within 5 years of each other (Premier Healthcare database 2006-2019). Overall, 1894 patients received bariatric surgery before TKA or THA, while 1000 patients underwent TKA or THA before bariatric surgery. Main outcomes and measures include major complications (acute renal failure, acute myocardial infarction, other cardiovascular complications, sepsis/septic shock, pulmonary complications, pulmonary embolism, pneumonia, and central nervous system-related adverse events), postoperative intensive care unit utilization, ventilator utilization, 30-day readmission, 90-day readmission, 180-day readmission and total hospital length of stay after the second surgery. Regression models measured the association between the complications and sequence of TKA/THA and bariatric surgery.

RESULTS

Undergoing TKA/THA before bariatric surgery (compared with the reverse) was associated with higher odds of major complications (7.0% vs 1.9%; adjusted OR 4.8, 95% CI 3.1, 7.6, p<0.001). Similar patterns were also observed for intensive care unit admission, ventilator use postoperatively, 30-day, and 90-day readmissions. Patients who received a second surgery within 6 months of their first surgery exhibited worse outcomes, especially among the TKA/THA first patient cohort. Major complication incidences occurred at 20.5%, 12.5%, 5.1%, 5.0%, 5.8% and 8.5% with time between TKA/THA and bariatric surgery at <6 months, 6 months-1 year, 1-2, 2-3, 3-4 and 4-5 years, respectively.

CONCLUSIONS

Patients who require both bariatric surgery and TKA/THA should consider bariatric surgery before TKA/THA as it is associated with improved outcomes. Procedures should be staged beyond 6 months.

Cost-Effectiveness of Bariatric Surgery Prior to Posterior Lumbar Decompression and Fusion in an Obese Population with Degenerative Spondylolisthesis

STUDY DESIGN

Cost-effectiveness analysis.

OBJECTIVE

To determine if bariatric surgery prior to posterior lumbar decompression and fusion (PLDF) for degenerative spondylolisthesis (DS) is a cost-effective strategy.

SUMMARY OF BACKGROUND DATA

Obesity poses significant perioperative challenges for DS. Treated operatively, obese patients achieve worse outcomes relative to non-obese peers. Concomitantly, they fare better with surgery than with nonoperative measures. These competing facts create uncertainty in determining optimal treatment algorithms for obese patients with DS. The role of bariatric surgery merits investigation as a potentially cost-effective optimization strategy prior to PLDF.

METHODS

We simulated a Markov model with two cohorts of obese individuals with DS. 10,000 patients with body mass index (BMI) more than or equal to 30 in both arms were candidates for both bariatric surgery and PLDF. Subjects were assigned either to (1) no weight loss intervention with immediate operative or nonoperative management ("traditional arm") or (2) bariatric surgery 2 years prior to entering the same management options ("combined protocol").Published costs, utilities, and transition probabilities from the literature were applied. A willingness to pay threshold of $100,000/QALY was used. Sensitivity analyses were run for all variables to assess the robustness of the model.

RESULTS

Over a 10-year horizon, the combined protocol was dominant ($13,500 cheaper, 1.15 QALY more effective). Changes in utilities of operative and nonoperative treatments in non-obese patients, the obesity cost-multiplier, cost of bariatric surgery, and the probability of success of nonoperative treatment in obese patients led to decision changes. However, all thresholds occurred outside published bounds for these variables.

CONCLUSION

The combined protocol was less costly and more effective than the traditional protocol. Results were robust with thresholds occurring outside published ranges. Bariatric surgery is a viable, cost-effective preoperative strategy in obese patients considering elective PLDF for DS.Level of Evidence: 3.

Elevated Body Mass Index Is a Risk Factor for Failure to Achieve the Knee Disability and Osteoarthritis Outcome Score-Physical Function Short Form Minimal Clinically Important Difference Following Total Knee Arthroplasty

BACKGROUND

The aims of this study are (1) to assess the association between body mass index (BMI) and failure to achieve the 1-year Knee Disability and Osteoarthritis Outcome Score-Physical Function Short Form (KOOS-PS) minimal clinically important difference (MCID) for total knee arthroplasty (TKA) patients and (2) to determine if there is a BMI threshold beyond which the risk of failing to achieve the MCID is significantly increased.

METHODS

A regional arthroplasty registry was queried for TKA patients from 2016 to 2019 with completion of preoperative and 1-year postoperative KOOS-PS. The MCID threshold was derived using a distribution-based approach. Demographic and patient-reported outcome measure variables were collected. BMI was analyzed continuously and categorically using cutoffs defined by the Centers for Disease Control and Prevention. The association between failure to achieve 1-year MCID and BMI was analyzed using multiple logistic regression. A BMI threshold was determined using the Youden index and receiver operating characteristic curve.

RESULTS

In total, 1059 TKAs were analyzed. BMI assessed continuously was significantly associated with failure to achieve the KOOS-PS MCID (odds ratio 1.03, 95% confidence interval 1.00-1.05, P = .025). Analysis of BMI categorically revealed that "overweight" (25-30 kg/m²), "obese class I" (30-35 kg/m²), "obese class II" (35-40 kg/m²), and "obese class III" (>40 kg/m²) patients faced 77%, 76%, 83%, and 106% greater risk, respectively, of failing to achieve the KOOS-PS MCID compared to "normal BMI" (<25 kg/m²) patients.

CONCLUSION

Elevated BMI was associated with an increased risk of failure to achieve the 1-year KOOS-PS MCID following TKA.

Obesity, Bariatric Surgery, and Hip/Knee Arthroplasty Outcomes

Obesity is an independent risk factor for osteoarthritis due to mechanical and inflammatory factors. The gold-standard treatment of end-stage knee and hip osteoarthritis is total joint arthroplasty (TJA). Weight loss decreases progression of osteoarthritis and complications following TJA in patients with obesity. Bariatric surgery allows significant, sustained weight loss and comorbidity resolution in patients with morbid obesity. Existing data describing bariatric surgery on TJA outcomes are limited but suggest a benefit to bariatric surgery prior to TJA. Further studies are needed to determine optimal risk stratification, bariatric procedure selection, and timing of bariatric surgery relative to TJA.

A Literature Review and Summary Recommendations of the Impact of Bariatric Surgery on Orthopedic Outcomes

Many surgeons recommend weight loss in preparation for orthopedic procedures, yet the impact of surgically induced weight loss before orthopedic procedures is not clear. We undertook a literature review to assess the impact of bariatric surgery on the outcomes of total joint arthroplasty (TJA). We searched PubMed, Medline, Cochrane Library, and Google Scholar for studies (2010-2017) that evaluated the associations between obesity, bariatric surgery, and orthopedic surgery. Nine studies found that prior bariatric surgery decreased major and minor post-operative complications, operating room (OR) time, length of stay (LOS), risk of re-operation, and 90-day re-admissions after TJA. Two studies found that bariatric surgery patients had a higher reoperation rate for stiffness and infection as well as need for revision within 90 days after TJA. One meta-analysis found no statistically significant differences in wound infections, revisions, or mortality irrespective of bariatric surgery status; and another meta-analysis showed reduced medical complications, LOS, and OR time. Our review highlights many gaps in our knowledge and the need for additional studies to define the impact of the bariatric-first approach on TJA outcomes. We propose a framework from lessons learned to raise awareness of medical and surgical options of weight management before elective orthopedic operations in patients with obesity.

The use of tobacco is a modifiable risk factor for poor outcomes and readmissions after shoulder arthroplasty

Aims

The impact of tobacco use on readmission and medical and surgical complications has been documented in hip and knee arthroplasty. However, there remains little information about the effect of smoking on the outcome after total shoulder arthroplasty (TSA). We hypothesized that active smokers are at an increased risk of poor medical and surgial outcomes after TSA.

Methods

Data for patients who underwent arthroplasty of the shoulder in the USA between January 2011 and December 2015 were obtained from the National Readmission Database, and 90-day readmissions and complications were documented using validated coding methods. Multivariate regression analysis was performed to quantify the risk of smoking on the outcome after TSA, while controlling for patient demographics, comorbidities, and hospital-level confounding factors.

Results

A total of 196,325 non-smokers (93.1%) and 14,461 smokers (6.9%) underwent TSA during the five-year study period. Smokers had significantly increased rates of 30- and 90-day readmission (p = 0.025 and 0.001, respectively), revision within 90 days (p < 0.001), infection (p < 0.001), wound complications (p < 0.001), and instability of the prosthesis (p < 0.001). They were also at significantly greater risk of suffering from pneumonia (p < 0.001), sepsis (p = 0.001), and myocardial infarction (p < 0.001), postoperatively.

Conclusion

Smokers have an increased risk of readmission and medical and surgical complications after TSA. These risks are similar to those found for smokers after hip and knee arthroplasty. Many surgeons choose to avoid these elective procedures in patients who smoke. The increased risks should be considered when counselling patients who smoke before undertaking TSA. Cite this article: Bone Joint J 2020;102-B(11):1549–1554.

The use of tobacco is a modifiable risk factor for poor outcomes and readmissions after shoulder arthroplasty

AIMS

The impact of tobacco use on readmission and medical and surgical complications has been documented in hip and knee arthroplasty. However, there remains little information about the effect of smoking on the outcome after total shoulder arthroplasty (TSA). We hypothesized that active smokers are at an increased risk of poor medical and surgial outcomes after TSA.

METHODS

Data for patients who underwent arthroplasty of the shoulder in the USA between January 2011 and December 2015 were obtained from the National Readmission Database, and 90-day readmissions and complications were documented using validated coding methods. Multivariate regression analysis was performed to quantify the risk of smoking on the outcome after TSA, while controlling for patient demographics, comorbidities, and hospital-level confounding factors.

RESULTS

A total of 196,325 non-smokers (93.1%) and 14,461 smokers (6.9%) underwent TSA during the five-year study period. Smokers had significantly increased rates of 30- and 90-day readmission (p = 0.025 and 0.001, respectively), revision within 90 days (p < 0.001), infection (p < 0.001), wound complications (p < 0.001), and instability of the prosthesis (p < 0.001). They were also at significantly greater risk of suffering from pneumonia (p < 0.001), sepsis (p = 0.001), and myocardial infarction (p < 0.001), postoperatively.

CONCLUSION

Smokers have an increased risk of readmission and medical and surgical complications after TSA. These risks are similar to those found for smokers after hip and knee arthroplasty. Many surgeons choose to avoid these elective procedures in patients who smoke. The increased risks should be considered when counselling patients who smoke before undertaking TSA.

Bariatric Surgery Prior to Total Hip Arthroplasty Is Cost-Effective in Morbidly Obese Patients

BACKGROUND

The cost-effectiveness of bariatric surgery to achieve weight loss prior to total hip arthroplasty (THA), and decrease the complications and costs associated with THA in the morbidly obese, is unknown. This study evaluated the cost-effectiveness of bariatric surgery prior to THA for morbidly obese patients with end-stage hip osteoarthritis (OA).

METHODS

A state-transition Markov model was constructed to compare the cost-utility of 2 treatment protocols for patients with morbid obesity and end-stage hip OA: (1) immediate THA and (2) bariatric surgery 2 years prior to THA (combined protocol). The analysis was performed from both a payer and a societal perspective using direct and indirect costs over a 40-year time horizon. Utilities, associated costs, and probabilities for health state transitions were derived from the literature. One-way, 2-way and probabilistic sensitivity analyses were performed to validate the robustness of the base case results, using the standard willingness-to-pay threshold of $100,000/quality-adjusted life years.

RESULTS

From the societal perspective, the combined protocol was more effective (13.16 vs 12.26) with less cost ($91,717 vs $92,684) and thus was the dominant strategy over immediate THA. These results were stable across broad ranges for independent model variables. Monte Carlo simulation with 100,000 samples demonstrated that bariatric surgery prior to THA was the preferred cost-effective strategy over 95% of the time from both a societal and payer perspective.

CONCLUSION

In the morbidly obese patient with end-stage hip OA, bariatric surgery prior to THA is a cost-effective strategy for improving quality of life and decreasing societal and payer costs.

LEVEL OF EVIDENCE

II.

Nutritional Counseling Program for Morbidly Obese Patients Enables Weight Optimization for Safe Total Joint Arthroplasty

Obesity affects one-third of total joint arthroplasty (TJA) patients and is the most common modifiable risk factor for increased complications in the TJA population. The authors' institution implemented a body mass index (BMI) cutoff of 40 kg/m² to define appropriate TJA candidates. Patients above the cutoff were referred for nutritional counseling. The study objective was to evaluate the efficacy of this protocol in optimizing patient BMI for safe and successful TJA. Between 2016 and 2018, the authors examined 133 patients (mean age, 62.6 years) with a BMI greater than 40 kg/m² seeking TJA (94 knee, 39 hip) seen by an arthroplasty surgeon and then a dietitian. Outcomes included weight loss, change in BMI, duration of counseling, and surgical status. For postoperative patients, 90-day complications were recorded. A total of 102 (92%) patients achieved weight loss during a mean 154 days (range, 8-601 days). Patients lost a mean of 17 lb, lowering their BMI by 2.7 points (range, +6.3 to -17.7 points). Twenty-two patients discontinued nutritional counseling after 1 visit, most commonly secondary to cost when not covered by insurance. Seventy-one patients successfully underwent TJA, representing 64% of those patients who participated in nutritional counseling. Complications included delayed wound healing (n=2), periprosthetic fracture (n=2), infection (n=1), cellulitis (n=1), and peroneal nerve palsy (n=1). Surgeons must actively counsel obese patients about weight optimization as part of the preoperative standard of care. Nutritional counseling with a dietitian and follow-up with the surgeon translated to safe and successful TJA in a majority of patients. [Orthopedics. 2020;43(4):e316-e322.].

Lifestyle information and access to a commercial weight management group to promote maternal postnatal weight management and positive lifestyle behaviour: the SWAN feasibility RCT

Background

Increasing numbers of UK women have overweight or obese body mass index scores when they become pregnant, or gain excessive weight in pregnancy, increasing their risk of adverse outcomes. Failure to manage postnatal weight is linked to smoking, non-healthy dietary choices, lack of regular exercise and poorer longer-term health. Women living in areas of higher social deprivation are more likely to experience weight management problems postnatally.

Objectives

The objectives were to assess the feasibility of conducting a definitive randomised controlled trial to determine the clinical effectiveness and cost-effectiveness of lifestyle information and access to a commercial weight management group focusing on self-monitoring, goal-setting and motivation to achieve dietary change commencing 8–16 weeks postnatally to achieve and maintain weight management and positive lifestyle behaviour.

Design

The design was a randomised two-arm feasibility trial with a nested mixed-methods process evaluation.

Setting

The setting was a single centre in an inner city setting in the south of England.

Participants

Participants were women with body mass index scores of > 25 kg/m2 at antenatal ‘booking’ and women with normal body mass index scores (18.0–24.9 kg/m2) at antenatal booking who developed excessive gestational weight gain as assessed at 36 weeks’ gestation.

Main outcome measures

Recruitment, retention, acceptability of trial processes and identification of relevant economic data were the feasibility objectives. The proposed primary outcome was difference between groups in weight at 12 months postnatally, expressed as percentage weight change and weight loss from antenatal booking. Other proposed outcomes included assessment of diet, physical activity, smoking, alcohol consumption, body image, maternal esteem, mental health, infant feeding and NHS costs.

Results

Most objectives were achieved. A total of 193 women were recruited, 98 allocated to the intervention arm and 95 to the control arm. High follow-up rates (> 80%) were achieved to 12 months. There was an 8.8% difference in weight loss at 12 months between women allocated to the intervention arm and women allocated to the control arm (13.0% vs. 4.2%, respectively; p = 0.062); 47% of women in the intervention arm attended at least one weight management session, with low risk of contamination between arms. The greatest benefit was among women who attended ≥ 10 sessions. Barriers to attending sessions included capability, opportunity and motivation issues. Data collection tools were appropriate to support economic evaluation in a definitive trial, and economic modelling is feasible to quantify resource impacts and outcomes not directly measurable within a trial.

Limitations

The trial recruited from only one site. It was not possible to recruit women with normal body mass index scores who developed excessive pregnancy weight gain.

Conclusions

It was feasible to recruit and retain women with overweight or obese body mass index scores at antenatal booking to a trial comparing postnatal weight management plus standard care with standard care only and collect relevant data to assess outcomes. Approaches to recruit women with normal body mass index scores who gain excessive gestational weight need to be considered. Commercial weight management groups could support women’s weight management as assessed at 12 months postnatally, with probable greater benefit from attending ≥ 10 sessions. Process evaluation findings highlighted the importance of providing more information about the intervention on trial allocation, extended duration of time to commence sessions following birth and extended number of sessions offered to enhance uptake and retention. Results support the conduct of a future randomised controlled trial.

Trial registration

Current Controlled Trials ISRCTN39186148.

Funding

This project was funded by the National Institute for Health Research (NIHR) Public Health Research programme and will be published in full in Public Health Research; Vol. 8, No. 9. See the NIHR Journals Library website for further project information.

Preoperative Bariatric Surgery Utilization Is Associated With Increased 90-day Postoperative Complication Rates After Total Joint Arthroplasty

BACKGROUND

This study evaluates the incidence of bariatric surgery (BS) before total joint arthroplasty (TJA) in New York State and compares patient comorbidities and 90-day postoperative complications of patients with and without BS before TJA.

METHODS

The NY Statewide Planning and Research Cooperative System database between 2005 and 2014 was reviewed and 343,710 patients with TJA were identified. Patients were stratified into the following three cohorts: group 1 (patients who underwent BS < 2 years before TJA [N = 1,478]); group 2 (obese patients without preoperative BS [N = 60,259]); and group 3 (nonobese patients without preoperative BS [N = 281,973]). Principal outcomes measured were patient comorbidities, 90-day complication rates, length of inpatient stay, discharge disposition, mortality rate, and total hospital costs.

RESULTS

BS before TJA incidence increased from 0.11 of 100,000 to 2.4 of 100,000 from 2006 to 2014. Preoperative BS did not notably change the number of patient comorbidities at the time of TJA. Group 1 had more patients with 90-day complications (40.7% versus 36.0%, P < 0.001) than group 2. No difference was found between group 1 and the other groups in home discharge, pulmonary embolism, deep vein thrombosis, and mortality rates. Total hospital costs were higher for group 1 ($18,869 ± 9,022 versus $17,843 ± 8,095, P < 0.001) compared with those for group 2.

CONCLUSION

BS before TJA has increased annually over a 10-year period in New York State and is associated with greater 90-day postoperative complication rates and higher immediate hospital costs when compared with obese patients without BS.

Patterns of Weight Change and Their Effects on Clinical Outcomes Following Total Knee Arthroplasty in an Asian Population

BACKGROUND

This prospective cohort study was designed to evaluate weight change patterns and their effects on clinical outcomes following total knee arthroplasty (TKA) in the Asian population. We hypothesized that Asian patients will have a different pattern of weight change following TKA compared to Western patients and that weight loss following TKA will be associated with better clinical outcomes.

METHODS

A cohort of consecutive patients who underwent TKA from 2004 to 2015 was included. All patients received a conventional posterior-stabilized TKA implant and underwent a standard perioperative care pathway. Assessments were done preoperatively, at 6 months, and 2 years after surgery. The range of motion, Knee Society Score, Oxford Knee Score, and the Short-Form 36 questionnaire were used to assess outcomes. Height and weight of patients were recorded for body mass index (BMI) calculation. Patterns of weight loss following TKA in this cohort were charted. Clinical outcomes were then analyzed against the change in BMI.

RESULTS

A total of 602 patients (602 knees) were reviewed. Mean age was 66.39 ± 7.27 years. Mean BMI was 27.75 ± 4.51 kg/m². Overall, 63.12% of all our patients gained weight following TKA. Moreover, weight loss did not influence patients' odds for better clinical outcomes. Furthermore, patients who were in the preoperative BMI category of obese class I were more likely to gain weight as compared to those in the normal category (odds ratio 0.35, 95% confidence interval 0.2-0.61, P < .001). Moreover, older people were more likely to gain more weight compared to younger people. We also showed that the mean 2-year Knee Society Knee Score was significantly higher in the patients who gained weight while the patients who lost weight had the highest mean 2-year Oxford Knee Score and the lowest mean 2-year Knee Society Function Score.

CONCLUSION

Asians tend to gain weight following TKA. However, this weight change following TKA does not affect clinical outcomes, which remain good across all BMI groups.

LEVEL OF EVIDENCE

Therapeutic Level III.

Enhanced recovery following hip and knee arthroplasty: a systematic review of cost-effectiveness evidence

OBJECTIVES

To assess cost-effectiveness of enhanced recovery pathways following total hip and knee arthroplasties. Secondary objectives were to report on quality of studies and identify research gaps for future work.

DESIGN

Systematic review of cost-utility analyses.

DATA SOURCES

Ovid MEDLINE, Embase, the National Health Service Economic Evaluations Database and EconLit, January 2000 to August 2019.

ELIGIBILITY CRITERIA

English-language peer-reviewed cost-utility analyses of enhanced recovery pathways, or components of one, compared with usual care, in patients having total hip or knee arthroplasties for osteoarthritis.

DATA EXTRACTION AND SYNTHESIS

Data extracted by three reviewers with disagreements resolved by a fourth. Study quality assessed using the Consensus on Health Economic Criteria list, the International Society for Pharmacoeconomics and Outcomes Research and Assessment of the Validation Status of Health-Economic decision models tools; for trial-based studies the Cochrane Collaboration's tool to assess risk of bias. No quantitative synthesis was undertaken.

RESULTS

We identified 17 studies: five trial-based and 12 model-based studies. Two analyses evaluated entire enhanced recovery pathways and reported them to be cost-effective compared with usual care. Ten pathway components were more effective and cost-saving compared with usual care, three were cost-effective, and two were not cost-effective. We had concerns around risk of bias for all included studies, particularly regarding the short time horizon of the trials and lack of reporting of model validation.

CONCLUSIONS

Consistent results supported enhanced recovery pathways as a whole, prophylactic systemic antibiotics, antibiotic-impregnated cement and conventional ventilation for infection prevention. No other interventions were subject of more than one study. We found ample scope for future cost-effectiveness studies, particularly analyses of entire recovery pathways and comparison of incremental changes within pathways. A key limitation is that standard practices have changed over the period covered by the included studies.

PROSPERO REGISTRATION NUMBER

CRD42017059473.

The impact of the enhanced recovery pathway and other factors on outcomes and costs following hip and knee replacement: routine data study

Background

There is limited evidence concerning the effectiveness of enhanced recovery programmes in hip and knee replacement surgery, particularly when applied nationwide across a health-care system.

Objectives

To determine the effect of hospital organisation, surgical factors and the enhanced recovery after surgery pathway on patient outcomes and NHS costs of hip and knee replacement.

Design

(1) Statistical analysis of national linked data to explore geographical variations in patient outcomes of surgery. (2) A natural experimental study to determine clinical effectiveness of enhanced recovery after surgery. (3) A qualitative study to identify barriers to, and facilitators of, change. (4) Health economics analysis to establish NHS costs and cost-effectiveness.

Setting

Data from the National Joint Registry, linked to English Hospital Episode Statistics and patient-reported outcome measures in both the geographical variation and natural experiment studies, together with the economic evaluation. The ethnographic study took place in four hospitals in a region of England.

Participants

Qualitative study – 38 health professionals working in hip and knee replacement services in secondary care and 37 patients receiving hip or knee replacement.

Interventions

Natural experiment – implementation of enhanced recovery after surgery at each hospital between 2009 and 2011. Enhanced recovery after surgery is a complex intervention focusing on several areas of patients’ care pathways through surgery: preoperatively (patient is in best possible condition for surgery), perioperatively (patient has best possible management during and after operation) and postoperatively (patient experiences best rehabilitation).

Main outcome measures

Patient-reported pain and function (Oxford Hip Score/Oxford Knee Score); 6-month complications; length of stay; bed-day costs; and revision surgery within 5 years.

Results

Geographical study – there are potentially unwarranted variations in patient outcomes of hip and knee replacement surgery. This variation cannot be explained by differences in patients, case mix, surgical or hospital organisational factors. Qualitative – successful implementation depends on empowering patients to work towards their recovery, providing post-discharge support and promoting successful multidisciplinary team working. Care processes were negotiated between patients and health-care professionals. ‘Good care’ remains an aspiration, particularly in the post-discharge period. Natural experiment – length of stay has declined substantially, pain and function have improved, revision rates are in decline and complication rates remain stable. The introduction of a national enhanced recovery after surgery programme maintained improvement, but did not alter the rate of change already under way. Health economics – costs are high in the year of joint replacement and remain higher in the subsequent year after surgery. There is a strong economic incentive to identify ways of reducing revisions and complications following joint replacement. Published cost-effectiveness evidence supports enhanced recovery pathways as a whole.

Limitations

Short duration of follow-up data prior to enhanced recovery after surgery implementation and missing data, particularly for hospital organisation factors.

Conclusion

No evidence was found to show that enhanced recovery after surgery had a substantial impact on longer-term downwards trends in costs and length of stay. Trends of improving outcomes were seen across all age groups, in those with and without comorbidity, and had begun prior to the formal enhanced recovery after surgery roll-out. Reductions in length of stay have been achieved without adversely affecting patient outcomes, yet, substantial variation remains in outcomes between hospital trusts.

Future work

There is still work to be done to reduce and understand unwarranted variations in outcome between individual hospitals.

Study registration

This study is registered as PROSPERO CRD42017059473.

Funding

This project was funded by the National Institute for Health Research (NIHR) Health Services and Delivery Research programme and will be published in full in Health Services and Delivery Research; Vol. 8, No. 4. See the NIHR Journals Library website for further project information.

Ninety-day and one-year healthcare utilization and costs after knee arthroplasty

OBJECTIVES

This study examined ninety-day and one-year postoperative healthcare utilization and costs following total knee arthroplasty (TKA) from the health sector and patient perspectives.

DESIGN

This study relied on: 1) patient-reported medical resource utilization data from diaries in the Knee Arthroplasty Pain Coping Skills Training (KASTPain) trial; and 2) Medicare fee schedules. Medicare payments, patient cost-sharing, and patient time costs were estimated. Generalized linear mixed models were used to identify baseline predictors of costs.

RESULTS

In the first ninety days following TKA, patients had an average of 29.7 outpatient visits and 6% were hospitalized. Mean total costs during this period summed to $3,720, the majority attributed to outpatient visit costs (84%). Over the year following TKA, patients had an average of 48.9 outpatient visits, including 33.2 for physical therapy. About a quarter (24%) of patients were hospitalized. Medical costs were incurred at a decreasing rate, from $2,428 in the first six weeks to $648 in the last six weeks. Mean total medical costs across all patients over the year were $8,930, including $5,328 in outpatient costs. Total costs were positively associated with baseline Charlson comorbidity score (P < 0.01). Outpatient costs were positively associated with baseline Charlson comorbidity score (P = 0.03) and a bodily pain burden summary score (P < 0.01). Mean patient cost-sharing summed to $1,342 and time costs summed to $1,346.

CONCLUSIONS

Costs in the ninety days and year after TKA can be substantial for both healthcare payers and patients. These costs should be considered as payers continue to explore alternative payment models.

Cost-Effectiveness of Total Hip Arthroplasty Versus Nonoperative Management in Normal, Overweight, Obese, Severely Obese, Morbidly Obese, and Super Obese Patients: A Markov Model

BACKGROUND

We estimated the cost-effectiveness of performing total hip arthroplasty (THA) vs nonoperative management (NM) among 6 body mass index (BMI) cohorts.

METHODS

We constructed a state-transition Markov model to compare the cost utility of THA and NM in the 6 BMI groups over a 15-year period. Model parameters for transition probability (risk of revision, re-revision, and 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 vs NM. One-way and Monte Carlo probabilistic sensitivity analyses of the model parameters were performed to determine the robustness of the model.

RESULTS

Over the 15-year time period, the ICERs for THA vs NM were the following: normal weight ($6043/QALYs [quality-adjusted life years]), overweight ($5770/QALYs), obese ($5425/QALYs), severely obese ($7382/QALYs), morbidly obese ($8338/QALYs), and super obese ($16,651/QALYs). The 2 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/QALYs.

CONCLUSION

Even at a willingness-to-pay threshold of $50,000/QALYs, which is considered low for the United States, our model showed that THA would be cost-effective for all obesity levels. BMI cut-offs for THA may lead to unnecessary loss of healthcare access.

Bariatric surgery, lifestyle interventions and orlistat for severe obesity: the REBALANCE mixed-methods systematic review and economic evaluation

BACKGROUND

Adults with severe obesity [body mass index (BMI) of ≥ 35 kg/m2] have an increased risk of comorbidities and psychological, social and economic consequences.

OBJECTIVES

Systematically review bariatric surgery, weight-management programmes (WMPs) and orlistat pharmacotherapy for adults with severe obesity, and evaluate the feasibility, acceptability, clinical effectiveness and cost-effectiveness of treatment.

DATA SOURCES

Electronic databases including MEDLINE, EMBASE, PsycINFO, the Cochrane Central Register of Controlled Trials and the NHS Economic Evaluation Database were searched (last searched in May 2017).

REVIEW METHODS

Four systematic reviews evaluated clinical effectiveness, cost-effectiveness and qualitative evidence for adults with a BMI of ≥ 35 kg/m2. Data from meta-analyses populated a microsimulation model predicting costs, outcomes and cost-effectiveness of Roux-en-Y gastric bypass (RYGB) surgery and the most effective lifestyle WMPs over a 30-year time horizon from a NHS perspective, compared with current UK population obesity trends. Interventions were cost-effective if the additional cost of achieving a quality-adjusted life-year is < £20,000-30,000.

RESULTS

A total of 131 randomised controlled trials (RCTs), 26 UK studies, 33 qualitative studies and 46 cost-effectiveness studies were included. From RCTs, RYGB produced the greatest long-term weight change [-20.23 kg, 95% confidence interval (CI) -23.75 to -16.71 kg, at 60 months]. WMPs with very low-calorie diets (VLCDs) produced the greatest weight loss at 12 months compared with no WMPs. Adding a VLCD to a WMP gave an additional mean weight change of -4.41 kg (95% CI -5.93 to -2.88 kg) at 12 months. The intensive Look AHEAD WMP produced mean long-term weight loss of 6% in people with type 2 diabetes mellitus (at a median of 9.6 years). The microsimulation model found that WMPs were generally cost-effective compared with population obesity trends. Long-term WMP weight regain was very uncertain, apart from Look AHEAD. The addition of a VLCD to a WMP was not cost-effective compared with a WMP alone. RYGB was cost-effective compared with no surgery and WMPs, but the model did not replicate long-term cost savings found in previous studies. Qualitative data suggested that participants could be attracted to take part in WMPs through endorsement by their health-care provider or through perceiving innovative activities, with WMPs being delivered to groups. Features improving long-term weight loss included having group support, additional behavioural support, a physical activity programme to attend, a prescribed calorie diet or a calorie deficit.

LIMITATIONS

Reviewed studies often lacked generalisability to UK settings in terms of participants and resources for implementation, and usually lacked long-term follow-up (particularly for complications for surgery), leading to unrealistic weight regain assumptions. The views of potential and actual users of services were rarely reported to contribute to service design. This study may have failed to identify unpublished UK evaluations. Dual, blinded numerical data extraction was not undertaken.

CONCLUSIONS

Roux-en-Y gastric bypass was costly to deliver, but it was the most cost-effective intervention. Adding a VLCD to a WMP was not cost-effective compared with a WMP alone. Most WMPs were cost-effective compared with current population obesity trends.

FUTURE WORK

Improved reporting of WMPs is needed to allow replication, translation and further research. Qualitative research is needed with adults who are potential users of, or who fail to engage with or drop out from, WMPs. RCTs and economic evaluations in UK settings (e.g. Tier 3, commercial programmes or primary care) should evaluate VLCDs with long-term follow-up (≥ 5 years). Decision models should incorporate relevant costs, disease states and evidence-based weight regain assumptions.

STUDY REGISTRATION

This study is registered as PROSPERO CRD42016040190.

FUNDING

The National Institute for Health Research Health Technology Assessment programme. The Health Services Research Unit and Health Economics Research Unit are core funded by the Chief Scientist Office of the Scottish Government Health and Social Care Directorate.

Orthopaedic Surgery Residency Training: Consideration for a Surgical and Procedural Skills Competency

This perspectives report discusses the need to create a surgical and procedural skills competency for orthopedic surgery residency training programs.

The Role of Bariatric Surgery in the Obese Total Joint Arthroplasty Patient

Although bariatric surgery is a proven means of weight loss and treatment of obesity-related comorbidities in morbidly obese patients, it is not yet clear how it affects outcomes after total joint arthroplasty in this high-risk patient population. This article explores the effects of obesity and bariatric surgery on osteoarthritis and total joint arthroplasty, and also discusses the financial and ethical implications of use of bariatric surgery for risk reduction before total joint arthroplasty.

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

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSION

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

Cost-Effectiveness of Total Knee Arthroplasty vs Nonoperative Management in Normal, Overweight, Obese, Severely Obese, Morbidly Obese, and Super-Obese Patients: A Markov Model

BACKGROUND

We estimated the cost-effectiveness of performing total knee arthroplasty (TKA) vs nonoperative management (NM) among 6 body mass index (BMI) cohorts.

METHODS

A Markov model was used to compare the cost-utility of TKA and NM in 6 BMI groups (nonobese [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) over a 15-year period. Model parameters for transition probability (ie, revision, re-revision, death), utility, and costs were estimated from the literature. Direct medical costs but not indirect societal costs were included in the model. Costs and utilities were discounted 3% annually. The primary outcome was the incremental cost-effectiveness ratio (ICER) of TKA vs NM. One-way and probabilistic sensitivity analyses of the model parameters were performed to determine the robustness of the model.

RESULTS

Over the 15-year period, the ICERs for the TKA vs NM for the different BMI categories were nonobese ($3317/quality-adjusted life years [QALYs]), overweight ($2837/QALY), obese ($2947/QALY), severely obese ($3536/QALY), morbidly obese ($5531/QALY), and super-obese ($11,878/QALY). The higher BMI groups tended to have higher incremental QALYs and also higher incremental costs. The probabilistic sensitivity analysis with an ICER threshold of $30,000/QALY showed that TKA would be cost-effective in 100% of simulations of patients with a BMI<50 and 99.16% of super-obese simulations.

CONCLUSION

While performing TKA on super-obese patients is more expensive, the substantial improvements in patient outcomes make it cost-effective. Therefore, withholding TKA care based on a BMI would lead to an unjustified loss of health-care access.

Alpha-defensin and the Synovasure lateral flow device for the diagnosis of prosthetic joint infection: a systematic review and meta-analysis

Aims

The aim of this review was to evaluate the available literature and to calculate the pooled sensitivity and specificity for the different alpha-defensin test systems that may be used to diagnose prosthetic joint infection (PJI).

Materials and Methods

Studies using alpha-defensin or Synovasure (Zimmer Biomet, Warsaw, Indiana) to diagnose PJI were identified from systematic searches of electronic databases. The quality of the studies was evaluated using the Quality Assessment of Studies of Diagnostic Accuracy (QUADAS) tool. Meta-analysis was completed using a bivariate model.

Results

A total of 11 eligible studies were included. The median QUADAS score was 13 (interquartile range 13 to 13) out of 14. Significant conflicts of interest were identified in five studies. The pooled sensitivity for the laboratory alpha-defensin test was 0.95 (95% confidence interval (CI) 0.91 to 0.98) and the pooled specificity was 0.97 (95% CI 0.95 to 0.98) for four studies with a threshold level of 5.2 mgl-1 The pooled sensitivity for the lateral flow cassette test was 0.85 (95% CI 0.74 to 0.92) and the pooled specificity was 0.90 (95% CI 0.91 to 0.98). There was a statistically significant difference in sensitivity (p = 0.019), but not specificity (p = 0.47).

Conclusion

Laboratory-based alpha-defensin testing remains a promising tool for diagnosing PJI. The lateral flow cassette has a significantly lower performance and pooled results are comparable to the leucocyte esterase test. Further studies are required before the widespread adoption of the lateral flow cassette alpha-defensin test. Cite this article: Bone Joint J 2018;100-B:703-11.

A Bundle Protocol to Reduce the Incidence of Periprosthetic Joint Infections After Total Joint Arthroplasty: A Single-Center Experience

BACKGROUND

Periprosthetic joint infection (PJI) represents a devastating complication of total hip arthroplasty (THA) or total knee arthroplasty (TKA). Modifiable patient risk factors as well as various intraoperative and postoperative variables have been associated with risk of PJI. In 2011, our institution formulated a "bundle" to optimize patient outcomes after THA and TKA. The purpose of this report is to describe the "bundle" protocol we implemented for primary THA and TKA patients and to analyze its impact on rates of PJI and readmission.

METHODS

Our bundle protocol for primary THA and TKA patients is conceptually organized about 3 chronological periods of patient care: preoperative, intraoperative, and postoperative. The institutional total joint database and electronic medical record were reviewed to identify all primary THAs and TKAs performed in the 2 years before and following implementation of the bundle. Rates of PJI and readmission were then calculated.

RESULTS

Thirteen of 908 (1.43%) TKAs performed before the bundle became infected compared to only 1 of 890 (0.11%) TKAs performed after bundle implementation (P = .0016). Ten of 641 (1.56%) THAs performed before the bundle became infected, which was not statistically different from the 4 of 675 (0.59%) THAs performed after the bundle that became infected (P = .09).

CONCLUSION

The bundle protocol we describe significantly reduced PJIs at our institution, which we attribute to patient selection, optimization of modifiable risk factors, and our perioperative protocol. We believe the bundle concept represents a systematic way to improve patient outcomes and increase value in total joint arthroplasty.