Obesity Severity Predicts Patient Dissatisfaction After Total Knee Arthroplasty

Impact of high body mass index on functionally aligned image-based robotic total knee arthroplasty: Comparable functional outcomes but higher mechanical failures

OBJECTIVES

Increased body mass index (BMI) poses challenges in total knee arthroplasty (TKA), including higher complication rates. Functional knee positioning (FKP) with robotic assistance provides a personalized approach to optimize alignment and soft-tissue balance, but its impact on patients with increased BMI remains unclear. This retrospective comparative study aims to evaluate the influence of obesity and its severity on clinical outcomes and complications in TKA performed with an image-based robotic system-guided by FKP principles.

METHODS

This retrospective comparative study included 372 patients who underwent robotic-assisted TKA following FKP principles. Patients were stratified into two main groups based on BMI (<30 ​kg/m2; 238 patients and ≥30 ​kg/m2; 134 patients). Outcomes included Knee Society Scores (KSS), Forgotten Joint Scores (FJS), range of motion (ROM), implant positioning, and complications, evaluated at a minimum follow-up of two years.

RESULTS

Patients with increased BMI (≥30 ​kg/m2) demonstrated similar functional outcomes to patients with BMI <30 ​kg/m2 in terms of ROM, KSS, and FJS. However, the revision rate due to mechanical failures was significantly higher in the obese group (2.99% vs. 0.42%, p ​= ​0.04; hazard ratio ​= ​6.8; 95% CI, 1.09-42.31). Implant positioning was consistent across groups, except for reduced femoral external rotation in the increased BMI group (p ​= ​0.004).

CONCLUSIONS

Robotic-assisted TKA with FKP principles achieves comparable functional outcomes for obese patients at a minimum of a 2-year follow-up, demonstrating the system's ability to address anatomical and functional challenges. However, obesity remains a critical risk factor for mechanical failures.

LEVEL OF EVIDENCE

III.

GLP-1 Agonists for Weight Loss: Do They Increase Complications in Non-diabetic Patients Undergoing Primary Total Hip Arthroplasty?

BACKGROUND

Glucagon-like peptide 1 (GLP-1) agonists are an effective medication for glycemic control and weight loss. These effects may reduce complications in diabetic patients undergoing total hip arthroplasty (THA). However, there remains a paucity of data on the impact of GLP-1 medications in nondiabetic patients using the medication solely for weight reduction. There is concern that rapid weight loss associated with GLP-1 agonists may lead to malnutrition and increase the risk of postoperative complications in patients undergoing THA.

METHODS

A retrospective query was performed from January 1, 2010, to January 1, 2022, using an insurance claims database to identify patients undergoing primary THA on GLP-1 agonists (n = 839,715). Patients on GLP-1 therapy (n = 5,345) at the time of surgery were propensity score-matched 1:1 to controls who were not on GLP-1 agonists (n = 5,345) based on age, sex, the Elixhauser Comorbidity Index, and its components. Patients who had diabetes mellitus were excluded. The 90-day outcomes were evaluated, including medical complications, readmission, and reoperation rates. We also examined the incidence of all-cause revision and implant-related complications at a 2-year follow-up. Odds ratios (ORs) were generated using logistic regression analyses.

RESULTS

Patients who were on GLP-1 agonist medications were less likely to develop acute blood loss anemia (OR: 0.57; 95% confidence interval [CI]: 0.34 to 0.96) and require postoperative transfusion (OR: 0.53; 95% CI: 0.36 to 0.78) or visit the emergency department within 90 days of surgery (OR: 0.81; 95% CI: 0.69 to 0.92) when compared to patients who did not have GLP-1 therapy. Patients were at comparable risk of deep venous thrombosis, pulmonary embolism, mortality, stroke, myocardial infarction, acute kidney injury, and sepsis regardless of GLP-1 status (P > 0.05). Notably, the rate of aspiration pneumonia was similar between groups (OR: 1.17; 95% CI: 0.62 to 2.19). Also, GLP-1 therapy did not put patients at higher risk of surgical complications, including periprosthetic joint infection, instability, fracture, loosening, or all-cause revision, at 90 days and two years (P > 0.05).

CONCLUSIONS

Use of a GLP-1 agonist does not appear to increase the odds of postoperative medical and surgical complications after THA in nondiabetic patients taking GLP-1 medications for weight loss alone.

Current Evidence Does Not Support the Use of Tibial Stem Extension in Total Knee Arthroplasty of Obese Patients: A Systematic Review

BACKGROUND

Obesity rates have been increasing globally, leading to a higher incidence of knee osteoarthritis and a surge in primary and revision total knee arthroplasty (TKA). The debate continues on the impact of obesity on TKA success, particularly regarding the use of stemmed tibial components in obese patients. This systematic review aimed to compare the effectiveness of stemmed tibial components versus standard keeled tibial components in obese patients undergoing TKA.

METHODS

A systematic review was conducted using databases including PubMed, Embase, Scopus, and Web of Science from inception to December 2023. The eligibility criteria were Participants: Patients who have obesity undergoing TKA; Intervention: stemmed TKA; Comparator: standard keeled tibial TKA; Outcomes: aseptic loosening, patient-reported outcome measures (PROMs), and overall revision. Data extraction and quality assessment were performed using the Newcastle-Ottawa Scale for cohort studies and the Cochrane risk-of-bias tool for randomized trials.

RESULTS

The search yielded 470 studies, with 10 studies (42,533 knees) meeting the inclusion criteria. These studies included 3 randomized controlled trials and 7 retrospective cohorts. The primary outcomes measured were aseptic loosening and overall revision rates, while secondary outcomes included PROMs. Results indicated mixed findings, with some studies suggesting improved outcomes with stemmed components in cases of aseptic loosening and mechanical failure, while others showed no significant difference. The PROMs did not show a significant difference between groups post-TKA. The certainty of the evidence was graded as "very low" using the Grading of Recommendations, Assessment, Development, and Evaluations framework.

CONCLUSIONS

Current literature does not provide conclusive evidence to support the routine use of stemmed tibial components in TKA for obese patients. The decision to use stem extensions should not solely rely on the patient's obesity status. Further high-quality studies are needed to clarify the role of stemmed components in TKA for this patient population.

LEVEL OF EVIDENCE

III.

Should Body Mass Index Be Considered a Hard Stop for Total Joint Replacement?: An Ethical Dilemma

Total joint arthroplasty (TJA) is one of the most common surgeries performed in the United States and is a durable and effective option in managing osteoarthritis of the hip and knee. Recent research regarding the procedure has focused on preoperative optimization and weight loss in particular. Obesity has been shown in prior studies to increase risks associated with TJA, and, as a result, debate has focused on whether a body mass index (BMI) cutoff is a prudent tool for preoperative optimization. This article discusses the ethical dilemma of instituting a BMI cutoff and reviews current literature regarding the topic.

Mid-term radiographic evaluation of a monoblock trabecular metal tibia following total knee arthroplasty in obese and morbidly obese patients

BACKGROUND

Indications for primary total knee arthroplasty (TKA) have become more inclusive of morbidly obese patients, however, higher rates of complications and lower implant survival have also been reported in this population. The purpose of this study was to investigate the mid-term survival, clinical, and radiographic outcomes of a cementless trabecular metal monoblock tibial component in severely obese patients.

METHODS

This was a retrospective study of class II and III obese (BMI > 35) patients who received a cementless primary TKA. Standing radiographs were assessed for the presence of progressive tibial radiolucent lines (RLL), and clinical measures were assessed at least 2 years post-operative via the Oxford Knee Score (OKS), UCLA Activity and Satisfaction Score, and the Euro-QoL 5-dimension (EQ-5D-5L) index and visual analogue scale (EQ-VAS) health status.

RESULTS

Patients (n = 176) were 61.2 ± 8.3 years of age, BMI 44.9 ± 6.5 kg/m2, and were predominantly female (n = 118, 66.7%). Mean follow-up was 59.2 ± 17.1 months. There were two total revisions at 6- and 57-months post-operative, respectively, and the 5-year survival estimate was 98.3% (95% confidence interval: 93.0%, 99.6%). Patient satisfaction was 93.9% and the post-operative OKS, EQ-5D-5L index, and EQ-VAS were 40.2 ± 7.9, 0.856 ± 0.205, and 73.6 ± 14.7, respectively. No cases of radiolucent lines were detected.

CONCLUSIONS

At 6 years this cementless monoblock tibial component demonstrated excellent survival without radiographic indications of aseptic loosening in a population of severely obese patients.

Aetiology of patient dissatisfaction following primary total knee arthroplasty in the era of robotic-assisted technology

Aims

Patient dissatisfaction following primary total knee arthroplasty (TKA) with manual jig-based instruments has been reported to be as high as 30%. Robotic-assisted total knee arthroplasty (RA-TKA) has been increasingly used in an effort to improve patient outcomes, however there is a paucity of literature examining patient satisfaction after RA-TKA. This study aims to identify the incidence of patients who were not satisfied following RA-TKA and to determine factors associated with higher levels of dissatisfaction.

Methods

This was a retrospective review of 674 patients who underwent primary TKA between October 2016 and September 2020 with a minimum two-year follow-up. A five-point Likert satisfaction score was used to place patients into two groups: Group A were those who were very dissatisfied, dissatisfied, or neutral (Likert score 1 to 3) and Group B were those who were satisfied or very satisfied (Likert score 4 to 5). Patient demographic data, as well as preoperative and postoperative patient-reported outcome measures, were compared between groups.

Results

Overall, 45 patients (6.7%) were in Group A and 629 (93.3%) were in Group B. Group A (vs Group B) had a higher proportion of male sex (p = 0.008), preoperative chronic opioid use (p < 0.001), preoperative psychotropic medication use (p = 0.01), prior anterior cruciate ligament (ACL) reconstruction (p < 0.001), and preoperative symptomatic lumbar spine disease (p = 0.004). Group A was also younger (p = 0.023). Multivariate analysis revealed preoperative opioid use (p = 0.012), prior ACL reconstruction (p = 0.038), male sex (p = 0.006), and preoperative psychotropic medication use (p = 0.001) as independent predictive factors of patient dissatisfaction.

Conclusion

The use of RA-TKA demonstrated a high rate of patient satisfaction (629 of 674, 93.3%). Demographics for patients not satisfied following RA-TKA included: male sex, chronic opioid use, chronic psychotropic medication use, and prior ACL reconstruction. Patients in these groups should be identified preoperatively and educated on realistic expectations given their comorbid conditions.

Sleeve gastrectomy prior to primary total hip and total knee arthroplasty is associated with increased risk of early complications

Aims

The purpose of this study was to determine the association between prior sleeve gastrectomy in patients undergoing primary total hip and knee arthroplasty, and 90-day complications, incidence of revision arthroplasty, and patient-reported outcome scores at final follow-up.

Methods

This is a retrospective, single-centre analysis. Patients undergoing primary hip or knee arthroplasty with a prior sleeve gastrectomy were eligible for inclusion (n = 80 patients). A morbidly obese control group was established from the same institutional registry using a 1:2 match, for cases:controls with arthroplasty based on propensity score using age, sex, pre-sleeve gastrectomy BMI, Current Procedural Terminology code to identify anatomical location, and presurgical haemoglobin A1C. Outcomes included 90-day complications, incidence of revision arthroplasty, and patient-reported outcome scores at final follow-up. Multivariable logistic regressions evaluated associations of underlying preoperative demographic and treatment characteristics with outcomes.

Results

Complications within 90 days of surgery were increased in the sleeve gastrectomy group relative to the obese control group after controlling for underlying preoperative demographic characteristics (odds ratio (OR) 4.00 (95% CI 1.14 to 13.9); p = 0.030). Postoperative revisions were similar in the sleeve gastrectomy group relative to the obese control group after controlling for underlying preoperative demographic characteristics (OR 17.8 (95% CI 0.64 to 494.3); p = 0.090). Patient-Reported Outcomes Measurement Information System (PROMIS) depression decreased by a greater amount from pre- to postoperative in the obese controls relative to the sleeve gastrectomy group (OR 4.04 (95% CI 0.06 to 8.02); p = 0.047). PROMIS pain interference and physical function change from pre- to postoperative was not associated with sleeve gastrectomy status.

Conclusion

We found a higher rate of complications at 90 days in patients who underwent sleeve gastrectomy prior to primary hip or knee arthroplasty relative to a matched, obese control population. Prosthetic revision rates were similar between the two groups, while improvements in PROMIS depression scores were larger in the obese cohort. This study suggests that sleeve gastrectomy to achieve preoperative weight loss prior to arthroplasty surgery may not mitigate early complication risks in obese patient populations.