Patient factors associated with weight gain and weight loss after knee or hip arthroplasty

Do Overall Weight, Body Mass Index, or Clinically Significant Weight Changes Occur After Total Joint Arthroplasty? A Meta-Analysis of 60,837 Patients

BACKGROUND

Total joint arthroplasty (TJA) is well-recognized for improving quality of life and functional outcomes of patients with osteoarthritis; however, TJA's impact on body weight remains unclear. Recent trends have demonstrated a shift among TJA patients, such that patients who have higher body mass indices (BMIs) are undergoing this common surgery. Given this trend, it is critical to characterize the impact TJA has on body weight or BMI. This meta-analysis aimed to quantitatively assess whether patients lose, gain, or maintain body weight or BMI after TJA.

METHODS

This study followed the 2020 Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. Ovid MEDLINE, Embase, and the Cochrane Central Register of Controlled Trials databases were queried from inception through July 2022. The included studies: (1) reported on weight or BMI after elective, primary total hip arthroplasty (THA) or total knee arthroplasty (TKA); and (2) weight or BMI change was deemed to be associated with THA or TKA. The excluded studies: (1) included weight or BMI interventions; and (2) reported on unicompartmental, partial, or revision arthroplasty or joint arthroscopy. Meta-analyses for weight change, BMI change, and proportion of patients achieving clinically significant change were performed using random-effects models. Factors associated with clinically significant change were systematically reported. A total of 60,837 patients from 39 studies were included.

RESULTS

No significant differences existed between preoperative and postoperative weights (P = 1.0; P = 0.28) or BMIs (P = 1.0; P = 1.0) after THA or TKA, respectively. Overall, 66% of THA patients (P < 0.01) and 65% of TKA patients (P < 0.01) did not experience clinically significant weight change.

CONCLUSIONS

Among a TJA cohort, two-thirds of the patients maintained their preoperative body weight or BMI after surgery. With these results, orthopaedic surgeons can better manage patient expectations of TJA.

Do patients with osteoarthritis lose weight prior to elective joint replacement?

BACKGROUND

Obesity is a known risk factor for the development of osteoarthritis and the subsequent need for joint replacement. Weight loss has been shown to reduce pain, disability, and the need for joint replacement, particularly in patients with knee osteoarthritis. The aim of this study was to investigate pre-operative weight change in patients with hip, knee, and shoulder osteoarthritis at a regional, public hospital in Australia, to identify opportunities for pre-operative weight-loss intervention.

METHODS

A retrospective review of patients who underwent elective primary total hip (THR), knee (TKR), and shoulder (TSR) replacement for osteoarthritis was conducted between December 2019 and December 2022. BMI data were collected at three time points: (1) general practitioner (GP) referral; (2) orthopaedic clinic review; and (3) pre-admission clinic (PAC) assessment.

RESULTS

A total of 496 patients were included in the study, of which 205 underwent THR, 251 underwent TKR, and 40 underwent TSR. The mean patient age was 67 years, and 46.4% were female. At the time of GP referral, the mean body mass index (BMI) was 31.4 kg/m2. Across the study period, only 2% of patients experienced clinically significant weight loss pre-operatively (≥5% of total body weight).

CONCLUSION

This study has demonstrated that very few patients lose weight prior to undergoing joint replacement in the public sector in Australia. This highlights the need for targeted non-surgical weight loss interventions for patients currently awaiting joint replacement.

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

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSION

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

Preoperative Weight Loss and Postoperative Weight Gain Independently Increase Risk for Revision After Primary Total Knee Arthroplasty

BACKGROUND

The current American Association of Hip and Knee Surgeons (AAHKS) guidelines recommend preoperative weight loss before total knee arthroplasty (TKA) in patients with body mass index (BMI) ≥40 kg/m². However, there is a paucity of evidence on TKA outcomes after preoperative weight loss. This study therefore evaluated predictors of preoperative and postoperative BMI changes and their impact on outcomes after TKA.

METHODS

This is a retrospective review of 3058 primary TKAs at an academic institution from 2015 to 2019. BMI was collected on the day of surgery. Preoperative and postoperative BMI at 6 months and 1 year were also obtained. BMI change of ≥5% was considered clinically significant. Mean follow-up was 3.2 years. Patient demographics, acute postoperative outcomes, and all-cause revisions were compared between patients who gained, lost, or maintained weight using univariate and multivariable analyses.

RESULTS

Preoperative weight loss was predictive of postoperative weight gain (P < .001), and preoperative weight gain was predictive of postoperative weight loss (P < .001). Cox regression analysis revealed that ≥5% BMI loss preoperatively increased risk for all-cause revisions (P = .030), while ≥5% BMI gain postoperatively increased risk for prosthetic joint infections (P = .016). Patients who lost significant weight both before and after surgery had the highest risk for all-cause revisions (P = .022).

CONCLUSION

Weight gain postoperatively was associated with inferior outcomes. Significant weight loss before surgery led to a "rebound" in weight gain, and independently increased risk for all-cause revision. Therefore, current recommendations for weight loss before TKA in morbidly obese patients should be re-evaluated.

Restoration of Continence after Prostatectomy is Associated With Weight Loss: A Pilot Study

OBJECTIVES

To examine association between post-prostatectomy incontinence (PPI) severity and weight changes before and after restoration of continence via artificial urinary sphincter (AUS).

METHODS

Single surgeon, retrospective review of urologic prosthetic surgery (UPS) after radical prostatectomy (RP). A cohort of post-RP inflatable penile prosthesis (IPP) patients served as a surgical control. Body Mass Index (BMI) and total body weight were assessed pre and post-UPS. Multivariable linear regression was utilized to assess BMI changes post-UPS.

RESULTS

187 AUS and 63 IPP patients met selection criteria. Greater PPI severity was associated with faster BMI gain after RP (coeff. 0.14 kg/m2, P = 0.03, per pad used) and magnitude of incontinence improvement (mean reduction in daily pad use) after AUS insertion was associated with greater BMI reduction at 12 months post-UPS (coeff. - 0.13 kg/m2, P = 0.04). On multivariable regression, AUS insertion was associated with a decrease in BMI by - 2.83 kg/m2 12 months post-UPS (P = 0.02). Twelve months post-UPS, men with AUS exhibited a mean BMI reduction of -1.0 kg/m² compared to a mean BMI increase in the IPP cohort of 0.4 kg/m² (P < 0.01). Compared to IPP, AUS patients experienced absolute body weight reduction by 6 kg [Median(IQR): 90.4 (80.3-100.1) vs 96.4 (87.1-108.8) kg, P = 0.03], with nearly one-third having clinically significant weight loss (>5% body weight) at 12 months post-UPS (31.8% vs 8.3%, P < 0.01).

CONCLUSION

Severe PPI appears to be associated with weight gain and correction of PPI via AUS insertion with weight loss.

Change in Body Mass Index after Simultaneous Bilateral Total Knee Arthroplasty: Risk Factors and Its Influence on Functional Outcomes

BACKGROUND

Previous studies evaluating weight changes following total knee arthroplasty (TKA) were performed on heterogenous cohorts. However, no study has evaluated weight changes in a cohort of simultaneous-bilateral TKA (SB-TKA) patients. This study aimed to evaluate the prevalence of patients who lost or gained weight, determine if postoperative weight change influences functional outcome, and identify predictors of weight change after SB-TKA.

METHODS

Prospectively collected registry data of 560 patients who underwent SB-TKA were reviewed. Patients were assessed preoperatively, at 6 months, and 2 years using the Knee Society Score, Oxford Knee Score, Short-Form 36, and range of motion. Change in body mass index (BMI) >5% was used to categorize patients into 3 groups: lost, maintained, or gained weight. Analysis of variance, Kruskal-Wallis test, and chi-squared test were used to compare functional outcomes between groups. Multivariable logistic regression evaluated predictors for postoperative weight changes.

RESULTS

At 2 years, 59% of patients maintained weight, 28% of patients gained weight, and 13% of patients lost weight. All groups experienced similar improvements in functional outcomes, rates of minimal clinically important difference attainment, and patient satisfaction (P > .05). Older patients were more likely to gain weight (P < .05). Patients with higher preoperative BMI were more likely to gain weight (P < .05) and less likely to lose weight (P < .05). Patients with greater preoperative comorbidities were less likely to lose weight (P < .05).

CONCLUSION

Up to 41% of patients experience significant weight changes after SB-TKA. Older patients with higher preoperative BMI were more likely to gain weight, while higher preoperative BMI with more comorbidities were less likely to lose weight following SB-TKA; however, postoperative weight changes do not appear to affect functional outcomes.

LEVEL OF EVIDENCE

III, therapeutic study.

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.