Effect of Body Mass Index on Complications and Reoperations After Total Hip Arthroplasty

Low-Level Evidence Used to Substantiate Insurance Coverage Policies for Knee and Hip Arthroplasty

INTRODUCTION

Access to total knee arthroplasty (TKA) or total hip arthroplasty (THA) has become increasingly regulated by healthcare insurance providers that require specific criteria be met prior to authorizing surgery as medically necessary. The purpose of this study was to examine references from coverage policies and assess whether they justify the pre-surgery criteria mandated by insurance providers for approval of total joint arthroplasty (TJA) in patients who have symptomatic knee and hip degenerative disease.

METHODS

The largest private commercial insurance providers in the United States were identified, of which nine had publicly accessible coverage policies for TKA and THA. Coverage criteria for procedural approval and respective references were retrieved. There are three coverage criteria were identified: 1) diagnosis of osteoarthritis, 2) nonsurgical treatment (e.g. preoperative physical therapy, nonsteroidal anti-inflammatories, etc.), and 3) exclusion criteria (e.g. body mass index (BMI) thresholds <40). Reviewers graded references cited in coverage policies by level of evidence (LOE), type of reference, and relationship to the three criteria groupings.

RESULTS

In total, out of 824 references, only 450 (54.6%) references were relevant to primary TKA and THA. Of the 824, 259 (31.4%) contained information pertinent to the diagnosis of osteoarthritis, 84 (10.2%) to nonsurgical treatment, and 107 (13.0%) to exclusion criteria. Of the 84 references relevant to nonsurgical treatment, only 16 (19.1%) had a LOE I-III. Among all references related to nonsurgical treatment, only four specifically tested the efficacy of nonoperative modalities, representing 0.5% of all references.

DISCUSSION AND CONCLUSION

Current prior authorization criteria found in insurance coverage policies for TKA and THA are unsubstantiated. Patients presenting for TJA would benefit from prior authorization criteria with recommendations grounded in evidence-based medicine. This is currently not the case.

Effect of BMI on the risk of postoperative complications following total hip arthroplasty

Aims

While obesity is associated with an increased risk of complications after total hip arthroplasty (THA), the relationship between BMI and the risk of early postoperative complications has not been fully characterized. This study sought to describe the relationship between BMI and the risk of early postoperative complications, including periprosthetic joint infection (PJI), and composite surgical and composite medical complications.

Methods

Primary, elective THAs performed from 1 October 2015 to 31 December 2021 were identified using the Premier Healthcare Database. The study's primary outcome was the diagnosis of PJI within 90 days of THA. Using BMI as a continuous variable, logistic regression was used to develop restricted cubic splines (RCSs) to determine the impact of BMI on PJI risk. Bootstrap simulation was used to identify an inflection point in the final RCS model. The same technique was used to characterize the effects of BMI on composite medical and surgical complications.

Results

We found that PJI risk increased exponentially beyond a BMI threshold of 37.4 kg/m2. Relative to this threshold, patients with a BMI of 40 or 50 kg/m2 were at a 1.22-fold and 2.55-fold increased risk of developing PJI, respectively. Surgical complications increased at a BMI of 32 kg/m2 and medical complications increased at a BMI of 39 kg/m2. Relative to these cut points, patients with a BMI of 50 kg/m2 were at a 1.36-fold and 2.07-fold increased risk of developing medical and surgical complications, respectively.

Conclusion

The results of this study indicate a non-linear relationship between patient BMI and early postoperative risk of PJI, composite medical complications, and composite surgical complications following THA. The identified cut points with associated odds ratios can serve as tools to help risk-stratify and counsel patients seeking primary THA.

The impact of obesity on functional outcomes in navigation-assisted total hip arthroplasty

INTRODUCTION

Functional outcomes after total hip arthroplasty (THA) are generally poorer in obese patients compared to non-obese individuals. However, the effect of obesity on functional improvement following navigation-assisted HA remains controversial. This study investigates whether BMI influences functional outcome improvements following navigation-assisted THA.

MATERIALS AND METHODS

We reviewed our institutional database from 2010 to 2024 for patients undergoing navigation-assisted unilateral primary THA. Patients were categorized as Healthy weight (18.5-25.0 Kg/m2), Overweight (25.0-29.9 Kg/m2), and Obese (30-39.9 Kg/m2), based on their preoperative BMI. Hip Disability and Osteoarthritis Outcome Score for Joint Replacement (HOOS JR) was compared across BMI groups as the primary outcome. Multiple linear regression models were used to investigate the effect of BMI groups on Delta HOOS JR and postoperative HOOS JR while controlling for confounding variables.

RESULTS

A total of 1,543 cases with a mean age of 62.80 years (range: 23-94) were included. Most patients were Overweight (40.5%), followed by Obese (32.9%) and Healthy weight (26.6%). Although obese patients had significantly lower preoperative and postoperative functional scores (p < 0.05), they demonstrated greater improvements in HOOS symptoms (44.68 ± 22.45 vs. 40.68 ± 22.29, p = 0.006) and activities of daily living (46.36 ± 20.85 vs. 42.10 ± 21.20, p = 0.002) compared to the Healthy weight group. Despite obesity being linked to lower postoperative HOOS JR, regression analysis showed age ≥ 60 years, men, and alcohol consumption-but not BMI status-negatively affected Delta HOOS JR.

CONCLUSIONS

The obese group exhibited better improvements in HOOS symptoms and ADL with comparable Delta HOOS JR, supporting navigation-assisted THA as a valuable option for obese patients. The results of this study may help surgeons provide evidence-based preoperative counseling to obese patients regarding the expected clinical outcomes of THA.

A History of Bariatric Surgery Negatively Affects the Rate of 90-Day Complications of Elective Primary Total Joint Arthroplasty: A Comparative Analyses of 2,979 Patients

BACKGROUND

The potential benefits of preoperative weight loss with bariatric surgery in reducing short-term complications of total joint arthroplasty (TJA) have been questioned. We studied the odds of 90-day postoperative complications by comparing TJA patients who had a history of bariatric surgery to a control group.

METHODS

There were 678 patients who had undergone bariatric surgery before TJA (199 total hip arthroplasty [THA], 479 total knee arthroplasty [TKA]) matched 1:4 for body mass index at the time of TJA, age, sex, replaced joint, and American Society of Anesthesiologists Class with a control group of 2,301 TJA (644 THA; 1,657 TKA) patients who did not have bariatric surgery. Matching was performed using propensity scores with refined calipers to ensure comparability. The 90-day complication data was collected through chart review. The primary outcome was the incidence of Hip Society or Knee Society complications, emergency department visits, and wound complications requiring deviation from the standard of care.

RESULTS

There were significantly more complications in the THA study than in the control group (11.6 and 6.3%, respectively, P = 0.018). The THA study group demonstrated 1.96 times higher odds of developing complications compared to controls (95% confidence interval 1.12 to 3.43). There were similar rates of complications in the study and control TKA groups (12.4 and 10.1%, respectively, P = 0.129). Wound-related complications were more common in the THA study group affecting 4.5 and 1.4% of study and control patients, respectively (P = 0.02).

CONCLUSIONS

While Bariatric surgery remains an effective weight loss intervention, its utility as a risk-reduction strategy before THA is not supported by our findings.

[Current AWMF guidelines on knee and hip arthroplasty - individual risks]

BACKGROUND

In the year 2022, more than 300,000 total hip and knee primary arthroplasties were recorded in the German Arthroplasty Registry. The ever-increasing number of interventions naturally leads to an increase in the absolute number of possible complications. The abundance of internationally available data makes it possible to determine risk factors for postoperative complications.

RISK FACTORS

Professional societies involved in the German guidelines in the field of orthopedics place great emphasis on modifiable risk factors, as their adequate management can consequently reduce the likelihood of postoperative complications. One of the most common modifiable risk factors is obesity, with its prevalence remaining consistently high in most developed countries. In the field of orthopedics, the Association of the Scientific Medical Societies in Germany focuses on modifiable risk factors including obesity, diabetes mellitus and smoking.

OBESITY

In the case of obesity in particular, the guidelines for knee and hip arthroplasty recommend a weight loss attempt for patients with a BMI > 30 kg/m2. A BMI ≥ 40 kg/m2 is considered a "relative contraindication" in the guidelines. Shared decision making is emphasized in both guidelines. Ultimately, the particularly critical individual assessment of risk and benefit for each obese patient remains crucial for the final decision.

A Systematic Review and Meta-Analysis of Periprosthetic Joint Infection Rates in Morbidly Obese Patients Undergoing Total Hip Arthroplasty

INTRODUCTION

Periprosthetic joint infection (PJI) is a severe complication associated with higher rates in obese individuals after total hip arthroplasty (THA). Hard cutoffs for body mass index (BMI) levels may lead to restricted access to care; however, a certain level of obesity may warrant these restrictions for patient safety. The purpose of this study was to perform a systematic review and meta-analysis of articles comparing PJI rates in morbidly versus nonmorbidly obese patients undergoing primary THA.

METHODS

A systematic search of PubMed, EMBASE, Cochrane, and Google Scholar databases was conducted following Preferred Reporting Items for Systematic Reviews and Meta-analyses guidelines. Original studies comparing PJI rates in morbidly obese (BMI ≥40 kg/m2) and nonobese (BMI <40 kg/m2) THA patients were included. Data extraction, bias assessment, and quantitative synthesis were done.

RESULTS

After exclusion criteria, 10 studies comprising 46,080 THAs were included. Morbidly obese patients were found to have markedly higher rates of PJI compared with nonmorbidly obese patients (odds ratio = 4.332, 95% confidence interval [CI], 2.943 to 6.375, I2 = 0, P-value = 0.901). Analysis of cohorts stratified by BMI showed consistent trends; morbidly obese patients demonstrated markedly increased risk of blood transfusions, postoperative fractures, superficial infections, dislocations, readmission within 90 days, surgical complications, and revision surgery.

CONCLUSION

Morbidly obese patients demonstrate markedly increased risk of PJI and other complications after primary THA. This should be discussed with patients to safely provide the option of THA while minimizing restrictions on access to care.

Higher Pulmonary Embolism Risk in Morbidly Obese Patients on Aspirin Monotherapy after Total Knee Arthroplasty: A Claims Database Analysis

BACKGROUND

Aspirin is the most common drug used for venous thromboembolism (VTE) prophylaxis after total knee arthroplasty (TKA). Morbid obesity is a potential risk factor for VTE, prompting some to use stronger anticoagulants. However, there are no established guidelines for VTE prevention in obese or morbidly obese patients undergoing primary TKA.

METHODS

Using a national administrative claims database, patients who underwent primary TKA were divided into the following three cohorts based on body mass index (BMI): < 30, 30 to 39.9, or ≥ 40. Each patient had a prescription claim for aspirin, but no other prophylaxis agents within 3 days after the index procedure. We assessed deep vein thrombosis (DVT) and pulmonary embolism (PE) incidence at 90 and 180 days postoperatively. Secondary outcomes included wound dehiscence; hematoma; periprosthetic joint infection; and debridement, antibiotics, and implant retention or explantation procedures. We included 20,097 patients, of whom 4,277 (21%), 10,663 (53%), and 5,157 (26%) had a BMI < 30, 30 to 39.9, and ≥ 40, respectively.

RESULTS

In the multivariable analysis, there was no difference in the incidence of DVT or PE within 90 or 180 days after surgery for the BMI 30 to 39.9 compared to the BMI < 30 cohort. However, the incidence of PE within 90 days after surgery was higher in the BMI ≥ 40 cohort (odds ratio: 2.74), an effect that disappeared by 180 days. There was a higher adjusted odds of debridement, antibiotics, and implant retention procedures in the BMI ≥ 40 compared to the BMI < 30 cohort; otherwise, the incidence of secondary outcomes did not differ by BMI.

CONCLUSIONS

When aspirin was used as a standardized monotherapy for VTE prophylaxis following primary TKA, there was an increased 90-day incidence of PE in morbidly obese patients but no difference in DVT or PE incidence in obese patients.

Increased Waist Circumference Is Associated With Severe Postoperative Medical Complications Following Total Knee Arthroplasty: Understanding Waist Circumference and Relation to Body Mass Index

BACKGROUND

Obesity is projected to affect nearly 42% of Americans nationwide by 2050. Waist circumference (WC), an estimate of central obesity or adiposity, has been shown to be a better predictor for cardiometabolic morbidity and mortality than body mass index (BMI), which does not consider body fat distribution. This study aimed to evaluate whether: 1) WC correlates with increasing BMI cohorts; and 2) WC is a predictor of severe Clavien-Dindo IV complications within 30 days following total knee arthroplasty (TKA).

METHODS

A national dataset was retrospectively queried to identify patients who received primary TKA for knee osteoarthritis between 2010 and 2020 (N = 385,996). A validated model converted each patient's BMI to WC. The BMI cohorts were grouped into underweight, healthy weight, overweight, and obesity classes 1 to 3. Primary outcomes included comparing WC among different BMI cohorts undergoing TKA. The secondary outcome was to evaluate if WC was associated with severe surgical complications within 30 days. Clavien-Dindo IV complications included cardiac arrests, myocardial infarctions, septic shock episodes, pulmonary emboli, acute renal failures, and cerebrovascular accidents. Multivariable logistic regressions were adjusted for age, functional status, frailty, various comorbidities, and obesity to evaluate the odds ratios (ORs) between WC and postoperative complications following TKA, with P-values less than 0.001 as significant.

RESULTS

The mean WC significantly correlated with increasing BMI cohorts (P < 0.001). The mean WC was significantly higher among patients who developed Clavien-Dindo IV complications (112.4 versus 110.5 centimeters, P < 0.001). For all TKA patients, each centimeter increase in WC was associated with developing a postoperative complication (OR: 1.11, P < 0.001). Subanalysis of only obese patients showed WC to be a better predictor than BMI class (OR: 1.35, P < 0.001).

CONCLUSIONS

Central adiposity, measured by WC, was associated with severe complications following TKA, even when controlling for obesity. Screening interventions using waist measurements may assist joint arthroplasty surgeons in risk-stratifying patients who have higher BMIs. Further study is warranted on how to integrate WC into TKA practice.

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

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

The Impact of Leg Length and Offset Change on Dislocation Risk Following Primary Total Hip Arthroplasty

BACKGROUND

Soft tissue management in total hip arthroplasty includes appropriate restoration and/or alteration of leg length (LL) and offset to re-establish natural hip biomechanics. The purpose of this study was to evaluate the effect of LL and offset-derived variables in a multivariable survival model for dislocation.

METHODS

Clinical, surgical, and radiographic data was retrospectively acquired for 12,582 patients undergoing primary total hip arthroplasty at a single institution from 1998 to 2018. There were twelve variables derived from preoperative and postoperative radiographs related to LL and offset that were measured using a validated automated algorithm. These measurements, as well as other modifiable and nonmodifiable surgical, clinical, and demographic factors, were used to determine hazard ratios for dislocation risk.

RESULTS

None of the LL or offset variables conferred significant risk or protective benefit for dislocation risk. By contrast, all other variables included in the multivariable model demonstrated a statistically significant effect on dislocation risk with a minimum effect size of 28% (range 0.72 to 1.54) (sex, surgical approach, acetabular liner type, femoral head size, neurologic disease, spine disease, and prior spine surgery).

CONCLUSIONS

Contrary to traditional teaching and our hypothesis, operative changes in LL and offset did not demonstrate any clinically or statistically significant effect in this large and well-characterized cohort. This does not imply that these variables are not important in individual cases, but rather suggests the overall impact of LL and offset changes is relatively minor for dislocation risk compared to other variables that were found to be highly clinically and statistically significant in this population. These results may also suggest that surgeons do a good job of restoring native LL and offset for patients, which may mitigate their analyzed impact.

Outcomes Following Direct Anterior Approach Total Hip Arthroplasty: A Contemporary Multicenter Study

BACKGROUND

The direct anterior approach (DAA) is a popular approach for primary total hip arthroplasty (THA). However, the contemporary outcomes for DAA THA need further elucidation. Therefore, we aimed to describe implant survivorship, complications, and clinical outcomes after DAA THA.

METHODS

From our multi-institutional total joint registry, 3,184 patients who had undergone 3,698 primary DAA THA between 2010 and 2019 were identified. The identified patients had a mean age of 65 years and a mean body mass index (BMI) of 29 kg/m 2 , and 53% of patients were female. The indications for revision and reoperation and the incidence of complications were collected and analyzed. Potential risk factors, including age, sex, BMI, and high-volume compared with low-volume operating surgeons, were examined. Descriptive statistics and Kaplan-Meier survivorship with Cox regression analyses were performed.

RESULTS

At 10 years following primary DAA THA, the cohort had 96% (95% confidence interval [CI], 95% to 98%) survivorship free of any revision and 94% (95% CI, 92% to 96%) survivorship free of any reoperation. The leading indications for revision were periprosthetic joint infection (PJI) (n = 24; 5-year cumulative incidence, 0.93% [95% CI, 0.6% to 1.5%]), periprosthetic fracture (n = 20; 5-year cumulative incidence, 0.62% [95% CI, 0.4% to 1.0%]), and aseptic loosening (n = 14; 11 femoral, 3 acetabular; 5-year cumulative incidence, 0.84% [95% CI, 0.5% to 1.5%]). A BMI of ≥40 kg/m 2 was found to be significantly associated with PJI (hazard ratio [HR], 6.4; p < 0.001), reoperation (HR, 3.5; p < 0.001), and nonoperative complications (HR, 2.3; p = 0.018). Survivorship free of recurrent instability was 99.6% (95% CI, 99.4% to 99.8%) at 5 and 10 years, and the cumulative incidence of revision for instability was 0.14% at 5 years.

CONCLUSIONS

In one of the largest published series to date, survivorship following DAA THA was satisfactory at early to intermediate follow-up. The leading indications for revision were PJI, periprosthetic fracture, and aseptic loosening. Instability after DAA THA was uncommon and infrequently led to revision. As a note of caution, a BMI of ≥40 kg/m 2 was identified as a risk factor for adverse outcome after DAA THA.

LEVEL OF EVIDENCE

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

Socioeconomic Indices Are Associated With Increased Resource Utilizations, but Not 90-Day Complications Following Total Hip and Knee Arthroplasty

BACKGROUND

Socioeconomic disadvantage has been associated with negative outcomes following total hip arthroplasty (THA) and total knee arthroplasty (TKA). The area deprivation index (ADI) and distressed communities index (DCI) are composite rankings that score socioeconomic status (SES) using patients' home addresses. The purpose of this study was to examine the association of ADI and DCI with outcomes following THA and TKA while controlling for potential confounding covariates.

METHODS

A series of 4,146 consecutive patients undergoing primary THA and TKA between January 2018 and May 2023 were queried from our institutional total joint registry. The 90-day medical and surgical complications and resource utilization were collected. The ADI and DCI scores were obtained for each patient, and the association between these scores and postoperative outcomes was analyzed.

RESULTS

The ADI and DCI were both associated with patient age, sex, race, comorbidity burden, and smoking status. After controlling for these variables, higher ADI and DCI scores were associated with increased length of stay (P = 0.003 and P = 0.008, respectively), but were not associated with the occurrence of any 90-day complication, reoperation, or revision.

CONCLUSIONS

The SES, as quantified by ADI and DCI, was associated with multiple known risk factors for complications following THA and TKA, but was not independently associated with complications, reoperations, or revision surgeries at 90 days postoperatively. While convenient metrics for the quantification of SES, in some populations, ADI and DCI may not be independently associated with detrimental outcomes following THA and TKA.

Justification of Body Mass Index cutoffs for hip and knee joint arthroplasty among California orthopedic surgeons

BACKGROUND

Many orthopedic surgeons choose not to perform joint arthroplasty on patients with a Body Mass Index (BMI) of 35 or above, citing poorer outcomes and increased procedure risk. Identifying and addressing factors surgeons use to determine procedure BMI cutoffs are necessary to increase access to orthopaedic care for this growing patient population. This will help reduce healthcare disparities while also identifying clinical facilities, equipment, training, and procedures that require improvements to accommodate larger individuals.

METHODS

Orthopaedic surgeons were surveyed to identify surgeon-specific BMI cutoffs for hip and knee arthroplasty. The survey was circulated within the California Orthopaedic Association (COA) report during March 2023. Questions aimed to identify BMI cutoffs and justifications such as infection risk, co-morbidities, inadequate equipment, and the American Academy of Orthopaedic Surgeons (AAOS) guidelines. Data on decision making about BMI cutoffs and exceptions were also collected.

RESULTS

75% of respondents use BMI cutoffs for hip and knee arthroplasty. 91% of respondents indicated they are either wholly or partially responsible for setting procedure BMI cutoffs. Mean hip and knee arthroplasty BMI cutoffs were 40.5 and 41, respectively. Four categories for BMI cutoff justifications were identified: (1) risk of complications; (2) surgery logistics; (3) concerns about facilities or resources; and (4) surgeon perception.

CONCLUSIONS

BMI-based justifications for denial of care define key addressable areas of improvement that can increase access to care for life-changing orthopaedic surgeries such as THA and TKA. Insight from the queried surgeons will help drive future research areas to address this need.

Super-Obesity is Associated With an Increased Risk of Complications Following Primary Total Knee Arthroplasty

BACKGROUND

Obesity, defined as a body mass index (BMI) ≥ 30, is an ever-growing epidemic, with > 35% of adults in the United States currently classified as obese. Super-obese individuals, defined as those who have a BMI ≥ 50, are the fastest-growing portion of this group. This study sought to quantify the infection risk as well as the incidence of surgical, medical, and thromboembolic complications among super-obese patients undergoing total knee arthroplasty (TKA).

METHODS

An all-payer claims database was used to identify patients who underwent elective, primary TKA between 2016 and 2021. Patients who had a BMI ≥ 50 were compared to those who had a normal BMI of 18 to 25. Demographics and the incidence of 90-days postoperative complications were compared between the 2 groups. Univariate analysis and multivariable regression were used to assess differences between groups.

RESULTS

In total, 3,376 super-obese TKA patients were identified and compared to 17,659 patients who had a normal BMI. Multivariable analysis indicated that the super-obese cohort was at an increased postoperative risk of periprosthetic joint infection (adjusted odds ratio [aOR] 3.7, 95% confidence interval [CI]: 2.1 to 6.4, P < .001), pulmonary embolism (aOR 2.2, 95%-CI: 1.0 to 5.0, P = .047), acute respiratory failure (aOR 4.1, 95%-CI: 2.7 to 6.1, P < .001), myocardial infarction (aOR 2.5, 95%-CI: 1.1 to 5.8, P = .026), wound dehiscence (aOR 2.3, 95%-CI: 1.4 to 3.8, P = .001), and acute renal failure (aOR 3.2, 95%-CI: 2.4 to 4.2, P < .001) relative to patients who have normal BMI.

CONCLUSIONS

Super-obese TKA patients are at an elevated risk of postoperative infectious, surgical, medical, and thromboembolic complications. As such, risk stratification, as well as appropriate medical management and optimization, is of utmost importance for this high-risk group.

The mononuclear phagocyte system obscures the accurate diagnosis of infected joint replacements

INTRODUCTION

Diagnosing infected joint replacements relies heavily on assessing the neutrophil response to bacteria. Bacteria form biofilms on joint replacements. Biofilms are sessile bacterial communities encased in a protective extracellular matrix, making them notoriously difficult to culture, remarkably tolerant to antibiotics, and able to evade phagocytosis. Phagocytized bacteria dramatically alter cytokine production and compromise macrophage antigen presentation. We hypothesize that a subset of joint replacements have a dormant infection that suppresses the neutrophil response to bacteria but can be distinguished from uninfected joint replacements by the response of the mononuclear phagocyte system (MPS) within periarticular tissue, synovial fluid, and circulating plasma.

METHODS

Single cell RNASeq transcriptomic and OLink proteomic profiling was performed on matched whole blood, synovial fluid, and periarticular tissue samples collected from 4 joint replacements with an active infection and 3 joint replacements without infection as well as 6 joint replacements with a prior infection deemed "infection-free" by the 2018 Musculoskeletal Infection Society criteria (follow-up of 26 ± 3 months).

RESULTS

The MPS and neutrophil responses differ by infected state; the cellular distribution of the MPS response in the subset of joints with dormant infections resembled actively infected joints (p = 0.843, Chi-square test) but was significantly different from uninfected joints (p < 0.001, Chi-square test) despite the absence of systemic acute phase reactants and recruitment of neutrophils (p < 0.001, t-test). When compared to no infection, the cellular composition of dormant infection was distinct. There was reduction in classically activated M1 macrophages (p < 0.001, Fischer's test) and alternatively activated M2 macrophages coupled with an increase in classical monocytes (p < 0.001, Fischer's test), myeloid dendritic cells (p < 0.001, Fischer's test), regulatory T-cells (p < 0.001, Fischer's test), natural killer cells (p = 0.009, Fischer's test), and plasmacytoid dendritic cells (p = 0.005, Fischer's test). Hierarchical cluster analysis and single-cell gene expression revealed that classically M1 and alternatively M2 activated macrophages as well as myeloid dendritic cells can independently distinguish the dormant and uninfected patient populations suggesting that a process that modulates neutrophil recruitment (C1QA, C1QB, LY86, SELL, CXCL5, CCL20, CD14, ITGAM), macrophage polarization (FOSB, JUN), immune checkpoint regulation (IFITM2, IFITM3, CST7, THBS1), and T-cell response (VISIG4, CD28, FYN, LAT2, FCGR3A, CD52) was occurring during dormant infection. Gene set variation analysis suggested that activation of the TNF (FDR < 0.01) and IL17 (FDR < 0.01) pathways may distinguish dormant infections from the active and uninfected populations, while an inactivation of neutrophil extracellular traps (NETs) may be involved in the lack of a clinical response to a dormant infection using established diagnostic criteria. Synovial inflammatory proteomics show an increase in synovial CXCL5 associated with dormant infection (p = 0.011, t-test), suggesting the establishment of a chronic inflammatory state by the MPS during a dormant infection involved in neutrophil inhibition. Plasma inflammatory proteomics also support a chronic inflammatory state (EGF, GZMN, FGF2, PTN, MMP12) during dormant infection that involves a reduction in neutrophil recruitment (CXCL5, p = 0.006, t-test), antigen presentation (LAMP3, p = 0.047, t-test), and T-cell function (CD28, p = 0.045, t-test; CD70, p = 0.002, t-test) that are also seen during the development of bacterial tolerance.

DISCUSSION

All current diagnostic criteria assume each patient can mount the same neutrophil response to an implant-associated infection. However, the state of the MPS is of critical importance to accurate diagnosis of an implant-associated infection. A reduction in neutrophil recruitment and function mediated by the MPS may allow joint replacements with a dormant infection to be mischaracterized as uninfected, thus limiting the prognostic capabilities of all current diagnostic tests.

Early adverse outcomes remain challenging to prevent in morbidly obese patients undergoing total hip arthroplasty

Aims

The prevalence of obesity is increasing substantially around the world. Elevated BMI increases the risk of complications following total hip arthroplasty (THA). We sought to evaluate trends in BMI and complication rates of obese patients undergoing primary THA over the last 30 years.

Methods

Through our institutional total joint registry, we identified 15,455 primary THAs performed for osteoarthritis from 1990 to 2019. Patients were categorized according to the World Health Organization (WHO) obesity classification and groups were trended over time. Cox proportional hazards regression analysis controlling for confounders was used to investigate the association between year of surgery and two-year risk of any reoperation, any revision, dislocation, periprosthetic joint infection (PJI), venous thromboembolism (VTE), and periprosthetic fracture. Regression was stratified by three separate groups: non-obese; WHO Class I and Class II (BMI 30 to 39 kg/m2); and WHO Class III patients (BMI ≥ 40 kg/m2).

Results

There was a significant increase in the proportion of all obesity classes from 1990 to 2019, and the BMI values within each WHO class significantly increased over time. Risk of any reoperation did not change over time among non-obese or WHO Class I/II patients, but increased for WHO Class III patients (hazard ratio (HR) 1.04; p = 0.044). Risk of dislocation decreased over time for non-obese (HR 0.96; p < 0.001) and WHO Class I/II (HR 0.96; p = 0.002) patients, but did not change over time for WHO Class III (HR 0.94; p = 0.073) patients. Risks of any revision and PJI did not change over time for any group.

Conclusion

The proportion of patients undergoing THA who are obese has increased dramatically at our institution between 1990 and 2019. Despite BMI values increasing within all WHO classes over time, two-year complication risks have remained stable or decreased in WHO Class I/II patients. However, continued efforts will be required to mitigate risks in the heaviest WHO Class III patients.

Time to Achieve the Minimal Clinically Important Difference in Primary Total Hip Arthroplasty: Comparison of Anterior and Posterior Surgical Approaches

BACKGROUND

Controversy remains over outcomes between total hip arthroplasty approaches. This study aimed to compare the time to achieve the minimal clinically important difference (MCID) for the Hip Disability and Osteoarthritis Outcome Score-Physical Function Short Form (HOOS-PS) and the Patient-Reported Outcomes Measurement Information System (PROMIS) Global-Physical for patients who underwent anterior and posterior surgical approaches in primary total hip arthroplasty.

METHODS

Patients from 2018 to 2021 with preoperative and postoperative HOOS-PS or PROMIS Global-Physical questionnaires were grouped by approach. Demographic and MCID achievement rates were compared, and survival curves with and without interval-censoring were used to assess the time to achieve the MCID by approach. Log-rank and weighted log-rank tests were used to compare groups, and Weibull regression analyses were performed to assess potential covariates.

RESULTS

A total of 2,725 patients (1,054 anterior and 1,671 posterior) were analyzed. There were no significant differences in median MCID achievement times for either the HOOS-PS (anterior: 5.9 months, 95% confidence interval [CI]: 4.6 to 6.4; posterior: 4.4 months, 95% CI: 4.1 to 5.1, P = .65) or the PROMIS Global-Physical (anterior: 4.2 months, 95% CI: 3.5 to 5.3; posterior: 3.5 months, 95% CI: 3.4 to 3.8, P = .08) between approaches. Interval-censoring revealed earlier times of achieving the MCID for both the HOOS-PS (anterior: 1.509 to 1.511 months; posterior: 1.7 to 2.3 months, P = .87) and the PROMIS Global-Physical (anterior: 3.0 to 3.1 weeks; posterior: 2.7 to 3.3 weeks, P = .18) for both surgical approaches.

CONCLUSIONS

The time to achieve the MCID did not differ by surgical approach. Most patients will achieve clinically meaningful improvements in physical function much earlier than previously believed.

LEVEL OF EVIDENCE

Level III, Retrospective Comparative Study.

The role of body mass index in survivorship and clinical outcomes in total shoulder arthroplasty

BACKGROUND

Increased body mass index (BMI) is a potential risk factor for poorer outcomes and complications. However, the influence of BMI on the long-term outcomes of anatomic total shoulder arthroplasty (aTSA) and reverse total shoulder arthroplasty (rTSA) remains to be fully elucidated.

METHODS

Institutional records were queried to identify patients who underwent primary total shoulder arthroplasty (TSA) between 2009 and 2020 with a minimum of 2 years of clinical follow-up. Retrospective review was performed to collect demographic characteristics; comorbidity status; and range-of-motion and strength measurements in forward elevation, external rotation, and internal rotation. Patients were contacted by telephone to provide patient-reported outcomes (PROs). Patients were stratified into 3 cohorts by BMI: underweight or normal weight (U/NW, BMI ≤25 kg/m2), overweight (OW, BMI >25 to ≤30 kg/m2), and obese (BMI >30 kg/m2).

RESULTS

Among 466 TSA patients, 245 underwent aTSA whereas 221 underwent rTSA. In the aTSA cohort, 40 patients were classified as U/NW; 72, as OW; and 133, as obese. Comparatively, the rTSA cohort was composed of 33 U/NW, 79 OW, and 209 obese patients. Patients in the aTSA and rTSA cohorts had an average follow-up period of 5.8 ± 3.2 years and 4.5 ± 2.3 years, respectively. No differences in age at surgery were found in the aTSA group (U/NW vs. obese, 65.2 ± 7.9 years vs. 61.9 ± 8.9 years; P = .133); however, in the rTSA cohort, BMI was found to be inversely related to age at surgery (U/NW vs. obese, 72.4 ± 8.8 years vs. 65.7 ± 8.3 years; P < .001). Across all BMI cohorts, patients saw great improvements in range of motion and strength. Postoperative PROs after TSA did not vary by BMI in terms of Single Assessment Numeric Evaluation, Simple Shoulder Test, visual analog scale pain, and American Shoulder and Elbow Surgeons scores. There was no significant difference in survival rates at 10-year follow-up in the aTSA cohort (U/NW vs. obese, 95.8% vs. 93.2%; P = .753) or rTSA cohort (U/NW vs. obese, 94.7% vs. 94.5%; P = .791).

CONCLUSION

With dramatic improvements in range of motion, minimal differences in PROs, and high rates of implant survival, TSA is a safe and effective treatment option for all patients, including overweight and obese patients.

Acute Surgical Site Complications in Direct Anterior Total Hip Arthroplasty: Impact of Local Subcutaneous Tissue Depth and Body Mass Index

Background

Body mass index (BMI) is an imperfect measure of patients' adiposity and operative risk. Radiographic and direct subcutaneous measurements have been utilized in attempts to more accurately characterize the risk of postoperative complications, including surgical site infection. This study aims to evaluate whether direct tissue depth measurement is a more accurate predictor of skin complication following direct anterior total hip arthroplasty (THA).

Methods

A retrospective chart review of patients who underwent elective THA between April 30, 2020, and January 31, 2023, was performed. Baseline demographics, antibiotics, anticoagulation, and intraoperatively measured tissue depths at proximal, middle, and distal portions of the incision were recorded. Patient follow-up was reviewed to assess the development of skin complication in the acute postoperative period.

Results

Data were collected from 280 patients who underwent THA via direct anterior approach by a single surgeon. The mean age was 66.0 years, and 52.1% were female. A total of 18/280 (6.4%) patients developed an abrasion (5/18) or superficial surgical site infection (13/18) within the first 60 days postoperatively. Patients who developed skin complications had a significantly higher BMI (33.7 kg/m2 vs 29.9 kg/m2; P = .0021). Patients with a BMI >30 kg/m2 had more than 5 times increased odds of developing a superficial skin complication in the acute 60-day postoperative period compared to those with a BMI <30 kg/m2 (Odds ratio = 5.318, P = .0059). None of the measured tissue depths, nor their average together, were shown to be significant predictors of skin complications.

Conclusions

This study showed that BMI is a significant predictor of acute skin complications in direct anterior THA patients. No other significant predictors were found to be associated with increased risk, including proximal, middle, and distal tissue depths.

Preoperative Laboratory Values Predicting Periprosthetic Joint Infection in Morbidly Obese Patients Undergoing Total Hip or Knee Arthroplasty

BACKGROUND

Morbidly obese patients are an ever-growing high-risk population undergoing total hip arthroplasty (THA) and total knee arthroplasty (TKA) for end-stage osteoarthritis. This study sought to identify preoperative laboratory values that may serve as predictors of periprosthetic joint infection (PJI) in morbidly obese patients undergoing THA or TKA.

METHODS

All morbidly obese patients with preoperative laboratory data before undergoing primary elective TKA or THA were identified using the Premier Healthcare Database. Patients who developed PJI within 90 days after surgery were compared with patients without PJI. Laboratory value thresholds were defined by clinical guidelines or primary literature. Univariate and multivariable regression analyses were utilized to assess the association between PJI and preoperative laboratory values, including total lymphocyte count, neutrophil-lymphocyte ratio (NLR), platelet-lymphocyte ratio (PLR), monocyte-lymphocyte ratio (MLR), systemic immune-inflammation index (SII), albumin level, platelet count, albumin-globulin ratio, hemoglobin level, and hemoglobin A1c.

RESULTS

Of the 6,780 patients identified (TKA: 76.67%; THA: 23.33%), 47 (0.69%) developed PJI within 90 days after surgery. The rate of PJI was 1.69% for patients with a hemoglobin level of <12 g/dL (for females) or <13 g/dL (for males), 2.14% for those with a platelet count of <142,000/µL or >417,000/µL, 1.11% for those with an NLR of >3.31, 1.69% for those with a PLR of >182.3, and 1.05% for those with an SII of >776.2. After accounting for potential confounding factors, we observed an association between PJI and an abnormal preoperative NLR (adjusted odds ratio [aOR]: 2.38, 95% confidence interval [CI]: 1.04 to 5.44, p = 0.039), PLR (aOR: 4.86, 95% CI: 2.15 to 10.95, p < 0.001), SII (aOR: 2.44, 95% CI: 1.09 to 5.44, p = 0.029), platelet count (aOR: 3.50, 95% CI: 1.11 to 10.99, p = 0.032), and hemoglobin level (aOR: 2.62, 95% CI: 1.06 to 6.50, p = 0.038).

CONCLUSIONS

This study identified preoperative anemia, abnormal platelet count, and elevated NLR, PLR, and SII to be associated with an increased risk of PJI among patients with a body mass index of ≥40 kg/m 2 . These findings may help surgeons risk-stratify this high-risk patient population.

LEVEL OF EVIDENCE

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

Risk Factors Associated with Thromboembolic Complications After total Hip Arthroplasty: An Analysis of 1,129 Pulmonary Emboli

INTRODUCTION

Venous thromboembolism (VTE) remains a dangerous complication after total hip arthroplasty (THA), despite advances in chemoprophylactic measures. This study aimed to identify risk factors of developing pulmonary embolism (PE) and deep vein thrombosis (DVT) after THA using a modern cohort of patients reflecting contemporary practices.

METHODS

The Premier Healthcare Database was queried for primary, elective THAs from January 1st, 2015, to December 31st, 2021. Patients who developed PE or DVT within 90 days of THA were compared with patients who did not develop any postoperative VTE. Differences in patient demographics, comorbidities, hospital factors, perioperative medications, chemoprophylactic agents, and allogeneic blood transfusion were compared between cohorts. Multivariable logistic regression models were used to identify independent risk factors of PE and DVT. In total, 544,298 THAs were identified, of which 1,129 (0.21%) developed a PE and 1,799 (0.33%) developed a DVT.

RESULTS

Patients diagnosed with a PE had significantly higher rates of in-hospital death (2.6% vs 0.1%, P < 0.001) compared with those without a PE. Age (adjusted odds ratio: 1.02 per year, 95% confidence interval [CI]: 1.01 to 1.03) and Black race (aOR: 1.52, 95% CI: 1.24 to 1.87) were associated with an increased risk of PE. Comorbidities associated with increased risk of PE included chronic pulmonary disease (aOR: 1.58, 95% CI: 1.36 to 1.84), pulmonary hypertension (aOR: 2.06, 95% CI: 1.39 to 3.04), and history of VTE (aOR: 2.38, 95% CI: 1.98 to 2.86). Allogeneic blood transfusion (aOR: 2.40, 95% CI: 1.88 to 3.06) was also associated with an increased risk of PE while dexamethasone utilization was associated with a reduced risk (aOR: 0.83, 95% CI: 0.73 to 0.95).

DISCUSSION

Increasing age; Black race; allogeneic blood transfusion; and comorbidities, including chronic pulmonary disease, pulmonary hypertension, and history of VTE, were independent risk factors of PE after THA. Given the increased mortality associated with PE, patients should be carefully evaluated for these factors and managed with an appropriate chemoprophylactic regimen.

The cementless taper wedge vs. fit-and-fill stem in primary total hip arthroplasty: risk of stem-related complication differs across Dorr types

INTRODUCTION

The choice between a cementless taper wedge stem and a fit-and-fill stem in total Hip arthroplasty (THA) for various proximal femoral morphological types has not been thoroughly evaluated. This study aimed to compare the risk of stem-related complications between these two stem types in Dorr type A, B, and C femurs.

MATERIALS AND METHODS

From January 2015 through April 2021, we retrospectively reviewed 1995 cementless THA procedures. We stratified all procedures into three groups: Dorr type A (N = 360, 18.0%), B (N = 1489, 74.7%) and C (N = 146, 7.3%). The primary outcome domain was stem-related complications, including stem subsidence ≥ 3 mm, intraoperative fracture, periprosthetic fracture and aseptic stem loosening. We performed multivariate regression analysis to compare the risk of stem-related complication between the two stem types. Other factors included age, sex, body mass index, diagnosis, age-adjusted Charlson comorbidity index, stem alignment and canal fill ratio.

RESULTS

The incidence of stem-related complications in the taper wedge and fit-and-fill stem groups was 4.4% (N = 15) and 6.5% (N = 107), respectively. Fit-and-fill stems showed an increased risk of stem-related complications (aOR: 9.903, 95% CI: 1.567-62.597) only in Dorr type C femurs. No significant difference in risk was observed in Dorr type A and B femurs. Furthermore, the canal fill ratio at the lesser trochanter, 2 cm and 7 cm below the lesser trochanter, did not exhibit an association with stem-related complications in any Dorr type.

CONCLUSIONS

Concerning the risk of stem-related complications, the taper wedge stem was a better choice in Dorr type C femurs. However, there was no difference in risk between the taper wedge stem and fit-and-fill stem in Dorr type A and B femurs.

Glucagon-Like Peptide Receptor-1 Agonists Used for Medically-Supervised Weight Loss in Patients With Hip and Knee Osteoarthritis: Critical Considerations for the Arthroplasty Surgeon

Patients with morbid obesity and concomitant hip or knee osteoarthritis represent a challenging patient demographic to treat as these patients often present earlier in life, have more severe symptoms, and have worse surgical outcomes following total hip and total knee arthroplasty. Previously, bariatric and metabolic surgeries represented one of the few weight loss interventions that morbidly obese patients could undergo prior to total joint arthroplasty. However, data regarding the reduction in complications with preoperative bariatric surgery remain mixed. Glucagon-like peptide receptor-1 (GLP-1) agonists have emerged as an effective treatment option for obesity in patients with and without diabetes mellitus. Furthermore, recent data suggest these medications may serve as potential anti-inflammatory and disease-modifying agents for numerous chronic conditions, including osteoarthritis. This review will discuss the GLP-1 agonists and GLP-1/glucose-dependent insulinotropic polypeptide dual agonists currently available, along with GLP-1/glucose-dependent insulinotropic polypeptide/glucagon triple agonists presently being developed to address the obesity epidemic. Furthermore, this review will address the potential problem of GLP-1-related delayed gastric emptying and its impact on the timing of elective total joint arthroplasty. The review aims to provide arthroplasty surgeons with a primer for implementing this class of medication in their current and future practice, including perioperative instructions and perioperative safety considerations when treating patients taking these medications.

Acetabular erosion after bipolar hip hemiarthroplasty for femoral neck fracture in elderly patients: a retrospective study

BACKGROUND

The choice between total hip arthroplasty (THA) and hemiarthroplasty (HA) to treat displaced femoral neck fractures, particularly among the elderly, is still controversial. Acetabular erosion consists of a late multifactorial process that may happen after hip HA resulting in significant postoperative burden. This study aims to investigate the impact of acetabular erosion progress after hip HA in patients over 70 years old.

MATERIALS AND METHODS

This is a 5-year (2013-2018) retrospective study including consecutive series of patients >70 years who were treated with bipolar hip HA for femoral neck fractures. Patients were categorised into 3 groups for analysis (A = 70-75 years, B = 75-80 years, C = >80 years). The study enrolled a total number of 813 patients who met the inclusion criteria. We assessed acetabular erosion through radiological examinations and measured functional deterioration using the modified Harris Hip Score (mHHS) at 6 and 12 months follow-up. Our comprehensive investigation extended over a maximum period of 5 years. The correlation of patients' characteristics and HA features on erosion progress was assessed.

RESULTS

There were no significant differences in sex distribution, injury side, BMI, ASA score, bipolar head diameter, mHHS and leg-length discrepancy among the groups (p > 0.05). During the follow-up period, acetabular erosion with consequential conversion to THA was observed in 6.13%, 4.22% and 1.96% for Groups A, B and C respectively (p = 0.009). A statistically significant difference of acetabular erosion was observed in Group A compared to patients of Group C.

CONCLUSIONS

Age constitutes a significant factor of acetabular wear after HA in the elderly. The higher rate of acetabular wear in patients <75 years suggests that THA is a more viable option, as HA is for patients >80 years old.

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.

Global mapping of institutional and hospital-based (Level II-IV) arthroplasty registries: a scoping review

PURPOSE

Four joint arthroplasty registries (JARs) levels exist based on the recorded data type. Level I JARs are national registries that record primary data. Hospital or institutional JARs (Level II-IV) document further data (patient-reported outcomes, demographic, radiographic). A worldwide list of Level II-IV JARs must be created to effectively assess and categorize these data.

METHODS

Our study is a systematic scoping review that followed the PRISMA guidelines and included 648 studies. Based on their publications, the study aimed to map the existing Level II-IV JARs worldwide. The secondary aim was to record their lifetime, publications' number and frequency and recognise differences with national JARs.

RESULTS

One hundred five Level II-IV JARs were identified. Forty-eight hospital-based, 45 institutional, and 12 regional JARs. Fifty JARs were found in America, 39 in Europe, nine in Asia, six in Oceania and one in Africa. They have published 485 cohorts, 91 case-series, 49 case-control, nine cross-sectional studies, eight registry protocols and six randomized trials. Most cohort studies were retrospective. Twenty-three per cent of papers studied patient-reported outcomes, 21.45% surgical complications, 13.73% postoperative clinical and 5.25% radiographic outcomes, and 11.88% were survival analyses. Forty-four JARs have published only one paper. Level I JARs primarily publish implant revision risk annual reports, while Level IV JARs collect comprehensive data to conduct retrospective cohort studies.

CONCLUSIONS

This is the first study mapping all Level II-IV JARs worldwide. Most JARs are found in Europe and America, reporting on retrospective cohorts, but only a few report on studies systematically.

A Longitudinal analysis of weight changes before and after total hip arthroplasty: Weight trends, patterns, and predictors

BACKGROUND

It is crucial to understand weight trends in patients undergoing total hip arthroplasty (THA).

OBJECTIVE

To evaluate preoperative and postoperative weight trends for patients undergoing primary THA and factors associated with clinically significant weight change.

METHODS

A prospective cohort who underwent primary unilateral THA (n= 3,011) at a tertiary healthcare system (January 2016 to December 2019) were included in the study. The primary outcomes were clinically significant weight change (> 5% change in body mass index [BMI]) during the one-year preoperative and one-year postoperative periods.

RESULTS

Preoperatively, 66.6% maintained a stable weight, 16.0% gained and 17.4% lost weight, respectively. Postoperatively, 64.0% maintained a stable weight, while 22.6% gained and 13.4% lost weight, respectively. Female sex, Black race, obesity, higher Charlson Comorbidity Index (CCI) scores, and older age were associated with preoperative weight loss. Female sex, obesity, higher CCI scores, and Medicare insurance were associated with postoperative weight loss. Preoperative weight loss was associated with postoperative weight gain (OR = 3.37 [CI: 2.67 to 4.25]; p< 0.001), and preoperative weight gain was associated with postoperative weight loss (OR = 1.74 [CI: 1.30 to 2.3]; p< 0.001).

CONCLUSION

Most patients maintained a stable BMI one-year before and one-year after THA. Several factors are associated with weight loss before and after THA. Preoperative weight changes were associated with a reciprocal rebound in BMI post-operatively.

Glucagon-like Peptide-1 Agonists: What the Orthopaedic Surgeon Needs to Know

» Orthopaedic surgeons are increasingly likely to encounter patients with obesity and/or type 2 diabetes taking glucagon-like peptide-1 (GLP-1) agonists for weight loss.» GLP-1 agonists are an effective treatment for weight loss with semaglutide and tirzepatide being the most effective agents. Randomized controlled trials using these agents have reported weight loss up to 21 kg (46 lb).» The use of GLP-1 agonists preoperatively can improve glycemic control, which can potentially reduce the risk of postoperative complications. However, multiple cases of intraoperative aspiration/regurgitation have been reported, potentially related to the effect of GLP-1 agonists on gastric emptying.» While efficacious, GLP-1 agonists may not produce sufficient weight loss to achieve body mass index cutoffs for total joint arthroplasty depending on individual patient factors, including starting bodyweight. Multifactorial approaches to weight loss with focus on lifestyle modification in addition to GLP-1 agonists should be considered in such patients.» Although GLP-1 agonists are efficacious agents for weight loss, they may not be accessible or affordable for all patients. Each patient's unique circumstances should be considered when creating an ideal weight loss plan during optimization efforts.

The Impact of Sarcopenia Risk on Postoperative Walking Independence in Older Adults Undergoing Total Joint Arthroplasty

BACKGROUND AND PURPOSE

Sarcopenia is known to be associated with poor outcomes after arthroplasty; however, no study has reported the relationship between sarcopenia and postoperative walking independence. This study aimed to determine the impact of sarcopenia risk screening using the SARC-CalF questionnaire and calf circumference on the time to walk independently after total hip or knee arthroplasty in older patients.

METHODS

We included 599 nonobese patients aged 65 years and older who underwent unilateral and primary total hip or knee arthroplasty. Preoperative sarcopenia risk was assessed using the SARC-CalF or calf circumference. The outcome of this study was the time to independent walking after surgery; it was calculated as the number of days from the date of surgery to the date when the patient was able to walk independently. The association between preoperative sarcopenia risk and time to independent walking after surgery was analyzed using Kaplan-Meier curves and Cox proportional hazards models.

RESULTS

Among the 599 patients undergoing total joint arthroplasty, 175 (29.2%) were determined to be at risk of sarcopenia using SARC-CalF and 193 (32.2%) using calf circumference. The Kaplan-Meier curve showed that sarcopenia risk assessed by SARC-CalF or calf circumference was associated with a prolonged time to independent walking in patients undergoing hip arthroplasty (log-rank test, P < .001 and P < .001, respectively). In patients undergoing hip arthroplasty, the Cox proportional hazards model showed that SARC-CalF score of 11 points and greater or a calf circumference less than the cutoff was a risk factor for delayed time to independent walking (hazard ratios: 0.55 and 0.57, P < .001 and P = .001, respectively). There was no association between preoperative sarcopenia risk and postoperative time to independent walking in patients who underwent knee arthroplasty.

CONCLUSIONS

Sarcopenia screening tools, such as SARC-CalF or calf circumference, should be useful for planning postoperative rehabilitation in older adults scheduled for hip arthroplasty. However, the accuracy of SARC-CalF or calf circumference measurement in patients scheduled for knee arthroplasty may be low.

Medical Weight Optimization for Arthroplasty Patients: A Primer of Emerging Therapies for the Joint Arthroplasty Surgeon

The obesity epidemic in the United States continues to grow with more than 40% of individuals now classified as obese (body mass index >30). Obesity has been readily demonstrated to increase the risk of developing hip and knee osteoarthritis and is known to increase the risk of complications following joint arthroplasty. Weight loss prior to arthroplasty may mitigate this risk of complications; however, the existing evidence remains mixed with no clear consensus on the optimal method of weight loss and timing prior to arthroplasty. Treatment options for weight loss have included nonsurgical lifestyle modifications consisting of structured diet, physical activity, and behavioral modification, as well as bariatric and metabolic surgery (ie, sleeve gastrectomy, Roux-en-Y gastric bypass, and the adjustable gastric band). Recently, glucagon-like peptide-1 receptor agonists have gained notable popularity within the scientific literature and media for their efficacy in weight loss. The aim of this review is to provide a foundational primer for joint arthroplasty surgeons regarding the current and emerging options for weight loss to aid surgeons in shared decision-making with patients prior to arthroplasty.

Impact of wound complications in obese versus non-obese patients undergoing total hip arthroplasty: A meta-analysis

This meta-analysis examined the post-operative wound effect of both obese and non-obese in total hip arthroplasty (THA) patients. To gather as complete an overview as possible, the researchers took advantage of 4 databases-PubMed, Embase, Cochrane Library and Web of Science-to conduct a critical assessment. Following the development of inclusion and exclusion criteria, the researchers evaluated the quality of each document. A total of 9 related trials were conducted to determine the 95% CI (CI) and OR using a fixed-effect model. The final meta-analyses were conducted with RevMan 5.3. Our findings indicate that there is no statistically significant benefit in terms of post-operative wound complications among obese and non-obese patients. Obese subjects had a significantly higher risk of injury than those without obesity (OR, 1.43; 95% CI, 1.04, 1.95, p = 0.03); obesity was also associated with a significantly higher risk of operative site infection than in non-obese subjects (OR, 1.96; 95% CI, 1.76, 2.18, p < 0.0001); and after surgery, there was also a significant increase in the risk of post-operative wound infections among obese subjects than in non-obese subjects (OR, 1.57; 95% CI, 1.34, 1.84, p < 0.0001). However, due to the small size of the cohort study in this meta-study, caution is required in the analysis. More randomized, controlled studies will be needed to validate these results.

2023 American College of Rheumatology and American Association of Hip and Knee Surgeons Clinical Practice Guideline for the Optimal Timing of Elective Hip or Knee Arthroplasty for Patients With Symptomatic Moderate-to-Severe Osteoarthritis or Advanced Symptomatic Osteonecrosis With Secondary Arthritis for Whom Nonoperative Therapy Is Ineffective

OBJECTIVE

To develop evidence-based consensus recommendations for the optimal timing of hip and knee arthroplasty to improve patient-important outcomes including, but not limited to, pain, function, infection, hospitalization, and death at 1 year for patients with symptomatic and radiographic moderate-to-severe osteoarthritis or advanced symptomatic osteonecrosis with secondary arthritis of the hip or knee who have previously attempted nonoperative therapy, and for whom nonoperative therapy was ineffective, and who have chosen to undergo elective hip or knee arthroplasty (collectively referred to as TJA).

METHODS

We developed 13 clinically relevant population, intervention, comparator, outcomes (PICO) questions. After a systematic literature review, the Grading of Recommendations Assessment, Development and Evaluation (GRADE) approach was used to rate the quality of evidence (high, moderate, low, or very low), and evidence tables were created. A Voting Panel, including 13 physicians and patients, discussed the PICO questions until consensus was achieved on the direction (for/against) and strength (strong/conditional) of the recommendations.

RESULTS

The panel conditionally recommended against delaying TJA to pursue additional nonoperative treatment including physical therapy, nonsteroidal antiinflammatory drugs, ambulatory aids, and intraarticular injections. It conditionally recommended delaying TJA for nicotine reduction or cessation. The panel conditionally recommended delay for better glycemic control for patients who have diabetes mellitus, although no specific measure or level was identified. There was consensus that obesity by itself was not a reason for delay, but that weight loss should be strongly encouraged, and the increase in operative risk should be discussed. The panel conditionally recommended against delay in patients who have severe deformity or bone loss, or in patients who have a neuropathic joint. Evidence for all recommendations was graded as low or very low quality.

CONCLUSION

This guideline provides evidence-based recommendations regarding the optimal timing of TJA in patients who have symptomatic and radiographic moderate-to-severe osteoarthritis or advanced symptomatic osteonecrosis with secondary arthritis for whom nonoperative therapy was ineffective to improve patient-important outcomes, including pain, function, infection, hospitalization, and death at 1 year. We acknowledge that the evidence is of low quality primarily due to indirectness and hope future research will allow for further refinement of the recommendations.

Joint fluid concentrations of amphotericin B after local application with calcium sulphate-report of 2 cases

Fungal periprosthetic joint infections (PJI) are difficult to treat, due to important biofilm formation and limited local penetration of systemically administered antifungals. Calcium sulphate (CaSO4 ) might be a promising carrier to increase local concentration of antifungals. We hypothesized that local amphotericin B release from CaSO4 is high enough to significantly contribute to treatment of fungal PJI. We report joint fluid and serum concentrations of amphotericin B after local application with CaSO4 as an implanted resorbable carrier material as adjunct to standard surgical and systemic antifungal treatment in two cases of PJI with Candida spp. Maximal joint fluid amphotericin B concentration was 14.01 mg/L 5 days after the second local administration of liposomal amphotericin in Case One and 25.77 mg/L 14 days after the second local administration in Case Two. Concentrations higher than minimal inhibitory concentrations (MIC) could be measured for 21 days and 17 days after local administration in Case One and Two, respectively. In Case Two, serum concentration of amphotericin B was <0.01 mg/L 3 days after local administration of 450 mg liposomal amphotericin B. No local or systemic adverse reaction was observed. Fungal PJI was successfully eradicated in both cases with a follow-up of 12 months in Case One and 20 months in Case Two. Application of amphotericin B-loaded CaSO4 was associated with joint fluid concentrations higher than minimal inhibitory concentrations for Candida spp. for approximately 3 weeks, with the advantage that the carrier material dissolves spontaneously and does not require secondary removal. Relapse of fungal infections did not occur in these two patients.

2023 American College of Rheumatology and American Association of Hip and Knee Surgeons Clinical Practice Guideline for the Optimal Timing of Elective Hip or Knee Arthroplasty for Patients With Symptomatic Moderate-to-Severe Osteoarthritis or Advanced Symptomatic Osteonecrosis With Secondary Arthritis for Whom Nonoperative Therapy Is Ineffective

OBJECTIVE

To develop evidence-based consensus recommendations for the optimal timing of hip and knee arthroplasty to improve patient-important outcomes including, but not limited to, pain, function, infection, hospitalization, and death at 1 year for patients with symptomatic and radiographic moderate-to-severe osteoarthritis or advanced symptomatic osteonecrosis with secondary arthritis of the hip or knee who have previously attempted nonoperative therapy, and for whom nonoperative therapy was ineffective, and who have chosen to undergo elective hip or knee arthroplasty (collectively referred to as TJA).

METHODS

We developed 13 clinically relevant population, intervention, comparator, outcomes (PICO) questions. After a systematic literature review, the Grading of Recommendations Assessment, Development and Evaluation (GRADE) approach was used to rate the quality of evidence (high, moderate, low, or very low), and evidence tables were created. A Voting Panel, including 13 physicians and patients, discussed the PICO questions until consensus was achieved on the direction (for/against) and strength (strong/conditional) of the recommendations.

RESULTS

The panel conditionally recommended against delaying TJA to pursue additional nonoperative treatment including physical therapy, nonsteroidal antiinflammatory drugs, ambulatory aids, and intraarticular injections. It conditionally recommended delaying TJA for nicotine reduction or cessation. The panel conditionally recommended delay for better glycemic control for patients who have diabetes mellitus, although no specific measure or level was identified. There was consensus that obesity by itself was not a reason for delay, but that weight loss should be strongly encouraged, and the increase in operative risk should be discussed. The panel conditionally recommended against delay in patients who have severe deformity or bone loss, or in patients who have a neuropathic joint. Evidence for all recommendations was graded as low or very low quality.

CONCLUSION

This guideline provides evidence-based recommendations regarding the optimal timing of TJA in patients who have symptomatic and radiographic moderate-to-severe osteoarthritis or advanced symptomatic osteonecrosis with secondary arthritis for whom nonoperative therapy was ineffective to improve patient-important outcomes, including pain, function, infection, hospitalization, and death at 1 year. We acknowledge that the evidence is of low quality primarily due to indirectness and hope future research will allow for further refinement of the recommendations.

2023 American College of Rheumatology and American Association of Hip and Knee Surgeons Clinical Practice Guideline for the Optimal Timing of Elective Hip or Knee Arthroplasty for Patients With Symptomatic Moderate-to-Severe Osteoarthritis or Advanced Symptomatic Osteonecrosis With Secondary Arthritis for Whom Nonoperative Therapy Is Ineffective

OBJECTIVE

To develop evidence-based consensus recommendations for the optimal timing of hip and knee arthroplasty to improve patient-important outcomes including, but not limited to, pain, function, infection, hospitalization, and death at 1 year for patients with symptomatic and radiographic moderate-to-severe osteoarthritis or advanced symptomatic osteonecrosis with secondary arthritis of the hip or knee who have previously attempted nonoperative therapy, and for whom nonoperative therapy was ineffective, and who have chosen to undergo elective hip or knee arthroplasty (collectively referred to as TJA).

METHODS

We developed 13 clinically relevant population, intervention, comparator, outcomes (PICO) questions. After a systematic literature review, the Grading of Recommendations Assessment, Development and Evaluation (GRADE) approach was used to rate the quality of evidence (high, moderate, low, or very low), and evidence tables were created. A Voting Panel, including 13 physicians and patients, discussed the PICO questions until consensus was achieved on the direction (for/against) and strength (strong/conditional) of the recommendations.

RESULTS

The panel conditionally recommended against delaying TJA to pursue additional nonoperative treatment including physical therapy, nonsteroidal antiinflammatory drugs, ambulatory aids, and intraarticular injections. It conditionally recommended delaying TJA for nicotine reduction or cessation. The panel conditionally recommended delay for better glycemic control for patients who have diabetes mellitus, although no specific measure or level was identified. There was consensus that obesity by itself was not a reason for delay, but that weight loss should be strongly encouraged, and the increase in operative risk should be discussed. The panel conditionally recommended against delay in patients who have severe deformity or bone loss, or in patients who have a neuropathic joint. Evidence for all recommendations was graded as low or very low quality.

CONCLUSION

This guideline provides evidence-based recommendations regarding the optimal timing of TJA in patients who have symptomatic and radiographic moderate-to-severe osteoarthritis or advanced symptomatic osteonecrosis with secondary arthritis for whom nonoperative therapy was ineffective to improve patient-important outcomes, including pain, function, infection, hospitalization, and death at 1 year. We acknowledge that the evidence is of low quality primarily due to indirectness and hope future research will allow for further refinement of the recommendations.

An Update on the Management and Optimization of the Patient with Morbid Obesity Undergoing Hip or Knee Arthroplasty

The prevalence of obesity in the United States is at a record high of 42%. In 1999, the Centers for Disease Control and Prevention recognized the obesity epidemic as a national problem, spurring the first generation of interventions for obesity prevention and control. Despite billions of dollars in funding, legislative changes, and public health initiatives, the trajectory of American obesity has not waivered. Obesity is also strongly associated with the development of osteoarthritis. The growing population of young, obese, and sick patients presents a unique dilemma for orthopedic surgeons performing joint replacement, as obesity levels and the demand for joint replacement are only expected to rise further.

No Difference in the Rate of Periprosthetic Joint Infection in Patients Undergoing the Posterolateral Compared to the Direct Anterior Approach

BACKGROUND

There remains inconsistent data about the association of surgical approach and periprosthetic joint infection (PJI). We sought to evaluate the risk of reoperation for superficial infection and PJI after primary total hip arthroplasty (THA) in a multivariate model.

METHODS

We reviewed 16,500 primary THAs, collecting data on surgical approach and all reoperations within 1 year for superficial infection (n = 36) or PJI (n = 70). Considering superficial infection and PJI separately, we used Kaplan-Meier survivorship to assess survival free from reoperation and a Cox Proportional Hazards multivariate models to assess risk factors for reoperation.

RESULTS

Between direct anterior approach (DAA) (N = 3,351) and PLA (N = 13,149) cohorts, rates of superficial infection (0.4 versus 0.2%) and PJI (0.3 versus 0.5%) were low and survivorship free from reoperation for superficial infection (99.6 versus 99.8%) and PJI (99.4 versus 99.7%) were excellent at both 1 and 2 years. The risk of developing superficial infection increased with high body mass index (BMI) (hazard ratio [HR] = 1.1 per unit increase, P = .003), DAA (HR = 2.7, P = .01), and smoking status (HR = 2.9, P = .03). The risk of developing PJI increased with the high BMI (HR = 1.04, P = .03), but not surgical approach (HR = 0.68, P = .3).

CONCLUSION

In this study of 16,500 primary THAs, DAA was independently associated with an elevated risk of superficial infection reoperation compared to the PLA, but there was no association between surgical approach and PJI. An elevated patient BMI was the strongest risk factor for superficial infection and PJI in our cohort.

LEVEL OF EVIDENCE

III, retrospective cohort study.

A Radiographic Abdominal Pannus Sign is Associated With Postoperative Complications in Anterior THA

BACKGROUND

Numerous studies have shown that elevated BMI is associated with adverse outcomes in THA; however, BMI alone does not adequately represent a patient's adipose and soft tissue distribution, especially when the direct-anterior approach is evaluated. Local soft tissue and adipose, especially in the peri-incisional region, has an unknown impact on patient outcomes after direct-anterior THA. Moreover, there is currently no known evaluation method to estimate the quantity of local soft tissue and adipose tissue. The current study introduced a new radiographic parameter that is measurable on supine AP radiographs: the abdominal pannus sign.

QUESTION/PURPOSE

Are patients who have an abdominal pannus extending below the upper (cephalad) border of the symphysis pubis more likely to experience problems after anterior-approach THA that are plausibly associated with that finding, including infections resulting in readmission, wound complications resulting in readmission, fractures, or longer surgical time, than patients who do not demonstrate this radiographic sign?

METHODS

Between 2015 and 2020, five surgeons performed 727 primary direct-anterior THAs. After exclusion criteria were applied, 596 procedures were included. Of those, we obtained postoperative radiographs in the postanesthesia care unit in 100% of procedures (596 of 596), and 100% of radiographs (596) were adequate for review in this retrospective study. The level of the pannus in relation to the pubic symphysis was assessed on immediate supine postoperative AP radiographs of the pelvis: above (pannus sign 1), between the upper and lower borders (pannus sign 2), or below the level of the pubic symphysis (pannus sign 3). In this study, we combined pannus signs 2 and 3 into a single group for analysis not only because there was a limited number of patients in each group, but also because there was no statistically significant difference between the two groups. Pannus sign 1 was identified in 82% of procedures (486 of 596), and pannus sign ≥ 2 was identified in 18% (110). We compared the groups (pannus sign 1 versus pannus sign ≥ 2) in terms of the percentage of patients who experienced problems within 90 days of THA that might be associated with that physical finding, including infections resulting in readmission including subcutaneous, subfascial, and prosthetic joint infections; wound complications resulting in readmission, defined as dehiscence or delayed healing; and all fractures, and we compared the groups in terms of surgical time-that is, the cut-to-close time.

RESULTS

Patients with a pannus sign of ≥ 2 were more likely than those with a pannus sign of 1 to have a postoperative infection (6.4% [seven of 110 procedures] versus 0.6% [three of 486], odds ratio 10.96 [95% confidence interval (CI) 2.83 to 42.38]; p < 0.01), wound complications (0.9% [one of 110] versus 0% [0 of 486] with an infinite odds ratio [95% CI indeterminate]; p = 0.18), and fractures (4.5% [five of 110] versus 0% [0 of 486], with an infinite odds ratio [95% CI indeterminate]; p < 0.01). The mean surgical time was longer in patients with a pannus sign of ≥ 2 than it was in those with a pannus sign of 1 (128 ± 25.3 minutes versus 118 ± 27.5 minutes, mean difference 10 minutes; p < 0.01).

CONCLUSION

Based on these findings, patients who have an abdominal pannus that extends below the upper (cephalad) edge of the pubic symphysis are at an increased risk of experiencing serious surgical complications. If THA is planned in these patients, an approach other than the direct-anterior approach should be considered. Surgeons performing THA who do not obtain supine radiographs preoperatively should use a physical examination to evaluate for this finding, and if it is present, they should use an approach other than the direct-anterior approach to minimize the risk of these complications. Future studies might compare the abdominal pannus sign using standing radiographs, which are used more often, with other well-documented associated risk factors such as elevated BMI or higher American Society of Anesthesiologists classification.

LEVEL OF EVIDENCE

Level III, retrospective cohort study.

Revision risk by using the direct superior approach (DSA) for total hip arthroplasty compared with postero-lateral approach: early nationwide results from the Dutch Arthroplasty Register (LROI)

BACKGROUND AND PURPOSE

The direct superior approach (DSA) is a modification of the classic posterolateral approach (PLA) for total hip arthroplasty (THA), in which the iliotibial band and short external rotators are spared. The revision rate of the DSA has not been investigated previously using arthroplasty registry data. We examined the reasons and risk of revision of the DSA, compared with the direct anterior approach (DAA) and PLA.

PATIENTS AND METHODS

In this population-based cohort study we included 175,543 primary THAs performed between 2014 and 2020 (PLA, n = 117,576; DAA, n = 56,626; DSA, n = 1,341). Competing risk survival analysis and multivariable Cox proportional hazard analyses, adjusted for potential confounders, were performed.

RESULTS

After 3 years, crude revision rates due to any reason were 2.1% (95% confidence interval [CI] 1.3-3.3) for DSA, and 2.9% (CI 2.8-3.0) for PLA. Crude dislocation revision rates were 0.3% (CI 0.1-0.8) for DSA, versus 1.0% (CI 0.9-1.0) for PLA. Dislocation revision rate for DSA did not differ from DAA (0.3% [CI 0.2-0.3]). Multivariable Cox regression analysis demonstrated no overall difference in revision rates for the DSA (HR 0.6 [CI 0.4-1.09) compared with the PLA. Lower risk of revision due to dislocation was found in patients operated on through the DSA (HR 0.3 [0.1-0.9]) compared with the PLA.

CONCLUSION

Early nationwide results suggest that the DSA for total hip arthroplasty seems to show a tendency towards a lower risk of revision for dislocation but no overall reduced revision risk compared with the PLA.

Total Hip and Knee Arthroplasty Surgery in the Morbidly Obese Patient: A Critical Analysis Review

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Obesity, defined as body mass index (BMI) ≥30, is a serious public health concern associated with an increased incidence of stroke, diabetes, mental illness, and cardiovascular disease resulting in numerous preventable deaths yearly.

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From 1999 through 2018, the age-adjusted prevalence of morbid obesity (BMI ≥40) in US adults aged 20 years and older has risen steadily from 4.7% to 9.2%, with other estimates showing that most of the patients undergoing hip and knee replacement by 2029 will be obese (BMI ≥30) or morbidly obese (BMI ≥40).

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In patients undergoing total joint arthroplasty (TJA), morbid obesity (BMI ≥40) is associated with an increased risk of perioperative complications, including prosthetic joint infection and mechanical failure necessitating aseptic revision.

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The current literature on the role that bariatric weight loss surgery before TJA has on improving surgical outcomes is split and referral to a bariatric surgeon should be a shared-decision between patient and surgeon on a case-by-case basis.

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Despite the increased risk profile of TJA in the morbidly obese cohort, these patients consistently show improvement in pain and physical function postoperatively that should be considered when deciding for or against surgery.

Direct Anterior Approach Provides Superior Prosthesis Adaptability in the Early Postoperative Period of Total Hip Arthroplasty

OBJECTIVES

Prosthesis awareness is the perception of foreign bodies, which has a critical effect on the function of the prosthetic joint. In total hip arthroplasty (THA), the direct anterior approach (DAA) has more advantages than the posterior approach (PA), including superior rehabilitation outcomes. This study was to evaluate the recovery of "prosthesis awareness" through these two approaches.

METHODS

Three hundred and seventy-six patients who received THA with either DAA (n = 41) or PA (n = 335) from January 2016 to December 2017 were retrospectively analyzed. The Forgotten Joint Score-12 (FJS-12), Harris hip score (HHS), and visual analog scale (VAS) analyses were used to evaluate the recovery of "prosthesis awareness" in these patients 2 weeks, 1, 3, 6, and 12 months after surgery. The student t-test, Wilcoxon rank sum test, chi-square test, and MANOVA were used to compare the differences among groups.

RESULTS

We found that DAA patients had higher FJS-12 scores than PA patients at 2 weeks (42.15 ± 3.36 vs. 38.09 ± 3.28, p = 0.042), 1 month (49.06 ± 5.14 vs. 41.11 ± 5.21, p = 0.038), and 3 months (53.23 ± 4.07 vs. 48.09 ± 3.71, t = 3.152, p = 0.045). And the recovery rates of FJS-12 scores in DAA and PA groups at 2 weeks, 1 month, and 3 months after surgery were 75.46% ± 6.04%, 84.05% ± 6.57%, 91.37% ± 7.13%, and 74.14% ± 5.54%, 78.16% ± 6.01%, 88.23% ± 6.42%, respectively. To compare the recovery effects of the two procedures in more detail, we classified the 12 items in FJS-12 that evaluate different types of gravity center motions into three categories: low-movement group (LG), middle-movement group (MG), and high-movement group (HG). Interestingly, DAA patients had significantly higher HG than PA patients at 2 weeks, 1 month, and 3 months after operation (t = 3.225, p = 0.022 at 2 weeks, t = 3.081, p = 0.041 at 1 month and t = 2.783, p = 0.046 at 3 months), whereas no significant differences were observed in LG- and MG-related items. In addition, there were no significant differences in HHS and VAS scores between DAA and PA patients at 2 weeks (p = 0.102, p = 0.093), or from 1 month to 12 months (each p > 0.05).

CONCLUSIONS

DAA-mediated THA is superior to PA in terms of prosthesis adaptability and recovery of hip joint motion in the first 3 months after surgery, especially concerning high-movement gravity center motions.

Underweight Patients are at Increased Risk for Complications following Total Hip Arthroplasty

BACKGROUND

Given the prevalence of obesity in the United States, much of the adult reconstruction literature focuses on the effects of obesity and morbid obesity. However, there is little published data on the effect of being underweight on postoperative outcomes. This study aimed to examine the risk of low body mass index (BMI) on complications after total hip arthroplasty (THA).

METHODS

A large national database was queried between 2010 and 2020 to identify patients who had THAs. Using International Classification of Disease codes, patients were grouped into the following BMI categories: morbid obesity (BMI>40), obesity (BMI 30 to 40), normal BMI (BMI 20 to 30), and underweight (BMI<20). There were 58,151 patients identified, including 2,484 (4.27%) underweight patients, 34,710 (59.69%) obese patients, and 20,957 (36.04%) morbidly obese patients. Control groups were created for each study group, matching for age, sex, and a comorbidity index. Complications that occurred within 1 year postoperatively were isolated. Subanalyses were performed to compare complications between underweight and obese patients. Statistical analyses were performed using Pearson Chi-squares.

RESULTS

Compared to their matched control group, underweight patients showed increased odds of THA revision (Odds Ratio (OR) = 1.32, P = .04), sepsis (OR = 1.51, P = .01), and periprosthetic fractures (OR = 1.63, P = .01). When directly comparing underweight and obese patients (BMI 30 and above), underweight patients had higher odds of aseptic loosening (OR = 1.62, P = .03), sepsis (OR = 1.34, P = .03), dislocation (OR = 1.84, P < .001), and periprosthetic fracture (OR = 1.46, P = .01).

CONCLUSION

Morbidly obese patients experience the highest odds of complications, although underweight patients also had elevated odds for several complications. Underweight patients are an under-recognized and understudied high risk arthroplasty cohort and further research is needed.

Does Metabolic Syndrome Impact the Risk of Reoperation, Revision, or Complication After Primary Total Knee Arthroplasty?

BACKGROUND

Metabolic syndrome (MetS) is an increasingly frequent condition characterized by insulin resistance, abdominal obesity, hypertension, and dyslipidemia. This study evaluated implant survivorship, complications, and clinical outcomes of primary TKAs performed in patients who have MetS.

METHODS

Utilizing our institutional total joint registry, 2,063 primary TKAs were performed in patients with a diagnosis of MetS according to the World Health Organization criteria. MetS patients were matched 1:1 based on age, sex, and surgical year to those who did not have the condition. The World Health Organization's body mass index (BMI) classification was utilized to evaluate the effect of obesity within MetS patients. Kaplan-Meier methods were utilized to determine implant survivorship. Clinical outcomes were assessed with Knee Society scores. The mean follow-up was 5 years.

RESULTS

MetS and non-MetS patients did not have significant differences in 5-year implant survivorship free from any reoperation (P = .7), any revision (P = .2), and reoperation for periprosthetic joint infection (PJI; P = .2). When stratifying, patients with MetS and BMI >40 had significantly decreased 5-year survivorship free from any revision (95 versus 98%, respectively; hazard ratio = 2.1, P = .005) and reoperation for PJI (97 versus 99%, respectively; hazard ratio = 2.2, P = .02). Both MetS and non-MetS groups experienced significant improvements in Knee Society Scores (77 versus 78, respectively; P < .001) that were not significantly different (P = .3).

CONCLUSION

MetS did not significantly increase the risk of any reoperation after TKA; however, MetS patients with BMI >40 had a two-fold risk of any revision and reoperation for PJI. These results suggest that obesity is an important condition within MetS criteria and remains an independent risk factor.

LEVEL OF EVIDENCE

Level 3, Case-control study.

Patient-specific Hip Arthroplasty Dislocation Risk Calculator: An Explainable Multimodal Machine Learning-based Approach

PURPOSE

To develop a multimodal machine learning-based pipeline to predict patient-specific risk of dislocation following primary total hip arthroplasty (THA).

MATERIALS AND METHODS

This study retrospectively evaluated 17 073 patients who underwent primary THA between 1998 and 2018. A test set of 1718 patients was held out. A hybrid network of EfficientNet-B4 and Swin-B transformer was developed to classify patients according to 5-year dislocation outcomes from preoperative anteroposterior pelvic radiographs and clinical characteristics (demographics, comorbidities, and surgical characteristics). The most informative imaging features, extracted by the mentioned model, were selected and concatenated with clinical features. A collection of these features was then used to train a multimodal survival XGBoost model to predict the individualized hazard of dislocation within 5 years. C index was used to evaluate the multimodal survival model on the test set and compare it with another clinical-only model trained only on clinical data. Shapley additive explanation values were used for model explanation.

RESULTS

The study sample had a median age of 65 years (IQR: 18 years; 52.1% [8889] women) with a 5-year dislocation incidence of 2%. On the holdout test set, the clinical-only model achieved a C index of 0.64 (95% CI: 0.60, 0.68). The addition of imaging features boosted multimodal model performance to a C index of 0.74 (95% CI: 0.69, 0.78; P = .02).

CONCLUSION

Due to its discrimination ability and explainability, this risk calculator can be a potential powerful dislocation risk stratification and THA planning tool.Keywords: Conventional Radiography, Surgery, Skeletal-Appendicular, Hip, Outcomes Analysis, Supervised Learning, Convolutional Neural Network (CNN), Gradient Boosting Machines (GBM) Supplemental material is available for this article. © RSNA, 2022.

Anterior hip replacement: lower dislocation rates despite less restrictions?

INTRODUCTION

Dislocation in Total hip arthroplasty (THA) is a common postoperative complication and reason for revision surgery. The direct anterior approach has become more popular over the last decade. The purpose of this study was to compare postoperative dislocation rates of the direct anterior and the posterior approach at a one-year follow-up.

MATERIAL AND METHODS

797 consecutive hips operated through a posterior approach [698 patients (307 male, 391 female)] between 2009 and 2012, were compared to 690 selected THA [610 patients (423 female, 187 male)] operated since 2012. Anterior hip replacement surgery was primarily indicated for patients demanding increased flexibility after surgery (Yoga) or were considered a higher risk for dislocation.

RESULTS

During a one-year follow-up there were eight dislocations out of 797 THA (1%) in the posterior group and none in the 690 THA (0%) in the anterior group (p-value of 0.008). Average time to dislocation was 7.5 weeks in the posterior group. Five of eight patients with dislocations needed revision surgery due to persistent instability.

CONCLUSION

Even in a higher-risk patient population, the direct anterior approach showed a lower dislocation rate compared to the posterior approach in the first year after surgery.

Instability After Primary Total Hip Arthroplasty: Dual Mobility Versus Jumbo Femoral Heads

BACKGROUND

The use of dual mobility (DM) articulations has grown substantially over the last decade to help minimize dislocation risk. The purpose of this study is to compare the results of DM articulations to jumbo femoral heads of equivalent sizes as they relate to postoperative dislocation.

METHODS

This is a retrospective cohort study of primary total hip arthroplasties (THAs) performed at a single institution between 2005 and 2018. DM articulations and large-diameter metal-on-metal femoral heads were included. Patients were followed with Harris Hip Scores and standard radiographs. Complications were prospectively recorded. Statistical analyses included chi-squared and Brown-Forsythe tests.

RESULTS

In total, 1,288 Magnum femoral head THAs and 365 Active Articulation DM THAs were included for analysis. The same monoblock cup was implanted via a posterior approach in all cases. Age, gender, body mass index, and diagnosis were similar between groups. Average follow-up in the DM group was 49 months, and 126 months in the jumbo head group. The average head sizes in the DM and jumbo head groups were 50 mm. There were no dislocations in the DM hips and only 2 (0.2%) in the jumbo femoral head group. Both groups had significant improvements in Harris Hip Score from their preoperative baseline.

CONCLUSION

Our study found similarly low dislocation rates in DM and jumbo femoral heads in primary THA. No evidence currently exists showing a benefit of the DM articulation beyond that of the large effective head size, and we recommend making every attempt at maximizing head size prior to using DM articulations.