Bariatric surgery does not improve outcomes in patients undergoing primary total knee arthroplasty

Nutritional Considerations in Hip and Knee Arthroplasty: A Critical Analysis of Current Evidence

» Initial screening for malnutrition can be initiated with a fibrinogen-albumin ratio threshold <11.7.» Protein supplementation to goal (1.2-1.9 g/kg), along with essential amino acid augmented with beta-hydroxy-beta-methylbutyrate and resistance training have shown benefit, especially in sarcopenic patients.» Omega-3 and omega-6 polyunsaturated fatty acid supplementation has a strong antioxidant role and gain of muscle mass.» Supplementation with adenosine triphosphate and magnesium sulfate provides an avenue to decrease postoperative pain and opioid consumption.» Motivational interviewing and multidisciplinary teams to achieve preoperative weight loss >20 lbs in morbidly obese patients can decrease complication rates.

Prior Bariatric Surgery Is Associated With Improved Total Hip Arthroplasty Outcomes in Patients Who Have Obesity: A National Cohort Study With 6 Years of Follow-Up

BACKGROUND

Obesity is a risk factor for end-stage hip osteoarthritis. While total hip arthroplasty (THA) is commonly performed to reduce pain and improve function associated with osteoarthritis, obesity has been associated with an increased risk of complications after THA. Although bariatric surgery may also be utilized to reduce weight, the impact of bariatric surgery on THA outcomes remains inadequately understood.

METHODS

This retrospective cohort analysis utilized multicenter electronic medical record data ranging from 2003 to 2023. Patients who have obesity who underwent THA were stratified based on prior bariatric surgery. The final bariatric cohort comprised 451 patients after propensity score matching. Complication rates and revision risks were compared between cohorts at 6, 24, and 72 months. Additional analysis stratified patients by interval between bariatric surgery and THA.

RESULTS

At 6-month follow-up, the bariatric cohort had significantly lower risks of surgical site infection, wound dehiscence, and deep vein thrombosis (DVT). At 24 months, the bariatric cohort had a lower risk of DVT. At 72-month follow-up, the bariatric cohort had reduced rates of revision, mortality, cardiac morbidity, and Clavien-Dindo grade IV complications.

CONCLUSIONS

Obese patients who underwent bariatric surgery prior to THA experienced reduced medical complications at all time points and reduced rates of revision at 72 months relative to a matched cohort who did not undergo bariatric surgery.

Total Knee Arthroplasty With or Without Prior Bariatric Surgery: A Systematic Review and Meta-Analysis

BACKGROUND

Studies comparing the outcomes of bariatric surgery followed by total knee arthroplasty (TKA) versus TKA alone in obese patients have disparate results. This systematic review and meta-analysis sought to compare TKA with and without prior bariatric surgery in obese patients.

METHODS

MEDLINE, PubMed, and Embase were searched from inception to April 9, 2023. There were twelve included studies that yielded 2,876,547 patients, of whom 62,818 and 2,813,729 underwent TKA with and without prior bariatric surgery, respectively. Primary outcomes were medical complications (ie, urinary tract infection, pneumonia, renal failure, respiratory failure, venous thromboembolism [VTE], arrhythmia, myocardial infarction, and stroke); surgical complications (ie, wound complications [eg, infection, hematoma, dehiscence, delayed wound healing, and seroma], periprosthetic joint infection, mechanical complications, periprosthetic fracture, knee stiffness, and failed hardware); revision, and mortality. Secondary outcomes were blood transfusion, length of stay (day), and readmission.

RESULTS

The odds ratios (OR) of 90-day VTE (OR = 0.75 [0.66, 0.85], P < .00001), 90-day stroke (OR = 0.58 [0.41, 0.81], P = .002), and 1-year periprosthetic fracture (OR = 0.74 [0.55, 0.99], P = .04) were lower in those who underwent bariatric surgery before TKA. Although the mean difference in hospital stays (-0.19 days [-0.23, -0.15], P < .00001) was statistically less in those who underwent bariatric surgery before TKA, it was not clinically relevant. The other outcomes were similar between the groups.

CONCLUSIONS

Bariatric surgery before TKA is beneficial in terms of a lower risk of VTE, stroke, and periprosthetic fracture. This analysis suggests surgeons consider discussing bariatric surgery before TKA in obese patients, especially those who are at risk of VTE and stroke.

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.

Cemented vs. Cementless Fixation in Primary Knee Replacement: A Narrative Review

Knee osteoarthritis (OA) is one of the leading causes of disability around the globe. Osteoarthritis is mainly considered a disease affecting the elderly. However, more and more studies show that sports overuse, obesity, or congenital disorders can initiate a pathologic cascade that leads to OA changes in the younger population. Nevertheless, OA mostly affects the elderly, and with increasing life expectancy, the disease will develop in more and more individuals. To date, the golden standard in the treatment of the end-stage of the disease is total joint replacement (TJR), which restores painless knee motion and function. One of the weakest elements in TJR is its bonding with the bone, which can be achieved by bonding material, such as poly methyl-methacrylate (PMMA), or by cementless fixation supported by bone ingrowth onto the endoprosthesis surface. Each technique has its advantages; however, the most important factor is the revision rate and survivor time. In the past, numerous articles were published regarding TJR revision rate, but no consensus has been established yet. In this review, we focused on a comparison of cemented and cementless total knee replacement surgeries. We introduced PICO rules, including population, intervention, comparison and outcomes of TJR in a PubMed search. We identified 783 articles published between 2010 and 2023, out of which we included 14 in our review. Our review reveals that there is no universally prescribed approach to fixate knee prostheses. The determination of the most suitable method necessitates an individualized decision-making process involving the active participation and informed consent of each patient.

Go Big or Go Home: Obesity and Total Joint Arthroplasty

Obesity is highly prevalent, and it is expected to grow considerably in the United States. The association between obesity and an increased risk of complications following total joint arthroplasty (TJA) is widely accepted. Many believe that patients with body mass index (BMI) >40 have complications rates that may outweigh the benefits of surgery and should consider delaying it. However, the current literature on obesity and outcomes following TJA is observational, very heterogeneous, and full of confounding variables. BMI in isolation has several flaws and recent literature suggests shifting from an exclusively BMI <40 cutoff to considering 5 to 10% preoperative weight loss. BMI cutoffs to TJA may also restrict access to care to our most vulnerable, marginalized populations. Moreover, only roughly 20% of patients instructed to lose weight for surgery are successful and the practice of demanding mandatory weight loss needs to be reconsidered until convincing evidence exists that supports risk reduction as a result of preoperative weight loss. Obese patients can benefit greatly from this life-changing procedure. When addressing the potential difficulties and by optimizing preoperative assessment and intraoperative management, the surgery can be conducted safely. A multidisciplinary patient-centered approach with patient engagement, shared decision-making, and informed consent is recommended.

Stemmed Versus Nonstemmed Tibia in Primary Total Knee Arthroplasty: A Similar Pattern of Aseptic Tibial Loosening in Obese Patients with Moderate Varus. 5-Year Outcomes of a Randomized Controlled Trial

Obesity is linked to early tibial tray failure after primary total knee arthroplasty (TKA) for osteoarthritis (OA), especially in patients with preoperative varus. This study compared standard and stemmed tibiae TKAs in patients with class I and II obesity with varus deformity. Between April 2013 and June 2020, a prospective study was conducted including patients with end-stage OA, body mass index between 30 and 40 kg/m2, and varus <15 degrees. Patients were randomly assigned to TKAs with either standard or long-stemmed tibiae and evaluated 5 years after surgery using the Knee Society Scoring (KSS). The knee society and modified radiographic evaluation systems were used for radiological evaluation. In total, 264 TKAs were performed in 264 patients (134 in the standard group and 130 in the stemmed group). The mean preoperative hip-knee-ankle angles for the standard and stemmed groups were 8.2 ± 3.2 degrees/varus and 9 ± 2.9 degrees/varus, respectively (p = 0.2), which improved to 5.1 ± 3 degrees/valgus and 5 ± 3.5 degrees/valgus after surgery (p = 0.52). There was no statistically significant difference between the objective KSS (92 vs. 92.9; p = 0.84) and the functioning KSS (73.4 vs. 74.8; p = 0.28). There were no aseptic loosening cases or radiographic differences. In-group analysis revealed significant outcomes differences in both groups if preoperative varus was >10 degrees irrespective of the stem design (p < 0.0001). Complications occurred in two patients; one with a late infection and one had a stem-related tibial fracture. Standard tibia TKAs yielded comparable results in obese patients to long-stemmed tibias. No aseptic tibial loosening was observed regardless of stem type, and worse clinical outcomes were associated with greater varus. CLINICAL TRIAL REGISTRY::  registered at http://www.researchregistry.com (researchregistry5717).LEVEL OF EVIDENCE: II; a prospective randomized trial.

A Radiographic Abdominal Pannus Sign is Associated With Postoperative Complications in Anterior THA

BACKGROUND

Numerous studies have shown that elevated BMI is associated with adverse outcomes in THA; however, BMI alone does not adequately represent a patient's adipose and soft tissue distribution, especially when the direct-anterior approach is evaluated. Local soft tissue and adipose, especially in the peri-incisional region, has an unknown impact on patient outcomes after direct-anterior THA. Moreover, there is currently no known evaluation method to estimate the quantity of local soft tissue and adipose tissue. The current study introduced a new radiographic parameter that is measurable on supine AP radiographs: the abdominal pannus sign.

QUESTION/PURPOSE

Are patients who have an abdominal pannus extending below the upper (cephalad) border of the symphysis pubis more likely to experience problems after anterior-approach THA that are plausibly associated with that finding, including infections resulting in readmission, wound complications resulting in readmission, fractures, or longer surgical time, than patients who do not demonstrate this radiographic sign?

METHODS

Between 2015 and 2020, five surgeons performed 727 primary direct-anterior THAs. After exclusion criteria were applied, 596 procedures were included. Of those, we obtained postoperative radiographs in the postanesthesia care unit in 100% of procedures (596 of 596), and 100% of radiographs (596) were adequate for review in this retrospective study. The level of the pannus in relation to the pubic symphysis was assessed on immediate supine postoperative AP radiographs of the pelvis: above (pannus sign 1), between the upper and lower borders (pannus sign 2), or below the level of the pubic symphysis (pannus sign 3). In this study, we combined pannus signs 2 and 3 into a single group for analysis not only because there was a limited number of patients in each group, but also because there was no statistically significant difference between the two groups. Pannus sign 1 was identified in 82% of procedures (486 of 596), and pannus sign ≥ 2 was identified in 18% (110). We compared the groups (pannus sign 1 versus pannus sign ≥ 2) in terms of the percentage of patients who experienced problems within 90 days of THA that might be associated with that physical finding, including infections resulting in readmission including subcutaneous, subfascial, and prosthetic joint infections; wound complications resulting in readmission, defined as dehiscence or delayed healing; and all fractures, and we compared the groups in terms of surgical time-that is, the cut-to-close time.

RESULTS

Patients with a pannus sign of ≥ 2 were more likely than those with a pannus sign of 1 to have a postoperative infection (6.4% [seven of 110 procedures] versus 0.6% [three of 486], odds ratio 10.96 [95% confidence interval (CI) 2.83 to 42.38]; p < 0.01), wound complications (0.9% [one of 110] versus 0% [0 of 486] with an infinite odds ratio [95% CI indeterminate]; p = 0.18), and fractures (4.5% [five of 110] versus 0% [0 of 486], with an infinite odds ratio [95% CI indeterminate]; p < 0.01). The mean surgical time was longer in patients with a pannus sign of ≥ 2 than it was in those with a pannus sign of 1 (128 ± 25.3 minutes versus 118 ± 27.5 minutes, mean difference 10 minutes; p < 0.01).

CONCLUSION

Based on these findings, patients who have an abdominal pannus that extends below the upper (cephalad) edge of the pubic symphysis are at an increased risk of experiencing serious surgical complications. If THA is planned in these patients, an approach other than the direct-anterior approach should be considered. Surgeons performing THA who do not obtain supine radiographs preoperatively should use a physical examination to evaluate for this finding, and if it is present, they should use an approach other than the direct-anterior approach to minimize the risk of these complications. Future studies might compare the abdominal pannus sign using standing radiographs, which are used more often, with other well-documented associated risk factors such as elevated BMI or higher American Society of Anesthesiologists classification.

LEVEL OF EVIDENCE

Level III, retrospective cohort study.

Total Hip and Knee Arthroplasty Surgery in the Morbidly Obese Patient: A Critical Analysis Review

»

Obesity, defined as body mass index (BMI) ≥30, is a serious public health concern associated with an increased incidence of stroke, diabetes, mental illness, and cardiovascular disease resulting in numerous preventable deaths yearly.

»

From 1999 through 2018, the age-adjusted prevalence of morbid obesity (BMI ≥40) in US adults aged 20 years and older has risen steadily from 4.7% to 9.2%, with other estimates showing that most of the patients undergoing hip and knee replacement by 2029 will be obese (BMI ≥30) or morbidly obese (BMI ≥40).

»

In patients undergoing total joint arthroplasty (TJA), morbid obesity (BMI ≥40) is associated with an increased risk of perioperative complications, including prosthetic joint infection and mechanical failure necessitating aseptic revision.

»

The current literature on the role that bariatric weight loss surgery before TJA has on improving surgical outcomes is split and referral to a bariatric surgeon should be a shared-decision between patient and surgeon on a case-by-case basis.

»

Despite the increased risk profile of TJA in the morbidly obese cohort, these patients consistently show improvement in pain and physical function postoperatively that should be considered when deciding for or against surgery.

Bariatric surgery, osteoarthritis and arthroplasty of the hip and knee in Swedish Obese Subjects - up to 31 years follow-up of a controlled intervention study

OBJECTIVE

To study the long-term effect of obesity and bariatric surgery on incidences of osteoarthritis and arthroplasty of hip and knee.

DESIGN

Hazard ratios (HR) and incidence rates (IR) of osteoarthritis and arthroplasty of hip and knee were studied in the prospective, controlled, non-randomized Swedish Obese Subjects (SOS) study (bariatric surgery group, n = 2007; matched controls given usual obesity care, n = 2040) and the SOS reference cohort (n = 1135, general population). Osteoarthritis diagnosis and arthroplasty for osteoarthritis were captured from the National Swedish Patient Register. Median follow-up time was 21.2 (IQR 16.4-24.8), 22.9 (IQR 19.1-25.7), and 20.1 years (IQR 18.7-20.9) for the control group, surgery group and reference cohort, respectively.

RESULTS

The surgery group displayed lower incidence of hip osteoarthritis (IR 5.3, 95% CI 4.7-6.1) compared to controls (IR 6.6, 95% CI 5.9-7.5, adjHR 0.83, 95% CI 0.69-1.00) but similar incidence of hip arthroplasty. Similar incidence of knee osteoarthritis was observed in the surgery group and controls, but knee arthroplasty was more common in the surgery group (IR 7.4, 95% CI 6.6-8.2 and 5.6, 95% CI 4.9-6.4, adjHR 1.45, 95% CI 1.22-1.74). The reference cohort displayed lower incidences of osteoarthritis and arthroplasty of hip and knee compared with the surgery group and controls.

CONCLUSION

Bariatric surgery did not normalize the increased risk of knee and hip osteoarthritis in patients with obesity but was associated with an increased incidence of knee arthroplasty compared to the control group. With the limitations inherent to the present data, additional studies are needed to confirm these results.

TRIAL REGISTRATION

clinicaltrials.gov Identifier: NCT01479452.

Functional recovery after total hip/knee replacement in obese people: A systematic review

OBJECTIVE

Several studies have investigated the influence of body mass index (BMI) on functional gain after total hip replacement (THR) or total knee replacement (TKR) in osteoarthritis, with contradictory results. This systematic literature review was conducted to ascertain whether obesity affects functional recovery after THR or TKR in the short (<1 year), medium (<3 years) and long term (>3 years).

METHODS

The study was registered with PROSPERO and conducted according to the PRISMA guidelines. A systematic literature search was conducted across Medline and EMBASE databases for articles published between 1980 and 2020 that investigated patient-reported measures of functional recovery after THR and TKR in participants with osteoarthritis and obesity (defined as BMI ≥30 kg/m²).

RESULTS

Twenty-six articles reporting on 68,840 persons (34,955 for THR and 33,885 for TKR) were included in the final analysis: 5 case-control studies, 21 cohort studies (9 for THR only, 10 for TKR only and 2 for both). The average minimum follow-up was 36.4 months, ranging from 6 weeks to 10 years. Most studies found significantly lower pre-operative patient-reported functional scores for participants with obesity. After THR, there was a small difference in functional recovery in favor of those without obesity in the short term (<6 months), but the difference remained below the minimal clinically important difference (MCID) threshold and disappeared in the medium and long term. After TKR, functional recovery was better for those with obesity than those without in the first year, similar until the third year, and then decreased thereafter.

CONCLUSIONS

Although there is a paucity of high-quality evidence, our findings show substantial functional gains in people with obesity after total joint replacement. Functional recovery after THR or TKR does not significantly differ, or only slightly differs, between those with and without obesity, and the difference in functional gain is not clinically important.

PROSPERO NUMBER

CRD42018112919.

Information and BMI limits for patients with obesity eligible for knee arthroplasty: the Swedish surgeons' perspective from a nationwide cross-sectional study

BACKGROUND

In the past decades, the incidence of obesity has increased worldwide. This disease is often accompanied with several comorbidities and therefore, surgeons and anesthesiologists should be prepared to provide optimal management for these patients. The aim of this descriptive cross-sectional study was to map the criteria and routines that are used by Swedish knee arthroplasty surgeons today when considering patients with obesity for knee arthroplasty.

METHODS

A survey including 21 items was created and sent to all the Swedish centers performing knee arthroplasty. The survey included questions about the surgeons' experience, hospital routines of preoperative information given and the surgeons' individual assessment of patients with obesity that candidates for knee arthroplasty. Descriptive statistics were used to present the data.

RESULTS

A total of 203 (64%) knee surgeons responded to the questionnaire. Almost 90% of the surgeons claimed to inform their patients with obesity that obesity has been associated with an increased risk of complications after knee arthroplasty. Seventy-nine percent reported that they had an upper BMI limit to perform knee arthroplasty, a larger proportion of the private centers had a BMI limit compared to public centers. The majority of the centers had an upper BMI limit of 35.

CONCLUSION

The majority of the knee arthroplasty surgeons in Sweden inform their patients with obesity regarding risks associated with knee arthroplasty. Most centers that perform knee arthroplasties in Sweden have an upper BMI limit.

Does bariatric surgery really benefit patients before total knee arthroplasty? A systematic review and meta-analysis

PURPOSE

At present, whether bariatric surgery before total knee arthroplasty (TKA) affects the prognosis of subsequent TKA has been a topic of debate in the academic community. The primary purpose of this systematic review and meta-analysis was to investigate the effect of previous bariatric surgery on prosthetic revisions and postoperative complications after TKA.

METHODS

We included prospective and observational studies published in English involving patients who had undergone bariatric surgery prior to TKA and compared them with morbidly obese patients with no history of bariatric surgery. The Newcastle-Ottawa Scale was used to assess the methodological quality of non-randomized case-control studies. The outcomes included revisions, infections, venous thromboembolism (VTE), blood transfusion, mortality, stiffness or manipulation under anesthesia (MUA), and medical complications.

RESULTS

Of the 9 included studies with 166047 patients, 4 were matched cohort studies, 2 were unmatched cohort, and 3 were database studies. Methodological quality was high in ten studies and moderate in thirteen studies. Our analysis demonstrated that patients with TKA who had undergone prior bariatric surgery were associated with increased risks of long-term revision, long-term infection, long-term stiffness or MUA and blood transfusions, whereas prior bariatric surgery did not increase the risk of short-term complications and short-term revision.

CONCLUSION

This meta-analysis highlights the risks of bariatric surgery prior to TKA and suggests that prior bariatric surgery may increase the risk of perioperative blood transfusion and also the risk of revision and infection in long-term follow-up. Surgeons can use this information to help counsel patients undergoing bariatric surgery before primary TKA.

Frank Stinchfield Award: Does Bariatric Surgery Prior to Primary Total Hip Arthroplasty Really Improve Outcomes?

BACKGROUND

Optimal management of morbid obesity before total hip arthroplasty (THA) remains debated. Recently, bariatric procedures have become more common with advancements in surgical techniques. We hypothesized that bariatric surgery prior to primary THA would mitigate acute postoperative complications and improve implant survivorship.

METHODS

A retrospective review from 1995 to 2020 identified 88 primary THA procedures in 71 unique patients who previously underwent bariatric surgery (73% Roux-en-Y). This cohort was matched 1:1:1 for age, gender, surgical year, American Society of Anesthesiologists score, and Charlson Comorbidity Index to cohorts of patients with body mass index (BMI) <40 kg/m² and BMI ≥40 kg/m². Revisions, reoperations, and acute complications were compared. Subgroup analysis then evaluated historical (pre-2012) relative to contemporary (2012 and after) bariatric procedures.

RESULTS

Revision rates for bariatric patients were higher relative to controls with low (hazard ratio [HR] 19, P < .01) and high BMI (HR 8, P < .01). Reoperation rates showed a similar increase for bariatric patients when compared to low (HR 9, P < .01) and high BMI (HR 4, P = .01) patients. Moreover, bariatric patients had an increased dislocation risk compared to the low (HR 7, P = .03) and high BMI (HR 17, P < .01) patients. Contemporary bariatric techniques had similar complications, revisions, and reoperations relative to historical procedures.

CONCLUSION

Morbidly obese patients undergoing THA have increased risks of certain complications, but it is unclear if bariatric surgery improves this risk. This study found that patients undergoing bariatric surgery have worse implant survivorship and higher dislocation rates compared to patients with naturally low and high BMIs. Further investigation into the post-bariatric metabolic state is warranted.

LEVEL OF EVIDENCE

Prognostic Level IV.

Does Bariatric Surgery Prior to Primary Total Knee Arthroplasty Improve Outcomes?

BACKGROUND

Recent advancements in bariatric surgical techniques have increased its utilization for the management of morbid obesity prior to total knee arthroplasty (TKA). We hypothesized that bariatric surgery prior to primary TKA would mitigate postoperative complications and improve implant survivorship.

METHODS

A retrospective review from 1992-2020 identified 205 bariatric surgery patients with subsequent primary TKA. This cohort was matched 1:1:1 to patients without bariatric surgery and with BMI <40 kg/m² and BMI ≥40 kg/m². Revisions, reoperations, and 90-day complications were evaluated. Subgroup analysis evaluated bariatric patients with BMI >40 kg/m² at TKA, the time between surgeries, and compared historical to contemporary bariatric techniques.

RESULTS

Bariatric patients demonstrated higher revision rates than low (HR 4, P < .01) and high BMI (HR 9, P < .01) controls, and increased reoperations when compared to the low (HR 2, P < .01) and high BMI (HR 6, P < .01) groups. Reoperation for instability was more common in bariatric patients than low (HR 15, P = .01) and high BMI (HR 17, P < .01) groups. Reoperation for infection was higher in bariatric patients relative to the high BMI (HR 6, P = .03), but not the low BMI cohort (HR 3, P = .06). There was no difference in 90-day complications (P = .33). Bariatric patients with high BMI and contemporary bariatric procedures did not significantly impact complications or survivorship, but bariatric surgery >2 years before TKA was associated with higher revision rates (P = .01).

CONCLUSION

This study found that bariatric surgery patients who undergo primary TKA have worse implant survivorship, mostly related to infection and instability. Further investigation into perioperative optimization is warranted.

LEVEL OF EVIDENCE

Prognostic Level IV.

Patterns and Predictors of Weight Change Before and After Total Hip Arthroplasty in Class 2 and 3 Obese Patients

BACKGROUND

This study aimed to better understand body mass index (BMI) change patterns and factors associated with BMI change before and after total hip arthroplasty (THA) in Class 2 and 3 obese patients, and assess if preoperative or postoperative BMI change affects postoperative clinical outcomes.

METHODS

We retrospectively reviewed World Health Organization Class 2 and 3 obese patients (BMI > 35.0 at surgery) who underwent THA at a tertiary medical center from 2010 to 2020. BMI was recorded at 1 year preoperatively (mean 11.6 months), and at most recent postoperative visit (mean 29.0 months). Baseline demographics and postoperative clinical outcomes were recorded.

RESULTS

We reviewed 436 THAs with a mean age of 59.9 (11.5) years. Leading up to surgery 55.5% had unchanged BMI, and postoperatively 48.2% had unchanged BMI. Multivariate logistic regression revealed that those who lost BMI preoperatively were more likely to gain BMI postoperatively (odds ratio [OR] 3.28, confidence interval [CI] 1.83-5.97, P = .005), but those who gained >5% BMI preoperatively had no association with BMI change postoperatively. Those in a higher BMI class preoperatively were less likely to gain BMI preoperatively (Class 3 obese patients: OR 0.001, CI 0.0002-0.004, P < .001). African American patients were more likely to gain BMI preoperatively (OR 2.32, CI 1.16-4.66, P = .017). We did not detect an association between BMI change and postoperative clinical outcomes.

CONCLUSION

In World Health Organization Class 2 or 3 obese patients, most maintained BMI between their first preoperative and final postoperative visit. Preoperatively, Class 3 obese patients were less likely to gain weight than Class 2 obese patients. The primary predictor of postoperative weight gain was preoperative weight loss. Weight change preoperatively and postoperatively were not associated with worse clinical outcomes.

Association Between Nonsurgical Weight Loss From Body Mass Index >40 to Body Mass Index <40 and Complications and Readmissions Following Total Hip Arthroplasty

BACKGROUND

Elevated body mass index (BMI) is a risk factor for adverse outcomes following total hip arthroplasty (THA). It is unknown if preoperative weight loss to a BMI <40 kg/m² is associated with reduced risk of adverse outcomes.

METHODS

We retrospectively reviewed elective, primary THA performed at an academic center from 2015 to 2019. Patients were split into groups based on their BMI trajectory prior to THA: BMI consistently <40 ("BMI <40"); BMI >40 at the time of surgery ("BMI >40"); and BMI >40 within 2 years preoperatively, but <40 at the time of surgery ("Weight Loss"). Length of stay (LOS), 30-day readmissions, and complications as defined by Centers for Medicare and Medicaid Services were compared between groups using parsimonious regression models and Fisher's exact testing. Adjusted analyses controlled for sex, age, and American Society of Anesthesiologists class.

RESULTS

In total, 1589 patients were included (BMI <40: 1387, BMI >40: 96, Weight Loss: 106). The rate of complications in each group was 3.5%, 6.3%, and 8.5% and the rate of 30-day readmissions was 3.0%, 4.2%, and 7.5%, respectively. Compared to the BMI <40 group, the weight loss group had a significantly higher risk of 30-day readmission (odds ratio [OR] 2.70, 95% confidence interval [CI] 1.19-6.17, P = .02), higher risk of any complication (OR 2.47, 95% CI 1.09-5.59, P = .03), higher risk of mechanical complications (OR 3.07, 95% CI 1.14-8.25, P = .03), and longer median LOS (16% increase, P = .002). The BMI >40 group had increased median LOS (10% increase, P = .03), but no difference in readmission or complications (P > .05) compared to BMI <40.

CONCLUSION

Weight loss from BMI >40 to BMI <40 prior to THA was associated with increased risk of readmission and complications compared to BMI <40, whereas BMI >40 was not.

LEVEL OF EVIDENCE

Level III - Retrospective Cohort Study.

Failure to Optimize Before Total Knee Arthroplasty: Which Modifiable Risk Factor is the Most Dangerous?

BACKGROUND

Complications after total knee arthroplasty (TKA) are devastating for patients, and surgeons are held accountable in alternative payment models. Optimization of modifiable risk factors has become a mainstay in the preoperative period. We sought to evaluate the consequence of failure to optimize key risk factors in a modern cohort of patients who underwent TKA.

METHODS

The American College of Surgeons National Surgical Quality Improvement Program database was searched to identify patients who underwent TKA in 2017-2018. Patients were considered optimized if they had a body mass index <40kg/m², had albumin >3.5g/dL, were nonsmokers, and were nondiabetic. Patients were then grouped based on the previous 4 risk factors. Thirty-day readmission, infection, general complications, and mortality were analyzed and compared between the groups.

RESULTS

Overall, 84,315 patients were included in the study. A total of 31.6% of patients were not considered optimized. Body mass index >40kg/m², albumin <3.5, smoking, and insulin-dependent diabetes were all found to be associated with postoperative infection, readmission, mortality, and complication in general (P < .05). When compared, the nonoptimized group was found to have significantly higher risk of readmission (5 vs 3%), infection (2 vs 1%), general complications (8 vs 5%), and mortality (0.35 vs 0.1%) (all P < .001). Logistic regression showed that those with albumin less than 3.5g/dL had 3.7-fold higher odds of infection and 7.2-fold higher odds of 30-day mortality.

CONCLUSION

Despite knowledge that modifiable risk factors significantly influence postoperative outcomes, surgeons continue to operate on patients who are not optimized. Among the modifiable risk factors analyzed, hypoalbuminemia appears to be the strongest risk factor for all complications evaluated. Special attention should be paid to preoperative nutritional optimization.

LEVEL OF EVIDENCE

Retrospective cohort study, level IV.

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.

Bariatric surgery prior to total knee arthroplasty is not associated with lower risk of revision: a register-based study of 441 patients

Background and purpose - Obesity is a considerable medical challenge in society. We investigated the risk of revision for any reasons and for infection in patients having total knee arthroplasty (TKA) for osteoarthritis (OA) within 2 years after bariatric surgery (BS) and compared them with TKAs without BS.Patients and methods - We used the Scandinavian Obesity Surgery Registry (SOReg) and the Swedish Knee Arthroplasty Register (SKAR) to identify patients operated on in 2009-2019 with BS who had had primary TKA for OA within 2 years after the BS (BS group) and compared them with TKAs without prior BS (noBS group). We determined adjusted hazard ratio (HR) for the BS group and noBS group using Cox proportional hazard regression for revision due to any reasons and for infection. Adjustments were made for sex, age groups, and BMI categories preoperatively.Results - 441 patients were included in the BS group. The risk of revision for infection was higher for the BS group with HR 2.2 (95% CI 1.1-4.7) adjusting for BMI before the TKA, while the risk of revision for any reasons was not statistically significant different for the BS group with HR 1.3 (CI 0.9-2.1). Corresponding figures when adjusting for BMI before the BS were HR 0.9 (CI 0.4-2) and HR 1.2 (CI 0.7-2).Interpretation - Our findings did not indicate that BS prior to TKA was associated with lower risk of revision.

Is obesity associated with short-term revision after total knee arthroplasty? An analysis of 121,819 primary procedures from the Dutch Arthroplasty Register

BACKGROUND

The prevalence of obesity is increasing. The association with knee osteoarthritis is well documented, resulting in the population requesting total knee arthroplasty (TKA) for invalidating symptoms to be heavier in nature. The purpose of the current analysis was to assess the association between preoperative body mass index (BMI) and short-term revision rate after TKA. The secondary aim was to investigate the influence of implant fixation method on the association between BMI and survivorship.

METHODS

This is a retrospective analysis of prospectively collected registry data (Dutch Arthroplasty Register; LROI). All primary TKA procedures in patients >18 years of age with registered BMI were selected (n = 121,819). Non-obese patients (BMI 18-25) were compared with overweight (BMI 25-30) and class I-III obese (BMI >30, >35, >40) patients. Crude all-cause revision rates were calculated using competing risk analysis. Adjusted hazard ratios (HRs) were determined with Cox multivariable regression analyses for all-cause, septic and aseptic revision and secondary patellar resurfacing.

RESULTS

Revision rates were 3.3% for non-obese patients, 3.5% for overweight patients, 3.7% for class I obese patients, 3.6% for class II obese patients and 3.7% for class III obese patients. Class III obese patients had a significant higher risk for septic revision compared with non-obese patients (HR 1.53, 95% confidence interval (CI) 1.06-2.22). Class I obese patients had a higher risk for secondary patellar resurfacing (HR 1.52, 95% CI 1.12-2.08). All-cause and aseptic revision rates were similar between BMI groups.

CONCLUSIONS

Obesity appeared to be associated with some short-term revision risks after TKA, but was not associated with an overall increase in revision rate.

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.

Rapid Bodyweight Reduction before Lumbar Fusion Surgery Increased Postoperative Complications

Study Design

Retrospective cohort study.

Purpose

To determine the effects of massive weight loss on perioperative complications after lumbar fusion surgery (LFS).

Overview of Literature

Patients who are obese are more likely to experience low back pain, which would require LFS. Nonetheless, they have a higher risk of perioperative complication development compared with individuals who are not obese.

Methods

Patients who underwent LFS at hospitals that participated in the National Surgical Quality Improvement Program database within the United States between 2005 and 2015. Outcomes included 30-day medical complications, surgical complications, and length of stay (LOS). We analyzed a total of 39,742 patients with the use of the International Classification of Disease, ninth revision codes. The patients were categorized in the following two groups: group 1, individuals with a history of massive weight loss within 6 months before LFS, and group 2, individuals without a history of massive weight loss before surgery. Massive weight loss was defined as loss of 10% of total body weight. Patients with a history of malignancy or chronic disease were excluded from the study. Patients in each group were randomly matched based on age, gender, sex, smoking status, and body mass index. Paired two-tailed Student t-tests were used to compare the outcomes.

Results

Of the 39,742 patients identified, 129 (0.32%) met the criteria for inclusion in the weight loss group (WL group) and were successfully matched to individuals in the non-weight loss group (non-WL group). Compared with the non-WL group, the WL group had a significantly longer LOS (9.7 vs. 4.0 days, p<0.05), higher surgical site infections (SSIs) (8.0 vs. 3.0, p<0.05), increased number of blood transfusions (40.0 vs. 20.0, p<0.05), and greater deep vein thrombosis (DVTs) (5.0 and 0.00, p<0.05).

Conclusions

On a nationwide scale, rapid weight loss before LFS is associated with a higher rate of postoperative complications, including SSI and DVTs, longer average LOS, and more frequent blood transfusions.

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.

Association Between Bariatric Surgery and Long-term Health Care Expenditures Among Veterans With Severe Obesity

Importance

Bariatric surgery has been associated with improvements in health in patients with severe obesity; however, it is unclear whether these health benefits translate into lower health care expenditures.

Objective

To examine 10-year health care expenditures in a large, multisite retrospective cohort study of veterans with severe obesity who did and did not undergo bariatric surgery.

Design, Setting, and Participants

A total of 9954 veterans with severe obesity between January 1, 2000, and September 30, 2011, were identified from veterans affairs (VA) electronic health records. Of those, 2498 veterans who underwent bariatric surgery were allocated to the surgery cohort. Sequential stratification was used to match each patient in the surgery cohort with up to 3 patients who had not undergone bariatric surgery but were of the same sex, race/ethnicity, diabetes status, and VA regional network and were closest in age, body mass index (calculated as weight in kilograms divided by height in meters squared), and comorbidities. A total of 7456 patients were identified and allocated to the nonsurgery (control) cohort. The VA health care expenditures among the surgery and nonsurgery cohorts were estimated using regression models. Data were analyzed from July to August 2018 and in April 2019.

Interventions

The bariatric surgical procedures (n = 2498) included in this study were Roux-en-Y gastric bypass (1842 [73.7%]), sleeve gastrectomy (381 [15.3%]), adjustable gastric banding (249 [10.0%]), and other procedures (26 [1.0%]).

Main Outcomes and Measures

The study measured total, outpatient, inpatient, and outpatient pharmacy expenditures from 3 years before surgery to 10 years after surgery, excluding expenditures associated with the initial bariatric surgical procedure.

Results

Among 9954 veterans with severe obesity, 7387 (74.2%) were men; the mean (SD) age was 52.3 (8.8) years for the surgery cohort and 52.5 (8.7) years for the nonsurgery cohort. Mean total expenditures for the surgery cohort were $5093 (95% CI, $4811-$5391) at 7 to 12 months before surgery, which increased to $7448 (95% CI, $6989-$7936) at 6 months after surgery. Postsurgical expenditures decreased to $6692 (95% CI, $6197-$7226) at 5 years after surgery, followed by a gradual increase to $8495 (95% CI, $7609-$9484) at 10 years after surgery. Total expenditures were higher in the surgery cohort than in the nonsurgery cohort during the 3 years before surgery and in the first 2 years after surgery. The expenditures of the 2 cohorts converged 5 to 10 years after surgery. Outpatient pharmacy expenditures were significantly lower among the surgery cohort in all years of follow-up ($509 lower at 3 years before surgery and $461 lower at 7 to 12 months before surgery), but these cost reductions were offset by higher inpatient and outpatient (nonpharmacy) expenditures.

Conclusions and Relevance

In this cohort study of 9954 predominantly older male veterans with severe obesity, total health care expenditures increased immediately after patients underwent bariatric surgery but converged with those of patients who had not undergone surgery at 10 years after surgery. This finding suggests that the value of bariatric surgery lies primarily in its associations with improvements in health and not in its potential to decrease health care costs.

Impact of Bariatric Surgery on Inpatient Complication, Cost, and Length of Stay Following Total Hip or Knee Arthroplasty

BACKGROUND

Morbid obesity is an important risk factor for arthroplasty and also closely associated with worse postoperative outcomes. Bariatric surgery is effective in losing weight and decreasing comorbidities associated with obesity. However, no study had demonstrated the influence of bariatric surgery on the outcome of arthroplasty in a large population.

METHODS

We used 2006-2014 discharge records from the Nationwide Inpatient Sample, and identified study population and inpatient complications by International Classification of Diseases, 9th Revision, Clinical Modification diagnosis/procedure codes. Propensity score analysis was used to match total hip arthroplasty (THA) or total knee arthroplasty (TKA) patients with morbid obesity and THA or TKA patients with bariatric surgery.

RESULTS

Proportion of morbid obesity in both TKA and THA patients demonstrated a rising trend, while proportion of bariatric surgery in morbidly obese TKA and THA patients remains steady after 2007. For THA patients, there was fewer pulmonary embolism, more blood transfusion and anemia, and shorter length of stay in bariatric surgery group. For TKA patients, bariatric surgery group had a lower risk of pulmonary embolism, respiratory complications, death, and shorter length of stay, but bariatric surgery group had a higher risk of blood transfusion and anemia.

CONCLUSION

There is evidence that bariatric surgery prior to arthroplasty, especially THA, appears to reduce rates of pulmonary complications and length of stay. But anemia and blood transfusion seem to be more common in patients with prior bariatric surgery.

Preoperative Weight Loss for Morbidly Obese Patients Undergoing Total Knee Arthroplasty: Determining the Necessary Amount

BACKGROUND

Many surgeons require or request weight loss among morbidly obese patients (those with a body mass index [BMI] of ≥40 kg/m) before undergoing total knee arthroplasty. We sought to determine how much weight reduction was necessary to improve operative time, length of stay, discharge to a facility, and physical function improvement.

METHODS

Using a retrospective review of cohort data that were prospectively collected from 2011 to 2016 at 1 tertiary institution, we identified 203 patients who were morbidly obese at least 90 days before the surgical procedure and had their BMI measured again at the immediate preoperative visit. All heights and weights were clinically measured. We used logistic and linear regression models that adjusted for preoperative age, sex, year of the surgical procedure, bilateral status, physical function (Patient-Reported Outcomes Measurement Information System [PROMIS]-10 physical component score [PCS]), mental function (PROMIS-10 mental component score [MCS]), and the Charlson Comorbidity Index.

RESULTS

Of the 203 patients in the study, 41% lost at least 5 pounds (2.27 kg) before the surgical procedure, 29% lost at least 10 pounds (4.54 kg), and 14% lost at least 20 pounds (9.07 kg). Among morbidly obese patients, losing 20 pounds before a total knee arthroplasty was associated with lower adjusted odds of discharge to a facility (odds ratio [OR], 0.28 [95% confidence interval (CI), 0.09 to 0.94]; p = 0.039), lower odds of extended length of stay of at least 4 days (OR, 0.24 [95% CI, 0.07 to 0.88]; p = 0.031), and an absolute shorter length of stay (mean difference, -0.87 day [95% CI, -1.39 to -0.36 days]; p = 0.001). There were no differences in operative time or PCS improvement. Losing 5 or 10 pounds was not associated with differences in any outcome.

CONCLUSIONS

Losing at least 20 pounds before total knee arthroplasty was associated with shorter length of stay and lower odds of facility discharge for morbidly obese patients, even while most patients remained morbidly or severely obese. Although there were no differences in operative time or physical function improvement, this has considerable implications for patient burden and cost reduction. Patients and providers may want to focus on larger preoperative weight loss targets.

LEVEL OF EVIDENCE

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

The Effect of Bariatric Surgery Prior to Lower-Extremity Total Joint Arthroplasty: A Systematic Review

BACKGROUND

Obesity is an independent risk factor for osteoarthritis and has been associated with increased rate of complications following lower-extremity total joint arthroplasty (TJA). Bariatric surgery (BS) is a surgical option for weight loss and for reducing obesity-related comorbidities in morbidly obese patients.

PURPOSE/QUESTIONS

The goal of this systematic review was to answer the following questions: (1) Does BS prior to TJA correlate with lower post-operative complication rates in morbidly obese patients undergoing TJA? (2) Does BS have an impact on revision rates following TJA?

METHODS

Using the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) statement and checklist, a systematic review of medical databases (PubMed/ MEDLINE, Cochrane Library, Web of Science, and Clinicaltrials.gov) was undertaken for articles published in English from January 1990 to September 2018. Inclusion criteria were studies that included at least ten patients who underwent BS prior to TJA, collected data on complications or other outcomes, and followed patients for at least 90 days after TJA. A descriptive and critical analysis of the results was performed.

RESULTS

From 799 studies, 13 met inclusion criteria. A total of 11,770 patients who had undergone bariatric surgery prior to TJA were analyzed. The quality of the evidence ranged between moderate and high. There was no consensus on the effect of previous BS on early- to short-term outcomes reported after TJA.

CONCLUSION

The literature remains conflicted on the impact of BS prior to TJA on early, short-term, and long-term complications after TJA. Additional well-matched, observational studies may further our understanding of the impact of BS prior to TJA on outcomes. In particular the effect of various types of BS prior to TJA on outcomes has yet to be elucidated. Ideally, prospective studies with higher level of evidence will be more definitive on the effects of BS prior to TJA.Prospero Registration Number: CRD42016043025.

Does Prior Bariatric Surgery Improve Outcomes Following Total Joint Arthroplasty in the Morbidly Obese? A Meta-Analysis

BACKGROUND

There remains a controversy regarding the risks in subsequent total joint arthroplasty (TJA) with and without previous bariatric surgery (BS). We performed a meta-analysis based on the current evidence-based study to determine the influences of prior BS on the short-term and long-term outcomes following TJA.

METHODS

From the inception to July 2018, the EMBASE, PubMed, Web of Science, and Cochrane Library electronic databases were searched for all relevant English language trials. The primary outcome measures were complications and revision, whereas the secondary outcomes included length of stay and operative time. Short-term follow-up was defined as that from hospital discharge to 90 days, and long-term follow-up was defined as more than 1 year.

RESULTS

A total of 9 studies with 38,728 patients were included. Overall, medical comorbidities were higher in the BS group compared with the control morbid obesity group before TJA. Our meta-analysis revealed that BS prior to TJA was associated with reduced short-term medical complications, length of stay, and operative time. However, BS did not reduce the short-term risks for superficial wound infection or venous thromboembolism, and the long-term risks for dislocation, periprosthetic infection, periprosthetic fracture, and revision. Subgroup analysis identified a significant reduction in the risk of short-term periprosthetic infection in the BS group after total knee arthroplasty, but not after total hip arthroplasty.

CONCLUSION

BS prior to TJA was associated with partially improved short-term outcomes after TJA. However, BS did not improve the risks for long-term outcomes. Limited by relatively higher comorbidities burden, the short-term benefits of BS should be further revealed by high-quality, controlled study in the future.

Ninety-Day Costs, Reoperations, and Readmissions for Primary Total Hip Arthroplasty Patients of Varying Body Mass Index Levels

BACKGROUND

The purpose of this study is to compare 90-day costs and outcomes for primary total hip arthroplasty patients between a nonobese (body mass index, 18.5-24.9) vs overweight (25-29.9), obese (30-34.9), severely obese (35-39.9), morbidly obese (40-44.9), and super obese (45+) cohorts.

METHODS

We conducted a retrospective review of an institutional database of primary total hip arthroplasty patients from 2006 to 2013. Thirty-three super-obese patients were identified, and the other 5 cohorts were randomly selected in a 2:1 ratio (n = 363). Demographics, 90-day outcomes (costs, reoperations, and readmissions), and outcomes after 3 years (revisions and change scores for Short-Form Health Survey, Harris Hip Score, and Western Ontario and McMaster Universities Arthritis Index) were collected. Costs were determined using unit costs from our institutional administrative data for all in-hospital resource utilization. Comparisons between the nonobese and other groups were made with Kruskal-Wallis tests for non-normal data and chi-square and Fisher exact test for categorical data.

RESULTS

The 90-day costs in the morbidly obese ($13,134 ± $7250 mean ± standard deviation, P < .01) and super-obese ($15,604 ± 6783, P < .01) cohorts were significantly greater than the nonobese cohorts ($10,315 ± 1848). Only the super-obese cohort had greater 90-day reoperation and readmission rates than the nonobese cohort (18.2% vs 0%, P < .01 and 21.2% vs 4.5%, P = .02, respectively). Reoperations and septic revisions after 3 years were greater in the super-obese cohort compared to the nonobese cohort 21.2% versus 3.0% (P = .01) and 18.2% versus 1.5% (P = .01), respectively. Improvements in Short-Form Health Survey, Harris Hip Score, and Western Ontario and McMaster Universities Arthritis Index were comparable in all cohorts.

CONCLUSION

Super-obese patients have greater risks and costs compared to nonobese patients, but also have comparable quality of life improvements.

Modifiable and Nonmodifiable Predictive Factors Associated with the Outcomes of Total Knee Arthroplasty

Total knee arthroplasty (TKA) is a valuable treatment option for advanced osteoarthritis in patients unresponsive to conservative treatments. Despite overall satisfactory results, the rate of unsatisfied patients after TKA remains high, ranging from 5 to 40%. Different modifiable and nonmodifiable prognostic factors associated with TKA outcomes have been described. The correction, whenever possible, of modifiable factors is fundamental in preoperative patients' optimization protocols. Nonmodifiable factors can help in predicting the outcomes and creating the right expectations in the patients undergoing TKA. The goal of this review is to summarize the modifiable and nonmodifiable prognostic factors associated with TKA outcomes.

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.

Comparative Effectiveness and Safety of Bariatric Procedures in Medicare-Eligible Patients: A Systematic Review

Importance

The prevalence of obesity in patients older than 65 years is increasing. A substantial number of beneficiaries covered by Medicare meet eligibility criteria for bariatric procedures.

Objective

To assess the comparative effectiveness and safety of bariatric procedures in the Medicare-eligible population.

Evidence Review

This systematic review was conducted according to the PRISMA guidelines. Articles were identified through searches of PubMed, Embase, CINAHL, PsycINFO, Cochrane Central Trials Registry, Cochrane Database of Systematic Reviews, and scientific information packages from manufacturers, ClinicalTrials.gov, World Health Organization International Clinical Trials Registry Platform, and US Food and Drug Administration drugs and devices portals from January 1, 2000, to June 31, 2017. Randomized and nonrandomized comparative studies that evaluated bariatric procedures in the Medicare-eligible population were eligible. Six researchers extracted data on design, interventions, outcomes, and study quality. Findings were synthesized qualitatively; a planned meta-analysis was not undertaken owing to clinical heterogeneity.

Findings

A total of 11 455 citations were screened for eligibility. Of those, 16 met the eligibility criteria. Compared with no surgery or conventional weight-loss treatment, bariatric surgery results in greater weight loss. Overall mortality after 30 days is lower among bariatric patients (hazard ratio, HR, 0.50; 95% CI, 0.31-0.79, in the study with the longest follow-up of 5.9 years), although, based on 1 study, mortality within 30 days of surgery was higher than in nonsurgically treated controls (1.55% vs 0.53%; P < .001). Bariatric surgery is associated with lower risk of cardiovascular disease (HR, 0.59; 95% CI, 0.44-0.79 in the largest study comparison) and with improvements in respiratory, musculoskeletal, metabolic, and renal outcomes (increase in estimated glomerular filtration rate, 9.84; 95% CI, 8.05-11.62 mL/min/1.73m2). Compared with sleeve gastrectomy (SG) and adjustable gastric banding (AGB), Roux-en-Y gastric bypass (RYGB) appears to be associated with greater weight loss (percent excess weight loss, 23.8% [95% CI, 16.2%-31.4%] at the longest follow-up of 4 years) but the 3 procedures have similar associations with most non-weight loss outcomes. Overall postoperative complications are not statistically significantly different between RYGB and SG, although major and/or serious complications are more common after RYGB. However, these associations are susceptible to at least moderate risk of confounding, selection, or measurement biases.

Conclusions and Relevance

In the Medicare population, there is low to moderate strength of evidence that bariatric surgery as a weight loss treatment improves non-weight loss outcomes. Well-designed comparative studies are needed to credibly determine the treatment effects for bariatric procedures in this patient population.

Trends in procedure type, patient characteristics, and outcomes among persons with knee osteoarthritis undergoing bariatric surgery, 2005-2014

OBJECTIVE

To evaluate trends in the utilization, clinical characteristics, and inpatient outcomes among persons with knee osteoarthritis undergoing bariatric surgery.

METHOD

We used the National Inpatient Sample (NIS) to examine trends of bariatric surgeries performed on adults with clinically documented knee osteoarthritis between 2005 and 2014. We abstracted hospital setting, procedure, demographic and clinical characteristics, and inpatient surgical outcomes from each discharge. We examined temporal trends using linear regression and Cochran-Armitage test for trend.

RESULTS

The utilization of bariatric surgery among persons with knee osteoarthritis from 2005 to 2014 remained consistent, with an annual total of about 3,300 procedures performed nationally. The most common procedure type changed from laparoscopic Roux-en-Y (65%) in 2005-2006 to laparoscopic sleeve gastrectomy (58%) in 2013-2014. The median age, proportion on Medicare, and age- and sex-adjusted prevalence of diabetes increased from 46 to 51 years, 7-23%, and 28-32%, respectively. From 2005 to 2014, the median adjusted costs, in 2017 USD, for laparoscopic and open Roux-en-Y surgeries decreased from $15,100 to $13,300 (p < 0.01) and $14,100 to $10,100 (p = 0.0001), respectively, whereas the costs of laparoscopic sleeve gastrectomy and laparoscopic banding did not change significantly. In-hospital mortality remained at 0.0-0.1% from 2005 to 2014.

CONCLUSION

Although growing evidence suggests that bariatric surgery is associated with improvements in osteoarthritis pain and functional status, the utilization of bariatric surgery among morbidly obese persons with knee osteoarthritis remained consistent from 2005 to 2014. Bariatric surgery in persons with knee osteoarthritis is generally safe, as inpatient complication and mortality rates remained low despite an increase in age and number of comorbidities.

Weighing in on Body Mass Index and Infection After Total Joint Arthroplasty: Is There Evidence for a Body Mass Index Threshold?

BACKGROUND

Although morbid obesity is considered a modifiable risk factor for periprosthetic joint infection (PJI), there is no consensus regarding an appropriate threshold for body mass index (BMI) above which a high risk for infection may outweigh the benefits of surgery.

QUESTIONS/PURPOSES

(1) Is there a BMI cutoff threshold that is associated with increased risk for PJI? (2) Is the risk of PJI increased in higher obesity classes?

METHODS

A retrospective study was conducted of all primary THAs and TKAs performed at one institution between 2006 and 2015. Overall 19,226 patients were eligible to be included in the study; 1053 patients were excluded as a result of incomplete data, resulting in a final cohort of 18,173 patients (8757 TKAs and 9416 THAs). PJI was defined using the International Consensus Meeting criteria. To ensure accurate followup, and because there is evidence to support the association between obesity and early infection, we identified PJI within 90 days of the index surgery. This relationship was examined separately for BMI as a continuous variable and for each BMI category as defined by the Centers for Disease Control and Prevention (underweight ≤ 18.49 kg/m; normal 18.5-24.9 kg/m; overweight 25-29.9 kg/m; obese class I 30-34.9 kg/m; obese class II 35-39.9 kg/m; obese class III ≥ 40 kg/m). Analyses were performed with logistic regression, accounting for both patient and surgical risk factors. A BMI threshold was evaluated with a receiver operating characteristic (ROC) curve and the Youden index.

RESULTS

The area under the ROC curve for BMI and risk of PJI within 90 days was only 0.58 (confidence interval [CI], 0.52-0.63) suggesting such a cutoff was not much better than random chance. Among the BMI classes, patients with class III obesity (≥ 40 kg/m) were the only ones showing a higher risk for PJI within 90 days (odds ratio [OR], 3.09 [1.46-6.54]; p = 0.003). The risk of developing PJI was not greater for overweight (OR, 0.72; 95% CI, 0.38-1.4), class I obese (OR, 1.06; 95% CI, 0.57-2.0), or class II obese (OR, 1.08; 95% CI, 0.52-2.2) patients. Underweight patients also demonstrated no increased risk for PJI (OR, 1.80; 95% CI, 0.23-13.9).

CONCLUSIONS

The risk for infection increases gradually throughout the full range of BMI, but no threshold exists. Weight reduction before surgery may mitigate risk for infection for all patients with a BMI above normal. Of note, patients with a BMI > 40 kg/m carried a threefold higher risk for PJI and for these patients, the risks of surgery must be carefully weighed against its benefits.

LEVEL OF EVIDENCE

Level III, therapeutic study.

Dislocation rate increases with bariatric surgery before total hip arthroplasty

INTRODUCTION

Annually in the USA, 113,000 patients with refractory obesity undergo bariatric surgery (BS), and a subset does so in order to lower body mass index to become a more desirable total hip arthroplasty (THA) candidate. This study aims to evaluate THA risk with and without bariatric surgery.

METHODS

12,160 patients were identified in a claim-based review of the entire Medicare database with ICD-9 codes to identify patients in three groups. Patients who underwent BS prior to THA (Group I: 1,545 experimental group) and two control groups that did not undergo BS but had either a body mass index >40 (Group II: 6,918 bariatric control) or <25 (Group III: 3,697 normal weight control). Preoperative demographics/comorbidities and short-term medical (30 day) and long-term surgical (90-day and 2-year) complications were evaluated.

RESULTS

Group I had female predominance, youngest age, and highest incidence of: deficiency anaemia, cardiovascular disease, liver disease, diabetes, polysubstance abuse, psychiatric disorders and smoking. At 2 years, Group I had approximately twice the dislocation and revision risk compared to both Groups II and III; Groups I and II had over four times the risk of infection and wound complications compared to Group III.

CONCLUSION

In the Medicare population, these patients continue to have complication rates similar to and sometimes greater than obese patients with no prior bariatric surgery. Greater dislocation risk is possibly due to ligamentous laxity related to decreased collagen/elastin and/or component malposition due to intraoperative visualisation challenges.

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.

Does Prior Bariatric Surgery Affect Implant Survivorship and Complications Following Primary Total Hip Arthroplasty/Total Knee Arthroplasty?

BACKGROUND

The purpose of this study is to evaluate the impact of prior bariatric surgery on survivorship, outcome, and complications following primary total hip arthroplasty (THA)/total knee arthroplasty (TKA).

METHODS

Using the Medicare 5% part B data from 1999 to 2012, we analyzed patients who underwent primary THA (n = 47,895) and primary TKA (n = 86,609). Patients with prior bariatric surgery before arthroplasty were compared to patients with other common metabolic conditions. Kaplan-Meier risk of revision THA/TKA for those with and without bariatric surgery and each of the metabolic bone conditions was calculated. The risk for infection was also evaluated. Regression analysis was used to determine the relative risk of revision at various time intervals for those with and without each of the metabolic conditions. Analysis was also adjusted for the metabolic conditions, age, gender, socioeconomic status, and Charlson comorbidity index.

RESULTS

The prevalence of patients with prior bariatric surgery within 24 months of primary THA/TKA was 0.1%. Benchmarked against other common chronic metabolic conditions, bariatric surgery prior to THA was not associated with an increased risk for revision surgery at all measured intervals but positively correlated with increased risk for developing infections. Conversely, patients undergoing primary TKA following bariatric surgery were at increased risk for revision compared to controls but not at increased risk for infection.

CONCLUSION

The impact of bariatric surgery prior to elective THA/TKA remains unclear. These patients remain at increased risk for infections following THA and revisions following TKA.

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.