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

Impact of obesity on early in-hospital postoperative outcomes following total knee arthroplasty in older adults: a comparative study of class I and class II obesity

INTRODUCTION

The rising prevalence of obesity has increased the demand for total knee arthroplasty (TKA), but the impact on outcomes, particularly in Class I and II obesity, remains inconclusive. This study aimed to compare early in-hospital post-TKA outcomes in older patients with Class I (BMI 30-34.9 kg/m²) and Class II obesity (BMI 35-39.9 kg/m²).

MATERIALS AND METHODS

Using data from the Nationwide Inpatient Sample (2016-2019), patients aged 65 and above who underwent TKA were categorized into Class I (n = 133,425) and Class II obesity groups (n = 122,432). Propensity score matching balanced baseline characteristics. Primary outcomes included in-hospital mortality and early postoperative complications.

RESULTS

Post-matching, a higher prevalence of type 2 diabetes was found in the Class II obesity group (32.5% vs. 29.5%, P = 0.001). The Class II group had a significantly higher risk of in-hospital mortality (9.004-fold, 95% CI: 3.57-22.68, P < 0.001), acute kidney injury (45.8% increase, 95% CI: 1.383-1.537, P < 0.001), and postoperative pneumonia (32.5% increase, 95% CI: 1.095-1.604, P = 0.004). The risk of blood loss anemia was 3.3% lower in the Class II group (95% CI: 0.946-0.988, P = 0.002). No significant differences were found in heart failure, acute coronary artery disease, pulmonary edema, venous thromboembolism, pulmonary embolism, and blood transfusion.

CONCLUSIONS

More intensive monitoring and preventive measures may be necessary for patients with Class II obesity to mitigate the heightened risks associated with TKA compared to those with Class I obesity.

The effect of body mass index and preoperative weight loss in people with obesity on postoperative outcomes to 6 months following total hip or knee arthroplasty: a retrospective study

BACKGROUND

Few studies have investigated the association between obesity, preoperative weight loss and postoperative outcomes beyond 30- and 90-days post-arthroplasty. This study investigated whether body mass index (BMI) and preoperative weight loss in people with obesity predict postoperative complications and patient-reported outcomes 6 months following total knee or hip arthroplasty.

METHODS

Two independent, prospectively collected datasets of people undergoing primary total knee or hip arthroplasty for osteoarthritis between January 2013 and June 2018 at two public hospitals were merged. First, the sample was grouped into BMI categories, < 35 kg/m2 and ≥ 35 kg/m2. Subgroup analysis was completed separately for hips and knees. Second, a sample of people with BMI ≥ 30 kg/m2 was stratified into participants who did or did not lose ≥ 5% of their baseline weight preoperatively. The presence of postoperative complications, Oxford Hip Score, Oxford Knee Score, EuroQol Visual Analogue Scale and patient-rated improvement 6 months post-surgery were compared using unadjusted and adjusted techniques.

RESULTS

From 3,552 and 9,562 patients identified from the datasets, 1,337 were included in the analysis after merging. After adjustment for covariates, there was no difference in postoperative complication rate to 6 months post-surgery according to BMI category (OR 1.0, 95%CI 0.8-1.4, P = 0.8) or preoperative weight loss (OR 1.1, 95%CI 0.7-1.8, P = 0.7). There was no between-group difference according to BMI or preoperative weight change for any patient-reported outcomes 6 months post-surgery.

CONCLUSION

Preoperative BMI or a 5% reduction in preoperative BMI in people with obesity was not associated with postoperative outcomes to 6 months following total knee or hip arthroplasty.

Is There a Difference in PROMs Between Morbidly Obese Patients and Nonobese Patients Following Primary Total Knee Arthroplasty?

Background

Patient satisfaction and patient-reported outcome measures (PROMs) are important for patients, surgeons, and payers in the current healthcare climate. Morbidly obese patients (body mass index [BMI] >40) have demonstrated higher incidence of complications after total knee arthroplasty (TKA) and can have difficulty obtaining access for their surgical care. The purpose of this study was to evaluate PROMs and patient satisfaction in morbidly obese patients undergoing primary TKA.

Methods

A total of 75 patients with BMI >40 kg/m² undergoing robotic-assisted TKA were retrospectively identified and matched 2:1 to a consecutive cohort of patients with BMI <35. The average BMI of the study cohort was 42.4 kg/m² (39.5-51.3) compared to 28.6 kg/m² (18.5-34.9) in the control group. Clinical outcomes, PROMs, and patient satisfaction were evaluated at a minimum 2-year follow-up.

Results

The patients of the BMI >40 cohort were less likely to be discharged home (P = .0076), had less active flexion at 2 years (P = .0046), and had worse knee scores at 2 years (0.0497). Despite this, the percentage of patients who were satisfied or very satisfied after surgery was similar between the groups (87.5% vs 91.2%, P = .1943).

Conclusions

Morbidly obese patients are less likely to be discharged directly to home and may have functional differences after primary TKA. However, morbidly obese patients have similar PROMs and are as satisfied as nonobese patients at 2 years. Morbidly obese patients with end-stage knee osteoarthritis should also be able to enjoy the benefits of primary TKA following medical and surgical optimization.

Length of Hospital Stay after Total Knee Arthroplasty: A Correlation Study on 1200 Patients

In countries with a high average population age, total knee arthroplasty is still carried out in an inpatient setting. The roadmap to performing major surgery on an outpatient basis passes through the understanding of those perioperative features that correlate with higher lengths of hospital stay (LOS). A retrospective database of 1200 patients was reviewed for retrieving preoperative and perioperative factors including anthropometric and demographic data, comorbidities, preoperative laboratory assessment, and surgical time. Considering the LOS as a discrete series, data were analyzed by means of logistic regression with multiple univariate and multivariate models. The results showed a median length of hospital stay of 3 (IQR 3, 4) days. According to multiple univariate analysis, arterial hypertension (p = 0.008), diabetes mellitus (p = 0.028), CCI score (p < 0.001), ASA score (p = 0.006), surgical time (p < 0.001) and intraoperative blood loss (p < 0.001) were significantly associated with the duration of hospital stay in days. Moreover, preoperative hemoglobin value was inversely correlated to the LOS (p = 0.008). Multivariate analysis showed a significant correlation between LOS and surgical time and intraoperative blood loss. Many factors influence the permanence of the inpatient and acting on those variables, by stabilizing comorbidities and optimizing laboratory values, may reduce the overall healthcare burden.

Obesity Does Not Affect Patient-Reported Outcomes following Patellofemoral Arthroplasty

Patellofemoral arthroplasty (PFA) has garnered attention in recent years as an effective alternative to total knee arthroplasty for patients with symptomatic, isolated patellofemoral joint arthritis. Obesity has previously been identified as a risk factor for revision surgery, but its effect on patient-reported outcome measures (PROMs) has not been evaluated. A retrospective review of a consecutive series of PFA surgeries was conducted at a single, specialized orthopedics center in a major urban center. Patients were dichotomized by body mass index (BMI) as obese (O, BMI >30) or nonobese (NO, BMI: 18.5-25). Demographic, surgical information, and PROMs were collected and analyzed accordingly. Seventy-six patients (41 nonobese, 35 obese) were identified. Patients who were obese presented with significantly worse preoperative PROMs regarding knee-specific quality of life, physical function, and MH or mental health (knee injury and osteoarthritis outcome score quality of life [KOOS QoL], NO: 26.2, O: 14.7, p = 0.019; KOOS PF, NO: 38.2, O: 50.5, p = 0.002; Veterans Rand-12 mental health [VR-12 MH], NO: 54.2, O: 47.0, p = 0.033). No significant difference was seen in improvement in knee function scores between patients who were obese or nonobese (KOOS QoL, NO: 39.5, O: 40.6, p = 0.898; KOOS PS [physical function], NO: -17.8, O: -17.3, p = 0.945). Additionally, no difference in the rate of PFA revision was observed and there were no postoperative complications reported. Obese patients with isolated PFA can expect the same improvement in function as nonobese patients following patellofemoral joint arthroplasty. This paper underscores the priority of patient selection in PFA and challenges the notion that surgeons should exclude patients from receiving a PFA on the basis of obesity.

Comparison of the Effect and Complications of Sequential Bilateral Arthroplasty at Different Time Intervals and Simultaneous Bilateral Total Knee Arthroplasty: A Single-Centre Retrospective Cohort Study

INTRODUCTION

To the authors' knowledge, there is no current consensus regarding the optimal interprocedural interval for patients who have undergone bilateral total knee arthroplasty (BTKA). The purpose of this study is to evaluate complication rates and functional outcome in patients who have undergone BTKA (simultaneous or sequential at different time intervals), and to determine an optimal time frame for the second knee.

METHODS

Data from 315 patients who were able to tolerate simultaneous BTKA according to the anaesthesiologist's preoperative assessment between 2016 and 2020 were analysed retrospectively. According to the operative time interval, they were divided into simultaneous, ≤ 1-month sequential, 1- to 3-month sequential, and ≥ 3-month sequential BTKA groups. The primary outcomes were revision and readmission rates during the follow-up period, and the secondary outcomes were hospital length of stay (LOS), transfusion and postoperative complications.

RESULTS

There was no difference in the implant survival or readmission rate between the groups (p > 0.05). Multivariable linear regression showed that interprocedural interval and body mass index (BMI) affected LOS; the LOS of simultaneous BTKA was the shortest (p < 0.05). BMI was associated with an increased LOS of 0.25 days (95% CI 0.02-0.48, p = 0.03). A modified Poisson regression model showed that the odds of blood transfusion were reduced in sequential BTKAs of any interval (p < 0.05), and preoperative haemoglobin (Hb) was also a risk factor (RR 0.96, 95% CI 0.95-0.98, p < 0.001). The interprocedural interval was not a risk factor for postoperative cardiovascular and cerebrovascular complications.

CONCLUSION

For appropriate patients, simultaneous BTKA is beneficial. However, higher preoperative haemoglobin was required to mitigate the high blood transfusion rate associated with simultaneous surgeries. If suitable patients refuse simultaneous BTKA for other non-medical reasons, sequential BTKA with an interval greater than 1 month is recommended.

Greater risk of all-cause revisions and complications for obese patients in 3 106 381 total knee arthroplasties: a meta-analysis and systematic review

BACKGROUND

Obesity is a major public health issue and has considerable implications on outcomes of total knee arthroplasty (TKA). However, there has been conflicting evidence and conclusions on the effects of obesity on TKA. This meta-analysis compares the outcomes, complications, and peri-operative parameters of TKA in the obese (body mass index [BMI] ≥ 30 kg/m² ) versus non-obese (BMI < 30 kg/m² ) population as well as subgroup analysis of morbidly obese (BMI ≥ 40 kg/m² ) versus non-obese population.

METHODS

A meta-analysis was conducted with a multi-database search according to PRISMA guidelines on 12 September 2019. Data from all published literature meeting inclusion criteria were extracted and analysed.

RESULTS

Ninety-one studies were included, consisting of 917 447 obese and 2 188 834 non-obese TKA. Obese patients had higher risk of all-cause revisions (odds ratio [OR] = 1.15, 95% CI: 1.08-1.24, p < 0.0001), all complications (OR = 1.21, 95% CI: 1.06-1.38, p = 0.004), deep infections (OR = 1.47, 95% CI: 1.27-1.69, p < 0.0001), superficial infections (OR = 1.59, 95% CI: 1.32-1.91, p < 0.0001), wound dehiscence (OR = 1.46, 95% CI: 1.24-1.72, p < 0.0001) and readmissions (OR = 1.21, 95% CI: 1.05-1.40, p = 0.009). Subgroup analysis of morbidly obese patients revealed greater risks of all-cause revisions (OR = 1.25, 95% CI: 1.10-1.43, p = 0.0009), deep infections (OR = 1.98, 95% CI: 1.05-3.75, p = 0.04), superficial infections (OR = 2.44, 95% CI: 2.08-2.88, p < 0.0001) and readmissions (OR = 1.33, 95% CI: 1.20-1.47, p < 0.0001). No analysis was performed on patient reported outcome measures due to heterogeneous reporting methods.

CONCLUSION

Obese and morbidly obese patients have higher risks of revisions and infections post TKA. Surgeons should counsel patients of these risks during the informed consenting process and adopt preventative strategies into clinical practice to reduce risks where possible. In conclusion, obesity is a significant, modifiable risk factor for increased complications following TKA.

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

BACKGROUND

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

AIM

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

METHODS

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

FINDINGS

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

CONCLUSION

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

Obesity does not increase blood loss or incidence of immediate postoperative complications during simultaneous total knee arthroplasty: A multicenter study

BACKGROUND

The purpose of the study was to determine blood loss, transfusion risk, and incidence of immediate postoperative complications in normal, overweight, and I-II obese patients undergoing simultaneous bilateral total knee arthroplasty (SBTKA).

METHOD

We identified 1070 SBTKA procedures, and separated the patients into three groups on the basis of body mass index (BMI), including normal (BMI: 18.0-24.9 kg/m²), overweight (BMI: 25.0-29.9 kg/m²), and obese groups (BMI: ≥30.0 kg/m²). The primary outcome was total blood loss and secondary outcomes were dominant and hidden blood loss, transfusion rate and volume, hemoglobin (Hb) and hematocrit drop and other complications.

RESULTS

Patient's blood volume increased gradually among normal, overweight, and obese groups. There was no significant difference in blood loss or incidence of complications among the three groups, while the transfusion rate in the normal group was higher than that in overweight (36.0% vs 27.6%, p = 0.007) and obese groups (36.0% vs 24.6%, p = 0.006). In addition, the independent risk factors for complications among all groups following SBTKA included lower level of preoperative Hb (p = 0.040), general anesthesia (p = 0.002), drain use (p = 0.005), and transfusion (p < 0.001).

CONCLUSIONS

I-II obesity does not increase patient's blood loss, transfusion risk, or immediate postoperative complications following SBTKA. Obese and overweight patients may have lower transfusion needs compared with normal patients because of their higher basal blood volume. The risk factors for complications after SBTKA are lower level of preoperative Hb, general anesthesia, drain use and transfusion.

The influence of obesity on clinical outcomes following primary total knee arthroplasty: A prospective cohort study

BACKGROUND

The aim of this study was to evaluate the influence of obesity on patients' function, pain, and complications following primary total knee arthroplasty (TKA) with an enhanced-recovery program.

METHODS

A total of 157 patients were enrolled into a prospective study and assigned into one of three groups on the basis of their body mass index (BMI): normal (BMI 18.0-24.9 kg/m²), overweight (BMI 25.0-29.9 kg/m²), or obese (BMI ≥30.0 kg/m²). The primary outcome was knee range of motion (ROM) on postoperative day (POD) 3, 15, 30, and 90, and secondary outcomes were visual analog scale (VAS) on POD 1, 2, 3, 15, 30, and 90, length of stay, and complications.

RESULTS

The ROM of patients in the obese group on POD 3 was higher than in the normal (104.4 ± 8.5 vs. 98.9 ± 8.9, P = .010) and overweight (104.4 ± 8.5 vs. 97.7 ± 7.8, P = .001) groups. Similarly, the VAS in the obese group at rest on POD 1 was lower than in the normal (2.0 ± 0.7 vs. 2.2 ± 0.6, P = .043) and overweight (2.0 ± 0.7 vs. 2.3 ± 0.6, P = .010) groups. In addition, the incidence of complications did not differ significantly among the three groups, but the length of hospital stay in the obese group was longer (P = .027).

CONCLUSIONS

Obesity may not affect patients' function and pain, and may not increase the incidence of complications following primary TKA. Obese patients may obtain satisfactory functional rehabilitation outcomes, but with a longer duration of rehabilitation.