Familial Clustering Identified in Periprosthetic Joint Infection Following Primary Total Joint Arthroplasty: A Population-Based Cohort Study

The John Charnley Award: The Impact of Human Leukocyte Antigen Genotype on Bacterial Infection Rates and Successful Eradication in Total Hip Arthroplasty

BACKGROUND

Genetics play an important role in several medical domains; however, the influence of human leukocyte antigen (HLA) genotype on the development of periprosthetic joint infection (PJI) in total hip arthroplasty (THA) remains unknown. The primary aim of this study was to determine if HLA genotype is associated with the development of bacterial PJI in THA. Secondarily, we evaluated the association between HLA genotype and PJI treatment success.

METHODS

A retrospective, matched, case-control study was performed using prospectively collected data from a single institution. A total of 49 patients who underwent primary THA were included, with a mean follow-up of 8.5 years (range, 4.2 to 12.9). The 23 cases (PJI) and 26 controls (no PJI) were matched for age, sex, follow-up, body mass index, primary diagnosis, and comorbidities (P > .05). High-resolution genetic analysis targeting 11 separate HLA loci was performed in all patients using serum samples. The HLA gene frequencies and carriage rates were determined and compared between cohorts. A subgroup analysis of PJI treatment success (18) and failure (5) was performed. Statistical significance was set at P = .10 for genetic analysis and at 0.05 for all other analyses.

RESULTS

There were 4 HLA alleles that were significantly associated with the development of PJI. The 3 at-risk alleles included HLA-C∗06:02 (odds ratio 5.25, 95% CI [confidence interval] 0.96 to 28.6, P = .064), HLA-DQA1∗04:01 (P = .096), and HLA-DQB1∗04:02 (P = .096). The single protective allele was HLA-C∗03:04 (odds ratio 0.12, 95% CI 0.01 to 1.10, P = .052). There were no specific HLA alleles that were associated with treatment success or failure.

CONCLUSIONS

This study suggests that there are at-risk and protective HLA alleles associated with the development of PJI in THA. To our knowledge, this is the first study to demonstrate an association between patient HLA genotype and the development of PJI. A larger study of the subject matter is necessary and warranted.

Analysis of acute extremity compartment syndrome using a genealogic population database

INTRODUCTION

Acute extremity compartment syndrome ("CS") is an under-researched, highly morbid condition affecting trauma populations. The purpose of this study was to analyze incidence rates and risk factors for extremity compartment syndrome using a high-quality population database. Additionally, we evaluated heritable risk for CS using available genealogic data. We hypothesized that diagnosis of extremity compartment syndrome would demonstrate heritability.

MATERIALS AND METHODS

Adult patients with fractures of the tibia, femur, and upper extremity were retrospectively identified by ICD-9, ICD-10, and CPT codes from 1996 to 2020 in a statewide hospital database. Exposed and unexposed cohorts were created based on a diagnosis of CS. Available demographic data were analyzed to determine risk factors for compartment syndrome using logistic regression. Mortality risk at the final follow-up was evaluated using Cox proportional hazard modeling. Patients with a diagnosis of CS were matched with those without a diagnosis for heritability analysis.

RESULTS

Of 158,624 fractures, 931 patients were diagnosed with CS. Incidence of CS was 0.59% (tibia 0.83%, femur 0.31%, upper extremity 0.27%). Male sex (78.1% vs. 46.4%; p < 0.001; RR = 3.24), younger age at fracture (38.8 vs. 48.0 years; p < 0.001; RR = 0.74), Medicaid enrollment (13.2% vs. 9.3%; p < 0.001; RR = 1.58), and smoking (41.1% vs. 31.1%; p < 0.001; RR 1.67) were significant risk factors for CS. CS was associated with mortality (RR 1.61, p < 0.001) at mean follow-up 8.9 years in the CS cohort. No significant heritable risk was found for diagnosis of CS.

CONCLUSIONS

Without isolating high-risk fractures, rates of CS are lower than previously reported in the literature. Male sex, younger age, smoking, and Medicaid enrollment were independent risk factors for CS. CS increased mortality risk at long-term follow-up. No heritable risk was found for CS.

LEVEL OF EVIDENCE

III.

Periprosthetic joint infection and immunity: Current understanding of host-microbe interplay

Periprosthetic joint infection (PJI) is a major complication of total joint arthroplasty. Even with current treatments, failure rates are unacceptably high with a 5-year mortality rate of 26%. Majority of the literature in the field has focused on development of better biomarkers for diagnostics and treatment strategies including innovate antibiotic delivery systems, antibiofilm agents, and bacteriophages. Nevertheless, the role of the immune system, our first line of defense during PJI, is not well understood. Evidence of infection in PJI patients is found within circulation, synovial fluid, and tissue and include numerous cytokines, metabolites, antimicrobial peptides, and soluble receptors that are part of the PJI diagnosis workup. Macrophages, neutrophils, and myeloid-derived suppressor cells (MDSCs) are initially recruited into the joint by chemokines and cytokines produced by immune cells and bacteria and are activated by pathogen-associated molecular patterns. While these cells are efficient killers of planktonic bacteria by phagocytosis, opsonization, degranulation, and recruitment of adaptive immune cells, biofilm-associated bacteria are troublesome. Biofilm is not only a physical barrier for the immune system but also elicits effector functions. Additionally, bacteria have developed mechanisms to evade the immune system by inactivating effector molecules, promoting killing or anti-inflammatory effector cell phenotypes, and intracellular persistence and dissemination. Understanding these shortcomings and the mechanisms by which bacteria can subvert the immune system may open new approaches to better prepare our own immune system to combat PJI. Furthermore, preoperative immune system assessment and screening for dysregulation may aid in developing preventative interventions to decrease PJI incidence.

Familial Analysis of Nonunion in a Genealogic Population Database Demonstrates No Evidence of Heritable Risk

OBJECTIVE

To determine whether there is evidence of heritable risk for nonunion using a large, state-wide population database.

DESIGN

Database.

SETTING

Level 1 Trauma Center.

POPULATION

All Utah residents from 1996 to 2021 who sustained a long bone fracture and their family members were included.

OUTCOMES

The primary outcome was nonunion and the prevalence of nonunion among the patients' first-, second-, and third-degree relatives. The secondary objective was to identify demographic, injury, and socioeconomic risk factors associated with nonunion.

RESULTS

In total, 150,263 fractures and 6577 nonunions (4.4%) were identified. This was highly refined to a 1:3 matched cohort of 4667 nonunions of 13,981 fractures for familial clustering analysis. Cox proportional hazards did not demonstrate excessive risk of nonunion among first- ( P = 0.863), second- ( P = 0.509), and third-degree relatives ( P = 0.252). Further analysis of the entire cohort demonstrated that male sex (relative risk [RR] = 1.15; P < 0.001), Medicaid enrollment (RR = 2.64; P < 0.001), open fracture (RR = 2.53; P < 0.001), age group 41-60 years (RR = 1.43; P < 0.001), and a history of obesity (RR = 1.20; P < 0.001) were independent risk factors for nonunion.

CONCLUSIONS

Our results demonstrate no evidence of heritable risk for nonunion. Independent risk factors for nonunion were male sex, Medicaid enrollment, open fracture, middle age, and a history of obesity. Although it is important to identify modifiable and nonmodifiable risk factors, these results continue to support that the risk of nonunion is multifactorial, relating to injury characteristics, operative techniques, and patient-specific risk factors.

LEVEL OF EVIDENCE

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

Associations between smoking and clinical outcomes after total hip and knee arthroplasty: A systematic review and meta-analysis

BACKGROUND

Smoking increases risk of several complications after total hip or knee arthroplasty (THA/TKA), so we systematically reviewed and meta-analyzed the literature to take into account all relevant evidence, particularly studies published since 2010.

METHODS

The PubMed, Ovid Embase, Web of Science, and EBSCOHost databases were searched and studies were selected and analyzed according to MOOSE recommendations. Methodological quality of included studies was assessed using the Newcastle-Ottawa Scale. Data were qualitatively synthesized or meta-analyzed using a random-effects model.

RESULTS

A total of 40 studies involving 3,037,683 cases were included. Qualitative analysis suggested that smoking is associated with worse patient-reported outcomes within one year after surgery, and meta-analysis showed that smoking significantly increased risk of the following outcomes: total complications (OR 1.41, 95% CI 1.01-1.98), wound complications (OR 1.77, 95% CI 1.50-2.10), prosthetic joint infection (OR 1.84, 95% CI 1.52-2.24), aseptic loosening (OR 1.62, 95% CI 1.12-2.34), revision (OR 2.12, 95% CI 1.46-3.08), cardiac arrest (OR 4.90, 95% CI 2.26-10.60), cerebrovascular accident (OR 2.22, 95% CI 1.01-4.85), pneumonia (OR 2.35, 95% CI 1.17-4.74), acute renal insufficiency (OR 2.01, 95% CI 1.48-2.73), sepsis (OR 4.35, 95% CI 1.35-14.00), inpatient mortality (OR 12.37, 95% CI 4.46-34.28), and persistent opioid consumption (OR 1.64, 95% CI 1.39-1.92).

CONCLUSION

Smoking patients undergoing THA and TKA are at increased risk of numerous complications, inpatient mortality, persistent opioid consumption, and worse 1-year patient-reported outcomes. Pre-surgical protocols for these outcomes should give special consideration to smoking patients.

Risk of Revision After Arthroplasty Associated with Specific Gene Loci: A Genomewide Association Study of Single-Nucleotide Polymorphisms in 1,130 Twins Treated with Arthroplasty

BACKGROUND

The risk of revision surgery following total joint arthroplasty (TJA) may be influenced by genetic factors. Therefore, we sought to identify genetic variants associated with the risk of revision surgery in a genomewide association study.

METHODS

We investigated a cohort of 1,130 twins from the Swedish Twin Registry treated with TJA. During a mean of 9.4 years of follow-up, 75 individuals underwent revision surgery for aseptic loosening (the primary outcome) and 94, for any reason (the secondary outcome). Genetic information was collected using the Illumina OmniExpress and PsychArray panels, and the Haplotype Reference Consortium served as the reference for gene imputation. Adjusted Cox regression models were fitted to calculate hazard ratios (HRs) with 95% confidence intervals (CIs).

RESULTS

Nine single-nucleotide polymorphisms (SNPs) reached genomewide significance for aseptic loosening. The first SNP, rs77149046, located in the endosome-lysosome associated apoptosis and autophagy regulator family member 2 (ELAPOR2) gene, conferred an HR of 5.40 (CI, 3.23-9.02; p = 1.32×10 -10 ), followed by 4 SNPs within the region coding for sodium-dependent taurine and beta-alanine transporter (SLC6A6), with HRs ranging from 3.35 to 3.43. The sixth SNP, rs7853989 (HR, 3.46; CI, 2.33-5.13; p = 6.91×10 -10 ), was located in a region coding for the ABO blood group system. This SNP has been described as predictive for blood type B. Seven significant SNPs were found for the risk of revision for any reason, with the first 4 again being located in the SLC6A6 region. The leading SNP, rs62233562, conferred an HR of 3.11 (CI, 2.19-4.40; p = 1.74×10 -10 ) for revision surgery. Similar HRs were found for SNPs 3:14506680 (p = 1.78×10 -10 ), rs2289129 (p = 1.78×10 -10 ), and rs17309567 (p = 3.16×10 -10 ). The fifth SNP, rs11120968, was located in the calmodulin-binding transcription activator 1 (CAMTA1) gene (HR, 2.34; CI, 1.74-3.13, p = 1.45×10 -8 ).

CONCLUSIONS

We identified 12 unique SNPs associated with an increased risk of revision surgery. Among these, 2 were in ELAPOR2, which is closely linked to bone formation. Another SNP is located in a gene region encoding for the ABO system, which merits further studies of causal relationships.

LEVEL OF EVIDENCE

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

Socioeconomic Status May Not Be a Risk Factor for Periprosthetic Joint Infection

BACKGROUND

Periprosthetic joint infection (PJI) is a devastating complication after total joint arthroplasty, carrying significant economic and personal burden. The goal of this study is to use an established database to analyze socioeconomic variables and assess their relationship to PJI. Additionally, we sought to evaluate whether socioeconomic factors, along with other known risk factors of PJI, when controlled for in a statistical model affected the familial risk of PJI.

METHODS

With approval from our Institutional Review Board we performed a population-based retrospective cohort study on all primary total joint arthroplasty cases of the hip or knee (n = 85,332), within a statewide database, between January 1996 and December 2013. We excluded 9854 patients due to age <18 years, missing data, history of PJI prior to index procedure, and no evidence of 2-year follow-up (excluding those with PJI). Cases that developed PJI following the index procedure (n = 2282) were compared to those that did not (n = 73,196).

RESULTS

After adjusting for covariates, patients with Medicaid as a primary payer were at greater risk for experiencing PJI (relative risk 1.40, 95% confidence interval [CI] 1.08-1.82, P = .01). There was no difference in risk between the groups associated with education level or median household income (all, P > .05). First-degree relatives of patients who develop PJI (hazard ratio 1.66, 95% CI 1.23-2.24, P = .001) and first-degree and second-degree relatives combined (hazard ratio 1.39, 95% CI 1.09-1.77, P = .007) were at greater risk despite controlling for the above socioeconomic factors.

CONCLUSION

Our study provides further support that genetic factors may underlie PJI as we did observe significant familial risk even after accounting for socioeconomic factors and payer status. We did not find a correlation between education level or household income and PJI; however, Medicaid payees were at increased risk. Continued study is needed to define a possible heritable disposition to PJI in an effort to optimize treatment and possibly prevent this complication.

Evaluation for Kienböck Disease Familial Clustering: A Population-Based Cohort Study

PURPOSE

Kienböck disease (KD) is rare and its etiology remains unknown. As a result, the ideal treatment is also in question. Our primary purpose was to test the hypothesis that KD would demonstrate familial clustering in a large statewide population with comprehensive genealogical records, possibly suggesting a genetic etiologic contribution. Our secondary purpose was to evaluate for associations between KD and known risk factors for avascular necrosis.

METHODS

Patients diagnosed with KD were identified by searching medical records from a comprehensive statewide database, the Utah Population Database. This database contains pedigrees dating back to the early 1800s, which are linked to 31 million medical records for 11 million patients from 1996 to the present. Affected individuals were then mapped to pedigrees to identify high-risk families with an increased incidence of KD relative to control pedigrees. The magnitude of familial risk of KD in related individuals was calculated using Cox regression models. Association of risk factors related to KD was analyzed using conditional logistic regression.

RESULTS

We identified 394 affected individuals linked to 194 unrelated high-risk pedigrees with increased incidence of KD. The relative risk of developing KD was significantly elevated in first-degree relatives. There was a significant correlation between alcohol, glucocorticoid, and tobacco use and a history of diabetes, and the diagnosis of KD.

CONCLUSIONS

Familial clustering of KD observed in the Utah Population Database cohort indicates a potential genetic contribution to the etiology of the disease. Identification of causal gene variants in these high-risk families may provide insight into the genes and pathways that contribute to the onset and progression of KD.

CLINICAL RELEVANCE

This study suggests that there is a potential genetic contribution to the etiology of KD and that the disease has a significant association with several risk factors.

Patients with Type-1 Diabetes Are at Greater Risk of Periprosthetic Joint Infection: A Population-Based, Retrospective, Cohort Study

BACKGROUND

The effect of diabetes type on the risk of periprosthetic joint infection is not well documented. We hypothesized that patients with diabetes mellitus type 1 would be at greater risk for periprosthetic joint infection than those with diabetes mellitus type 2 and that a history of diabetic complications would be associated with an increased risk of periprosthetic joint infection.

METHODS

We performed a retrospective cohort study, within a statewide database, on all adult patients who underwent hip or knee arthroplasty, with follow-up of ≥2 years, from 1996 to 2013. Of the 75,478 patients included, 1,668 had type-1 diabetes and 18,186 had type-2 diabetes. Risk factors were calculated using Cox regression, adjusting for siblings and stratified by age. Logistic regression was used to analyze the effect of diabetic complications on the risk of periprosthetic joint infection, controlling for other known risks for periprosthetic joint infection.

RESULTS

There was no difference in age or sex between groups (p > 0.05). The frequency of periprosthetic joint infection in patients without diabetes was 2.6% compared with 4.3% in all patients with diabetes (relative risk, 1.47; p < 0.001). Patients with type-1 diabetes were at a 1.8 times greater risk for periprosthetic joint infection than patients with type-2 diabetes (7% compared with 4%; p < 0.001). The following diabetic complications increased the risk of periprosthetic joint infection: peripheral circulatory disorders (odds ratio [OR], 2.59 [95% confidence interval (CI), 1.70 to 3.94]), ketoacidosis (OR, 2.52 [95% CI, 1.51 to 4.19]), neurological manifestations (OR, 2.33 [95% CI, 1.96 to 2.78]), renal manifestations (OR, 2.15 [95% CI, 1.66 to 2.79]), and ophthalmic manifestations (OR, 1.76 [95% CI, 1.24 to 2.51]). The odds of periprosthetic joint infection increased with each added complication and patients with ≥4 complications were 9 times more likely to have a periprosthetic joint infection than patients with uncomplicated diabetes (OR, 9.47 [95% CI, 4.97 to 18.03]). Overweight and obese patients with type-2 diabetes and underweight patients with type-1 diabetes were at greater risk for periprosthetic joint infection compared with the general population (all p < 0.05).

CONCLUSIONS

Our data showed an increased risk of periprosthetic joint infection in patients with type-1 diabetes compared with those with type-2 diabetes, along with an increasing risk associated with additional diabetic complications. These findings emphasize the need to better understand the medical history of patients with diabetes for more appropriate risk management.

LEVEL OF EVIDENCE

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

Tobacco Use and Risk of Wound Complications and Periprosthetic Joint Infection: A Systematic Review and Meta-Analysis of Primary Total Joint Arthroplasty Procedures

BACKGROUND

The purpose of this study was to perform a systematic review and meta-analysis to quantitatively assess the association between tobacco use and the risk of any wound complication and periprosthetic joint infection (PJI) after primary total hip and total knee arthroplasty procedures.

METHODS

Relevant articles published before January 2018 were identified by systematically searching PubMed, EMBASE, and Cochrane library databases. Pooled odds ratios (OR) and 95% confidence intervals were calculated for end points of any wound complication and PJI. Additional analyses were performed to evaluate risks between current, former, and non-tobacco users.

RESULTS

Fourteen studies were included in the meta-analysis. Tobacco users had a significantly higher risk of wound complications (OR, 1.78 [1.32-2.39]) and PJI (OR, 2.02 [1.47-2.77]) compared to non-tobacco users. Compared to non-tobacco users, there was an increased risk of PJI among current (OR, 2.16 [1.57-2.97] and former (OR, 1.52 [1.16-1.99]) tobacco users. Current tobacco users also had a significantly increased risk of PJI compared to former tobacco users (OR, 1.52 [1.07-2.14]).

CONCLUSION

Tobacco use before total hip and total knee arthroplasty significantly increases the risk of wound complications and PJI. This increased risk is present for both current and former tobacco users. However, former tobacco users had a significantly lower risk of wound complications and PJI compared to current tobacco users, suggesting that cessation of tobacco use before TJA can help to mitigate these observed risks.