The influence of obesity on total joint arthroplasty

The influence of body mass index on patient-reported outcome measures following total hip arthroplasty: a retrospective study of 3,903 Cases

BACKGROUND

The influence of obesity on patient-reported outcome measures (PROMs) following total hip arthroplasty (THA) is currently controversial. This study aimed to compare PROM scores for pain, functional status, and global physical/mental health based on body mass index (BMI) classification.

METHODS

Primary, elective THA procedures at a single institution between 2018 and 2021 were retrospectively reviewed, and patients were stratified into four groups based on BMI: normal weight (18.5-24.99 kg/m2), overweight (25-29.99 kg/m2), obese (30-39.99 kg/m2), and morbidly obese (> 40 kg/m2). Patient-Reported Outcome Measurement Information System (PROMIS) and Hip Disability and Osteoarthritis Outcome Score for Joint Replacement (HOOS, JR) scores were collected. Preoperative, postoperative, and pre/post- changes (pre/post-Δ) in scores were compared between groups. Multiple linear regression was used to assess for confounders.

RESULTS

We analyzed 3,404 patients undergoing 3,903 THAs, including 919 (23.5%) normal weight, 1,374 (35.2%) overweight, 1,356 (35.2%) obese, and 254 (6.5%) morbidly obese cases. HOOS, JR scores were worse preoperatively and postoperatively for higher BMI classes, however HOOS, JR pre/post-Δ was comparable between groups. All PROMIS measures were worse preoperatively and postoperatively in higher BMI classes, though pre/post-Δ were comparable for all groups. Clinically significant improvements for all BMI classes were observed in all PROM metrics except PROMIS mental health. Regression analysis demonstrated that obesity, but not morbid obesity, was independently associated with greater improvement in HOOS, JR.

CONCLUSIONS

Obese patients undergoing THA achieve lower absolute scores for pain, function, and self-perceived health, despite achieving comparable relative improvements in pain and function with surgery. Denying THA based on BMI restricts patients from clinically beneficial improvements comparable to those of non-obese patients, though morbidly obese patients may benefit from additional weight loss to achieve maximal functional improvement.

Body Mass Index Between 15 and 30 Does Not Influence Patient-Reported Outcomes After Anterior Cruciate Ligament Surgery Using a 10-mm-Diameter Bone-Tendon-Bone Graft

Purpose

To investigate the relation between body mass index (BMI) and outcomes after anterior cruciate ligament reconstruction (ACLR) using 10-mm-diameter bone-patellar tendon-bone grafts.

Methods

In this retrospective study, the Surgical Outcome System was used to measure patient-reported outcomes before and after ACLR between 2015 and 2019. The inclusion criteria consisted on patients undergoing primary ACLR performed by the senior surgeon, with recorded age of 15 years or older and BMI of 15.0 to 30. The exclusion criteria included revisions, concomitant procedures, age younger than 15 years, and unknown BMI. Patients were divided into cohorts to evaluate the Marx Activity Rating Scale (MARS), Tegner, International Knee Documentation Committee (IKDC), and Lysholm scores at various time points from injury to 2 years postoperatively.

Results

A total of 137 patients (100 male and 37 female patients) with an average age of 33 years (95% confidence interval, 30.6-35.4 years) and average BMI of 23.58 (95% confidence interval, 23.1-24.0) were divided into those with a BMI of 15 to 23.4 (group A, n = 69) and those with a BMI of 23.5 to 30 (group B, n = 68). A significant difference in MARS scores was found between the BMI groups before treatment, with mean scores of 11.55 (group A) and 9.41 (group B) (P = .011), and Tegner scores showed significance at 2 years, with scores of 6.45 and 5.41 for groups A and B, respectively (P = .009). Daily function scores were all insignificant. Female patients exhibited no significant differences across any patient-reported outcome measures or time points. Contrarily, male patients showed a significant difference in pretreatment MARS scores (14.30 in group A vs 9.96 in group B, P = .011). Additionally, scores at 2 years depicted Tegner values of 7.40 in group A versus 5.30 in group B (P = .012) and IKDC values of 96.92 in group A versus 90.47 in group B (P = .048). All results for female and male patients aged 30 years or younger indicated no significance.

Conclusions

Regardless of patient age or sex, BMI is not significantly associated with patient-reported outcomes after ACLR using 10-mm-diameter bone-patellar tendon-bone grafts.

Level of Evidence

Level III, retrospective cohort study.

Preoperative and Postoperative Weight Change has Minimal Influence on Health Care Utilization and Patient-Reported Outcomes Following Total Knee Arthroplasty

As obesity becomes more prevalent, more patients are at risk of lower extremity osteoarthritis and subsequent total knee arthroplasty (TKA). This study aimed to test (1) the association of preoperative weight change with health care utilization and (2) the association of pre- and postoperative weight changes with failure to achieve satisfaction and minimal clinically important difference (MCID) in Knee injury and Osteoarthritis Outcome Score for pain (KOOS-Pain) and function (KOOS-PS) 1 year after TKA. Prospectively collected monocentric data on patients who underwent primary TKA were retrospectively reviewed. Multivariable logistic regression assessed the influence of BMI and weight change on outcomes while controlling for confounding variables. Outcomes included prolonged length of stay (LOS >3 days), nonhome discharge, 90-day readmission rate, satisfaction, and achievement of MCID for KOOS-Pain and KOOS-PS. Preoperative weight change had no impact on prolonged LOS (gain, p = 0.173; loss, p = 0.599). Preoperative weight loss was associated with increased risk of nonhome discharge (odds ratio [OR]: 1.47, p = 0.003). There was also increased risk of 90-day readmission with preoperative weight gain (OR: 1.27, p = 0.047) and decreased risk with weight loss (OR: 0.73, p = 0.033). There was increased risk of nonhome discharge with obesity class II (OR: 1.6, p = 0.016) and III (OR: 2.21, p < 0.001). Weight change was not associated with failure to achieve satisfaction, MCID in KOOS-Pain, or MCID in KOOS-PS. Obesity class III patients had decreased risk of failure to reach MCID in KOOS-Pain (OR: 0.43, p = 0.005) and KOOS-PS (OR: 0.7, p = 0.007). Overall, pre- and postoperative weight change has little impact on the achievement of satisfaction and clinically relevant differences in pain and function at 1 year. However, preoperative weight gain was associated with a higher risk of 90-day readmissions after TKA. Furthermore, patients categorized in Class III obesity were at increased risk of nonhome discharge but experienced a greater likelihood of achieving MCID in KOOS-Pain and KOOS-PS. Our results raise awareness of the dangers of using weight changes and BMI alone as a measure of TKA eligibility.

Does Your Patient Need to Lose Weight? Weight Change Before and After Total Hip Arthroplasty Does Not Affect Health Care Utilization and Achievement of the Minimal Clinically Important Difference

BACKGROUND

Despite the potential negative impact of preoperative obesity on total hip arthroplasty (THA) outcomes, the association between preoperative and postoperative weight change and outcomes is much less understood. Therefore, this study aimed to determine the impact of preoperative and postoperative weight change and preoperative body mass index (BMI) on health care utilization, satisfaction, and achievement of minimal clinically important difference (MCID) for Hip Disability and Osteoarthritis Outcome Score Physical Function Short-Form (HOOS PS) and HOOS Pain.

METHODS

Patients who underwent primary elective unilateral THA between January 2016 and December 2019 were included (N = 2,868). Multivariable logistic regression assessed the association between BMI and preoperative and postoperative weight change on outcomes while controlling for demographic characteristics.

RESULTS

There was no association between preoperative weight change and prolonged length of stay (> 3 days), 90-day readmission, nonhome discharge, patient dissatisfaction at 1 year, or achievement of HOOS Pain or HOOS PS MCID. Postoperative weight loss was an independent risk factor for patient dissatisfaction at 1 year but was not associated with achievement of either HOOS Pain or HOOS PS MCID at 1-year postoperative. Preoperative obesity classes I to III were independent risk factors for nonhome discharge. Nevertheless, preoperative obesity class I and class II were associated with an increased probability of reaching HOOS Pain MCID. Preoperative BMI was not associated with an increased risk of patient dissatisfaction.

CONCLUSIONS

Preoperative weight change does not appear to influence health care utilization, satisfaction, or achievement of MCID in pain and function following THA. Postoperative weight loss may play a role as a risk factor for dissatisfaction following THA. Additionally, patients who had a higher baseline BMI may be more likely to see improvement in pain following THA. Therefore, when counseling obese patients for THA, surgeons must balance the risk of perioperative complications with the expectation of greater improvements in pain.

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.

Recent Advances in Nutraceuticals for the Treatment of Sarcopenic Obesity

Sarcopenic obesity, low muscle mass, and high body fat are growing health concerns in the aging population. This review highlights the need for standardized criteria and explores nutraceuticals as potential therapeutic agents. Sarcopenic obesity is associated with insulin resistance, inflammation, hormonal changes, and reduced physical activity. These factors lead to impaired muscle activity, intramuscular fat accumulation, and reduced protein synthesis, resulting in muscle catabolism and increased fat mass. Myostatin and irisin are myokines that regulate muscle synthesis and energy expenditure, respectively. Nutritional supplementation with vitamin D and calcium is recommended for increasing muscle mass and reducing body fat content. Testosterone therapy decreases fat mass and improves muscle strength. Vitamin K, specifically menaquinone-4 (MK-4), improves mitochondrial function and reduces muscle damage. Irisin is a hormone secreted during exercise that enhances oxidative metabolism, prevents insulin resistance and obesity, and improves bone quality. Low-glycemic-index diets and green cardamom are potential methods for managing sarcopenic obesity. In conclusion, along with exercise and dietary support, nutraceuticals, such as vitamin D, calcium, vitamin K, and natural agonists of irisin or testosterone, can serve as promising future therapeutic alternatives.

Does body mass index influence improvement in patient reported outcomes following total knee arthroplasty? A retrospective analysis of 3918 cases

PURPOSE

The study aimed to determine whether body mass index (BMI) classification for patients undergoing total knee arthroplasty (TKA) is associated with differences in mean patient reported outcome measure (PROM) score improvements across multiple domains-including pain, functional status, mental health, and global physical health. We hypothesized that patients with larger BMIs would have worse preoperative and postoperative PROM scores, though improvements in scores would be comparable between groups.

MATERIALS AND METHODS

Patients undergoing primary TKA from 2018 to 2021 were retrospectively reviewed and stratified into four groups: Normal Weight; 18.5-25 kg/m², Overweight; 25.01-30 kg/m², Obese; 30.01-40 kg/m², and Morbidly Obese > 40 kg/m². Preoperative, postoperative, and pre/post-changes (Δ) in knee injury and osteoarthritis, joint replacement (KOOS, JR) and Patient-Reported Outcome Measurement Information System (PROMIS) measures of pain intensity, pain interference, physical function, mobility, mental health, and physical health were compared. Multivariate linear regression was used to assess for confounding comorbid conditions.

RESULTS

In univariate analysis, patients with larger BMIs had worse scores for KOOS, JR and all PROMIS metrics preoperatively. Postoperatively, scores for KOOS, JR and PROMIS pain interference, mobility, and physical health were statistically worse in higher BMI groups, though differences were not clinically significant. Morbidly obese patients achieved greater pre/post-Δ improvements in KOOS, JR and global physical health scores. Multivariate regression analysis showed high BMI was independently associated with greater pre/post-Δ improvements in KOOS, JR and global health scores.

CONCLUSION

Obese patients report worse preoperative scores for function and health, but greater pre/post-Δ improvements in KOOS, JR and physical health scores following TKA. Quality of life benefits of TKA in obese patients should be a factor when assessing surgical candidacy.

Total Ankle Arthroplasty: Does Obesity Matter?

BACKGROUND

There is limited data evaluating the effect of obesity on outcomes following total ankle arthroplasty (TAA), especially in adequate sample sizes to detect impacts on patient-reported outcomes (PROs). The purpose of this study was to assess the effect of obesity on complication rates and PROs.

METHODS

This was a single-institution, retrospective study of 1093 primary TAA performed between 2001 and 2020. Minimum follow-up was 2 years. Patients were stratified by body mass index (BMI) into control (BMI = 18.5-29.9; n = 615), obesity class I (BMI = 30.0-34.9; n = 285), and obesity class II (BMI > 35.0; n = 193) groups. Patient information, intraoperative variables, postoperative complications, and PRO measures were compared between groups using univariable statistics. Multivariable Cox regression was performed to assess risk for implant failure. Mean follow-up was 5.6 years (SD: 3.1).

RESULTS

Compared to control and class I, class II patients had the lowest mean age (P = .001), highest mean ASA score (P < .001), and greatest proportion of female sex (P < .001) and Black/African American race (P = .005). There were no statistically significant differences in postoperative complications (infection, implant failure, or impingement) across the BMI classes (P > .05).Preoperatively, class II had lower (worse) mean scores for Foot and Ankle Outcome Score pain and ADL subscales than controls (post hoc pairwise P < .001 for both). At final follow-up, both class II and class I had lower (worse) mean Short Musculoskeletal Function Assessment (post hoc pairwise P < .001 and P = .030, respectively) and 36-Item Short Form Health Survey scores (post hoc pairwise P < .001 and P = .005, respectively) than controls.

CONCLUSION

At midterm follow-up, obesity was not associated with increased rates of complications after TAA. Patients with obesity reported worse musculoskeletal function and overall quality of life after TAA but there was no differential improvement in PROs across BMI classes. To our knowledge, this is the largest single-institution study to date examining the effect of obesity on outcomes after primary TAA.

LEVEL OF EVIDENCE

Level III, retrospective comparative study.

The Association of Total Knee Arthroplasty With Weight Loss in the Look AHEAD (Action for Health in Diabetes) Clinical Trial

BACKGROUND

Patients who have obesity seldom lose weight after total knee arthroplasty (TKA). The Look AHEAD (Action for Health in Diabetes) trial randomized patients with type 2 diabetes who were overweight or had obesity to a 10-year intensive lifestyle intervention (ILI) or diabetes support and education (DSE).

METHODS

Of the total 5,145 participants enrolled who had a median 14-year follow-up, a subset of 4,624 met inclusion criteria. The ILI aimed at achieving and maintaining a 7% weight loss and included weekly counseling the first 6 months, with decreasing frequency thereafter. This secondary analysis was undertaken to determine what effects a TKA had on patients participating in a known successful weight loss program and specifically if there was a negative impact on weight loss or their Physical Component Score.

RESULTS

The analysis suggests that the ILI remained effective for maintaining or losing weight after TKA. Participants in ILI had significantly greater percent weight loss than those in DSE both before and after TKA (ILI-DSE before TKA: -3.6% (-5.0, -2.3); after TKA: -3.7% (-4.1, -3.3); both P < .0001). When comparing percent weight loss before to after TKA, there was no significant difference within either the DSE or ILI group (least square means ± standard error ILI: -0.36% ± 0.3, P = .21; DSE: -0.41% ± 0.29, P = .16). Physical Component Scores improved after TKA (P < .001), but no difference was found between TKA ILI and DSE groups before or after surgery.

CONCLUSION

Participants who had a TKA did not have an altered ability to adhere to intervention goals to maintain weight loss or obtain further weight loss. The data suggest patients who have obesity can lose weight after TKA on a weight loss program.

[Analysis of rising treatment cost of elevated BMI in patients with proximal femoral fracture]

Driven by the aging population, the proximal femoral fracture is a rising fracture entity, challenging trauma surgeons as well as the German healthcare system as a whole. The rising average age of the population is accompanied by a rising BMI in the German population, resulting in longer operation times, longer average length of stay (ALOS) as well as more postoperative complications.The aim of this study was to demonstrate the economic correlation between body mass index and hospital costs. The retrospective analysis of 950 patient cases suffering from a proximal femoral fracture resulted in the finding of rising treatment costs being positively associated with rising BMI due to longer operation times and longer length of hospitalization (10,452 €, 11,505 €, 12,085 € and 13,681 € for patients with BMI < 18.5 kg/m², BMI = 18.5-24.9 kg/m², BMI = 25.0-29.9 kg/m² and BMI ≥ 30.0 kg/m², respectively).

What Patient and Implant Factors Affect Trunnionosis Severity? An Implant Retrieval Analysis of 664 Femoral Stems

BACKGROUND

Corrosion at the modular head-neck taper interface of total and hemiarthroplasty hip implants (trunnionosis) is a cause of implant failure and thus a clinical concern. Patient and device factors contributing to the occurrence of trunnionosis have been investigated in prior implant retrieval studies but generally with limited sample sizes and a narrow range of models. The purpose of the present investigation was to determine which patient and device factors were associated with corrosion damage on the femoral stem taper across a large collection of different implant models retrieved following revision hip arthroplasty.

METHODS

A retrieval study of 664 hip arthroplasty modular stem components was performed. Patient and device information was collected. Trunnions were imaged under digital microscopy and scored for corrosion damage using a scaling system. Damage was related to patient and device factors using regression analyses.

RESULTS

Greater duration of implantation (P = .005) and larger head size (P < .001) were associated with an elevated corrosion class. Older age at index surgery (P = .035), stainless steel stem material (P = .022), indication for revision as bone or periprosthetic fracture (P = .017), and infection (P = .018) and certain larger taper geometries were associated with a decreased corrosion class.

CONCLUSION

Factors identified as contributing to a higher or lower risk of more severe corrosion are consistent with most prior smaller retrieval studies. Surgeons should be aware of these risk factors when selecting implants for their patients and when diagnosing trunnionosis in symptomatic hip arthroplasty patients.

The accuracy of patient-reported weight prior to total joint arthroplasty and arthroscopy of the lower extremity

PURPOSE

The accuracy of preoperative patient-reported weight was never evaluated in patients undergoing lower extremity procedures. The purpose of this study was to: (1) compare the disparity between patient-reported and measured weights in patients undergoing lower extremity total joint arthroplasty (LE-TJA) and arthroscopy; and (2) investigate the association between patient-specific factors (patient age, BMI, zip code, and psychiatric comorbidities) and the accuracy of patient-reported weight.

METHODS

Preoperative self-reported weights were retrospectively compared to measured weights in 400 LE-TJA and 85 control arthroscopy patients. The difference between reported and measured weights was calculated. Additionally, the percent of accurate reporting within 0.5, 1, and 5 kg ranges of the measured weight was calculated. Outcomes were compared between surgical modalities as well as between patient-specific factors.

RESULTS

There was low disparity (p = 0.838) between patient-reported and measured weights among LE-TJA (mean difference 0.18 ± 3.63 kg; p = 0.446) and that of arthroscopy (0.27 ± 4.08 kg; p = 0.129) patients. Additionally, LE-TJA patients were equally likely to report weights accurately within 0.5 kg of the measured weight (74% vs. 71.76%; p = 0.908). LE-TJA and arthroscopy patients had similar reporting accuracy within 1 and 5 kg of the measured weights (p > 0.05).

CONCLUSION

Preoperative patient-reported weights demonstrated acceptable accuracy in both LE-TJA and lower extremity arthroscopic orthopaedic patient populations making it a potentially reliable parameter of preoperative assessment.

The Impact of Metabolic Syndrome on Reoperations and Complications After Primary Total Hip Arthroplasty

BACKGROUND

Metabolic syndrome (MetS) represents a constellation of interrelated conditions including insulin resistance, abdominal obesity, hypertension, and dyslipidemia. The goals of this study are to determine the impact of MetS on implant survivorship, complications, and clinical outcomes after primary total hip arthroplasty (THA).

METHODS

Utilizing our institutional total joint registry, 1,268 patients undergoing primary THA were identified with MetS based on the World Health Organization definition and matched 1:1 to those without MetS based on age, gender, and surgical year. MetS patients were further stratified according to the World Health Organization body mass index (BMI) classification to contextualize obesity. Kaplan-Meier analyses were utilized to compare survivorship free of any reoperation, revision, and complications. Clinical outcomes were assessed with Harris hip scores. Mean follow-up after THA was 5 years.

RESULTS

MetS patients had significantly worse 5-year survivorship free from any reoperation compared to those without MetS (93.5% vs 96.1%, respectively; hazard ratio [HR] 1.4, P = .04). When stratifying MetS and BMI classification, the BMI >40 kg/m² had significantly decreased 5-year implant survivorship free from any reoperation (85.9% vs 96.1%, HR 3.4, P < .001), any revision (91.7% vs 97.3%, HR 2.7, P < .001), and reoperation for periprosthetic joint infection (95% vs 99%, HR 5.1, P < .001). Both groups experienced significant and similar improvement in final Harris hip scores (P < .001).

CONCLUSION

Patients with MetS had a 1.4-fold increased risk of reoperation after primary THA compared to a matched cohort without the condition. MetS patients with a BMI >40 kg/m² had the highest risk of reoperation, and had a significantly higher revision and periprosthetic joint infection rates, suggesting that morbid obesity remains a critical, independent risk factor beyond MetS.

LEVEL OF EVIDENCE

Level 3, Case-control study.

The influence of obesity on achievement of a 'forgotten joint' following total knee arthroplasty

INTRODUCTION

Obesity has been associated with poorer outcomes following total knee arthroplasty (TKA); however, data remain sparse on its impact on patients' joint awareness following surgery. This study aims to investigate the impact of body mass index (BMI) on improvement in outcomes following TKA as assessed by the Forgotten Joint Score-12 (FJS-12).

MATERIALS AND METHODS

We retrospectively reviewed 1075 patients who underwent primary TKA from 2017 to 2020 with available postoperative FJS-12 scores. Patients were stratified based on their BMI (kg/m²): < 30, 30.0-34.9 (obese class I), 35.0-39.9 (obese class II), and ≥ 40 (obese class III). FJS-12 and KOOS, JR scores were collected at various time points. Demographic differences were assessed with Chi-square and ANOVA tests. Mean scores between BMI groups were compared using univariate ANCOVA, controlling for observed demographic differences.

RESULTS

Of the 1075 patients included, there were 457 with a BMI < 30, 331 who were obese class I, 162 obese class II, and 125 obese class III. There were no statistical differences in FJS-12 scores between the BMI groups at 3 months (27.24 vs. 25.33 vs. 23.57 vs. 22.48; p = 0.99), 1 year (45.07 vs. 41.86 vs. 40.51 vs. 36.22; p = 0.92) and 2 years (51.31 vs. 52.86 vs. 46.17 vs. 44.97; p = 0.94). Preoperative KOOS, JR scores significantly differed between the various BMI categories (49.33 vs. 46.63 vs. 44.24 vs. 39.33; p < 0.01); however, 3-month (p = 0.20) and 1-year (p = 0.13) scores were not statistically significant. Mean improvement in FJS-12 scores from 3 months to 2 years was statistically greatest for obese class I patients and lowest for obese class III patients (24.07 vs. 27.53 vs. 22.60 vs. 22.49; p = 0.01). KOOS, JR score improvement from baseline to 1 year was statistically greatest for obese class III patients and lowest for non-obese patients (22.34 vs. 25.49 vs. 23.77 vs. 27.58; p < 0.01).

CONCLUSION

While all groups demonstrated postoperative improvement, those with higher BMI reported lower mean FJS-12 scores but these differences were not found to be significant. Our study showed no significant impact of BMI on postoperative joint awareness, which implies that obese patients, in all obesity classes, experience similar functional improvement following TKA.

LEVEL III EVIDENCE

Retrospective Cohort Study.

Obesity, Comorbidities, and the Associated Risk among Patients Who Underwent Total Knee Arthroplasty in Alberta

Obesity, a common risk factor for osteoarthritis (OA), accelerates joint deterioration resulting in the need for early total knee arthroplasty (TKA). The role of obesity in the management of OA remains a controversial topic. In this study, we examined whether obesity along with other comorbidities is associated with peri/postoperative complications in patients who underwent primary unilateral TKA in Alberta, Canada. A retrospective secondary analysis was performed on data extracted from data repository of patients (n = 15,151) who underwent TKA between 2012 and 2016. The sample was divided into five groups based on body mass index (BMI) classification developed by the World Health Organization. The associations between dependent variable (presence or absence of a complication or comorbidity) with the independent variables (year of surgery, age, sex, length of surgery, and BMI groups) were examined using binomial logistic regression. Results showed that obese classes I, II, and III, irrespective of other covariates, were more likely to have diabetes and pulmonary embolism (p < 0.001) compared with the normal BMI group. Patients with obese class III compared with the patients in normal BMI group were more likely to have deep wound infection (p = 0.04). Patients with comorbidities were more likely to have a blood transfusion, infection, pulmonary embolism, and readmission. Patients in higher BMI groups or with comorbidities were more likely to experience peri/postoperative complications following TKA, though the level of risk depends on the severity of obesity. These findings may be used by health care providers to educate patients in higher BMI groups about the risks of TKA and optimize comorbidities prior to the surgery.

Evaluation of Appropriateness of the Reimbursement Criteria of Korean Health Insurance Review and Assessment Service for Total Knee Arthroplasty

Background

We evaluated and compared South Korea's total knee arthroplasty (TKA) reimbursement criteria set by Health Insurance Review and Assessment Service (HIRA) with other TKA appropriateness criteria to find additional criterion to improve its appropriateness by reviewing TKA inappropriate cases.

Methods

Two TKA appropriateness criteria and HIRA's reimbursement criteria for TKA were adapted for use on patients undergoing TKA in one institute from December 2017 to April 2020. Preoperative data including 9 validated questionnaires on knee joint-specific parameters, age, and radiography were used. We categorized cases into appropriate, inconclusive, inappropriate groups and analyzed each group.

Results

Data on 448 cases that underwent TKA were examined. According to the HIRA's reimbursement criteria, 434 cases (96.9%) were appropriate and 14 cases (3.1%) were inappropriate; superior to other TKA appropriateness criteria. The inappropriate group had Knee Injury and Osteoarthritis Outcome score (KOOS) pain, KOOS symptoms, Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) total score, and Korean Knee score total score with worse symptoms compared to the appropriate group classified by HIRA's reimbursement criteria.

Conclusions

In terms of insurance coverage, HIRA's reimbursement criteria was more effective in providing healthcare access to patients who had the most pressing need for TKA compared to other TKA appropriateness criteria. However, we found the lower age limit and patient-reported outcome measures of other criteria as useful tools in improving appropriateness of the current reimbursement criteria.

Total hip arthroplasty through the direct anterior approach in morbidly obese patients

Aims

There is evidence that morbidly obese patients have more intra- and postoperative complications and poorer outcomes when undergoing total hip arthroplasty (THA) with the direct anterior approach (DAA). The aim of this study was to determine the efficacy of DAA for THA, and compare the complications and outcomes of morbidly obese patients with nonobese patients.

Methods

Morbidly obese patients (n = 86), with BMI ≥ 40 kg/m² who underwent DAA THA at our institution between September 2010 and December 2017, were matched to 172 patients with BMI < 30 kg/m². Data regarding demographics, set-up and operating time, blood loss, radiological assessment, Harris Hip Score (HHS), International Hip Outcome Tool (12-items), reoperation rate, and complications at two years postoperatively were retrospectively analyzed.

Results

No significant differences in blood loss, intra- and postoperative complications, or implant position were observed between the two groups. Superficial wound infection rate was higher in the obese group (8.1%) compared to the nonobese group (1.2%) (p = 0.007) and relative risk of reoperation was 2.59 (95% confidence interval 0.68 to 9.91). One periprosthetic joint infection was reported in the obese group. Set-up time in the operating table and mean operating time were higher in morbidly obese patients. Functional outcomes and patient-related outcome measurements were superior in the obese group (mean increase of HHS was 52.19 (SD 5.95) vs 45.1 (SD 4.42); p < 0.001), and mean increase of International Hip Outcome Tool (12-items) was 56.8 (SD 8.88) versus 55.2 (SD 5.85); p = 0.041).

Conclusion

Our results suggest that THA in morbidly obese patients can be safely and effectively performed via the DAA by experienced surgeons.

Cite this article: Bone Jt Open 2022;3(1):4–11.

Effects of Sarcopenic Obesity and Its Confounders on Knee Range of Motion Outcome after Total Knee Replacement in Older Adults with Knee Osteoarthritis: A Retrospective Study

Sarcopenic obesity is closely associated with knee osteoarthritis (KOA) and has high risk of total knee replacement (TKR). In addition, poor nutrition status may lead to sarcopenia and physical frailty in KOA and is negatively associated with surgery outcome after TKR. This study investigated the effects of sarcopenic obesity and its confounding factors on recovery in range of motion (ROM) after total knee replacement (TKR) in older adults with KOA. A total of 587 older adults, aged ≥60 years, who had a diagnosis of KOA and underwent TKR, were enrolled in this retrospective cohort study. Sarcopenia and obesity were defined based on cutoff values of appendicular mass index and body mass index for Asian people. Based on the sarcopenia and obesity definitions, patients were classified into three body-composition groups before TKR: sarcopenic-obese, obese, and non-obese. All patients were asked to attend postoperative outpatient follow-up admissions. Knee flexion ROM was measured before and after surgery. A ROM cutoff of 125 degrees was used to identify poor recovery post-surgery. Kaplan-Meier curve analysis was performed to measure the probability of poor ROM recovery among study groups. Cox multivariate regression models were established to calculate the hazard ratios (HRs) of postoperative poor ROM recovery, using potential confounding factors including age, sex, comorbidity, risk of malnutrition, preoperative ROM, and outpatient follow-up duration as covariates. Analyses results showed that patients in the obese and sarcopenic-obese groups had a higher probability of poor ROM recovery compared to the non-obese group (all p < 0.001). Among all body-composition groups, the sarcopenic-obese group yielded the highest risk of postoperative physical difficulty (adjusted HR = 1.63, p = 0.03), independent to the potential confounding factors. Sarcopenic obesity is likely at the high risk of poor ROM outcome following TKR in older individuals with KOA.

The Fate of Morbidly Obese Patients With Joint Pain: A Retrospective Study of Patient Outcomes

BACKGROUND

The number of obese patients seeking a total joint arthroplasty (TJA) continues to increase. Weight loss is often recommended to treat joint pain and reduce risks associated with TJA. We sought to determine the effectiveness of an orthopedic surgeon's recommendation to lose weight.

METHODS

We identified morbidly obese (body mass index (BMI) 40-49.9 kg/m²) and super obese (BMI ≥50 kg/m²) patients with hip or knee osteoarthritis. Patients with less than 3-month follow-up were excluded. Patient characteristics (age, gender, BMI, comorbidities), disease characteristics (joint affected, radiographic osteoarthritis grading), and treatments were recorded. Clinically meaningful weight loss was defined as weight loss greater than 5%.

RESULTS

Two hundred thirty morbid and 50 super obese patients were identified. Super obese patients were more likely to be referred to weight management (52.0% vs 21.7%, P < .001) and were less likely to receive TJA (20.0% vs 41.7%, P = .004). Each 1 kg/m² increase in BMI decreased the odds of TJA by 10.9% (odds ratio = 0.891, 95% confidence interval: 0.833-0.953, P = .001). Forty (23.0%) of the nonoperatively treated patients achieved clinically meaningful weight loss, and 19 (17.9%) patients who underwent TJA lost weight before surgery. After surgery, the number of patients who achieved a clinically meaningful weight loss grew to 32 (30.2%).

CONCLUSION

In morbid and super obese patients, increasing BMI reduces the likelihood that a patient will receive TJA, and when counseled by their orthopedic surgeon, few patients participate in weight-loss programs or are otherwise able to lose weight. Weight loss is an inconsistently modifiable risk factor for joint replacement surgery.

Impact of Obesity on the Forgotten Joint Score Following Primary Total Hip Arthroplasty

BACKGROUND

Obesity is a growing public health concern. This study aims to identify the association of body mass index (BMI) on postoperative Forgotten Joint Score-12 (FJS-12) in patients undergoing primary total hip arthroplasty (THA).

METHODS

We retrospectively reviewed 2130 patients at a single urban, academic, tertiary institution who underwent primary THA from 2016-2020 with available postoperative FJS-12 scores. Patients were stratified into two groups based on their BMI (kg/m²):<30 (nonobese) and ≥30 (obese). FJS-12 scores were collected postoperatively at 3 months, 1 year, and 2 years. Demographic differences were assessed with chi-square and independent sample t-tests. Mean scores between the groups were compared using multilinear regression analysis, controlling for demographic differences.

RESULTS

Of the 2130 patients included, 1378 were nonobese, and 752 were obese. Although obese patients reported lower FJS-12 scores all time periods, there were no statistical differences between the two groups at 3 months (53.61 vs 49.62;P = .689), 1 year (68.11 vs 62.45; P = .349), and 2 years (73.60 vs 65.58; P = .102). A subanalysis comparing patients who were of normal BMI (<25), overweight (25.0-29.9), and obese (≥30) followed a similar inverse trend in scores but showed no statistical differences at all postoperative time points (3m:P = .612,1y:P = .607,2y:P = .253). Mean improvement in FJS-12 scores from 3 months to 1 year (14.50 vs 12.83; P = .041), 1 year to 2 years (5.49 vs 3.13; P = .004), and from 3 months to 2 years (20.00 vs15.96; P < .001) were significantly greater for nonobese patients compared to obese patients.

CONCLUSION

While obesity trended toward lower FJS-12 scores, the differences in scores were not statistically significant compared to nonobese patients. BMI did not influence overall FJS-12 scores; however, obese patients achieved a slightly smaller statistical improvement during the first 2 years, though this may not be clinically significant.

LEVEL III EVIDENCE

Retrospective Cohort Study.

Revision Rates and Functional Outcomes Among Severely, Morbidly, and Super-Obese Patients Following Primary Total Knee Arthroplasty: A Systematic Review and Meta-Analysis

BACKGROUND

Obesity has been associated with a greater burden of symptomatic knee osteoarthritis. There is some evidence that patients with a very high body mass index (BMI) may have a higher risk of complications and poor outcomes following total knee replacement compared with non-obese patients or obese patients with a lower BMI. We hypothesized that increasing degrees of obesity would be associated with deteriorating outcomes for patients following total knee replacement.

METHODS

We performed a comprehensive systematic review of 4 medical databases (MEDLINE, AMED, Ovid Healthstar, and Embase) from inception to August 2016. We extracted data to determine revision risk (all-cause, septic, and aseptic) and functional outcome scores (Western Ontario and McMaster Universities Osteoarthritis Index [WOMAC], Knee Society Score, Oxford Knee Score, EuroQol-5D, and Short Form [SF]-12 Physical Component Summary) in patients with severe obesity (BMI ≥35 kg/m), morbid obesity (BMI ≥40 kg/m), and super-obesity (BMI ≥50 kg/m) in comparison with patients with a normal BMI (<25 kg/m). Meta-analysis was performed using a random effects model.

RESULTS

We screened 3,142 titles and abstracts and 454 full-text articles to identify 40 eligible studies, of which 37 were included in the meta-analysis. Compared with patients with a normal BMI, the risk ratio for an all-cause revision surgical procedure was 1.19 (95% confidence interval [CI], 1.03 to 1.37; p = 0.02) in patients with severe obesity, 1.93 (95% CI, 1.27 to 2.95; p < 0.001) in patients with morbid obesity, and 4.75 (95% CI, 2.12 to 10.66; p < 0.001) in patients with super-obesity. The risk ratio for septic revision was 1.49 (95% CI, 1.28 to 1.72; p < 0.001) in patients with severe obesity, 3.69 (95% CI, 1.90 to 7.17; p < 0.001) in patients with morbid obesity, and 4.58 (95% CI, 1.11 to 18.91; p = 0.04) in patients with super-obesity. There were no significant differences (p > 0.05) in risk of aseptic revision. Based on the Knee Society Scores reported in a single study, patients with super-obesity had outcome scores, expressed as the standardized mean difference, that were 0.52 lower (95% CI, 0.80 lower to 0.24 lower; p < 0.001) than non-obese controls; however, no difference was observed for severe or morbidly obese patients.

CONCLUSIONS

The risk of septic revision is greater in patients with severe obesity, morbid obesity, and super-obesity, with progressively higher BMI categories associated with a higher risk. However, the risk of aseptic revision was similar between all obese and non-obese patients. Functional outcome improvements are also similar, except for super-obese patients, in whom data from a single study suggested slightly lower scores. These findings may serve to better inform evidence-based clinical, research, and policy decision-making.

LEVEL OF EVIDENCE

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

Concomitant Malnutrition and Frailty Are Uncommon, but Significant Risk Factors for Mortality and Complication Following Primary Total Knee Arthroplasty

BACKGROUND

Total knee arthroplasty (TKA) demand continues to rise, but we are also gaining greater insight into patient risk factors for postoperative complications and excess resource utilization. There has been growing interest in frailty and malnutrition as risk factors, although they are often mistakenly used interchangeably. We aimed at identifying the incidence of their coexistence, and the magnitude of risk they confer to TKA patients.

METHODS

We queried the American College of Surgeons-National Surgery Quality Improvement Program database to identify 4 patient cohorts: healthy/normal serum albumin, healthy/hypoalbuminemic patients, normoalbuminemic/medically frail patients (defined by modified frailty index), and hypoalbuminemic/frail patients. We performed both univariate and multivariate analyses to quantify the risk conferred by each condition in isolation, and in coexistence.

RESULTS

Of 179,702 elective TKA cases from 2006 to 2018, 18.6% of patients were frail only, 3.0% were hypoalbuminemic -only, and just 1.2% were both frail and hypoalbuminemic. The raw rate of any complication was highest in frail/hypoalbuminemic patients (8.7%), 5.2% in hypoalbuminemic patients, 4.8% in frail patients, and just 3.4% in healthy patients (P < .001); the multivariate model revealed odds ratio of a complication in frail/hypoalbuminemic group of 2.40 (95% confidence interval = 1.27-1.63; P < .001). Mortality within 30 days was highest in the frail/hypoalbuminemic cohort (1.0%), and just 0.1% in healthy patients, and the multivariate model noted an odds ratio of 9.43 for these patients (95% confidence interval = 5.92-14.93; P < .001). The odds of all studied complications were highest in the frail/hypoalbuminemic group.

CONCLUSION

Frailty and hypoalbuminemia represent distinct conditions and are independent risk factors for a complication after TKA. Their coexistence imparts a synergistic association with the risk of post-TKA complications.

Obesity and its effect on outcomes in same-day bilateral total knee arthroplasty

Background

The niche surgery of same-day bilateral total knee arthroplasty (sd-BTKA) continues to create debate amongst specialists in arthroplasty. To date, there is a significant lack of literature on obese patients undergoing sd-BTKA, and no study has evaluated outcomes of this procedure when compared to non-obese patients. Therefore, this study will perform a retrospective analysis to compare (I) incidence, (II) demographics, and (III) complications of sd-BTKA in non-obese, obese, and morbidly obese patients in the United States from 2009 to 2016.

Methods

The National Inpatient Sample (NIS) database was queried for all individuals that underwent sd-BTKA from 2009 to 2016. This returned 184,844 non-obese patients, 39,901 obese patients, and 20,394 morbidly obese patients. Analyzed variables included mean age, mean length of stay (LOS), race, payer, age-adjusted Charlson Comorbidity Index score, discharge disposition, hospital charges, hospital costs, and complications. Chi-square analyses and analyses of variance were utilized to assess categorical and continuous variables, respectively.

Results

Non-obese patients most commonly underwent sd-BTKA over the course of the study. As weight status increased, mean age decreased and the proportion of females, LOS, hospital charges and costs, and proportion of discharges to skilled nursing facilities increased. Regression analysis demonstrated obese and morbidly obese cohorts were at an overall increased odds for experiencing complications. Specifically, obese patients were at increased risk for pulmonary emboli, periprosthetic joint infections, and respiratory failures, while morbidly obese patients are at increased risk for pulmonary emboli, respiratory failures, and urinary tract infections.

Conclusions

Surgeons should thoroughly evaluate the risks and benefits of performing sd-BTKA on obese and morbidly obese patients, as both confer higher overall complication rates and increased length of stay. More research is necessary to characterize the cost analysis of this procedure, as health care models continue to transition to more cost-effective procedures.

Total Hip Arthroplasty in the Obese Patient: Tips and Tricks and Review of the Literature

AIM

There is a lack of consensus on the optimal method of performing primary hip arthroplasty in obese patients and limited evidence. This article presents a series of considerations based on the authors' experiences as well as a review of the literature.

PREOPERATIVE CARE

In the preoperative phase, an informed consent process is recommended. Weight loss is recommended according to NHS England guidelines, and body habitus should be taken into account. When templating, steps are taken to avoid overestimating the implant size.

SURGICAL PROCEDURE

During the surgical procedure, specialist bariatric equipment is utilised: bariatric beds, extra supports, hover mattresses, longer scalpels, diathermy, cell saver and minimally invasive surgery equipment. Communication with the anaesthetist and surgical team to anticipate is vital. Intraoperative sizing and imaging, if required, should be considered. Pneumatic foot pumps are preferable for VTE prophylaxis. Regional anaesthesia is preferred due to technical difficulty. IV antibiotics and tranexamic acid are recommended. The anterior and posterior surgical approaches are most frequently used; we advocate posterior. Incisions are extensile and a higher offset is considered intraoperatively, as well as dual mobility and constrained liners to reduce dislocation risk. When closing the wound, Charnely button and sponge should be considered as well as negative pressure wound dressings (iNPWTd) and drains.

POST-OPERATIVE CONSIDERATIONS

Postoperatively, difficult extubation should be anticipated with ITU/HDU beds available. Epidural anaesthetics for postoperative pain management require higher nursing vigilance. Chemical prophylaxis is recommended.

CONCLUSION

Despite being technically more difficult with higher risks, functional outcomes are comparable with patients with a normal BMI.

Association of the Intensive Lifestyle Intervention With Total Knee Replacement in the Look AHEAD (Action for Health in Diabetes) Clinical Trial

BACKGROUND

Evidence has established obesity as a risk factor for total knee replacement (TKR) due to osteoarthritis. Obesity is a risk factor for TKR. Randomized trials such as Look AHEAD (Action for Health in Diabetes) have shown long-term successful weight loss with an intensive lifestyle intervention (ILI). It is unknown, however, if intentional weight loss can reduce the risk of TKR.

METHODS

Look AHEAD randomized persons aged 45-76 with type 2 diabetes who had overweight or obesity to either an ILI to achieve/maintain 7% weight loss or to standard diabetes support and education (DSE). Reported knee pain was assessed using the Visual Analog Scale and Western Ontario McMaster University Osteoarthritis Index questionnaire in 5125 participants without previous TKR. Cox proportional hazard regression was used to model differences in risk of TKR in relation to randomization group assignment (ILI vs DSE) along with baseline body mass index category and baseline knee pain as potential confounders from baseline through Look AHEAD-Extension.

RESULTS

Baseline mean ± SD Western Ontario McMaster University Osteoarthritis Index knee pain scores did not differ by treatment assignment (ILI: 3.6 ± 2.9, DSE: 3.9 ± 3.0, P = .08); as expected due to randomization. During follow up, the 631 (12%) participants who reported having a TKR were more likely to have been heavier (P < .001) and older (P < .001) at enrollment, but risk of TKR did not differ by treatment group assignment (hazard ratio [HR] 1.07, 95% confidence interval [CI] 0.91-1.25, P = .43). Heterogeneity of treatment effect was observed according to baseline knee pain (interaction P = .02). In persons without knee pain at baseline, there was a 29% reduced risk of TKR in ILI compared to DSE (HR 0.71, 95% CI 0.52-0.96). However, in persons with knee pain at baseline, there was no statistically significant association of treatment assignment with respect to subsequent TKR incidence (HR 1.11, 95% CI 0.92-1.33).

CONCLUSION

Findings suggest that intensive lifestyle change including physical activity, dietary restriction and behavioral changes to achieve weight loss for prevention of TKR may be most effective in preventing TKR prior to the development of knee pain.

Ten-year risk of complication and mortality after total hip arthroplasty in morbidly obese patients: a population study

Background

The relationship between morbid obesity and long-term patient outcomes after primary total hip arthroplasty (THA) has been understudied. The purpose of this study was to determine the association between morbid obesity and 10-year complications (revision surgery, reoperation, dislocation) and mortality in patients undergoing primary THA.

Methods

We conducted a population-based cohort study of patients aged 45–74 years who underwent primary THA for osteoarthritis between 2002 and 2007 using Ontario administrative health care databases. Patients were followed for 10 years. We estimated risk ratios (RRs) of mortality, reoperation, revision and dislocation in patients with body mass index (BMI) greater than 45 kg/m2 (morbidly obese patients) compared with patients with a BMI of 45 kg/m2 or less (nonmorbidly obese patients).

Results

There were 22 251 patients in the study cohort, of whom 726 (3.3%) were morbidly obese. Morbid obesity was associated with higher 10-year risk of death (RR 1.38, 95% confidence interval [CI] 1.18–1.62). Risks of revision (RR 1.43, 95% CI 0.96–2.13) and dislocation (RR 2.38, 95% CI 1.38–4.10) were higher in morbidly obese men than in nonmorbidly obese men; there were no associations between obesity and revision or dislocation in women. Risk of reoperation was higher in morbidly obese women than in nonmorbidly obese women (RR 1.59, 95% CI 1.05–2.40); there was no association between obesity and reoperation in men.

Conclusion

Morbidly obese patients undergoing primary THA are at higher risk of long-term mortality and complications. There were differences in complication risk by sex. The results of this study should inform perioperative counselling of patients considering THA.

Does body mass index affect the rate of adverse outcomes in total hip and knee arthroplasty? A retrospective review of a total joint replacement database

Background

Total hip arthroplasty (THA) and total knee arthroplasty (TKA) are reliable surgical options to treat pain and disability resulting from degenerative conditions around the hip and knee. Obesity is a modifiable risk factor that contributes to significant morbidity. The purpose of this study was to retrospectively compare outcomes in primary hip and knee arthroplasty for patients with increased body mass index (BMI) and those with normal BMI, using data from the registry of the Alberta Bone and Joint Health Institute (ABJHI).

Methods

We retrospectively reviewed the data compiled in the ABJHI registry between March 2010 and July 2016. We reviewed outcomes with respect to length of stay, discharge destination, 30-day readmission, postoperative infection, postoperative transfusion requirements, postoperative adverse events and in-hospital postoperative mechanical complications.

Results

A total of 10 902 patients (6076 women, 4826 men) who underwent THA and 16 485 patients (10 057 women, 6428 men) who underwent TKA were included in the study. For both THA and TKA, patients with increased BMI had an increased number of in-hospital medical events, had an increased rate of deep infection, were less likely to be discharged home (p < 0.001) and had decreased transfusion requirements (p < 0.001) than patients whose weight was in the normal range. Increased BMI increased the rate of 30-day readmission and length of stay in the THA cohort but not in the TKA cohort. Increased BMI had no effect on acute postoperative dislocation or periprosthetic fractures. Patients with a BMI of 30 kg/m2 or greater required a THA 1.7 years earlier than patients of normal weight, patients whose BMI was 35 kg/m2 or greater required a THA 3.4 years earlier, and patients whose BMI was 40 kg/m2 or greater required a THA 5.8 years earlier. In the TKA cohort, patients with a BMI of 30 kg/m2 or greater required a TKA 2.7 years earlier than patients whose weight was in the normal range, patients with a BMI of 35 kg/m2 or greater required a TKA 4.6 years earlier, and patients whose BMI was 40 kg/m2 or greater required a TKA 7.6 years earlier.

Conclusion

Our study quantifies the effects of obesity in primary hip and knee arthroplasty. It provides a greater understanding of the risks in the obese population when contemplating joint arthroplasty.

The effect of body mass index on 30-day complications after total hip arthroplasty

BACKGROUND

Evaluating body mass index (BMI) as a continuous variable eliminates the potential pitfalls of only considering BMI as a binary or categorical variable, as most studies do when correlating BMI and total hip arthroplasty (THA) outcomes. Therefore, the objective of this study was to correlate the effect of continuous BMI on 30-day complications post-THA. Specifically, we correlated BMI to: (1) 30-day readmissions and reoperations; (2) medical complications; and (3) surgical complications in: (a) normal-weight; (b) over-weight; (c) obese; and (d) morbidly obese patients.

METHODS

Using the NSQIP database, 93,598 primary THAs were identified. 30-day rates of readmissions, reoperations, and medical/surgical complications as well as patient BMI data were extrapolated. A comparative analysis using univariate, multivariate, and spline regression models adjusting for demographics and comorbidities were created to study the continuous effect of BMI on different outcomes.

RESULTS

Readmission (p < 0.001), reoperation (p = 0.007), superficial infection (p = 0.003), prosthetic joint infection (p < 0.001), and sepsis (p = 0.026) had a J-shaped relationship with BMI, with the lowest rates seen in patients with BMI around 28 kg/m². The risks of mortality (p = 0.007) and transfusion (p < 0.001) had a reverse J-shaped relationship, with the risk steadily decreasing for BMIs in the normal weight and overweight range, and then flattening afterwards.

CONCLUSION

This data proposes a multifactorial effect of BMI on post-THA complications. Considering BMI as a continuous variable allows for a better assessment when considering the interplay between modifiable risk factors, such as smoking or alcohol use, as well as multiple comorbidities.

Higher body mass index is not a risk factor for in-hospital adverse outcomes following total knee arthroplasty

PURPOSE

To investigate the association between body mass index (BMI) and perioperative complications until hospital discharge, following primary total knee arthroplasty (TKA).

METHODS

This retrospective study reviewed 1665 cases of elective primary unilateral TKA performed between 2006 and 2010, from a prospective secure electronic database. Types of complications, length of operating time, and duration of hospital stay were analyzed in both adjusted (for known confounders) and unadjusted analyses. A further matched analysis was also performed.

RESULTS

In terms of overall complications, there was no statistically significant difference between the BMI categories. When individual obesity category was considered, obese 2 had the lowest odds of developing complications, both with unadjusted (odds ratio (OR): 0.61, 95% confidence interval (CI) 0.41-0.91, p < 0.015) and adjusted regression analysis (OR: 0.65, 95% CI: 0.43-0.99, p = 0.044). Compared to normal weight category, obese class 3 (≥40 kg/m²) individuals were at 66% (OR: 0.34, 95% CI: 0.21-0.55) lower (unadjusted) odds of developing cardiac complications (overall p < 0.001). With the matched analysis, compared to normal weight category, obese class 3 (≥40 kg/m²) individuals were at a 60% (OR: 0.40, 95% CI: 0.23-0.68) lower (unadjusted) odds of developing cardiac complications (overall p = 0.004). Obese 3 patients had significantly higher operating time compared with other groups ( p < 0.001).

CONCLUSION

This study did not find a significant association between BMI and increased overall in-hospital medical or surgical complications following primary TKA. Obesity significantly increased the length of operating time.

Body mass index and in-hospital postoperative complications following primary total hip arthroplasty

BACKGROUND

The influence of obesity measured in terms of body mass index (BMI) on the complication rates following total hip arthroplasty (THA) is a matter of debate.

METHODS

This retrospective study conducted at a tertiary referral centre at Brisbane, Australia, examines the association between BMI and in-hospital postoperative complications, length of operating time and duration of hospital stay in 964 patients, who underwent THA from 2006 to 2010.

RESULTS

Amongst patients undergoing primary THA, when compared to the normal weight patients, those with BMI between 25 kg/m² and 29.9 kg/m² (overweight) and those with BMI between 35 kg/m² and 39.9 kg/m² (obese class II) had lower odds of perioperative complications (odds ratio [OR]: 0.62 (95% confidence intervals [CI], 0.43-0.92, p = 0.016) and OR: 0.60 (95% CI, 0.36- 0.99, p = 0.047 respectively). Patients with BMI less than or equal to 40 kg/m² were also associated with significantly lower odds of cardiac complications ( p = 0.02). With unadjusted regression analysis, it was noted that those with BMI ≥40 kg/m² had the highest odds of developing infectious complications (OR 2.68, 95% CI, 1.08-6.65, p < 0.05). As the BMI increased, there was a statistically significant increase in length of operating time ( p < 0.001).

CONCLUSION

There is a significant impact of BMI on the occurrence of perioperative complications following THA. Compared to normal weight category, the overweight and obese class II patients had a lower likelihood of developing overall, especially cardiac complications. Length of operating time increases along with an increase in BMI.

The impact of sarcopenic obesity on knee and hip osteoarthritis: a scoping review

BACKGROUND

The progressive, debilitating nature of knee and hip osteoarthritis can result in severe, persistent pain and disability, potentially leading to a need for total joint arthroplasty (TJA) in end-stage osteoarthritis. TJA in adults with obesity is associated with increased surgical risk and prolonged recovery, yet classifying obesity only using body mass index (BMI) precludes distinction of obesity phenotypes and their impact on surgical risk and recovery. The sarcopenic obesity phenotype, characterized by high adiposity and low skeletal muscle mass, is associated with higher infection rates, poorer function, and slower recovery after surgery in other clinical populations, but not thoroughly investigated in osteoarthritis. The rising prevalence and impact of this phenotype demands further attention in osteoarthritis treatment models of care, particularly as osteoarthritis-related pain, disability, and current treatment practices may inadvertently be influencing its development.

METHODS

A scoping review was used to examine the extent of evidence of sarcopenic obesity in adults with hip or knee osteoarthritis. Medline, CINAHL, Web of Science and EMBASE were systematically searched from inception to December 2017 with keywords and subject headings related to obesity, sarcopenia and osteoarthritis.

RESULTS

Eleven studies met inclusion criteria, with indications that muscle weakness, low skeletal muscle mass or sarcopenia are present alongside obesity in this population, potentially impacting therapeutic outcomes, and TJA surgical risk and recovery.

CONCLUSIONS

Consideration of sarcopenic obesity should be included in osteoarthritis patient assessments.

Saphenous Nerve Block From Within the Knee Is Feasible for TKA: MRI and Cadaveric Study

BACKGROUND

Surgeon-performed periarticular injections and anesthesiologist-performed femoral nerve or adductor canal blocks with local anesthetic are in common use as part of multimodal pain management regimens for patients undergoing TKA. However, femoral nerve blocks risk causing quadriceps weakness and falls, and anesthesiologist-performed adductor canal blocks are costly in time and resources and may be unreliable. We investigated the feasibility of a surgeon-performed saphenous nerve ("adductor canal") block from within the knee at the time of TKA.

QUESTIONS/PURPOSES

(1) Can the saphenous nerve consistently be identified distally on MRI studies, and is there a consistent relationship between the width of the femoral transepicondylar axis (TEA) and the proximal (cephalad) location where the saphenous nerve emerges from the adductor canal? With these MRI data, we asked the second question: (2) Can we utilize this anatomic relationship to simulate a surgeon-performed intraoperative block of the distal saphenous nerve from within the knee with injections of dyes after implantation of trial TKA components in cadaveric lower extremity specimens?

METHODS

A retrospective analysis of 94 thigh-knee MRI studies was performed to determine the relationship between the width of the distal femur at the epicondylar axis and the proximal location of the saphenous nerve after its exit from the adductor canal and separation from the superficial femoral artery. These studies, obtained from one hospital's MRI library, had to depict the saphenous nerve in the distal thigh and the femoral epicondyles and excluded patients younger than 18 years of age or with metal implants. These studies were performed to evaluate thigh and knee trauma or unexplained pain, and 55 had some degree of osteoarthritis. After obtaining these data, TKA resections and trial component implantation were performed, using a medial parapatellar approach, in 11 fresh cadaveric lower extremity specimens. There were six male and five female limbs from cadavers with a mean age of 70 years (range, 57-80 years) and mean body mass index of 20 kg/m (range, 15-26 kg/m) without known knee arthritis. Using a blunt-tipped 1.5-cm needle, we injected 10 mL each of two different colored solutions from inside the knee at two different locations and, after 30 minutes, dissected the femoral and saphenous nerves and femoral artery from the hip to the knee. Our endpoints were whether the saphenous nerve was bathed in dye and if the dye or needle was located in the femoral artery or vein.

RESULTS

Based on the MRI analysis, the mean ± SD TEA was 75 ± 4 mm in females and 87 ± 4 mm in males. The saphenous nerve exited the adductor canal and was located at a mean of 1.5 ± 0.16 times the TEA width in females and a mean of 1.3 ± 0.13 times the TEA width in males proximal to the medial epicondyle. After placement of TKA trial components and injection, the proximal injection site solution bathed the saphenous nerve in eight of 11 specimens. In two cachectic female cadaver limbs, the dye was located posteriorly to the nerve in hamstring muscle. The proximal blunt needle and colored solution were directly adjacent to but did not penetrate the femoral artery in only one specimen.

CONCLUSIONS

This study indicates, based on MRI measurements, cadaveric injections, and dissections, that a surgeon-performed injection of the saphenous nerve from within the knee after it exits from the adductor canal seems to be a feasible procedure.

CLINICAL RELEVANCE

This technique may be a useful alternative to an ultrasound-guided block. A trial comparing surgeon- and anesthesiologist-performed nerve block should be considered to determine the clinical efficacy of this procedure.

A Preoperative Scale for Determining Surgical Readmission Risk After Total Knee Arthroplasty

BACKGROUND

Total knee arthroplasty (TKA) is one of the most common orthopaedic procedures performed in the U.S. The purpose of this study was to develop and verify a scale to preoperatively stratify a patient's risk of being readmitted to the hospital following a TKA.

METHODS

Discharge data on 433,638 patients from New York and California (derivation cohort) and 269,934 patients from Florida and Washington (validation cohort) who underwent TKA were collected from the State Inpatient Database, a part of the Healthcare Cost and Utilization Project of the Agency for Healthcare Research and Quality (2006 to 2011). Demographic and clinical characteristics of patients were abstracted and analyzed to develop the Readmission After Total Knee Arthroplasty (RATKA) Scale.

RESULTS

Overall 30-day readmission rates in the derivation and validation cohorts were 5.11% and 4.98%, respectively. The following factors were significantly associated with increased 30-day readmission rates in the derivation cohort: age of 41 to 50 years (odds ratio [OR] = 1.13), age of 71 to 80 years (OR = 1.21), age of 81 to 90 years (OR = 1.70), male sex (OR = 1.19), African-American race (OR = 1.37), "other" race/ethnicity (OR = 1.08), Medicaid payer (OR = 1.43), Medicare payer (OR = 1.27), anemia (OR = 1.19), chronic obstructive pulmonary disease (OR = 1.29), coagulopathy (OR = 1.22), congestive heart failure (OR = 1.64), diabetes (OR = 1.19), fluid and electrolyte disorder (OR = 1.25), hypertension (OR = 1.10), liver disease (OR = 1.27), renal failure (OR = 1.33), and rheumatoid arthritis (OR = 1.14). These factors were used to create the RATKA Scale. The RATKA score was then used to define 3 levels of risk for readmission: low (RATKA score of <13; 3.7% readmission rate), moderate (RATKA score of 13 to 16; 5.4% readmission rate), and high (RATKA score of >16; 7.6% readmission rate). The relative risk of readmission was 2.06 for the high-risk group compared with the low-risk group.

CONCLUSIONS

The RATKA Scale derived from patient data from the derivation cohort was reliably able to explain readmission variability after TKA for patients in the validation cohort at a rate of >95%. Models such as the RATKA Scale will enable identification of the risk of readmission following TKA based on a patient's risk profile prior to surgery.

LEVEL OF EVIDENCE

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

Morbid Obesity in Total Knee Arthroplasty: Joint-Specific Variance in Outcomes for Operative Time, Length of Stay, and Readmission

BACKGROUND

It is increasingly apparent that the effect of obesity in arthroplasty is joint-specific. This study evaluates the effects of morbid obesity on primary total knee arthroplasty by comparing short-term outcomes between a morbidly obese (body mass index ≥40 kg/m²) and a normal weight (body mass index 18.5-<25 kg/m²) cohort at our institution between January 2003 and December 2010.

METHODS

One hundred seventeen morbidly obese patients were compared with 94 normal weight patients. Operative time, length of stay, complications, 30-day readmission, and readmission length were compared.

RESULTS

Morbid obesity conveyed no significant increase in 30-day readmission. Operative time was increased at 100 minutes in the morbidly obese group, compared with 90.5 minutes (P = .026).

CONCLUSION

Morbid obesity conveyed no increased risk of length of stay or readmission in this cohort.

Influence of Body Mass Index on Sagittal Knee Range of Motion and Gait Speed Recovery 1-Year After Total Knee Arthroplasty

BACKGROUND

The purpose of this prospective study was to investigate the influence of body mass index (BMI) on gait parameters preoperatively and 1 year after total knee arthroplasty (TKA).

METHODS

Seventy-nine patients were evaluated before and 1 year after TKA using clinical gait analysis. The gait velocity, the knee range of motion (ROM) during gait, their gains (difference between baseline and 1 year after TKA), the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC), quality of life, and patient satisfaction were assessed. Nonobese (BMI <30 kg/m²) and obese patients (BMI ≥30 kg/m²) were compared. Healthy controls were also assessed. Univariate and multivariate linear regression analyses were used to assess the association between gait speed and ROM gains. Adjustment was performed for gender, age, and WOMAC pain improvement.

RESULTS

At baseline, gait velocity and knee ROM were significantly lower in obese compared with those in the nonobese patients (0.99 ± 0.27 m/s vs 1.11 ± 0.18 m/s; effect size, 0.53; P = .021; and ROM, 41.33° ± 9.6° vs 46.05° ± 8.39°; effect size, 0.52; P = .022). Univariate and multivariate linear regressions did not show any significant relation between gait speed gain or knee ROM gain and BMI. At baseline, obese patients were more symptomatic than nonobese (WOMAC pain: 36.1 ± 14.0 vs 50.4 ± 16.9; effect size, 0.9; P < .001), and their improvement was significantly higher (WOMAC pain gain, 44.5 vs 32.3; effect size, 0.59; P = .011).

CONCLUSION

These findings show that all patients improved biomechanically and clinically, regardless of their BMI.

Do patients lose weight after total knee replacement?

OBJECTIVE

Several studies show that patients undergoing total knee arthroplasty (TKA) tend to maintain or gain weight after the procedure, which would result in increased wear of the prosthesis and new surgical interventions in a smaller period of time in comparison with patients with adequate body mass index (BMI). The aim of this study was to investigate the effect of TKA surgery on these patients' BMI.

METHODS

Initially the records were analyzed, chosen at random from 91 patients undergoing TKA during the period from August 2011 to July 2013. Patients were stratified by BMI as normal weight (BMI between 20 and 25), overweight (BMI between 25 and 30), and obesity (BMI > 30). They were re-evaluated in a minimum period of 18 months.

RESULTS

The mean age of the sample population was 68.1 years; 69.1 for men and 67.2 for women. The mean preoperative BMI was 27.24 kg/m². Among the study participants, in the preoperative period, 17 patients had normal weight, 65 were overweight, and nine were obese. Postoperative analysis showed weight loss in 41 patients (46%), and weight gain in 50 patients (54%). The mean postoperative BMI was 27.16 kg/m², in general, experiencing a slight decline in the mean BMI of 0.08 kg/m².

CONCLUSION

Patients who underwent TKA did not achieve significant reduction in BMI after surgery.

Fracture of the femoral component after a lightning strike injury: A case report

A fracture of the stem in a total hip arthroplasty (THA) is an uncommon complication. We report a case of femoral stem fracture in a 55-year-old male patient after a lightning strike. A revision was conducted using a Wagner osteotomy and a revision prosthesis. Dall-Milles cerclages were used to close the osteotomy. The postoperative evolution was satisfactory, with an immediate partial weight bearing, consolidation of the osteotomy after three months and return to daily activity without pain.

Risk Factors for Wound Complications After Direct Anterior Approach Hip Arthroplasty

BACKGROUND

Previous studies have suggested that wound complications may be higher after direct anterior approach (DAA) hip arthroplasty, but, specific risk factors have not been closely examined.

METHODS

We conducted a retrospective case-control study of 651 consecutive DAA hip arthroplasty surgeries performed by 2 surgeons over a 3-year period. Outcome measures included any postoperative wound problem (including prolonged drainage, wound dehiscence, wound necrosis, suture granuloma, and superficial infection) requiring additional intervention or reoperation. Univariate odds ratios (ORs) were calculated, and multivariate logistic regression analysis was performed to determine risk correlation. Receiver operator characteristic (ROC) curves were created to determine disease predictability.

RESULTS

A total of 75 patients (11.5%) experienced wound complications requiring additional intervention, of which, 13 (1.9%) required reoperation. Multivariate regression analysis found that development of wound complications was significantly and independently associated with body mass index (BMI) 30-35 kg/m² (OR 2.05; 95% confidence interval [CI] 1.08-3.88), BMI 35-40 kg/m² (OR 3.40; 95% CI 1.42-8.26), BMI > 40 kg/m² (OR 7.28; 95% CI 2.55-20.78), and diabetes mellitus (OR 2.97; 95% CI 1.46-6.07). Reoperation for wound complication was significantly associated with BMI > 40 kg/m² (OR 5.68; 95% CI 1.17-27.48) and diabetes mellitus (OR 13.08; 95% CI 3.97-43.11). Optimal cutoff values for BMI were found through receiver operator characteristic curve analysis to be 28.0 kg/m² for development of wound complications and 28.2 kg/m² for reoperation for wound complications.

CONCLUSION

Obesity and diabetes mellitus are significantly associated with postoperative wound-healing complications and the need for reoperation for these wound complications after DAA hip arthroplasty.

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

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSION

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

Morbidly Obese vs Nonobese Aseptic Revision Total Hip Arthroplasty: Surprisingly Similar Outcomes

BACKGROUND

We aimed to compare the outcomes between matched morbidly obese (BMI ≥ 40 kg/m(2)) and nonobese (BMI <30 kg/m(2)) patients undergoing first-time aseptic revision THA with at least 4 years of follow-up.

METHODS

Groups were matched 1:1 using sex, age, and date of revision surgery (123 patients in each group).

RESULTS

The overall incidence and risk of complication, reoperation, and re-revision were similar between groups. Morbidly obese patients were more likely to dislocate (odds ratio [OR], 3.3; P = .03), but were less likely to develop polyethylene wear (OR, 0.1; P = .04) and aseptic loosening (OR, 0.3; P = .03).

CONCLUSION

Quality outcome measures such as hospital readmission were not addressed by this study and could be the basis for future studies.

LEVEL OF EVIDENCE

level III, prognostic study.

Contemporary Surgical Indications and Referral Trends in Revision Total Hip Arthroplasty: A 10-Year Review

BACKGROUND

Revision total hip arthroplasty (THA) represents nearly 15% of all hip arthroplasty procedures in the United States and is projected to increase. The purpose of our study was to summarize the contemporary indications for revision THA surgery at a tertiary referral medical center. We also sought to identify the indications for early and late revision surgery and define the prevalence of outside institution referral for revision THA.

METHODS

Using our institution's arthroplasty registry, we identified a retrospective cohort of 870 consecutive patients who underwent revision THA at our hospital from 2004 to 2014. Records were reviewed to collect data on patient's primary and revision THA procedures, and the interval between primary THA and revision surgery was determined.

RESULTS

Aseptic loosening (31.3%), osteolysis (21.8%), and instability (21.4%) were the overall most common indications for revision THA and the most common indications for revision surgery within 5 years of primary THA. Aseptic loosening and osteolysis were the most common indications for revision greater than 5 years from primary THA. Only 16.4% of revised hips had their index arthroplasty performed at our hospital, whereas 83.6% were referred to our institution.

CONCLUSIONS

Aseptic loosening, osteolysis, and instability remain the most common contemporary indications for revision THA in an era of alternative bearings and modular components. Most of our revisions were referred from outside institutions, which highlights the transfer of a large portion of the revision THA burden to tertiary referral centers, a pattern that could be exacerbated under future bundled payment models.

Obesity is associated with increased postoperative complications after total elbow arthroplasty

BACKGROUND

Obesity has become a significant public health concern in the United States. Few published data have examined the association between obesity and postoperative complications after total elbow arthroplasty (TEA).

METHODS

Patients who underwent TEA were identified using the PearlDiver database Current Procedural Terminology codes. Patients were divided into obese and nonobese cohorts using International Classification of Diseases, Ninth Revision codes. Each cohort was then assessed for major and minor complications within 90 days postoperatively. Odds ratios, 95% confidence intervals, and χ(2) tests were calculated, with P < .05 considered significant.

RESULTS

From 2005 to 2011, 7580 patients who underwent TEA were identified, of whom 1030 patients (14%) were coded as obese (body mass index > 30) and 611 patients (8%) were coded as morbidly obese (body mass index > 40). The obese TEA patients had increased risk of 90-day major and minor complications. The rate of postoperative venous thromboembolism differed significantly between groups, with a trend toward a higher venous thromboembolism rate in obese patients (2.2%) vs. nonobese patients (0.7%). Rate of postoperative stiffness was similar between groups. Infection rates were higher in obese patients compared with nonobese patients. Medical complications were higher in obese patients (16.7%) compared with the nonobese cohort (4.7%). A significant difference in implant removal was notable at 6 months and 1 year in morbidly obese patients compared with nonobese counterparts.

CONCLUSIONS

Obesity and associated medical comorbidities place patients at increased risk for complications after TEA. Obese patients and especially morbidly obese patients thinking of undergoing TEA should be appropriately counseled preoperatively about their increased risk for complications.

Quantifying the Burden of Revision Total Joint Arthroplasty for Periprosthetic Infection

Periprosthetic joint infection (PJI) represents substantial clinical and economic burdens. This study evaluated patient and procedure characteristics and resource utilization associated with revision arthroplasty for PJI. The Nationwide Inpatient Sample (Q4 2005-2010) was analyzed for 235,857 revision THA (RTHA) and 301,718 revision TKA (RTKA) procedures. PJI was the most common indication for RTKA, and the third most common reason for RTHA. PJI was most commonly associated with major severity of illness (SOI) in RTHA, and with moderate SOI in RTKA. RTHA and RTKA for PJI had the longest length of stay. Costs were higher for RTHA/RTKA for PJI than for any other diagnosis except periprosthetic fracture. Epidemiologic differences exist in the rank, severity and populations for RTHA and RTKA for PJI.

Dealing with the predicted increase in demand for revision total knee arthroplasty: challenges, risks and opportunities

Worldwide rates of primary and revision total knee arthroplasty (TKA) are rising due to increased longevity of the population and the burden of osteoarthritis. Revision TKA is a technically demanding procedure generating outcomes which are reported to be inferior to those of primary knee arthroplasty, and with a higher risk of complication. Overall, the rate of revision after primary arthroplasty is low, but the number of patients currently living with a TKA suggests a large potential revision healthcare burden. Many patients are now outliving their prosthesis, and consideration must be given to how we are to provide the necessary capacity to meet the rising demand for revision surgery and how to maximise patient outcomes. The purpose of this review was to examine the epidemiology of, and risk factors for, revision knee arthroplasty, and to discuss factors that may enhance patient outcomes.

The Effect of BMI on 30 Day Outcomes Following Total Joint Arthroplasty

Hip and knee arthroplasty (THA, TKA) are safe, effective procedures with reliable, reproducible outcomes. We aim to investigate obesity's effect on complications following arthroplasty surgery. Using the American College of Surgeons-National Surgical Quality Improvement Program database, 13,250 subjects were stratified into 5 groups based on BMI and matched for gender, age, surgery type and ASA class. Matched, multivariable generalized linear models adjusting for demographics and comorbidities demonstrated an association between elevated BMI and overall (P<0.001), medical (P=0.005), surgical complications (P<0.001), including superficial (P=0.019) and deep wound infection (P=0.040), return to OR (P=0.016) and time from OR to discharge (P=0.003). Elevated BMI increases risk for post-operative complications following total joint arthroplasty.

Weight changes after total hip or knee arthroplasty: prevalence, predictors, and effects on outcomes

BACKGROUND

Conflicting evidence exists with regard to weight loss after total hip arthroplasty or total knee arthroplasty. The purposes of this study were to determine whether patients lose weight after total hip arthroplasty or total knee arthroplasty, whether there are predictors of weight change after total hip arthroplasty or total knee arthroplasty, and whether weight changes after total hip arthroplasty or total knee arthroplasty affect patient-reported outcomes.

METHODS

Using our institutional registry, we evaluated the two-year change in self-reported body mass indices for all patients who underwent elective, unilateral total hip arthroplasty or total knee arthroplasty for osteoarthritis. A 5% change in body mass index was considered clinically meaningful. Patient-reported outcomes were compared between patients who underwent total hip arthroplasty and those who underwent total knee arthroplasty and between obesity classes, on the basis of whether patients gained, lost, or maintained weight.

RESULTS

We reviewed 3893 total hip arthroplasties and 3036 total knee arthroplasties. Of the patients who underwent total joint arthroplasty, 73% (2850 patients) in the total hip arthroplasty group and 69% (2090 patients) in the total knee arthroplasty group demonstrated no change in body mass index. Patients who underwent total knee arthroplasty were more likely to lose weight than patients who underwent total hip arthroplasty. Increasing preoperative obesity correlated with a greater likelihood of weight loss. Patients who underwent total knee arthroplasty and lost weight demonstrated better clinical outcome scores, but weight gain in general was associated with inferior clinical outcomes. Greater body mass index, total knee arthroplasty, and female sex were significant predictors of weight loss (p < 0.05). Better preoperative functional status was significantly associated with a lower likelihood of weight gain (p < 0.05).

CONCLUSIONS

Most patients maintained their body mass index after total hip arthroplasty or total knee arthroplasty. Female patients, patients with higher preoperative body mass index, and those who underwent total knee arthroplasty were more likely to lose weight after surgery.

LEVEL OF EVIDENCE

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