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

Weighing the Impact: The Influence of Body Mass Index on Facility Costs in Total Joint Arthroplasty

BACKGROUND

Using time-driven activity-based costing (TDABC), a novel cost calculation method that more accurately reflects true resource utilization in health care, we sought to compare the total facility costs across different body mass index (BMI) groups following total joint arthroplasty (TJA).

METHODS

The study consisted of 13,806 TJAs (7,340 total knee arthroplasties [TKAs] and 6,466 total hip arthroplasties [THAs]) performed between 2019 and 2023. The TDABC data from an analytics platform was employed to depict total facility costs, comprising personnel and supply costs. For the analysis, patients were stratified into four BMI categories: <30, 30 to <35, 35 to <40, and ≥40. Multivariable regression was used to determine the independent effect of BMI on facility costs.

RESULTS

When indexed to patients who had BMI <30, elevated BMI categories (30 to <35, 35 to <40, and ≥40) were associated with higher total personnel costs (TKA 1.03x versus 1.07x versus 1.13x, P < .001; THA 1.00x versus 1.08x versus 1.08x, P < .001), and total supply costs (TKA 1.01x versus 1.04x versus 1.04x, P < .001; THA 1.01x versus 1.02x versus 1.03x, P = .007). Total facility costs in TJAs were significantly greater in higher BMI categories (TKA 1.02x versus 1.05x versus 1.08x, P < .001; THA 1.01x versus 1.05x versus 1.05x, P < .001). Notably, when incorporating adjustments for demographics and comorbidities, BMI values of 35, 40, and 45 relative to BMI of 25, exhibit a significant association with a 2, 3, and 5% increase in total facility cost for TKAs and a 3, 5, and 7% increase for THAs.

CONCLUSIONS

Using TDABC methodology, this study found that overall facility costs of TJAs increase with BMI. The present study provides patient-level cost insights, indicating the potential need for reassessment of physician compensation models in this population. Further studies may facilitate the development of risk-adjusted procedural codes and compensation models for public and private payors.

LEVEL OF EVIDENCE

Level IV, economic and decision analyses.

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.

Body Mass Index, Sex, and Age Are Predictors of Discharge to a Post-acute Care Facility Following Total Ankle Arthroplasty

BACKGROUND

The utilization of total ankle arthroplasty (TAA) continues to increase. Discharge to a post-acute care (PAC) facility can increase patient morbidity and postoperative costs. The purpose of this study is to investigate the effects of age and body mass index (BMI) on discharge to a PAC facility and hospital length of stay (LOS) following TAA.

METHODS

A retrospective review of patients who underwent TAA from the National Surgical Quality Improvement Program (NSQIP) database was performed. Using overweight patients as the reference BMI group, sex- and age-adjusted log-binomial regression models were utilized to estimate risk ratios of BMI categories for being discharged to a PAC facility. A linear regression was utilized to estimate the effect of BMI category on hospital LOS.

RESULTS

Obese patients had 1.36 times the risk of overweight patients (P = .040), and morbidly obese patients had 2 times risk of overweight patients (P = .001) of being discharged to a PAC facility after TAA. Men had 0.48 times the risk of women (P < .001). Compared with patients aged 18 to 44 years, patients aged ≥65 years had 4.13 times the risk (P = .012) of being discharged to a PAC facility after TAA. Relative to overweight patients, on average there was no difference in hospital LOS for underweight patients, but healthy weight patients stayed an additional 0.30 days (P=.003), obese patients stayed an additional 0.18 days (P = .011), and morbidly obese patients stayed an additional 0.33 days (P = .009). Men stayed 0.29 fewer hospital days than women (P < .001) on average.

CONCLUSION

Women and patients who are obese or morbidly obese have a longer hospital LOS and an increased chance of being discharged to a PAC facility. Increasing age is also associated with an increased risk of being discharged to a PAC. These may be important factors when developing and discussing the postoperative plan with patients prior to TAA.

LEVELS OF EVIDENCE

Level III.

Effect of body mass index on acute postoperative complications following Total Ankle Arthroplasty (TAA)

BACKGROUND

Total ankle arthroplasty (TAA) is an effective treatment for various ankle pathologies, but some concern remains for the high associated complication and failure rates relative to major joint arthroplasty of the hip and knee. Patient body mass index (BMI) is a modifiable and potentially important preoperative variable when evaluating postoperative complications. The purpose of this study is to evaluate the effect of BMI, age and sex on the acute postoperative complication rate after TAA.

METHODS

We retrospectively reviewed adult patients who underwent TAA between 2006 and 2021 from the NSQIP database. Using overweight patients as the reference BMI group, we utilized log-binomial models to estimate risk ratios on outcomes while adjusting for sex and age to investigate whether there were significant adjusted differences in complication rates among the BMI groups.

RESULTS

We found that, relative to overweight patients, there were no statistically significant differences in the risk of acute complications for underweight (BMI < 18.5) (P = .118), healthy weight (18.5≤BMI < 25) (P = .544), obese (30≤BMI < 40) (P = .930), or morbidly obese (BMI < 40) (P = .602) patients who underwent TAA. There were also no statistically significant differences in the risk of acute complications based on age category (P = .482,.824) or sex (P = .440) for TAA. Additionally, there were no significant differences between the BMI groups for either major complications (P = .980) or minor complications (P = .168).

CONCLUSION

Ultimately, we found that BMI, age, and sex did not lead to statistically significant differences in the risk of complications within 30 days postoperatively for TAA, even when stratified by major vs minor complications.

LEVEL OF EVIDENCE

Level III.

Effect of Taiwan's Diabetes Shared Care Program on the risk of periprosthetic joint infection after total joint arthroplasty in patients with type 2 diabetes mellitus: an eight-year population-based study

BACKGROUND

Periprosthetic joint infection (PJI) is a significant post-arthroplasty complication for diabetic patients, with uncontrolled diabetes identified as a PJI risk factor. Taiwan's Diabetes Shared Care Program (DSCP) was established for holistic diabetes care.

AIM

To evaluate the DSCP's impact on PJI incidence and patients' medical costs.

METHODS

Data were analysed from Taiwan's National Health Insurance Research Database from 2010 to 2020, focusing on type 2 diabetes mellitus (DM) patients who had undergone arthroplasty. The study group involved DSCP participants, while a comparison group comprised non-participants with matched propensity scores for age, sex, and comorbidities. The primary outcome was the PJI incidence difference between the groups; the secondary outcome was the medical expense difference.

FINDINGS

The study group consisted of 11,908 type 2 DM patients who had arthroplasty and joined the DSCP; PJI occurred in 128 patients. Among non-participants, 184 patients had PJI. The PJI incidence difference between the groups was statistically significant (1.07% vs 1.55%). The study group's medical costs were notably lower, regardless of PJI incidence. Multivariate regression showed higher PJI risk in patients in comparison group, aged >70 years, male, or who had obesity, anaemia.

CONCLUSION

The study indicates that DSCP involvement reduces PJI risks and decreases annual medical costs for diabetic patients after arthroplasty. Consequently, the DSCP is a recommendable option for such patients who are preparing for total joint arthroplasty.

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.

Risk Factors Associated With Poor Outcomes After Quadriceps Tendon Repair

Background

Ruptures of the quadriceps tendon present most frequently in older adults and individuals with underlying medical conditions.

Purpose

To examine the relationship between patient-specific factors and tear characteristics with outcomes after quadriceps tendon repair.

Study Design

Case-control study; Level of evidence, 3.

Methods

A retrospective review was conducted on all patients who underwent quadriceps tendon repair between January 1, 2016, and January 1, 2021, at a single institution. Patients <18 years and those with chronic quadriceps tendon tears (>6 weeks to surgery) were excluded. Information was collected regarding patient characteristics, presenting symptoms, tear characteristics, physical examination findings, and postoperative outcomes. Poor outcome was defined as a need for revision surgery, complications, postoperative range of motion of (ROM) <110° of knee flexion, and extensor lag of >5°.

Results

A total of 191 patients met the inclusion criteria. Patients were aged 58.5 ± 13.2 years at the time of surgery, were predominantly men (90.6%), and had a mean body mass index (BMI) of 32.2 ± 6.3 kg/m2. Patients underwent repair with either suture anchors (15.2%) or transosseous tunnels (84.8%). Postoperatively, 18.5% of patients experienced knee flexion ROM of <110°, 11.3% experienced extensor lag of >5°, 8.5% had complications, and 3.2% underwent revision. Increasing age (odds ratio [OR], 1.03 [95% CI, 1.004-1.07]) and female sex (OR, 3.82 [95% CI, 1.25-11.28]) were significantly associated with postoperative knee flexion of <110°, and increasing age (OR, 1.08 [95% CI, 1.04-1.14]) and greater BMI (OR, 1.14 [95% CI, 1.05-1.23]) were significantly associated with postoperative extensor lag of >5°. Current smoking status (OR, 15.44 [95% CI, 3.97-65.90]) and concomitant retinacular tears (OR, 9.62 (95% CI, 1.67-184.14]) were associated with postoperative complications, and increasing age (OR, 1.05 [95% CI, 1.02-1.08]) and greater BMI (OR, 1.08 [95% CI, 1.02-1.14]) were associated with risk of acquiring any poor outcome criteria.

Conclusion

Patient-specific characteristics-such as increasing age, greater BMI, female sex, retinacular involvement, and current smoking status-were found to be risk factors for poor outcomes after quadriceps tendon repair. Further studies are needed to identify potentially modifiable risk factors that can be used to set patient expectations and improve outcomes.

Preoperative COVID-19 infection status negatively impacts postoperative outcomes of geriatric hip fracture surgery

OBJECTIVES

Compare outcomes for patients with recently diagnosed COVID-19 infection to those without COVID-19 infection undergoing operative treatment of hip fractures using the American College of Surgeons National Surgical Quality Improvement Program (NSQIP) database.

DESIGN

Retrospective propensity score matched cohort.

METHODS

Patients who received surgery for an acute hip fracture (intramedullary nail (IMN), open reduction internal fixation (ORIF) or hemiarthroplasty) in 2021 were identified from the NSQIP database. Propensity score matching was implemented using patient demographics and preoperative medical conditions to compare outcomes for COVID-19-positive and COVID-19-negative cohorts.

RESULTS

After matching, COVID-19-positive patients exhibited a higher risk of 30-day mortality (Odds ratio (OR) 1.48, 95 % confidence interval (CI) 1.01 - 2.04), pneumonia (OR 2.90, 95 % CI: 1.91 - 4.33), unplanned intubation (OR 2.53, 95 % CI: 1.39 - 4.39), and septic shock (OR 2.51, 95 % CI: 1.10 - 4.67). COVID-19-positive patients were also more likely to have a longer length of hospital stay (Hazard Ratio 1.3, 95 % CI: 1.20 - 1.41) and were more likely to be discharged to an acute care hospital (OR 1.90, 95 % CI: 1.03 - 3.06).

CONCLUSIONS

Active COVID-19 infection is an independent risk factor for complications as well as increased resource utilization in patients undergoing surgical treatment of acute hip fracture. Using the results of this multicenter study, quantification of these risks can help inform practice and treatment protocols for this population.

LEVEL OF EVIDENCE

III.

Wound complications are affected by different skin closure methods in primary hip and knee arthroplasty

INTRODUCTION

There is a lack of consensus on optimal skin closure and dressing strategies to reduce early wound complication rates after primary total hip (THA) and total knee arthroplasty (TKA).

METHODS

All 13,271 patients at low risk for wound complications undergoing primary, unilateral THA (7,816) and TKA (5,455) for idiopathic osteoarthritis at our institution between August 2016 and July 2021 were identified. Skin closure, dressing type, and post-operative events related to wound complications were recorded during the first 30 postoperative days.

RESULTS

The need for unscheduled office visits to address wound complications was more frequent after TKA than THA (2.74 vs 1.78%, p<0.001), and after direct-anterior vs. posterior approach THA (2.94 vs 1.39%, p<0.001). Patients who developed a wound complication, had a mean of 2.9 additional office visits. Compared to the use of topical adhesives, skin closure with staples had the highest risk of wound complications (Odds Ratio 1.8 [1.07-3.11], p=0.028). Topical adhesives with polyester mesh had higher rates of allergic contact dermatitis than topical adhesives without mesh (1.4 vs 0.5%, p<0.0001).

DISCUSSION

Wound complications after primary THA and TKA were often self-limited but increased burden on the patient, surgeon, and care team. These data, which suggest different rates of certain complications with different skin closure strategies, can inform a surgeon on optimal closure methods in their practice. Adoption of the skin closure technique with the lowest risk of complications in our hospital would conservatively result in a reduction of 95 unscheduled office visits and save a projected $585,678 annually.

A Novel Method for Stratification of 30-Day Major Complication Risk Using Body Mass Index Thresholds for Patients Undergoing Total Knee Arthroplasty: A National Cohort of 443,157 Patients

INTRODUCTION

Many organizations have utilized pre-established body mass index (BMI) cut-offs to guide surgical decision making. As there have been many improvements in patient optimization, surgical technique, and perioperative care over time, it is important to reassess these thresholds as well as contextualize them to total knee arthroplasty (TKA). The purpose of this study was to calculate data-driven BMI thresholds that predict significant differences in risk of 30-day major complications following TKA.

METHODS

Patients who underwent primary TKA from 2010 to 2020 were identified in a national database. Stratum-specific likelihood ratio (SSLR) methodology was utilized to determine data-driven BMI thresholds at which the risk of 30-day major complications increased significantly. These BMI thresholds were tested using multivariable logistic regression analyses. A total of 443,157 patients were included, who had a mean age of 67 (range, 18 to 89), mean BMI of 33 (range 19 to 59), and 11,766 (2.7%) of patients had a 30-day major complication RESULTS: SSLR analysis identified four BMI thresholds that were associated with significant differences in 30-day major complications: 19 to 33, 34 to 38, 39 to 50, and 51+. When compared to those who had a BMI between 19 and 33, the odds of sustaining a major complication sequentially and significantly increased by 1.1, 1.3, and 2.1 times (p<0.05 for all) for the other thresholds.

CONCLUSION

This study identified four data-driven BMI strata utilizing SSLR analysis that were associated with significant differences in the risk of 30-day major complications following TKA. These strata can be utilized to guide shared decision making in patients undergoing TKA.

Understanding the risk of developing weight-related complications associated with different body mass index categories: a systematic review

BACKGROUND

Obesity and overweight are major risk factors for several chronic diseases. There is limited systematic evaluation of risk equations that predict the likelihood of developing an obesity or overweight associated complication. Predicting future risk is essential for health economic modelling. Availability of future treatments rests upon a model's ability to inform clinical and decision-making bodies.  This systematic literature review aimed to identify studies reporting (1) equations that calculate the risk for individuals with obesity, or overweight with a weight-related complication (OWRC), of developing additional complications, namely T2D, cardiovascular (CV) disease (CVD), acute coronary syndrome, stroke, musculoskeletal disorders, knee replacement/arthroplasty, or obstructive sleep apnea; (2) absolute or proportional risk for individuals with severe obesity, obesity or OWRC developing T2D, a CV event or mortality from knee surgery, stroke, or an acute CV event.

METHODS

Databases (MEDLINE and Embase) were searched for English language reports of population-based cohort analyses or large-scale studies in Australia, Canada, Europe, the UK, and the USA between January 1, 2011, and March 29, 2021. Included reports were quality assessed using an adapted version of the Newcastle Ottawa Scale.

RESULTS

Of the 60 included studies, the majority used European cohorts. Twenty-nine reported a risk prediction equation for developing an additional complication. The most common risk prediction equations were logistic regression models that did not differentiate between body mass index (BMI) groups (particularly above 40 kg/m²) and lacked external validation. The remaining included studies (31 studies) reported the absolute or proportional risk of mortality (29 studies), or the risk of developing T2D in a population with obesity and with prediabetes or normal glucose tolerance (NGT) (three studies), or a CV event in populations with severe obesity with NGT or T2D (three studies). Most reported proportional risk, predominantly a hazard ratio.

CONCLUSION

More work is needed to develop and validate these risk equations, specifically in non-European cohorts and that distinguish between BMI class II and III obesity. New data or adjustment of the current risk equations by calibration would allow for more accurate decision making at an individual and population level.

Obesity increases the risk of conversion to total knee arthroplasty after unicompartimental knee arthroplasty: a meta-analysis

PURPOSE

The aim of this meta-analysis was to to determine the influence of obesity on patient outcome and implant survivorship after primary unicompartmental knee arthroplasty (UKA).

METHODS

A PRISMA systematic review was conducted by searching the Medline (PubMed), EMBASE, and Cochrane electronic databases to identify clinical studies investigating the effect of obesity on outcomes after UKA. Data were collected on aspecifically designed extraction form. Methodological quality was assessed using the Methodological Index for Nonrandomized Studies score. Quantitative meta-analysis was carried out using RevMan 5.4 software.

RESULTS

A total of 17 studies were included; 43,845 primary UKA patients were classified by their BMI: on-obese (BMI 25 to < 30 kg/m²); obese (BMI 30 to < 35 kg/m²); severely obese (BMI > 35 kg/m²). Pooled analysis showed no statistically significant difference in Knee Society Score (KSS) pain in the obese (n.s.) and the severely obese (n.s.) group compared to the non-obese group, while the KSS function score was lower in the severely obese (P = 0.0002) compared to the obese (P = 0.06) and the non-obese group. Postoperative Oxford Knee Score (OKS) was lower in the obese group (P = 0.01) but not in the severely obese group (P = 0.16). Postoperative Range of Motion (ROM) was comparable in the obese and non-obese group (P = 0.16). Implant survival at 10 years follow-up was significantly lower in the obese (82.5-95.3%; P < 0.0001) and the severely obese group (87.5-93.8%; P < 0.0001) thanthe non-obese group (83.6-98.6%).

CONCLUSION

Obesity and severe obesity were associated with significantly higher revision and lower implant survival rates. Obesity did not influence clinical and most functional outcomes after UKA, whereas KSS function score was significantly lower only for the severely obese patient group.

LEVEL OF EVIDENCE

III, meta-analysis.

Effect of Weight Change on Patient-Reported Outcomes Following Total Joint Arthroplasty

BACKGROUND

Increased body mass index (BMI) has been previously described as a risk factor for complications after total joint arthroplasty (TJA); however, its effect on patient-reported outcomes has not been thoroughly investigated. This study examines the effect of postoperative weight change on the Patient-Reported Outcomes Measurement Information System Physical Function (PROMIS-PF) scores for total knee arthroplasty (TKA) and total hip arthroplasty (THA) patients.

METHODS

A retrospective review of 988 patients undergoing THA or TKA was performed. PROMIS-PF scores and BMI were recorded throughout the study duration. Patients were classified by a 5% change in BMI. A univariate analysis evaluated differences across groups. Mixed-effect models evaluated predictors of change in functional score over the postoperative follow-up time.

RESULTS

43.1% patients had a THA and 56.9% patients had a TKA. At 0 to 3 months, 92% of patients had no change in BMI, 3 to 6 months 82% had no change, and 6 to 12 months 80% had no change. There were no significant demographic or comorbidity differences across groups for both THA and TKA. Similar improvements in PROMIS-PF scores were observed across weight change groups. In the mixed-effect models, postoperative time was found to be a significant predictor of postoperative PF score. Both THA and TKA patients saw greater improvements in PROMIS-PF scores in patients with lower preoperative BMIs.

CONCLUSION

These results demonstrate most patients do not experience substantial changes in weight following TJA. However, lower BMIs at the time of surgery were associated with an increased functional improvement. Therefore, efforts to optimize BMI should be focused preoperatively to improve surgical outcomes.

A Novel Method for Stratification of Major Complication Risk Using Body Mass Index Thresholds for Patients Undergoing Total Hip Arthroplasty: A National Cohort of 224,413 Patients

INTRODUCTION

Elevated body mass index (BMI) is associated with complications following Total Hip Arthroplasty (THA). Since obese individuals are almost 10 times more likely to require THA compared to non-obese individuals, we need to understand the risk-benefit continuum while considering THA in obese patients. We aimed to determine data-driven thresholds for BMI at which the risk of major complications following THA increases significantly.

METHODS

Patients were identified in a national database who underwent primary THA from 2010 to 2020. BMI thresholds were identified using the stratum-specific likelihood ratio (SSLR) methodology, which is an adaptive technique that allows for identification of BMI cut-offs, at which the risk of major complications is increased significantly . BMI cutoffs identified using SSLR were used to create a logistic regression model.

RESULTS

A total of 224,413 patients were identified with a mean age of 66 ± 10, BMI 32 ± 6.7, and 7,186 (3%) sustained a major complication. BMI thresholds were defined as 19-31, 32-37, 38-49 and 50+. Overall, the absolute risk of major complications increased from 2.9% in the lowest BMI strata to 7.5% in the highest BMI strata. Compared to patients with a BMI between 19-31, the odds of sustaining a major complication sequentially increased by 1.2, 1.6, and 2.5-times for patients in each higher BMI strata (all, P < .05).

CONCLUSIONS

We have identified BMI cutoffs using SSLR that categorizes patients into four categories of risk for major complications in a nationally representative patient sample. These thresholds can be used in the surgical decision-making process between patients and surgeons.

Higher 1-year risk of implant removal for culture-positive than for culture-negative DAIR patients following 359 primary hip or knee arthroplasties

Background and purpose: To date, the value of culture results after debridement, antibiotics, and implant retention (DAIR) for early (suspected) prosthetic joint infection (PJI) as risk indicators in terms of prosthesis retention is not clear. At the 1-year follow-up, the relative risk of prosthesis removal was determined for culture-positive and culture-negative DAIR patients after primary total hip or knee arthroplasty. The secondary aim of this work was to explore differences in patient characteristics, infection characteristics, and outcomes between these two groups. Methods: A retrospective regional registry study was performed in a group of 359 patients (positive cultures: n=299; negative cultures: n=60) undergoing DAIR for high suspicion of early PJI in the period from 2014 to 2019. Differences in patient characteristics, the number of deceased patients, and the number of subsequent DAIR treatments between the culture-positive and culture-negative DAIR groups were analysed using independent t tests, Mann–Whitney U tests, Pearson's chi-square tests, and Fisher's exact tests. Results: The overall implant survival rate following DAIR was 89 %. The relative risk of prosthesis removal was 7.4 times higher (95 % confidence interval (CI) 1.0–53.1) in the culture-positive DAIR group (37 of 299, 12.4 %) compared with the culture-negative DAIR group (1 of 60, 1.7 %). The culture-positive group had a higher body mass index (p=0.034), a rate of wound leakage of >10 d (p=0.016), and more subsequent DAIR treatments (p=0.006). Interpretation: As implant survival results after DAIR are favourable, the threshold to perform a DAIR procedure for early (suspected) PJI should be low in order to retain the prosthesis. A DAIR procedure in the case of negative cultures does not seem to have unfavourable results in terms of prosthesis retention.

The Impact of Surgeon Variability on Patient-Reported Outcomes in Total Hip Arthroplasty

BACKGROUND

Patient-related and surgery-related factors have been shown to be drivers of outcomes after total hip arthroplasty (THA); however, the impact of intersurgeon variability is poorly understood. The purpose of this study is to assess the following: (1) overall effect of surgeon on 1-year patient-reported outcome measures (PROMs), length of stay (LOS), discharge disposition, and 90-day readmission following THA; and (2) variability in 1-year PROMs among surgeons.

METHODS

A prospective cohort of 3,695 patients who underwent THA between 2016 and 2018 was included. Seventy-eight percent of patients completed 1-year follow-up. Thirty-one surgeons from a large healthcare system were included. Likelihood ratio tests analyzed the relationship among surgeon and 1-year Hip Disability and Osteoarthritis Outcome Score (HOOS)-Pain, HOOS-Physical Function Short-Form, HOOS-Joint Replacement, University of California, Los Angeles activity score, Patient Acceptable Symptom State, LOS, discharge disposition, and 90-day readmission. Mixed-effect proportional odds and logistic regression models were used to determine variable importance for each outcome.

RESULTS

In total, 90.5% of patients responded positively to 1-year Patient Acceptable Symptom State. There was a significant association among surgeon and 1-year PROMs, LOS, discharge disposition (P < .001), and readmission (P = .002). For HOOS-Pain, Physical Function Short-Form, and Joint Replacement, surgeon (Akaike information criterion increase: 34.6, 18.7, 17.1, respectively) was a greater contributor to outcome than patient-level factors, including age, gender, and comorbidity. Differences in the highest and lowest median probability of achieving any given score on 1-year PROMs ranged from 11% to 18.5%. Variability was not explained by approach (P = .431) or case volume (correlation coefficient, ρ = 0.19).

CONCLUSION

Surgeon-level variability appears to be a greater driver of 1-year PROMs than some patient-level characteristics. Incorporating surgeon as a variable is beneficial for model-fitting and important for increasing value in THA.

Long-Term Postoperative Total Knee Arthroplasty Flexion Scores in Relation to Body Mass Index

Knee range of motion (ROM) is an important postoperative measure of total knee arthroplasty (TKA). There is conflicting literature whether patients who are obese have worse absolute ROM outcomes than patients who are not obese. This study analyzed whether preoperative body mass index (BMI) influences knee ROM after patients' primary TKA. A retrospective investigation was performed on patients, who underwent primary TKA at an academic institution, by one of three fellowship-trained adult reconstruction surgeons. Patients were stratified according to their preoperative BMI into nonobese (BMI < 30.0 kg/m²) and obese (BMI ≥ 30.0 kg/m²) classifications. Passive ROM was assessed preoperatively as well as postoperatively at patients' most recent follow-up visit that was greater than 2 years. Mann-Whitney U tests were performed to determine statistical significance at p-value <0.05 for ROM outcomes. No statistically significant differences were observed when ROM in the nonobese group was compared with ROM in the obese group both preoperatively (105.73 ± 11.58 vs. 104.14 ± 13.58 degrees, p-value = 0.417) and postoperatively (105.83 ± 14.19 vs. 104.49 ± 13.52 degrees, p-value = 0.777). Mean follow-up time for all patients was 4.49 ± 1.92 years. In conclusion, long-term postoperative ROM outcomes were similar between patients who were nonobese and patients who were obese.

Return to work after primary total hip or knee arthroplasty. First French study. Retrospective study of 241 cases

INTRODUCTION

The quality and reliability of the results of primary total hip or knee arthroplasty (THA, TKA) have allowed indications to be extended to younger, working-age patients, raising the issue of return to work. This question has never been specifically addressed in THA and TKA in a French population. We therefore conducted a retrospective study to determine: (1) the rates and intervals of return to work, and (2) factors affecting return to work and reasons for non-return.

HYPOTHESIS

Rates and intervals of return to work are comparable to those in Western countries as a whole: 1.1-10.5 weeks in THA and 8-12 weeks in TKA.

MATERIAL AND METHOD

A single-center retrospective study included patients aged under 65 at surgery, between 2009 and 2013. A questionnaire collected population and occupational data. The patients' occupational situation was collected at a minimum 1 year postoperatively. During the study period, 289 TKAs or THAs were performed; 241 patients were recontacted, 144 of whom had been working at the time of surgery: 72 THAs and 72 TKAs. The sex-ratio was well balanced: 69 males, 75 females. Mean age was 55.8±8 years (range, 18.6-65.7 years). The mean time from surgery to data collection was 34.5 months (95% CI, 32.2-36.8 months).

RESULTS

In all, 86 patients (57.6%) returned to work, at a mean 124 days (range, 15-540 days; 95% CI, 102.8-144.4 days). At 3 months, 55.4% of patients (n=46) had returned to work, and 97.6% (n=81) at 12 months. In most cases, patients returned to the same occupation.

CONCLUSION

The study hypothesis was not confirmed. French primary THA or TKA patients returned to work later and less frequently than in other Western countries.

LEVEL OF EVIDENCE

IV, retrospective study without control group.

The Use of Artificial Neural Networks for the Prediction of Surgical Site Infection Following TKA

This is a retrospective study. Surgical site infection (SSI) is associated with adverse postoperative outcomes following total knee arthroplasty (TKA). However, accurately predicting SSI remains a clinical challenge due to the multitude of patient and surgical factors associated with SSI. This study aimed to develop and validate machine learning models for the prediction of SSI following primary TKA. This is a retrospective study for patients who underwent primary TKA. Chart review was performed to identify patients with superficial or deep SSIs, defined in concordance with the criteria of the Musculoskeletal Infection Society. All patients had a minimum follow-up of 2 years (range: 2.1-4.7 years). Five machine learning algorithms were developed to predict this outcome, and model assessment was performed by discrimination, calibration, and decision curve analysis. A total of 10,021 consecutive primary TKA patients was included in this study. At an average follow-up of 2.8 ± 1.1 years, SSIs were reported in 404 (4.0%) TKA patients, including 223 superficial SSIs and 181 deep SSIs. The neural network model achieved the best performance across discrimination (area under the receiver operating characteristic curve = 0.84), calibration, and decision curve analysis. The strongest predictors of the occurrence of SSI following primary TKA, in order, were Charlson comorbidity index, obesity (BMI >30 kg/m²), and smoking. The neural network model presented in this study represents an accurate method to predict patient-specific superficial and deep SSIs following primary TKA, which may be employed to assist in clinical decision-making to optimize outcomes in at-risk patients.

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.

Sodium Abnormalities Are an Independent Predictor of Complications in Total Joint Arthroplasty: A Cautionary Tale!

BACKGROUND

Electrolyte levels are commonly obtained as part of the preoperative workup for total joint arthroplasty, but limited information exists on the interplay between electrolyte abnormalities and outcomes.

METHODS

The National Surgical Quality Improvement Program was queried for primary, elective total hip arthroplasty and total knee arthroplasty (THA, TKA) performed between 2011 and 2017. Three patient groups were compared: normal (control), hypernatremia, and hyponatremia. The primary outcomes were length of stay (LOS) and 30-day adverse events: complications, readmissions, reoperations, and mortality.

RESULTS

A total of 244,538 TKAs and 145,134 THAs were analyzed. The prevalence of hyponatremia and hypernatremia was 6.9% and 1.0%, respectively. After controlling for any baseline differences, hypernatremia was an independent predictor of ventilation >48 hours (THA, odds ratio [OR] 3.53), unplanned intubation (THA, OR 3.14), cardiac arrest (THA, OR 2.42), pneumonia (THA, OR 2.16), Clostridium difficile infection (OR 4.66 and 3.25 for THA and TKA, respectively), LOS >2 days (THA, OR 1.16), and mortality (THA, OR 4.69). Similarly, hyponatremia was an independent predictor of LOS >2 days (TKA, OR 1.21), readmission (TKA, OR 1.40), reoperation (OR 1.32 and 1.47 for THA and TKA, respectively), surgical site infections (OR 1.39 and 1.54 for THA and TKA, respectively), and transfusion (OR 1.13 and 1.20 for THA and TKA, respectively).

CONCLUSION

As the focus of total joint arthroplasty continues to shift toward value-based payment models and outpatient surgery, caution should be exercised in patients with abnormal preoperative sodium levels, particularly hypernatremia, because of significantly increased risk of prolonged LOS and 30-day adverse events.

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.

Comparison of Area Deprivation Index, Socioeconomic Parameters, and Preoperative Demographics With Postoperative Emergency Department Visits After Total Knee Arthroplasty

BACKGROUND

This study aims to determine if socioeconomic (SE) parameters, primarily area deprivation index (ADI), relate to postoperative emergency department (ED) visits after total knee arthroplasty (TKA).

METHODS

We retrospectively reviewed 2655 patients who underwent TKA in a health system of 4 hospitals. The primary outcome was an ED visit within 90 days, which was divided into those with and without readmission. SE parameters including ADI as well as preoperative demographics were analyzed. Univariable and multiple logistic regressions were performed determining risk of 90-day postoperative ED visits, as well as once in the ED, risks for readmission.

RESULTS

436 patients (16.4%) presented to the ED within 90 days. ADI was not a risk factor. The multiple logistic regression demonstrated men, Medicare or Medicaid, and preoperative ED visits were consistently risk factors for a postoperative ED visit with and without readmission. Preoperative anticoagulation was only a risk factor for ED visits with readmission. Among patients who visited the ED, if the patient was Caucasian, a lower BMI, or higher American Society of Anesthesiologists score, they were likely to be readmitted.

CONCLUSION

The study demonstrated that the percentage of early ED returns after TKA was high and that ADI was not a predictor for 90-day postoperative ED visit. The only SE factor that may contribute to this phenomenon was insurance type. Once in the ED, race, preoperative ED visits, preoperative anticoagulation, BMI, gender, and preoperative American Society of Anesthesiologists score contributed to a risk of readmission. The study supports hospitals' mission to provide equal access health care.

Obesity Increases Risk of Failure to Achieve the 1-Year PROMIS PF-10a Minimal Clinically Important Difference Following Total Joint Arthroplasty

INTRODUCTION

The aims of this study were to determine if increasing body mass index (BMI) is a risk factor for failure to attain the 1-year Patient Reported Outcomes Measurement Information System Physical Function (PROMIS PF-10a) minimal clinically important difference (MCID) following total joint arthroplasty (TJA) and to determine a possible BMI threshold beyond which this risk increases significantly.

METHODS

This retrospective study was performed using 3506 TJAs sourced from a regional-based registry. An anchor-based MCID threshold of 7.9 was chosen. PROMIS PF-10a scores were collected at the preoperative and 1-year postoperative timepoints, and the change was used to determine failure to achieve the 1-year MCID. Demographic and surgical variables were also collected. The association between BMI and failure to achieve 1-year PROMIS PF-10 MCID was then evaluated using logistic regression. A BMI threshold was determined using receiver operating characteristic (ROC) curve analysis.

RESULTS

Increasing BMI assessed continuously was a significant risk factor for failure to achieve the MCID (P < .001). "Obese Class I" (30-35 kg/m²), "Obese Class II" (35-40 kg/m²), and "Obese Class III" (>40 kg/m²) subgroups compared to "Normal BMI" (<25 kg/m²) were significantly associated (P < .05) with this adverse outcome as well.

CONCLUSION

Our study showed that increasing BMI is a risk factor for failure to achieve the 1-year PROMIS PF-10a MCID following TJA. Among our patients, an increase in 1 kg/m² increased the risk of failure to achieve the MCID by 2%. With these findings, surgeons will be better equipped to preoperatively advise patients with elevated BMIs considering TJA.

Preoperative risk stratification minimizes 90-day complications in morbidly obese patients undergoing primary total knee arthroplasty

AIMS

It has been shown that the preoperative modification of risk factors associated with obesity may reduce complications after total knee arthroplasty (TKA). However, the optimal method of doing so remains unclear. The aim of this study was to investigate whether a preoperative Risk Stratification Tool (RST) devised in our institution could reduce unexpected intensive care unit (ICU) transfers and 90-day emergency department (ED) visits, readmissions, and reoperations after TKA in obese patients.

METHODS

We retrospectively reviewed 1,614 consecutive patients undergoing primary unilateral TKA. Their mean age was 65.1 years (17.9 to 87.7) and the mean BMI was 34.2 kg/m² (SD 7.7). All patients underwent perioperative optimization and monitoring using the RST, which is a validated calculation tool that provides a recommendation for postoperative ICU care or increased nursing support. Patients were divided into three groups: non-obese (BMI < 30 kg/m², n = 512); obese (BMI 30 kg/m² to 39.9 kg/m², n = 748); and morbidly obese (BMI > 40 kg/m², n = 354). Logistic regression analysis was used to evaluate the outcomes among the groups adjusted for age, sex, smoking, and diabetes.

RESULTS

Obese patients had a significantly increased rate of discharge to a rehabilitation facility compared with non-obese patients (38.7% (426/1,102) vs 26.0% (133/512), respectively; p < 0.001). When stratified by BMI, discharge to a rehabilitation facility remained significantly higher compared with non-obese (26.0% (133)) in both obese (34.2% (256), odds ratio (OR) 1.6) and morbidly obese (48.0% (170), OR 3.1) patients (p < 0.001). However, there was no significant difference in unexpected ICU transfer (0.4% (two) non-obese vs 0.9% (seven) obese (OR 2.5) vs 1.7% (six) morbidly obese (OR 5.4); p = 0.054), visits to the ED (8.6% (44) vs 10.3% (77) (OR 1.3) vs 10.5% (37) (OR 1.2); p = 0.379), readmissions (4.5% (23) vs 4.0% (30) (OR 1.0) vs 5.1% (18) (OR 1.4); p = 0.322), or reoperations (2.5% (13) vs 3.3% (25) (OR 1.2) vs 3.1% (11) (OR 0.9); p = 0.939).

CONCLUSION

With the use of a preoperative RST, morbidly obese patients had similar rates of short-term postoperative adverse outcomes after primary TKA as non-obese patients. This supports the assertion that morbidly obese patients can safely undergo TKA with appropriate perioperative optimization and monitoring. Cite this article: Bone Joint J 2021;103-B(6 Supple A):45-50.

The association of preoperative blood markers with postoperative readmissions following arthroplasty

Aims

While preoperative bloodwork is routinely ordered, its value in determining which patients are at risk of postoperative readmission following total knee arthroplasty (TKA) and total hip arthroplasty (THA) is unclear. The objective of this study was to determine which routinely ordered preoperative blood markers have the strongest association with acute hospital readmission for patients undergoing elective TKA and THA.

Methods

Two population-based retrospective cohorts were assembled for all adult primary elective TKA (n = 137,969) and THA (n = 78,532) patients between 2011 to 2018 across 678 North American hospitals using the American College of Surgeons National Quality Improvement Programme (ACS-NSQIP) registry. Six routinely ordered preoperative blood markers - albumin, haematocrit, platelet count, white blood cell count (WBC), estimated glomerular filtration rate (eGFR), and sodium level - were queried. The association between preoperative blood marker values and all-cause readmission within 30 days of surgery was compared using univariable analysis and multivariable logistic regression adjusted for relevant patient and treatment factors.

Results

The mean TKA age was 66.6 years (SD 9.6) with 62% being females (n = 85,163/137,969), while in the THA cohort the mean age was 64.7 years (SD 11.4) with 54% being female (n = 42,637/78,532). In both cohorts, preoperative hypoalbuminemia (< 35 g/l) was associated with a 1.5- and 1.8-times increased odds of 30-day readmission following TKA and THA, respectively. In TKA patients, decreased eGFR demonstrated the strongest association with acute readmission with a standardized odds ratio of 0.75 per two standard deviations increase (p < 0.0001).

Conclusion

In this population level cohort analysis of arthroplasty patients, low albumin demonstrated the strongest association with acute readmission in comparison to five other commonly ordered preoperative blood markers. Identification and optimization of preoperative hypoalbuminemia could help healthcare providers recognize and address at-risk patients undergoing TKA and THA. This is the most comprehensive and rigorous examination of the association between preoperative blood markers and readmission for TKA and THA patients to date.

Cite this article: Bone Jt Open 2021;2(6):388–396.

A Novel Biofilm-Disrupting Wound Care Technology for the Prevention of Surgical Site Infections Following Total Joint Arthroplasty: A Conceptual Review

Surgical site infections (SSIs) are a major driver for increased costs following lower extremity joint arthroplasty procedures. It has been estimated that these account for over $2 billion in annual costs in the United States. While many of the current strategies for the prevention and treatment of SSIs target planktonic bacteria, 80 to 90% of bacterial pathogens exist in a sessile state. These sessile bacteria can produce extracellular polymeric substance (EPS) as protective barriers from host immune defenses and antimicrobial agents and thus, can be exceedingly difficult to eradicate. A novel wound care gel that disrupts the EPS and destroys the inciting pathogens has been developed for the treatment and prevention of biofilm-related infections. This is achieved by the simultaneous action of four key ingredients: (1) citric acid; (2) sodium citrate; (3) benzalkonium chloride; and (4) polyethylene glycol. Together, these constituents create a high osmolarity, pH-controlled environment that deconstructs and prevents biofilm formation, while destroying pathogens and promoting a moist environment for optimal wound healing. The available clinical evidence demonstrating the efficacy of this technology has been summarized, as well as the economic implications of its implementation and the authors' preferred method of its use. Due to the multifaceted burden associated with biofilm-producing bacteria in arthroplasty patients, this technology may prove to be beneficial for patients who have higher risks for infection, or perhaps, as a prophylactic measure to prevent infections for all patients.

Predictive risk factors for facial nerve injury in temporomandibular joint replacement surgery

The objective of this study was to determine the prevalence of temporary and permanent facial nerve injury in total temporomandibular joint (TMJ) replacement surgery and to identify potential predictive risk factors. We made a retrospective review of case notes and opportunistic review of patients treated in a single tertiary referral unit by a single surgeon. For each patient a number of potential risk factors were determined, and the presence or absence of nerve injury recorded at 2 week follow up and a minimum of 12 months follow up. At 2-week review, facial nerve weakness was noted in 38/133 cases (28%) and at last follow up there were 4/133 cases (3%) with continuing (permanent) facial nerve weakness. Bilateral surgery, revision TMJ replacement, primary diagnosis, the number of previous surgeries and a history of recovered facial nerve injury all significantly increased the likelihood of temporary facial nerve injury, but not the likelihood of permanent facial nerve injury. Factors which increase the risk of temporary facial nerve injury are relatively predictable and include bilateral surgery, revision TMJ replacement, and multiple open TMJ surgeries. Risk factors associated with permanent injury are less predictable but are likely to be similar. The identification of such factors allows for the risk stratification of patients and improve informed consent. We also recommend that patients with a single, previously failed open TMJ surgery should be considered for early TMJ replacement and in multiply operated patients a subfascial plane of dissection is adopted.

Diabetes Status Affects Odds of Body Mass Index-dependent Adverse Outcomes After Total Hip Arthroplasty

INTRODUCTION

Obesity and diabetes have independently been shown to predispose to adverse outcomes after total hip arthroplasty (THA). These may have a coupled effect on perioperative risks. The purpose of this study was to evaluate the effect of body mass index (BMI) on adverse outcomes in nondiabetic (ND), non-insulin-dependent diabetes mellitus (NIDDM), and insulin-dependent diabetes mellitus (IDDM) patients.

METHODS

Patients undergoing primary THA were selected from the National Surgical Quality Improvement Program Database from 2012 to 2016 and categorized as ND, NIDDM, and IDDM. BMI, demographics, and 30-day perioperative outcomes were assessed for each group. Multivariate logistic regressions controlling for demographics, functional status, and American Society of Anesthesiologists were used to determine the odds ratio of serious adverse event (SAE) in each diabetes group for patients with BMI ≥ 40 kg/m compared with a control group of ND patients with a normal BMI (18.5 to 24.9 kg/m).

RESULTS

A total of 108,177 patients were included. The results demonstrate that ND (odds ratio 1.65; P < 0.001) and NIDDM (odds ratio 1.75; P = 0.007) patients have similar risks of SAE, whereas IDDM (odds ratio 2.79; P < 0.001) patients have a greater risk of adverse events, particularly at BMIs greater than 40 kg/m.

DISCUSSION

Consistent with previous reports, ND (odds ratio 1.65; P < 0.001) and NIDDM (odds ratio 1.75; P = 0.007) morbidly obese patients (BMI > 40 kg/m) had an increased odds of SAEs after THA, but for IDDM (odds ratio 2.79; P < 0.001) patients this increased odds was notably higher. Although patients with IDDM have increased rates of adverse events compared with ND and NIDDM patients, these findings should not be used to establish strict BMI cutoffs in patients with IDDM. Nonetheless, the results suggest additional factors, such as patient medical history and diabetes control, should be considered when evaluating patients with IDDM for THA.

LEVEL OF SIGNIFICANCE

Level III.

Patient-Related Risk Factors for Unplanned 30-Day Hospital Readmission Following Primary and Revision Total Knee Arthroplasty: A Systematic Review and Meta-Analysis

Total knee arthroplasty (TKA) is a highly effective procedure for advanced osteoarthritis of the knee. Thirty-day hospital readmission is an adverse outcome related to complications, which can be mitigated by identifying associated risk factors. We aimed to identify patient-related characteristics associated with unplanned 30-day readmission following TKA, and to determine the effect size of the association between these risk factors and unplanned 30-day readmission. We searched MEDLINE and EMBASE from inception to 8 September 2020 for English language articles. Reference lists of included articles were searched for additional literature. Patients of interest were TKA recipients (primary and revision) compared for 30-day readmission to any institution, due to any cause, based on patient risk factors; case series were excluded. Two reviewers independently extracted data and carried out critical appraisal. In-hospital complications during the index admission were the strongest risk factors for 30-day readmission in both primary and revision TKA patients, suggesting discharge planning to include closer post-discharge monitoring to prevent avoidable readmission may be warranted. Further research could determine whether closer monitoring post-discharge would prevent unplanned but avoidable readmissions. Increased comorbidity burden correlated with increased risk, as did specific comorbidities. Body mass index was not strongly correlated with readmission risk. Demographic risk factors included low socioeconomic status, but the impact of age on readmission risk was less clear. These risk factors can also be included in predictive models for 30-day readmission in TKA patients to identify high-risk patients as part of risk reduction programs.

Prevention of Periprosthetic Joint Infection (PJI): A Clinical Practice Protocol in High-Risk Patients

Background: Periprosthetic joint infection (PJI) represents 25% of failed total knee arthroplasties (TKA). The European Knee Associates (EKA) formed a transatlantic panel of experts to perform a literature review examining patient-related risk factors with the objective of producing perioperative recommendations in PJI high-risk patients. Methods: Multiple databases (Pubmed/MEDLINE, EMBASE, Scopus, Cochrane Library) and recommendations on TKA PJI prevention measures from the International Consensus Meetings on PJI from the AAOS and AAHKS were reviewed. This represents a Level IV study. Results: Strong evidence was found on poor glycemic control, obesity, malnutrition, and smoking being all associated with increased rates of PJI. In the preoperative period, patient optimization is key: BMI < 35, diet optimization, Hemoglobin A1c < 7.5, Fructosamine < 292 mmol/L, smoking cessation, and MRSA nasal screening all showed strong evidence on reducing PJI risk. Intraoperatively, a weight-based antibiotic prophylaxis, accurate fluid resuscitation, betadine and chlorhexidine dual skin preparation, diluted povidone iodine solution irrigation, tranexamic acid administration, and monofilament barbed triclosan-coated sutures for soft tissues closure all represented effective prevention measures. In the postoperative period, failure to reach normalization of ESR, CRP, D-dimer, and IL-6 six weeks postoperatively suggested early PJI. Conclusion: The current recommendations from this group of experts, based on published evidence, support risk stratification to identify high-risk patients requiring implementation of perioperative measures to reduce postoperative PJI.

Obesity does not adversely impact the outcome of unicompartmental knee arthroplasty for osteoarthritis: a meta-analysis of 80,798 subjects

BACKGROUND

Patients with end-stage single compartment osteoarthritis benefit from the less invasive unicompartmental knee arthroplasty (UKA). With increasing financial restraints, some healthcare services have set specific BMI cut-offs when determining patient eligibility for knee arthroplasty due to perceived obesity-related complications. The aim of this systematic review is to determine the effect obesity has on outcomes following UKA, and thus elucidate whether obesity should be a contraindication for UKA.

METHODS

A PRISMA systematic review was conducted using five databases (MEDLINE, EMBASE, Cochrane, PubMed and Web of Science) to identify all clinical studies that examined the effect of obesity on outcomes following UKA. Quantitative meta-analysis was carried out using RevMan 5.3 software. Quality assessment was carried out using the Critical Appraisal Skills Programme (CASP) checklist.

RESULTS

Thirty studies, including a total of 80 798 patients were analysed. The mean follow- up duration was 5.42 years. Subgroup meta-analyses showed no statistically significant difference following UKA between patients cohorts with and without obesity in overall complication rates (95% CI, P = 0.52), infection rates (95% CI, P = 0.81), and revision surgeries (95% CI, P = 0.06). When further analysing complications, no differences were identified in minor (95% CI, P = 0.23) and major complications (95% CI, P = 0.68), or venous thromboembolism rates (95% CI, P = 0.06). When further analysing revision surgeries, no differences were identified for revisions specifically for infection (95% CI, P = 0.71) or aseptic loosening (95% CI, P = 0.75).

CONCLUSIONS

This meta-analysis shows that obesity does not result in poorer post-operative outcomes following UKA and should not be considered a contraindication for UKA. Future studies, including long-term follow-up RCTs and registry-level analyses, should examine factors associated with obesity and consider stratifying obesity to better delineate any potential differences in outcomes.

Modeling the impact of obesity on cost of hip and knee arthroplasty

PURPOSE

This study aimed to determine the proportions of total knee arthroplasty (TKA) and total hip arthroplasty (THA) attributable to obesity in Ireland and the associated hospital costs.

METHODS

Sex- and age-specific numbers of primary TKA and THA procedures and length of stay were estimated using Irish population data from the Central Statistics Office (sex and age) and data from the national Hospital Inpatient Enquiry (numbers of TKA and THA procedures, length of stay, diagnostic-related group codes, sex, and age). Population attributable fractions of TKA and THA related to obesity were calculated using relative risks for different weight groups obtained from published literature. Nationally representative weight and height data were available from the 2015 Healthy Ireland Survey (n = 6142) and extrapolated to the Irish population. Diagnostic-related group tariffs from the Healthcare Pricing Office were used to estimate hospital costs of TKA and THA.

RESULTS

In 2015, 2296 TKA and 3411 THA procedures were performed in public hospitals in Ireland. Of those procedures, 43% of TKA and 20% of THA were attributable to obesity. This equates to €16.0 million out of €52.1 million of TKA- and THA-related hospital costs.

CONCLUSIONS

Effective obesity control has potential to decrease the demand for joint replacements and associated costs.

The Obesity Paradox: Body Mass Index Complication Rates Vary by Gender and Age Among Primary Total Hip Arthroplasty Patients

BACKGROUND

High body mass index (BMI) has long been recognized as a risk factor for postoperative complication among total hip arthroplasty (THA) patients. However, recent studies showed mixed results in the effect of high BMI on surgical outcomes. Our study is to examine the association of preoperative BMI with complication incidence, stratified by age and gender.

METHODS

We queried the American College of Surgeons National Surgical Quality Improvement Project database to identify patients who underwent elective primary THA between 2012 and 2016. We examined the associations between BMI as a continuous and a categorical variable and risk of 30-day postoperative complication, using 2 multiple polynomial logistic regression models. We also created predictive plots to graphically assess the relationship between BMI and complication by gender and age.

RESULTS

In total, 117,567 eligible patients were included in the analyses. The predictive probability of all-type postoperative complications showed a U-shaped relationship with continuous BMI values (range 10-65 kg/m²). The lowest complication risks occurred in patients with BMI between 35 and 40. Females had higher complication rate than males across all BMI values. This U-shaped relationship was only observed among patients younger than 60 years old, while the associations appear to be inversely linear among patients aged greater than 60 years.

CONCLUSION

Our results suggest that the current theory of a linear association between BMI and complication risk may not apply to elective primary THA. Strict BMI cutoffs may not minimize risk, especially among patients over 60 years old. Orthopedic surgeons should factor in patient-specific variables of age and gender when determining acceptable surgical risk given a particular BMI value.

Outcomes of Elective Total Hip Arthroplasty in Nonagenarians and Centenarians

BACKGROUND

Nonagenarians and centenarians are among the fastest growing demographics in the United States. Although consequent demand for joint replacement is projected to rise precipitously, outcomes of total hip arthroplasty (THA) have seldom been studied in this population.

METHODS

A retrospective cohort of patients undergoing primary THA was established using the 2008-2017 American College of Surgeons National Quality Improvement Program. Propensity scores were used to match 858 patients aged 90 or older to 858 patients aged 65-89, controlling for demographic factors and comorbidities. Thirty-day outcomes were compared between matched age cohorts using multiple regression modeling.

RESULTS

Statistically equivalent 30-day rates of surgical infection (P = .73), pneumonia (P = .39), deep venous thrombosis/thrombophlebitis (P = .55), pulmonary embolism (P = .69), stroke (P = .73), myocardial infarction (P = .44), cardiac arrest (P = .69), and sepsis (P = .77) were observed between matched age cohorts, although nonagenarians and centenarians were significantly more likely to experience urinary tract infection (2.8% vs 0.9%, P = .004). In addition, matched patients aged 90 or older were more likely to have longer hospital stays (3.52 vs 2.81 days, P < .001) and be discharged to a nonhome facility (75.4% vs 34.6%, P < .001) but were at no higher than 30-day risk of reoperation (P = .45), readmission (P = .23), or mortality (P = .59).

CONCLUSION

Overall, THA remains a safe and viable treatment modality beyond the ninth decade of life. Patient comorbidity profiles, rather than age, should principally guide shared clinical decision making.

Nutritional Counseling Program for Morbidly Obese Patients Enables Weight Optimization for Safe Total Joint Arthroplasty

Obesity affects one-third of total joint arthroplasty (TJA) patients and is the most common modifiable risk factor for increased complications in the TJA population. The authors' institution implemented a body mass index (BMI) cutoff of 40 kg/m² to define appropriate TJA candidates. Patients above the cutoff were referred for nutritional counseling. The study objective was to evaluate the efficacy of this protocol in optimizing patient BMI for safe and successful TJA. Between 2016 and 2018, the authors examined 133 patients (mean age, 62.6 years) with a BMI greater than 40 kg/m² seeking TJA (94 knee, 39 hip) seen by an arthroplasty surgeon and then a dietitian. Outcomes included weight loss, change in BMI, duration of counseling, and surgical status. For postoperative patients, 90-day complications were recorded. A total of 102 (92%) patients achieved weight loss during a mean 154 days (range, 8-601 days). Patients lost a mean of 17 lb, lowering their BMI by 2.7 points (range, +6.3 to -17.7 points). Twenty-two patients discontinued nutritional counseling after 1 visit, most commonly secondary to cost when not covered by insurance. Seventy-one patients successfully underwent TJA, representing 64% of those patients who participated in nutritional counseling. Complications included delayed wound healing (n=2), periprosthetic fracture (n=2), infection (n=1), cellulitis (n=1), and peroneal nerve palsy (n=1). Surgeons must actively counsel obese patients about weight optimization as part of the preoperative standard of care. Nutritional counseling with a dietitian and follow-up with the surgeon translated to safe and successful TJA in a majority of patients. [Orthopedics. 2020;43(4):e316-e322.].

Are We Treating Similar Patients? Hospital Volume and the Difference in Patient Populations for Total Knee Arthroplasty

BACKGROUND

Early findings of superior total knee arthroplasty (TKA) outcomes at high volume centers have been thought to have led to distinct referral patterns. However, the effect of these selective referral processes has not been well assessed. Therefore, this study compared the characteristics of primary TKA patients at high, intermediate, and low volume hospitals.

METHODS

A total of 12,541 primary TKA patients were stratified into risk groups based on age (>65 years), body mass index (>40), and Charlson Comorbidity Index (≥4). Hospitals were classified as low, intermediate, or high volume based on mean annual TKA volumes (<250, 250-499, and >500). Multivariate logistic regression models evaluated the relationship between baseline patient characteristics and hospital volume.

RESULTS

There was a greater percentage of high risk patients at high volume (19%, n = 853) compared to those at intermediate (16%, n = 899) or low volume (17%, n = 444) hospitals (P < .001). Patients with a body mass index >40 were more likely to be treated at high compared to intermediate (odds ratio [OR] 1.4, 95% confidence interval [CI] 1.2-1.6, P < .001) and low volume centers (OR 1.4, 95% CI 1.2-1.7, P < .001). Patients with Charlson Comorbidity Index scores ≥4 were also more likely be treated at high compared to intermediate (OR 1.5, 95% CI 1.3-1.6, P < .001) or low (OR 1.2, 95% CI 1.0-1.4, P = .002) volume centers.

CONCLUSION

This study found that TKA patients at high volume centers have significantly different baseline characteristics compared to those at lower volume centers. This study highlights the importance of considering hospital volume status and the associated disparity in the preoperative risk of patients when comparing primary TKA outcomes between centers.

Preoperative cut-off values for body mass index deny patients clinically significant improvements in patient-reported outcomes after total hip arthroplasty

Aims

Thresholds for operative eligibility based on body mass index (BMI) alone may restrict patient access to the benefits of arthroplasty. The purpose of this study was to evaluate the relationship between BMI and improvements in patient-reported outcome measures (PROMs), and to determine how many patients would have been denied improvements in PROMs if BMI cut-offs were to be implemented.

Methods

A prospective cohort of 3,449 primary total hip arthroplasties (THAs) performed between 2015 and 2018 were analyzed. The following one-year PROMs were evaluated: hip injury and osteoarthritis outcome score (HOOS) pain, HOOS Physical Function Shortform (PS), University of California, Los Angeles (UCLA) activity, Veterans Rand-12 Physical Component Score (VR-12 PCS), and VR-12 Mental Component Score (VR-12 MCS). Positive predictive values for failure to improve and the number of patients denied surgery in order to avoid a failed improvement were calculated for each PROM at different BMI cut-offs.

Results

There was a trend to improved outcomes in terms of pain and function improvements with higher BMI. Patients with BMI ≥ 40 kg/m2 had median (Q1, Q3) HOOS pain improvements of 58 points (interquartile range (IQR) 41 to 70) and those with BMI 35 to 40 kg/m2 had median improvements of 55 (IQR 40 to 68). With a BMI cut-off of 30 kg/m2, 21 patients would have been denied a meaningful improvement in HOOS pain score in order to avoid one failed improvement. At a 35 kg/m2 cut-off, 18 patients would be denied improvement, at a 40 kg/m2 cut-off 21 patients would be denied improvement, and at a 45 kg/m2 cut-off 21 patients would be denied improvement. Similar findings were observed for HOOS-PS, UCLA, and VR-12 scores.

Conclusion

Patients with higher BMIs show greater improvements in PROMs. Using BMI alone to determine eligibility criteria did not improve the rate of clinically meaningful improvements. BMI thresholds prevent patients who may benefit the most from surgery from undergoing THA. Surgeons should consider PROMs improvements in determining eligibility for THA while balancing traditional metrics of preoperative risk stratification. Cite this article: Bone Joint J 2020;102-B(6):683–692.

Effect of Patient Body Mass Index, Recommendation for Weight Modification, and Nonmodifiable Factors on Patient Satisfaction

INTRODUCTION

Patient satisfaction serves an increasingly important role in health care. Multiple nonmodifiable patient factors have been found to influence patient satisfaction. To the best of our knowledge, however, no study has investigated the influence of body mass index (BMI) on satisfaction scores. The objective of this study was to evaluate whether BMI and provider recommendation for patient weight modification were associated with patient satisfaction.

METHODS

We reviewed Press Ganey patient satisfaction survey scores from 3,044 clinical encounters in an academic orthopaedic center between November 2010 and May 2017. Multiple patient factors, BMI, and recommendation for weight loss, or requirement of weight loss, before surgery were recorded. Patient satisfaction was operationalized as a binary outcome of completely satisfied or not completely satisfied, and multiple logistic regression was used to estimate the odds of being completely satisfied from the subset of potential predictors.

RESULTS

White patients (odds ratio [OR] = 1.340, 95% confidence interval [CI]: 1.113 to 1.584, P = 0.0007) and Medicare-insured patients (OR = 1.260, 95% CI: 1.044 to 1.521, P = 0.0164) were more likely to be completely satisfied, whereas patients being seen by a provider for the first time were less likely to be completely satisfied (OR = 0.728, 95% CI: 0.626 to 0.847, P < 0.0001). BMI, recommendation for weight loss, and requirement of weight modification before surgery were not found to be associated with patient satisfaction.

DISCUSSION

Neither patient BMI nor provider recommendation for weight loss, or as a requirement for surgery, was associated with patient satisfaction. Race, insurance status, and previous visits with the care provider were identified as nonmodifiable patient factors that influence patient satisfaction.

LEVEL OF EVIDENCE

Level III.

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.

Experience-optimised fast track improves outcomes and decreases complications in total knee arthroplasty

PURPOSE

The aim of this study was to describe an advanced total knee arthroplasty (TKA) fast-track programme and determine discharge parameters during hospitalisation, as well as patient satisfaction, outcomes and complications within the first 12 months after surgery.

METHODS

This prospective study was based on patients selected consecutively for primary elective TKA, undergoing surgery between 2014 and 2017 in an established fast-track setting. Hospitalisation-related parameters were collected: demographics, body mass index (BMI), surgical time, ischaemia time, haemoglobin values, blood transfusions, length of stay, weight-bearing and stair-climbing time, opioid administration, preoperative and discharge loss of extension and maximum active flexion of the knee, visual analogue scale (VAS), 12-month follow-up satisfaction rate and range of motion, any complications, hospital re-admission and re-operation within the first 12 months. Differences were determined using t-tests.

RESULTS

A total of 704 total knee replacements implanted in 481 patients were included in the study and 223 patients had a bilateral TKA. Their mean age was 69.8 years (range 57-88 years). At the 12-month follow-up, 623 patients (88.5%) reported being satisfied or very satisfied and 15 (2.1%) were dissatisfied with their TKA, mean active flexion and loss of extension were 104.4° and 2.3°, respectively. A total of 15 complications occurred (two percent): five painful knees, three knee stiffness, three haematomas, two infections, one hospital re-admission and one deep venous thrombosis. No cases of pulmonary embolism and death related to surgery were reported.

CONCLUSION

The study reports on an advanced fast-track programme for TKA with a low incidence of surgery- and hospitalisation-related issues and complications and without any severe adverse events during the first year. On average, the fast-track programme had a short length of stay, an early recovery of weight-bearing, knee mobility, pain control and a high satisfaction rate, accompanied with an acceptable 12 month range of motion.

Patient-related risk factors for unplanned 30-day readmission following total knee arthroplasty: a narrative literature review

Osteoarthritis is a debilitating condition as well as a growing global health problem, and total knee arthroplasty (TKA) is an effective treatment for advanced disease. Unplanned 30-day hospital readmission is an indicator of complications, which is a significant financial burden on healthcare systems. We reviewed the literature to better understand the patient-related factors associated with unplanned 30-day readmission following TKA. MEDLINE and EMBASE were searched for studies reporting on patient-related risk factors for unplanned 30-day readmission following primary or revision TKA for any indication. The impact of specific medical comorbidities on increasing the risk of 30-day readmission following TKA is quite well established. The following comorbidities are strongly associated with readmission: bleeding disorder, diabetes, chronic kidney disease and dialysis, chronic immunosuppressant use and history of cancer. Other significant comorbidities include: dementia; depression; haematological (coagulopathy and anaemia), cardiovascular (atrial fibrillation, cardiovascular disease, coronary artery disease and congestive heart failure), respiratory (chronic obstructive pulmonary disease) and liver diseases; and cerebrovascular accident/transient ischaemic attack (but only in revision TKA patients). The influence of variation in sex, age and body mass index each demonstrate a more complex pattern. A systematic review and meta-analysis is required to quantify the impact of the various patient-related factors on 30-day readmission following TKA. Clinicians can use this information in preoperative decision-making.

Greater risks of complications, infections, and revisions in the obese versus non-obese total hip arthroplasty population of 2,190,824 patients: a meta-analysis and systematic review

BACKGROUND

Obesity is an epidemic, especially in developed countries. This affects the general health of these patients, especially when they are having a major surgical procedure such as total hip arthroplasty (THA). Several articles have described the effects of obesity on THA with varying conclusions. This meta-analysis aims to compare the outcomes, complications, and peri-operative parameters of THA in the obese (BMI≥30 kg/m²) vs non-obese (BMI<30 kg/m²) population as well as a subgroup analysis of morbidly obese (BMI≥40 kg/m²) vs non-obese population.

METHODS

A multi-database search was performed according to PRISMA guidelines. Data from studies assessing the outcomes and complications of THA in the obese and non-obese population were extracted and analyzed.

RESULTS

Sixty-seven studies were included in this meta-analysis, consisting of 581,012 obese and 1,609,812 non-obese patients. Meta-analysis could not be performed on patient reported outcome measures due to heterogeneous reporting methods. Obese patients had a higher risk of all complications (OR = 1.53, 95%CI: 1.30-1.80, P < 0.001), deep infections (OR = 2.71, 95%CI: 2.08-3.53, P < 0.001), superficial infections (OR = 1.99, 95%CI: 1.55-2.55, P < 0.001), dislocations (OR = 1.72, 95%CI: 1.66-1.79, P < 0.001), reoperations (OR = 1.61, 95%CI: 1.40-1.85, P < 0.001), revisions (OR = 1.44, 95%CI: 1.32-1.57, P < 0.001), and readmissions (OR = 1.37, 95%CI: 1.15-1.63, P < 0.001). When sub-group analysis of morbidly obese (BMI≥40 kg/m²) patients was performed, the risks of all these parameters were even greater.

CONCLUSION

Obese and morbidly obese patients are at higher risks of complications post THA than non-obese patients. Surgeons should be aware of these risks in order to counsel patients and adopt prophylactic strategies to reduce these risks where applicable.

Effect of hospital volume on outcomes of total hip arthroplasty: a systematic review and meta-analysis

BACKGROUND

A shift in the healthcare system towards the centralization of common yet costly surgeries, such as total hip arthroplasty (THA), to high-volume centers of excellence, is an attempt to control the economic burden while simultaneously enhancing patient outcomes. The "volume-outcome" relationship suggests that hospitals performing more treatment of a given type exhibit better outcomes than hospitals performing fewer. This theory has surfaced as an important factor in determining patient outcomes following THA. We performed a systematic review with meta-analyses to review the available evidence on the impact of hospital volume on outcomes of THA.

MATERIALS AND METHODS

We conducted a review of PubMed (MEDLINE), OVID MEDLINE, Google Scholar, and Cochrane library of studies reporting the impact of hospital volume on THA. The studies were evaluated as per the inclusion and exclusion criteria. A total of 44 studies were included in the review. We accessed pooled data using random-effect meta-analysis.

RESULTS

Results of the meta-analyses show that low-volume hospitals were associated with a higher rate of surgical site infections (1.25 [1.01, 1.55]), longer length of stay (RR, 0.83[0.48-1.18]), increased cost of surgery (3.44, [2.57, 4.30]), 90-day complications (RR, 1.80[1.50-2.17]) and 30-day (RR, 2.33[1.27-4.28]), 90-day (RR, 1.26[1.05-1.51]), and 1-year mortality rates (RR, 2.26[1.32-3.88]) when compared to high-volume hospitals following THA. Except for two prospective studies, all were retrospective observational studies.

CONCLUSIONS

These findings demonstrate superior outcomes following THA in high-volume hospitals. Together with the reduced cost of the surgical procedure, fewer complications may contribute to saving considerable opportunity costs annually. However, a need to define objective volume-thresholds with stronger evidence would be required.

TRIAL REGISTRATION

PROSPERO CRD42019123776.

Reduced wound leakage in arthroplasty with modified wound closure: a retrospective cohort study

INTRODUCTION

Wound leakage has been shown to increase the risk of prosthetic joint infections (PJIs) in primary total hip (THA) and knee arthroplasty (unicondylar and total knee arthroplasty; KA). The aim of this study is to determine whether the addition of a continuous subcuticular bonding stitch to a conventional three-layer closure method reduces the incidence of prolonged wound leakage and PJIs after THA and KA.

MATERIALS AND METHODS

This retrospective cohort study included all patients receiving a THA or KA. Patients in the control group with a three-layer closure method had surgery between November 1st 2015 and October 31^st 2016, and were compared to the study group with a four-layer closure method that had surgery between January 1st 2017 and December 31^st 2018. The primary outcome was incidence of prolonged wound leakage longer than 72 h. Differences were evaluated using logistic regression. Incidence of PJIs was the secondary outcome.

RESULTS

A total of 439 THA and 339 KA in the control group and 460 THA and 350 KA in the study group were included. In the control group, 11.7% of the patients had a prolonged leaking wound compared to 1.9% in the study group (p < 0.001). The modified wound closure method showed a protective effect for obtaining prolonged wound leakage; odds ratios were 0.09 (95% CI 0.04-0.22; p < 0.001) for THA and 0.21 (95% CI 0.10-0.43; p < 0.001) for KA. PJIs decreased from 1.54 to 0.37% (p = 0.019).

CONCLUSIONS

The addition of a continuous subcuticular bonding stitch reduces the incidence of prolonged wound leakage and PJIs after THA and KA compared to a conventional three-layer wound closure method. The large reduction of incidence in wound leakage and PJIs in this study, combined with relatively negligible cost and effort of the modified wound closure method, would advocate for implementing this wound closure method in arthroplasty.

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.

Effect of Antibiotic-Impregnated Bone Cement in Primary Total Knee Arthroplasty

BACKGROUND

The purpose of this study is to evaluate the effect of commercially available antibiotic-impregnated bone cement (AIBC) on (1) prosthetic joint infections (PJIs) and (2) surgical site infections (SSIs) after primary total knee arthroplasty (TKA).

METHODS

A review of primary TKAs between 2014 and 2017 from an institutional database was conducted. This identified 12,541 cases which were separated into AIBC (n = 4337) and non-AIBC (8,164) cohorts. Medical records were reviewed for PJIs and SSIs (mean 2-year postoperative period). Infection rates between the cohorts were compared with univariate analyses followed by subanalysis of high risk patients (defined as having 2 or more of the following characteristics: >65 years, body mass index >40, or Charlson Comorbidity Index score >3). To control for confounders, multivariate analyses were performed with regression models adjusted for age, gender, body mass index, comorbidities, year, operative times, and lengths of stay.

RESULTS

On univariate analysis, PJI rates were higher in the AIBC cohort (1.0%) compared to the non-AIBC cohort (0.5%, P < .001). Subanalysis of the high risk patients also showed that PJI rates were higher in the AIBC cohort (1.9% vs 0.6%, P < .01). After adjusting for potential confounders, no significant associations between PJIs and AIBC use were found (odds ratio 1.4, 95% confidence interval 0.9-2.3, P = .133). Similarly, no significant differences in SSI rates were observed between the AIBC (2.9%) and non-AIBC cohorts (2.4%, P = .060) and no significant associations between SSIs and AIBC were found with multivariate analysis (odds ratio 1.0, 95% confidence interval CI 0.8-1.3, P = .948).

CONCLUSION

This study found that there was no clinically or statistically significant decrease in infection rates with AIBC in primary TKAs.