The epidemiology of revision total knee arthroplasty in the United States

What Is the Correlation between Coronal Plane Alignment Measured on Pre- and Postoperative Weight-bearing Radiographs and Intraoperative Navigation When Stress Is Applied to the Knee?

This study examines the correlation between the weight-bearing (WB) long leg radiograph (LLR)-derived hip-knee-ankle angle (HKAA) and intraoperative supine computer-assisted surgery (CAS)-derived HKAA measurements at the beginning and end of total knee arthroplasty (TKA). The primary aim of the study was to determine if WB alignment could be mimicked or inferred based on intraoperative alignment findings. We conducted a prospective analysis from a cohort of 129 TKAs undergoing a CAS TKA at a single center by a single surgeon. The HKAA was recorded using the CAS navigation system immediately postregistration of navigation data and after implantation of the prosthesis. The intraoperative HKAA was recorded in both the supine "resting" position of the knee and also while the knee was manipulated in an effort to replicate the patient's WB alignment. These measurements were compared with the HKAA recorded on pre- and postoperative WB LLRs. There was a strong correlation between the preoperative WB LLR HKAA and the intraoperative preimplant CAS-derived stressed HKAA (R = 0.946). However, there was no correlation between the postoperative WB LLR HKAA and the postimplant insertion HKAA as measured intraoperatively via CAS for either a "resting" or "stressed" position of the operated knee (R = 0.165 and R = 0.041, respectively). Thus, the interpretation of intraoperative alignment data is potentially problematic. Despite technological advances in the development and utilization of computer navigation and robotics in arthroplasty to help obtain the optimal alignment, it would seem apparent from our study that this alignment does not correlate to upright stance postoperatively. Surgeons should apply caution to the strength of assumptions they place on intraoperative coronal plane alignment findings.

An umbrella review of the diagnostic value of next-generation sequencing in infectious diseases

BACKGROUND

An increasing number of systematic reviews (SRs) have evaluated the diagnostic values of next-generation sequencing (NGS) in infectious diseases (IDs).

AIM

This umbrella analysis aimed to assess the potential risk of bias in existing SRs and to summarize the published diagnostic values of NGS in different IDs.

METHOD

We searched PubMed, Embase, and the Cochrane Library until September 2023 for SRs assessing the diagnostic validity of NGS for IDs. Two investigators independently determined review eligibility, extracted data, and evaluated reporting quality, risk of bias, methodological quality, and evidence certainty in the included SRs.

RESULTS

Eleven SRs were analyzed. Most SRs exhibited a moderate level of reporting quality, while a serious risk of bias was observed in all SRs. The diagnostic performance of NGS in detecting pneumocystis pneumonia and periprosthetic/prosthetic joint infection was notably robust, showing excellent sensitivity (pneumocystis pneumonia: 0.96, 95% CI 0.90-0.99, very low certainty; periprosthetic/prosthetic joint infection: 0.93, 95% CI 0.83-0.97, very low certainty) and specificity (pneumocystis pneumonia: 0.96, 95% CI 0.92-0.98, very low certainty; periprosthetic/prosthetic joint infection: 0.95, 95% CI 0.92-0.97, very low certainty). NGS exhibited high specificity for central nervous system infection, bacterial meningoencephalitis, and tuberculous meningitis. The sensitivity to these infectious diseases was moderate. NGS demonstrated moderate sensitivity and specificity for multiple infections and pulmonary infections.

CONCLUSION

This umbrella analysis indicates that NGS is a promising technique for diagnosing pneumocystis pneumonia and periprosthetic/prosthetic joint infection with excellent sensitivity and specificity. More high-quality original research and SRs are needed to verify the current findings.

Clinical outcomes and survival rates of a uncemented modular revision stem system in hip arthroplasty: a 10-year single-institution study on a frail population

INTRODUCTION

The increasing prevalence of primary hip arthroplasty has led to a parallel rise in revision cases. Femoral revision often entails compromised bone integrity, requiring consideration of various solutions for optimal reconstructive options. Despite technological advancements, there is limited evidence on the clinical outcomes of the latest modular revision stems. This study aimed to evaluate the clinical outcomes and survival rates of next generation uncemented modular revision stem in patients undergoing hip revision surgery.

MATERIALS AND METHODS

This retrospective single-center study assessed the survival and failure causes of a specific uncemented modular stem in 48 patients undergoing hip revision surgery between 2012 and 2022. Data included preoperative parameters, surgical details, and postoperative outcomes measured through clinical and radiographic assessments. Forty-eight patients (25 males, 23 females; mean age 72 years) were included, with a mean Charlson Comorbidity Index of 5. Preoperative diagnoses varied, with periprosthetic joint infection (PJI) being the most common (45.8%), followed by periprosthetic fractures (27.1%). Partial revisions occurred in 60.4%, total revisions in 39.6%. According to Paprosky classification of femoral bone loss, type II and III were the most represented, respectively 35.4% and 50%.

RESULTS

At a mean follow-up of 4.6 years, stem survival was 92.5%. Complications (20%) included dislocation, PJI, fracture, and loosening; the overall reoperation rate was 12.5%. The SF-12 physical score was 43.6, while the mental score was 51.1. The HOOS score was 71.8, and the HHS score was 71.4. Radiographic analysis identified nonprogressive osteolysis in 15.1% of patients.

CONCLUSIONS

This study on this uncemented modular revision stem demonstrated favorable outcomes in an elder fragile population with moderate to severe femoral bone loss. The implant's modularity provides versatility in addressing various defects, without any implant breakage observed during the study period. Literature comparison highlighted similar outcomes despite sample size differences. The promising results warrant continued investigation into the long-term survivorship of this modular stem system.

Cementless Total Knee Arthroplasty: Is it Safe in Demineralized Bone?

There is concern for cementless total knee arthroplasty (TKA) in patients with decreased bone mineral density (BMD) due to the potential increase in complications, namely failed in-growth or future aseptic loosening. Some data suggest that advances in cementless prostheses mitigate these risks; however this is not yet born out in long-term registry data. It is crucial to expand our understanding of the prevalence and etiology of osteoporosis in TKA patients, survivorship of cementless implants in decreased BMD, role of bone-modifying agents, indications and technical considerations for cementless TKA in patients with decreased BMD. The purpose of this study is to review current literature and expert opinion on such topics.

Periprosthetic Joint Infections of the Knee-Comparison of Different Treatment Algorithms

Background: Periprosthetic joint infection (PJI) following total knee arthroplasty is a serious complication lacking evidence-based diagnostic and treatment protocols, particularly in ruling out persisting infection before reimplantation. Methods: This retrospective analysis assessed the mid-term outcomes of 66 patients undergoing septic two-stage knee revision surgeries from 2007 to 2013, diagnosed as per the Musculoskeletal Infection Society criteria. After implant removal and antibiotic treatment, reimplantation decisions were based on either joint aspiration, blood counts, and clinical examination (group A) or an open biopsy (group B). Both groups underwent meticulous debridement and spacer exchange during the interim period. Results: Late re-infection occurred in 12.1% of all patients. In group A, 13.8% experienced late re-infection, with 14.3% in subgroup A1 and 13.3% in subgroup A2. In group B, 10% had a late re-infection. No significant difference in re-infection or complication rates was found between the groups. Conclusions: The study did not demonstrate the superiority of group B's approach of open biopsy over group A's joint aspiration, clinical examination, and blood counts in preventing re-infection or reducing complications.

Long-Term Prevention of Arthroplasty Infections via Incorporation of Activated AgNbO3 Nanoparticles in PMMA Bone Cement

We investigated the possibility of loading PMMA bone cement with antimicrobial nanostructured AgNbO3 particles to counter biofilm formation at the cement-tissue interface. We found that a formulation containing (1-4)% AgNbO3 showed high antibacterial activity against Gram-positive Staphylococcus aureus and Gram-negative Pseudomonas aeruginosa while not showing any toxicity against THP1 human cell lines. In addition, loading the particles did not impact the mechanical properties of the cement. The results thus obtained illustrate the potential of the approach to replace the current technique of mixing cement with conventional antibiotics, which is associated with shortcomings such as efficacy loss from antibiotic depletion.

Methodological Assessment of the 100 Most-Cited Articles in Total Knee Arthroplasty in the Last Decade Compared to the All-Time List

BACKGROUND

Recent advances in total knee arthroplasty (TKA) have been driven by a growing focus on evidence-based medicine. This transition is reflected in the critical appraisal of both, the quality of work and the potential impact on the orthopedic community. The purpose of our study was to (1) identify the top 100 most-cited articles in TKA in the last decade and from all-time, and (2) compare methodological rigor of the most-cited articles in TKA in the last decade to articles all-time by level of evidence.

METHODS

The top 100 cited articles were recorded for manuscripts from the last decade, January 1, 2012 to December 31, 2022, and manuscripts from all-time for TKA. We collected authors, year of publication, journal of the article, country of origin of authors, article type (basic science article, clinical research article), level of evidence, methodological index for non-randomized studies score, physiotherapy evidence database scale, and citation density (total citations/years published).

RESULTS

The largest number of studies for all-time TKA (53.0%) and decade TKA (42.0%) were Level III. The average methodological index for non-randomized studies score for comparative studies was 18.7 for all-time TKA and 20.7 for decade TKA (P < .001). The average physiotherapy evidence database score was 6.1 for all-time TKA and 8.1 for decade TKA (P > .05). The highest citation density for all-time TKA was 111 and for past decade was 63. The number of level II studies in TKA increased from 19.0% from all time to 38.0% from the last decade (P < .05).

CONCLUSIONS

Our findings of improved methodologies over time reflect positive steps toward evidence-based practice in TKA. A continued focus on producing methodologically sound studies may guide evidence-based clinical decision-making.

Antibiotic calcium sulphate beads lower the bacterial burden and prevent infection in a mouse model of periprosthetic joint infection

Aims

Delayed postoperative inoculation of orthopaedic implants with persistent wound drainage or bacterial seeding of a haematoma can result in periprosthetic joint infection (PJI). The aim of this in vivo study was to compare the efficacy of vancomycin powder with vancomycin-eluting calcium sulphate beads in preventing PJI due to delayed inoculation.

Methods

A mouse model of PJI of the knee was used. Mice were randomized into groups with intervention at the time of surgery (postoperative day (POD) 0): a sterile control (SC; n = 6); infected control (IC; n = 15); systemic vancomycin (SV; n = 9); vancomycin powder (VP; n = 21); and vancomycin bead (VB; n = 19) groups. Delayed inoculation was introduced during an arthrotomy on POD 7 with 1 × 105 colony-forming units (CFUs) of a bioluminescent strain of Staphylococcus aureus. The bacterial burden was monitored using bioluminescence in vivo. All mice were killed on POD 21. Implants and soft-tissue were harvested and sonicated for analysis of the CFUs.

Results

The mean in vivo bioluminescence in the VB group was significantly lower on POD 8 and POD 10 compared with the other groups. There was a significant 1.3-log10 (95%) and 1.5-log10 (97%) reduction in mean soft-tissue CFUs in the VB group compared with the VP and IC groups (3.6 × 103 vs 7.0 × 104; p = 0.022; 3.6 × 103 vs 1.0 × 105; p = 0.007, respectively) at POD 21. There was a significant 1.6-log10 (98%) reduction in mean implant CFUs in the VB group compared with the IC group (1.3 × 100 vs 4.7 × 101, respectively; p = 0.038). Combined soft-tissue and implant infection was prevented in 10 of 19 mice (53%) in the VB group as opposed to 5 of 21 (24%) in the VP group, 3 of 15 (20%) in the IC group, and 0% in the SV group.

Conclusion

In our in vivo mouse model, antibiotic-releasing calcium sulphate beads appeared to outperform vancomycin powder alone in lowering the bacterial burden and preventing soft-tissue and implant infections.

Computational Lower Limb Simulator Boundary Conditions to Reproduce Measured TKA Loading in a Cohort of Telemetric Implant Patients

Recent advancements in computational modeling offer opportunities to refine total knee arthroplasty (TKA) design and treatment strategies. This study developed patient-specific simulator external boundary conditions (EBCs) using a PID-controlled lower limb finite element (FE) model. Calibration of the external actuation required to achieve measured patient-specific joint loading and motion was completed for nine patients with telemetric implants during gait, stair descent, and deep knee bend. The study also compared two EBC scenarios: activity-specific hip AP motion and pelvic rotation (that was averaged across all patients for an activity) and patient-specific hip AP motion and pelvic rotation. Including patient-specific data significantly improved reproduction of joint-level loading, reducing root mean squared error between the target and achieved loading by 28.7% and highlighting the importance of detailed patient data in replicating joint kinematics and kinetics. The principal component analysis (PCA) of the EBCs for the patient dataset showed that one component represented 77.8% of the overall variation, while the first three components represented 97.8%. Given the significant loading variability within the patient cohort, this group of patient-specific models can be run individually to provide insight into expected TKA mechanics variability, and the PCA can be utilized to further create reasonable EBCs that expand the variability evaluated.

Phage therapy in prosthetic joint infections caused by Staphylococcus aureus - A literature review

Prosthetic joint infections (PJIs) are dreaded arthroplasty complications often caused by Staphylococcus aureus. Due to methicillin-resistant S. aureus (MRSA) strains or biofilm formation, successful treatment remains difficult. Currently, two-stage revision surgery constitutes the gold standard therapy of PJIs, sometimes replaced or supplemented by debridement, antibiotics, and implant retention (DAIR). Given the dire consequences of therapeutic failure, bacteriophage therapy might be another treatment option. Here we provide a comprehensive literature review addressing the efficacy of phages applied against S. aureus as causative agent of PJIs. The included 17 publications had in common that the applied phages proved to be effective against various S. aureus isolates including MRSA even in biofilms. Experiments with mice, rats, rabbits, and moth larvae confirmed favorable features of phage preparations in PJI treatment in vivo; including its synergistic with antibiotics. Case reports of PJI patients unanimously described the bacterial eradication following, alongside other measures, intravenous and intra-articular phage administration. Generally, no major side effects occurred, but in some cases elevated liver transaminases were observed. To conclude, our review compiled promising evidence suggesting the safety and suitability of phage therapy as an adjuvant to DAIR in S. aureus PJIs, and thus, underscores the significance of further research.

Interleukin-1β Polymorphisms Are Genetic Markers of Susceptibility to Periprosthetic Joint Infection in Total Hip and Knee Arthroplasty

Periprosthetic joint infections (PJIs) are serious complications of prosthetic surgery. The criteria for the diagnosis of PJI integrate clinical and laboratory findings in a complex and sometimes inconclusive workflow. Host immune factors hold potential as diagnostic biomarkers in bone and joint infections. We reported that the humoral pattern-recognition molecule long pentraxin 3 (PTX3) predicts PJI in total hip and knee arthroplasty (THA and TKA, respectively). If and how genetic variation in PTX3 and inflammatory genes that affect its expression (IL-1β, IL-6, IL-10, and IL-17A) contributes to the risk of PJI is unknown. We conducted a case-control study on a Caucasian historic cohort of THA and TKA patients who had prosthesis explant due to PJI (cases) or aseptic complications (controls). Saliva was collected from 93 subjects and used to extract DNA and genotype PTX3, IL-1β, IL-6, IL-10, and IL-17A single-nucleotide polymorphisms (SNPs). Moreover, the concentration of IL-1β, IL-10, and IL-6 was measured in synovial fluid and plasma. No association was found between PTX3 polymorphisms and PJI; however, the AGG haplotype, encompassing rs2853550, rs1143634, and rs1143627 in IL-1β, was linked to the infection (p = 0.017). Also, synovial levels of all inflammatory markers were higher in cases than in controls, and a correlation emerged between synovial concentration of PTX3 and that of IL-1β in cases only (Spearman r = 0.67, p = 0.004). We identified a relationship between rs2853550 and the synovial concentration of IL-1β and PTX3. Our findings suggest that IL-1β SNPs could be used for the early identification of THA and TKA patients with a high risk of infection.

Advancing the Diagnosis of Periprosthetic Joint Infections: Integrated Microfluidic Platform for Alpha-Defensins-Specific Aptamer Selection and Its Analytical Applications

Periprosthetic joint infections (PJIs) pose a significant challenge in orthopedic surgery, particularly total joint arthroplasty (TJA), due to the potential for implant failure and increased patient morbidity. Early and accurate detection of PJIs is crucial for timely intervention and better patient prognosis. Herein, we successfully screened a high-affinity aptamer targeting alpha-defensin complex human neutrophil protein 1-3 (HNP 1-3; potential PJI biomarkers in synovial fluid [SF]) for the first time using systematic evolution of ligands by exponential enrichment (SELEX) on an integrated microfluidic platform. The compact microfluidic device enabled efficient screening, with each round completed within <2 h, comprising five rounds of positive selection, two rounds of negative selection, and one round of competitive selection. A novel one-aptamer-one-antibody assay was further developed from the optimal aptamer screened, and it could accurately quantify HNP 1-3 in SF within 3 h with only ∼50 μL of SF. The assay demonstrated strong binding affinity and specificity for the target protein in SF. Thirteen PJI SF samples were accurately diagnosed and the assay was accurate over a wide dynamic range (0.32-100 mg/L). This study has showcased a rapid and accurate diagnostic tool for PJI detection, which should see widespread use in the clinic, holding promise for potential analytical applications in orthopedic surgery and improving patient care.

Comprehensive Guidance for the Prevention of Periprosthetic Joint Infection After Total Joint Arthroplasty and Pitfalls in the Prevention

Total joint arthroplasty (TJA) is a surgical procedure, in which parts of damaged joints are removed and replaced with a prosthesis. The main indication of TJA is osteoarthritis, and the volume of TJA is rising annually along with the increase of aged population. Hip and knee are the most common joints, in which TJAs are performed. The TJA prosthesis is composed of metal, plastic, or ceramic device. Even though TJA is the most successful treatment for end-stage osteoarthritis, it is associated with various complications, and periprosthetic joint infection (PJI) is the most serious complication after TJA. With the increasing volume of TJAs, there is a simultaneous rise in the incidence of PJI. Contamination of the surgical wound and the adherence of bacteria to the surface of prosthetic component represent the initial step in the pathogenesis of PJI. The main sources of the contamination are 1) patient's own flora, 2) droplets in the operation room air, and 3) surgical gloves and instruments. Even though modern techniques have markedly reduced the degree of contamination, TJAs cannot be done in completely germ-free conditions and some degree of contamination is inevitable in all surgical procedures. However, not all contamination leads to PJI. It develops when the burden of contamination exceeds the immune threshold or the colony forming units (CFUs) and various factors contribute to a decrease in the CFU level. Surgeons should be aware of the germ burden/CFU concept and should monitor sources of contamination to maintain the germ burden below the CFU to prevent PJI.

Anatomical Safety Area for Periarticular Analgesic Infiltration through the Posterior Capsule in Total Knee Arthroplasty: Radiological Study in Magnetic Resonance

Background: One of the main challenges of orthopedic surgery is adequate pain management after total knee arthroplasty. This work aimed to determine the anatomical safety area for infiltration through the posterior capsule of the knee in prosthetic surgery using Magnetic Resonance Imaging (MRI). Methods: A descriptive, observational, cross-sectional study was performed on 126 knee MRIs. The variables studied were age, sex, and distance between different neurovascular structures of the popliteal fossa (tibial nerve, common peroneal nerve, and vascular bundle). Data were analyzed for normality (Kolmogorov-Smirnov) and variance homogeneity (Levène). A value of p < 0.05 and a confidence interval of 9% were considered statistically significant for all comparisons. Student's t-test was used to compare the means between independent samples. Results: We observed statistically significant differences between the sexes regarding EP-EPS (external plateau-external popliteal sciatic nerve (common peroneal)), EP-IPS (external plateau-internal popliteal sciatic nerve (tibial)), and IP-PA (internal plateau-popliteal artery) measurements. The average distance between both nerves, EPS-IPS (external popliteal sciatic nerve and internal popliteal sciatic nerve), was 25.96 mm in females, while the value obtained in males was 29.93 mm, but this difference was not statistically significant. Conclusions: The average distance from the posterior capsule to the EPS and IPS nerves is greater in males than in females, despite no statistical differences. The presence of a lateralized arteriovenous bundle reduces the infiltration area of the external compartment. Regarding the safety area, infiltration of the internal compartment is safe since the volume diffuses into the muscle mass of the internal gastrocnemius upon injection. To infiltrate the external compartment, the needle must move at least 2 cm from the midline toward the external side (to exceed the maximum displacement of the neurovascular bundle established at 1.82 cm), and not advance beyond 0.76 cm (minimum distance at which we located the common peroneal nerve in the external compartment).

Current Concepts on the Clinical and Economic Impact of Periprosthetic Joint Infections

Total joint arthroplasty (TJA) is a common procedure performed throughout the entire world in hopes of alleviating debilitating hip or knee pain. The projected number of TJAs performed in the United States alone is projected to exceed 1.9 million by 2030 and 5 million by 2040. With the significant increase in TJA performed, more periprosthetic joint infections (PJIs) are likely to be encountered. PJIs are a devastating complication of TJA. The economic and clinical burden must be understood and respected to minimize occurrence and allow optimal patient outcomes.

Real-World Evidence of the Impact of a Novel Surgical Irrigant on Surgical Site Infections in Primary Total Knee Arthroplasty Performed at an Ambulatory Surgery Center

Background: Total knee arthroplasty (TKA) is one of the most common inpatient and outpatient surgical procedures performed in the United States and is predicted to increase 401% by 2040. Surgical site infections (SSIs) at an incidence rate of approximately 2% are costly post-operative complications in TKA. Intra-operative surgical irrigants are used to decrease contaminating microbial bioburden within the surgical site to prevent SSI. The primary objective of this retrospective study was to evaluate the impact of a novel surgical irrigant called XPERIENCE® Advanced Surgical Irrigation (XP; Next Science, Jacksonville, FL) on SSI incidence in primary TKA performed at an ambulatory surgery center (ASC). Patients and Methods: Primary TKAs were performed at a free-standing ASC. The novel surgical irrigant was used intra-operatively to rinse away debris and micro-organisms from the surgical site. Retrospective data collation included SSI rates, complication rates, and re-admissions due to SSI within 90 days of index surgery. Results: Among the 524 primary TKA surgeries, one peri-prosthetic joint infection (PJI) was diagnosed within 90 days of index surgery and one superficial incisional SSI was diagnosed within 30 days of index surgery. The PJI was attributed to an exogenously acquired upper respiratory tract infection rather than due to the failure of intra-operative regimes. The 0.19% PJI incidence rate indicated significant efficacy of XP in decreasing PJI. An overall complication rate of 7.82% was noted with none of the complications associated with usage of the novel surgical irrigant. Conclusions: XPERIENCE is a promising intra-operative antimicrobial irrigant that can be easily incorporated into a broader infection prevention strategy.

What to Know about Antimicrobial Coatings in Arthroplasty: A Narrative Review

Periprosthetic joint infections (PJIs) are one of the most worrying complications orthopedic surgeons could face; thus, methods to prevent them are evolving. Apart from systemic antibiotics, targeted strategies such as local antimicrobial coatings applied to prosthetics have been introduced. This narrative review aims to provide an overview of the main antimicrobial coatings available in arthroplasty orthopedic surgery practice. The search was performed on the PubMed, Web of Science, SCOPUS, and EMBASE databases, focusing on antimicrobial-coated devices used in clinical practice in the arthroplasty world. While silver technology has been widely adopted in the prosthetic oncological field with favorable outcomes, recently, silver associated with hydroxyapatite for cementless fixation, antibiotic-loaded hydrogel coatings, and iodine coatings have all been employed with promising protective results against PJIs. However, challenges persist, with each material having strengths and weaknesses under investigation. Therefore, this narrative review emphasizes that further clinical studies are needed to understand whether antimicrobial coatings can truly revolutionize the field of PJIs.

What Is the Rate of Antimicrobial Resistance of a Prosthetic Joint Infection in a Major Orthopaedic Centre?

Periprosthetic joint infections (PJIs) are important factors in decreasing the success of hip and knee arthroplasties. It is a necessity to explore the epidemiological data and develop applications for rational antibiotic use, to address future infection control concerns. We aimed to investigate the microorganisms that were responsible and the related antibiograms in 121 patients with PJI, who were managed by two-stage revision surgery. Patients' data records, demographics, comorbidities, sites of arthroplasty, synovial fluid and deep tissue culture results and antibiotic treatment were summarized on a standardized case report form. There were 43 (35.5%) culture-negative PJI cases and 12 (9.9%) polymicrobial growths. The causative pathogens included Gram-positive (50.4%) and Gram-negative microorganisms (23.1%) and fungi (0.8%). Methicillin resistance was 64.3% for S. aureus and 89.5% for coagulase-negative staphylococcus (CoNS). The extended spectrum beta lactamase (ESBL) rate for Enterobacteriaceae was 68.4%. This study shows that antibiotic resistance is encountered in more than half of the cases, which is valid for all microorganisms most common in PJI. The success of treatment decreases significantly in cases where antibiotic-resistant microorganisms are isolated or in cases where the culture is negative.

Preoperative Risk Factors for Periprosthetic Joint Infection: A Narrative Review of the Literature

Periprosthetic joint infection (PJI) poses a challenging complication for many patients undergoing arthroplasty, and the literature identifies numerous risk factors. A comprehensive understanding of the primary risk and protective factors for PJI is valuable for surgeons. This article aims to compile and summarize the key risk factors for PJI documented in the literature. Some risk factors are related to the nutritional status of patients, with obesity, weight loss, hypovitaminosis, and malnutrition being frequently reported. Pathologies affecting patients also contribute to PJI risk, including septic arthritis, hepatitis, diabetes, urinary tract infections, anemia, hypothyroidism, osteoporosis, and dental pathologies. Unhealthy habits, such as tobacco and drug abuse, are significant factors. Previous corticosteroid injections may also play a role in infection development. A few protective factors are also reported in the literature (use of statins, preoperative decolonization, and preadmission skin preparation). The identification of risk factors and the implementation of evidence-based preoperative protocols are essential steps in reducing the incidence of PJI.

Warfarin and bisphosphontes interaction in patients undergoing total knee arthroplasty

Background

Patients undergoing knee arthroplasty (TKA) surgery need anticoagulant therapy, mainly warfarin for prevention of venous thromboembolism (VTE). Warfarin is mainly eliminated by renal glomerular filtration where 92 % of warfarin is excreted in urine. Warfarin overdose may lead to significant bleeding and warfarin underdosing may cause VTE and other complications. Thus, international normalized ratio (INR) monitoring is crucial in TKA patients taking warfarin. Great interest has been expressed in bisphosphonate to reduce periprosthetic osteoporosis in patients undergoing total joint arthroplasty. Many human case reports and cohort studies proved bisphosphonates induced impaired renal function.

Objectives

The main goal of the current study is to examine the pharmacodynamin effect of bisphosphonates on warfarin excretion and clinical effects in patients undergoing TKA surgery.

Methods

Fifty patients undergoing TKA were recruited in the current study. Twenty five patients were given warfarin and twenty five patients were given warfarin and bisphosphonates starting three days after surgery. INR, major bleeding events and minor bleeding events were followed up in all recruited patients for one month after surgery.

Results

warfarin plus zoledronic acid group had significantly higher percent of post INR greater than 4 (p = 0.022) and significantly higher percent of minor bleeding events (p = 0.041) than warfarin only group.

Conclusion

Concomitant administration of bisphosphonates may increase warfarin bleeding adverse effects in elderly patient undergoing TKA.

Transfemoral amputation versus knee arthrodesis for failed total knee replacement: A systematic review of outcomes

BACKGROUND

The options available to salvage a failed total knee replacement (TKR) include transfemoral amputation (TFA) and knee arthrodesis (KA). This systematic review aims to evaluate outcomes following either TFA or KA, comparing ambulatory status, additional subsequent surgery, postoperative infection, pain, health-related quality of life (HRQoL), and mortality rate.

METHODS

A literature search was conducted in EMBASE, Ovid Medline, and PubMed. Only primary research studies were included and data were independently extracted using a standardized form. The methodological quality of the studies was evaluated using Newcastle-Ottawa Scale.

RESULTS

Forty-four papers were included, comprising 470 TFA and 1034 KA patients. The methodological quality of the studies was moderate. No TFA versus KA randomized controlled trials could be identified. Pooled data totals via subgroup analyses were performed, owing to inconsistent reporting methods in the included studies. Prosthesis use rate by TFA patients was 157/316 = 49.7%. Significant differences included that TFA patients had lower rates of ambulatory capacity than KA patients (139/294 = 45.6% versus 248/287 = 86.4%, p < 0.001), TFA ambulators were less likely to use an ambulatory aid (55/135 = 40.7% versus 167/232 = 72.0%, p < 0.001), and TFA was associated with a greater postoperative infection rate than KA (29/118 = 24.6% versus 129/650 = 17.2%, p = 0.054). There was a similar rate of revision surgery between TFA and KA (37/183 = 20.2% versus 145/780 = 18.6%, p = 0.612). Data on HRQoL for both TFA and KA were limited, contradictory, and heterogeneous.

CONCLUSION

No randomized controlled trials comparing TFA versus KA exist;therefore, current data likely reflects substantial selection bias. The currently available evidence suggests that KA patients are significantly more likely to achieve independent bipedal ambulation than TFA patients. In both treatment cohorts, subsequent infection and revision surgery remain a relatively common occurrence.

The Current Epidemiology of Revision Total Knee Arthroplasty in the United States From 2016 to 2022

BACKGROUND

The number of revision total knee arthroplasties (TKAs) is projected to reach 268,200 cases annually by 2030 in the United States. The growing demand for revision TKA can be attributed to the successes of primary TKAs combined with an aging population, patient desires to remain active, as well as expanded indications for younger patients. Given the evolving nature of revision TKAs, an epidemiological analysis of: (1) etiologies; (2) demographics, including age and region; as well as (3) lengths of stay (LOS) offers a way to minimize the gap between appropriate understanding and effective intervention.

METHODS

From 2016 to 2022, a national, all-payer database was queried. Incidences and indications were analyzed for a total of 135,983 patients who had revision TKA procedures.

RESULTS

The most common etiologies for revision TKA procedures were infection (19.3%) and aseptic loosening (12.8%), followed by mechanical complications (7.9%). The largest age group was 65 to 74 years (34.9%) followed by 55 to 64 years (32.2%), then age >75 years (20.5%). The South had the largest total procedure cohort (39.8%), followed by the Midwest (28.6%), then the Northeast (18.6%), and the West (13.0%). The mean length of stay was 3.86 days (range, 1.0 to 15.0).

CONCLUSIONS

Our study details the current status of revision TKA through 2022. While infection and aseptic loosening remain leading causes, we found a low aseptic loosening rate of 12.8%.

Cathodic voltage-controlled electrical stimulation and betadine decontaminate nosocomial pathogens from implant surfaces

Periprosthetic joint infection (PJI) after total joint arthroplasty is a major concern requiring multiple surgeries and antibiotic interventions. Staphylococcus aureus, Pseudomonas aeruginosa, and Escherichia coli are the predominant causes of these infections. Due to biofilm formation, antibiotic treatment for patients with PJI can prolong resistance, further complicating the use of current treatments. Previous research has shown that cathodic voltage-controlled electrical stimulation (CVCES) is an effective technique to prevent/treat implant-associated biofilm infections on titanium (Ti) surfaces. This study thus evaluated the efficacy of CVCES via the use of 10% betadine alone and in combination with CVCES to eradicate lab-grown biofilms on cemented and cementless cobalt-chromium (CoCr) and Ti surfaces. CVCES treatment alone for 24 hours demonstrated no detectable CFU for E. coli and P. aeruginosa biofilms on cementless CoCr implants. In the presence of cement, E. coli biofilms had 106 CFUs/implant remaining after CVCES treatment alone; however, P. aeruginosa biofilms on cemented implants were reduced to below detectable limits. The use of 10% betadine treatment for 3 minutes followed by 24-hour CVCES treatment brought CFU levels to below detectable limits in E. coli and P. aeruginosa. The same was true for S. aureus biofilms on cementless patellofemoral implants as well as femoral and tibial implants. These treatment methods were not sufficient for eradication of S. aureus biofilms on cemented implants. These results suggest that CVCES alone and CVCES with 10% betadine are effective approaches to treating biofilms formed by certain bacterial species potentially leading to the treatment of PJI.IMPORTANCEPeriprosthetic joint infections (PJIs) are problematic due to requiring multiple surgeries and antibiotic therapies that are responsible for increased patient morbidity and healthcare costs. These infections become resistant to antibiotic treatment due to the formation of biofilms on the orthopedic surfaces. Cathodic voltage-controlled electrical stimulation (CVCES) has previously been shown to be an effective technique to prevent and treat biofilm infections on different surfaces. This study shows that CVCES can increase the efficacy of 10% betadine irrigation used in debridement, antibiotics, and implant retention by 99.9% and clear infection to below detection limits. PJI treatments are at times limited, and CVCES could be a promising technology to improve patient outcomes.

Compliant Intramedullary Stems for Joint Reconstruction

The longevity of current joint replacements is limited by aseptic loosening, which is the primary cause of non-infectious failure for hip, knee, and ankle arthroplasty. Aseptic loosening is typically caused either by osteolysis from particulate wear, or by high shear stresses at the bone-implant interface from over-constraint. Our objective was to demonstrate feasibility of a compliant intramedullary stem that eliminates over-constraint without generating particulate wear. The compliant stem is built around a compliant mechanism that permits rotation about a single axis. We first established several models to understand the relationship between mechanism geometry and implant performance under a given angular displacement and compressive load. We then used a neural network to identify a design space of geometries that would support an expected 100-year fatigue life inside the body. We additively manufactured one representative mechanism for each of three anatomic locations, and evaluated these prototypes on a KR-210 robot. The neural network predicts maximum stress and torsional stiffness with 2.69% and 4.08% error respectively, relative to finite element analysis data. We identified feasible design spaces for all three of the anatomic locations. Simulated peak stresses for the three stem prototypes were below the fatigue limit. Benchtop performance of all three prototypes was within design specifications. Our results demonstrate the feasibility of designing patient- and joint-specific compliant stems that address the root causes of aseptic loosening. Guided by these results, we expect the use of compliant intramedullary stems in joint reconstruction technology to increase implant lifetime.

In-Hospital Complications and Costs of Simultaneous Bilateral Total Hip Arthroplasty: The Case for Selection and Potential Cost Savings

Background

Published comparisons between bilateral and unilateral total hip arthroplasty (THA) remain controversial regarding the potential risks and benefits. Our objectives were to compare (1) postoperative complications and (2) resource utilization of patients having simultaneous bilateral THA with patients having unilateral procedures.

Methods

The Nationwide Inpatient Sample was used to identify patients undergoing primary elective THA from January 2016 to December 2019. Complications and costs were compared between unilateral and simultaneous bilateral patients. Binary logistic regression analysis controlling demographics, comorbidities, and the primary diagnosis was performed to compare the cohorts of unilateral and bilateral patients.

Results

Nine thousand nine hundred fifty-five Bilateral procedures and 785,609 unilateral procedures were identified. Patients with bilateral procedures were at increased risk for many medical complications including gastrointestinal complications (OR: 4.1; 95% CI: 2.4-6.9, P < .01), postoperative blood transfusions (OR: 3.6; 95% CI: 3.3-3.9, P < .01), and pulmonary embolisms (OR: 3.2; 95% CI: 2.0-5.1, P < .01). Patients with bilateral procedures were also at increased risk for joint complications, including periprosthetic fractures (OR: 7.4; 95% CI: 5.2-10.5, P < .01) and other mechanical complications (OR: 27.0; 95% CI: 23-30, P < .01). These patients also incurred higher index hospitalization costs ($25,347 vs $16,757, P < .001) and were discharged more commonly to a rehabilitation facility (17.8% vs 13.4%, P < .001).

Conclusions

Bilateral THA are at increased risk of developing postoperative complications despite being younger and having fewer comorbidities on average when compared with unilateral patients. While bilateral patients had a higher index hospitalization cost, the overall cost of one episode of care is lower than two separate hospitalizations.

Etiology of Total Knee Arthroplasty Revisions: A Two-Decade Institutional Perspective

Total knee arthroplasty (TKA) implant survival time is determined by various patient and implant-related factors and varies significantly in recent worldwide reports. In our study, we have included 247 TKA revisions in 203 patients performed in our hospital over the last 20 years. Multiple etiologies of revisions were identified and classified into 10 categories. Time to failure was analyzed with regard to etiology, patient demographics, and other relevant data. The overall average time to revision was 44.08 months (95% confidence interval (CI) between 33.34 and 49.82 months). Age at primary implant was negatively correlated with time to revision (hazard ratio (HR) = 1.0521 and 95% CI of HR = 1.0359 to 1.0685) and female patients showed a 1.59 times higher risk of implant failure than males. Periprosthetic joint infection was the cause of 46.56% (n=115) of revisions (out of which 12.55% (n=31) were early infections, diagnosed within the first three months), while aseptic loosening was found in 31.98% (n=79) of cases. Infection correlated with a shorter time to revision compared to aseptic loosening (p<0.05). These findings emphasize the need to intensify efforts to deliver the best patient care, select the best antibiotic regimen, and improve surgical techniques to decrease the incidence of infectious complications.

Prevalence of Depressive Symptoms in Aseptic Revision Total Knee Arthroplasty Based on the Mode of Failure

Background

Complications following total knee arthroplasty (TKA) that necessitate revision cause considerable psychological distress and symptoms of depression, which are linked to poorer postoperative outcomes, increased complications, and increased healthcare utilization. We aimed to identify the prevalence of mental health disorders and symptoms preoperatively and postoperatively in patients undergoing aseptic revision TKA and to stratify these patients based on their mechanism of failure.

Methods

All patients undergoing aseptic revision TKA from 2008 to 2019 with a minimum 1-year follow-up were retrospectively reviewed at a single institution. Patients (n = 394) were grouped based on 7 failure modes previously described. Patients were considered to have depressive symptoms if their Veterans RAND-12 mental component score was below 42. Preoperative and postoperative Veterans RAND-12 mental component scores at the latest follow-up were evaluated.

Results

Overall comparative prevalence of preoperative to postoperative depressive symptoms was 23.4%-18.8%. By mode of failure are as follows: arthrofibrosis (25.8%-16.7%), aseptic loosening (25.3%-18.9%), extensor mechanism disruption (25%-50%), failed unicompartmental knee arthroplasty (8.6%-14.3%), instability (25.7%-17.1%), osteolysis or polyethylene wear (23.1%-23.1%), and patellar failure (11.8%-23.5%). There was no difference in depressive symptoms among failure modes preoperatively (P = .376) or at the latest postoperative follow-up (P = .175).

Conclusions

The prevalence of depressive symptoms in revision TKA patients appears to be independent of failure mode. Surgeon awareness and screening for depressive symptoms in this patient population preoperatively with referral for potential treatment may improve early postoperative outcomes.

Outcomes After Successful Debridement, Antibiotic, and Implant Retention Therapy for Periprosthetic Joint Infection in Total Knee Arthroplasty

BACKGROUND

Controversy surrounds debridement, antibiotic and implant retention (DAIR) for treatment of acute periprosthetic joint infection (PJI). Data regarding DAIR's rate of infection resolution is variable with little investigation of functional outcomes.

METHODS

We identified 191 DAIR cases at a single institution from 2008 to 2020. Knee Injury and Osteoarthritis Outcome Score for Joint Replacement (KOOS-JR) and Patient Reported Outcome Measurement Information System-10 (PROMIS) scores were collected. Patient Reported Outcome Scores were obtained from 60 cases. Median follow-up (IQR) was 4.5 (2.1 to 7.6) versus 3.0 (1.2 to 5.3) years for the control group. Mean scores were compared to a cohort of uncomplicated total knee arthroplasties matched by age, body mass index, and sex using generalized linear models adjusted for follow-up duration. Kaplan-Meier survivorship curves for PJI were constructed.

RESULTS

Mean Patient Reported Outcome Scores for the DAIR cohort were 57.2 ± 19.7 for KOOS-JR, 41.6 ± 7.1 for PROMIS physical health (PH), and 46.6 ± 8.7 for PROMIS mental health (MH). Mean control group values were 65.8 ± 21.0 for KOOS-JR, 44.6 ± 8.4 for PROMIS PH, and 49.2 ± 9.2 for PROMIS MH. No difference was observed in KOOS-JR (P = .83) or PROMIS MH (P = .11). PROMIS PH was lower in the DAIR cohort compared to the control group (P = .048). Median follow-up (years) for all 191 cases was 5.9 (range, 0.5 to 13.1). Survivorship (years) without subsequent operation for infection was 84% at 1, 82% at 2, and 79% at 5.

CONCLUSION

Knee and MH outcomes in successful DAIR procedures were similar to uncomplicated total knee arthroplasty. DAIR's success rate was 79% in treating acute PJI at 5 years.

LEVEL OF EVIDENCE

Level III.

Relationship between biofilm-forming microorganisms (BFM: Staphylococcus aureus and Pseudomonas aeruginosa) and DEFB1 gene variants on β-defensin levels in periprosthetic joint infection (PJI)

BACKGROUND

The purpose of this study was to investigate the relationship between biofilm-forming microorganisms (BFM) and DEFB1 gene variants on β-defensin levels in patients with periprosthetic joint infection (PJI) of Mexican origin.

METHODS AND RESULTS

One hundred and five clinical aspirates were obtained from patients with suspected PJI. After microbiologic culture, samples were classified as non-septic and septic; of the latter, only those positive for Staphylococcus aureus and Pseudomonas aeruginosa were selected. β-Defensin levels were quantified by ELISA, DNA was extracted from total leukocytes of the samples, and - 20G > A (rs11362) and - 44 C > G (rs1800972) variants were genotyped using TaqMan probes. Forty-one clinical aspirates were non-septic, 18 were positive for S. aureus and 18 were positive for P. aeruginosa. It was observed that β-defensin levels were higher in the P. aeruginosa group compared to S. aureus group (2339.0 pg/mL IQR = 1809.2 vs. 1821.3 pg/mL IQR = 1536.4) and non-septic group (2339.0 pg/mL IQR = 1809.2 vs. 1099.7 pg/mL IQR = 1744.5, P < 0.001). The CG genotype of the rs1800972 variant was associated with higher β-defensin levels compared to the CC genotype for both P. aeruginosa and S. aureus (1905.8 vs. 421.7 pg/mL, P = 0.004; and 1878.2 vs. 256.4 pg/mL, P = 0.006, respectively).

CONCLUSIONS

Our results show that β-defensin levels are significantly elevated in patients with BFM-associated PJI compared to those without infection. Furthermore, carriers of the CG genotype of the rs1800972 variant have an increased risk of PJI. Further research is needed to replicate these findings in a larger population.

How are Oral Antibiotics Being Used in Total Joint Arthroplasty? A Review of the Literature

While the role and benefit of perioperative intravenous (IV) antibiotics in patients undergoing total joint arthroplasty (TJA) is well-established, oral antibiotic use in TJA remains a controversial topic with wide variations in practice patterns. With this review, we aimed to better educate the orthopedic surgeon on when and how oral antibiotics may be used most effectively in TJA patients, and to identify gaps in the literature that could be clarified with targeted research. Extended oral antibiotic prophylaxis (EOAP) use in high-risk primary, aseptic revision, and exchange TJA for infection may be useful in decreasing periprosthetic joint infection (PJI) rates. When prescribing oral antibiotics either as EOAP or for draining wounds, patient factors, type of surgery, and type of infectious organisms should be considered in order to optimally prevent and treat PJI. It is important to maintain antibiotic stewardship by administering the proper duration, dose, and type of antibiotics and by consulting infectious disease when necessary.

Utility of Debridement, Antibiotics, and Implant Retention for Acute Periprosthetic Joint Infection in Revision Total Knee Arthroplasty

Background

Periprosthetic joint infection (PJI) in revision arthroplasty presents as a challenging complication that is difficult to manage. Debridement, antibiotics, and implant retention (DAIR) is a recognized treatment option, although few studies have investigated success rates in addition to eventual amputation rates for failed cases.

Methods

A retrospective review of 365 DAIR cases was performed at a single institution from 2008-2020. Patient records were thoroughly reviewed for inclusion and exclusion criteria by multiple members of the research team, discovering 45 cases met criteria for the study cohort. Demographic information, medical history, culture data, and surgical history, were recorded. DAIR's overall survivorship was evaluated with a Kaplan-Meier (KM) survival curve. Additional KM curves were constructed to compare acute postoperative versus acute hematogenous infections as well as DAIR survivorship relative to infecting organism.

Results

DAIR's success rate in revision TKA was 77% at 0.5 years, 56% at 2 years and 46% at 5 years. No significant difference was noted in survivorship when comparing acute postoperative and acute hematogenous cases at 5 years (29 vs 51%, P=0.64). No significance differences in survivorship were noted according to infecting organism (P =0.30). Median follow up duration was significantly lower in the failed DAIR cohort with a median time of 0.5 years in comparison to 1.7 years for the successful DAIR group (P =0.012). There were 20 DAIR cases that failed, 10 of which resulted in eventual amputation.

Conclusion

DAIR's success rate for managing acute PJI in revision arthroplasty cases was 46% at 5 years. Of the 20 failed DAIR cases, 10 resulted in eventual amputation. DAIRs utility in managing these complicated PJI cases in the setting of revision arthroplasty is concerning with low success rates and high rates of amputation in failed cases. Level of Evidence: III.

Impact of the blood group on postoperative CRP and leukocyte levels after primary total hip and knee arthroplasty

BACKGROUND

C-reactive protein (CRP)- and leukocyte levels are common parameters to evaluate the inflammatory response after orthopaedic surgery and rule out infectious complications. Nevertheless, both parameters are vulnerable to disturbing biases and therefore leave room for interpretation.

OBJECTIVE

Since blood groups are repeatedly discussed to influence inflammatory response, our aim was to observe their impact on CRP and leukocyte levels after total hip and knee arthroplasty (THA/TKA).

METHODS

Short term postoperative CRP and leukocyte levels of 987 patients, who received either primary TKH (n= 479) or THA (n= 508), were retrospectively correlated with their blood group. ABO, Rhesus and a combination of both blood groups were differentiated.

RESULTS

CRP levels after TKA were significantly higher in blood type AB than in type A and O on day 2-4 and also than in type A on day 6-8. Leukocyte levels after THA were significantly higher in blood group type O than in type A on day 6-8 while still remaining in an apathological range. We observed no significant differences between Rhesus types and Rhesus types and CRP or leukocyte levels.

CONCLUSION

We observed significantly increased CRP levels after TKA in patients with blood group AB. Since the elevated CRP levels do not account for early periprosthetic infection, surgeons should include this variation in their postoperative evaluation.

Uncemented trabecular metal high-flex posterior-stabilized monoblock total knee arthroplasty in patients aged 60 years or younger

BACKGROUND

Uncemented trabecular metal (TM) monoblock tibial components in total knee arthroplasty (TKA) have shown excellent clinical results for up to 10 years. However, these studies were performed in highly specialized units, with few surgeons and often excluding knees with secondary osteoarthritis (OA), severe malalignments and previous surgery. The purpose of this study was to investigate implant survivorship and clinical and radiological outcome of the uncemented TM high-flex posterior stabilized (PS) monoblock tibial component in routine clinical practice.

METHODS

A retrospective study of 339 knees (282 patients) operated with the implant in routine clinical practice at two hospitals on patients aged 60 years or younger between 2007 and 2015. The operations were performed by 12 surgeons and there were no specific contraindications for use of the implant. Follow up ended in 2020. The status of the implant of deceased patients at death and those not attending follow up was checked with the Swedish Knee Arthroplasty Register. Clinical follow up consisted of clinical investigation, PROMs, and knee X-ray.

RESULTS

Follow up was mean (range) 8.5 (5-13.8) years, and the 8-year survival rate was 0.98 (standard error 0.007). Five patients five knees) were deceased, five knees were revised (none due to aseptic loosening), and 16 patients did not attend the clinical follow up. Forty-four percent of the knees had secondary OA and 45% had had previous operations. 93% were satisfied or very satisfied with the operation and forgotten joint score (FJS) was median (interquartile range) 81 (44-94). Radiographic analysis revealed bone in close contact with the tibial tray and pegs in most cases, and in only 2% of the knees were potential radiolucent lines found.

CONCLUSION

The results indicate that this uncemented implant performs excellently in routine clinical practice and also in younger patients with secondary OA or previous knee operations.

The Use of Artificial Intelligence for the Prediction of Periprosthetic Joint Infection Following Aseptic Revision Total Knee Arthroplasty

Periprosthetic joint infection (PJI) following revision total knee arthroplasty (TKA) for aseptic failure is associated with poor outcomes, patient morbidity, and high health care expenditures. The aim of this study was to develop novel machine learning algorithms for the prediction of PJI following revision TKA for patients with aseptic indications for revision surgery. A single-institution database consisting of 1,432 consecutive revision TKA patients with aseptic etiologies was retrospectively identified. The patient cohort included 208 patients (14.5%) who underwent re-revision surgery for PJI. Three machine learning algorithms (artificial neural networks, support vector machines, k-nearest neighbors) were developed to predict this outcome and these models were assessed by discrimination, calibration, and decision curve analysis. This is a retrospective study. Among the three machine learning models, the neural network model achieved the best performance across discrimination (area under the receiver operating characteristic curve = 0.78), calibration, and decision curve analysis. The strongest predictors for PJI following revision TKA for aseptic reasons were prior open procedure prior to revision surgery, drug abuse, obesity, and diabetes. This study utilized machine learning as a tool for the prediction of PJI following revision TKA for aseptic failure with excellent performance. The validated machine learning models can aid surgeons in patient-specific risk stratifying to assist in preoperative counseling and clinical decision making for patients undergoing aseptic revision TKA.

Distal Femoral Osteotomy for the Management of Coronal Deformity Following Total Knee Arthroplasty: A Report of 2 Cases

CASE

We present 2 cases demonstrating the management of coronal malalignment with an existing total knee arthroplasty using opening wedge distal femur osteotomy. The mechanical axis was corrected, and the primary total knee implants were maintained. Patients resumed full activity 3 to 4 months after surgery.

CONCLUSION

In certain cases, opening wedge distal femoral osteotomy is an option to correct coronal malalignment with an existing total knee arthroplasty without revising the implant.

History of Diabetic Foot Ulcer is Associated With Increased Risk of Prosthetic Joint Infection and Sepsis After Total Joint Arthroplasty

BACKGROUND

Diabetic foot ulcers (DFUs) are common sequelae of diabetes mellitus. Currently, the effect of DFUs on total joint arthroplasty (TJA) outcomes is sparsely evaluated. This study investigated whether DFU patients undergoing TJA increases risk of (1) prosthetic joint infections (PJI), (2) surgical site infections (SSI), (3) sepsis, (4) readmissions, and (5) revisions.

METHODS

Using PearlDiver, a retrospective query from January 1, 2010 to October 31, 2020 was performed. DFU patients undergoing total knee arthroplasty (TKA) and total hip arthroplasty (THA) were included and 1:5 propensity score matched with controls using age, sex, body mass index, and various comorbidities (33,155 TKA patients [DFU = 5,529; control = 27,626]; 17,146 THA patients [DFU = 2,862; control = 14,284]). Outcomes included rates of PJI, SSI, sepsis, readmissions, and revisions. Multivariate logistical regressions calculated odds ratios (ORs), 95% confidence intervals, and P values (P < .001 as significance threshold).

RESULTS

DFU increased risk of sepsis within 90 days of TKA (OR 4.59; P < .001) and THA (OR 4.87; P < .001). DFU did not increase risk of PJI at 90 days for TKA (OR 0.8; P = .1) or THA (OR 0.85; P = .34) but did by 2 years post-TKA (OR 1.51; P < .001) and THA (OR 1.55; P < .001). Risk of SSI increased in DFU cohort following TKA and THA at 90 days and 2 years and at 90-day readmissions and 2-year revisions.

CONCLUSION

DFU patients undergoing TJA demonstrated increased risk of postoperative sepsis and PJI. Furthermore, DFU patients demonstrated an increased risk of SSI, readmissions, and revisions. Providers should counsel DFU patients about postoperative risks.

Combined Edge Loss UNet for Optimized Segmentation in Total Knee Arthroplasty Preoperative Planning

Bone segmentation and 3D reconstruction are crucial for total knee arthroplasty (TKA) surgical planning with Personalized Surgical Instruments (PSIs). Traditional semi-automatic approaches are time-consuming and operator-dependent, although they provide reliable outcomes. Moreover, the recent expansion of artificial intelligence (AI) tools towards various medical domains is transforming modern healthcare. Accordingly, this study introduces an automated AI-based pipeline to replace the current operator-based tibia and femur 3D reconstruction procedure enhancing TKA preoperative planning. Leveraging an 822 CT image dataset, a novel patch-based method and an improved segmentation label generation algorithm were coupled to a Combined Edge Loss UNet (CEL-UNet), a novel CNN architecture featuring an additional decoding branch to boost the bone boundary segmentation. Root Mean Squared Errors and Hausdorff distances compared the predicted surfaces to the reference bones showing median and interquartile values of 0.26 (0.19-0.36) mm and 0.24 (0.18-0.32) mm, and of 1.06 (0.73-2.15) mm and 1.43 (0.82-2.86) mm for the tibia and femur, respectively, outperforming previous results of our group, state-of-the-art, and UNet models. A feasibility analysis for a PSI-based surgical plan revealed sub-millimetric distance errors and sub-angular alignment uncertainties in the PSI contact areas and the two cutting planes. Finally, operational environment testing underscored the pipeline's efficiency. More than half of the processed cases complied with the PSI prototyping requirements, reducing the overall time from 35 min to 13.1 s, while the remaining ones underwent a manual refinement step to achieve such PSI requirements, performing the procedure four to eleven times faster than the manufacturer standards. To conclude, this research advocates the need for real-world applicability and optimization of AI solutions in orthopedic surgical practice.

Preventative and therapeutic potential of tocotrienols on musculoskeletal diseases in ageing

Musculoskeletal health is paramount in an ageing population susceptible to conditions such as osteoporosis, arthritis and fractures. Age-related changes in bone, muscle, and joint function result in declining musculoskeletal health, reduced mobility, increased risk of falls, and persistent discomfort. Preserving musculoskeletal wellbeing is essential for maintaining independence and enhancing the overall quality of life for the elderly. The global burden of musculoskeletal disorders is significant, impacting 1.71 billion individuals worldwide, with age-related muscle atrophy being a well-established phenomenon. Tocotrienols, a unique type of vitamin E found in various sources, demonstrate exceptional antioxidant capabilities compared to tocopherols. This characteristic positions them as promising candidates for addressing musculoskeletal challenges, particularly in mitigating inflammation and oxidative stress underlying musculoskeletal disorders. This review paper comprehensively examines existing research into the preventive and therapeutic potential of tocotrienols in addressing age-related musculoskeletal issues. It sheds light on the promising role of tocotrienols in enhancing musculoskeletal health and overall wellbeing, emphasizing their significance within the broader context of age-related health concerns.

Patient "No-Show" Increases the Risk of 90-Day Complications Following Primary Total Knee Arthroplasty: A Retrospective Cohort Study of 6,776 Patients

BACKGROUND

Patients who "no-show" (NS) clinical appointments are at a high risk of adverse health outcomes. The objective of this study was to evaluate and characterize the relationship between NS visits prior to primary total knee arthroplasty (TKA) and 90-day complications after TKA.

METHODS

We retrospectively reviewed 6,776 consecutive patients undergoing primary TKA. Study groups were separated based on whether patients who NS versus always attended their appointment. A NS was defined as an intended appointment that was not canceled or rescheduled ≤2 hours before the appointment in which the patient did not show. Data collected included total number of follow-up appointments prior to surgery, patient demographics, comorbidities, and 90-day postoperative complications.

RESULTS

Patients who have ≥3 NS appointments had 1.5 times increased odds of a surgical site infection (odds ratio (OR) 1.54, P = .002) compared to always attended patients. Patients who were ≤65 years old (OR: 1.41, P < .001), smokers (OR: 2.01, P < .001), and had a Charlson comorbidity index ≥3 (OR: 4.48, P < .001) were more likely to miss clinical appointments.

CONCLUSION

Patients who have ≥3 NS appointments prior to TKA had an increased risk for surgical site infection. Sociodemographic factors were associated with higher odds of missing a scheduled clinical appointment. These data suggest that orthopaedic surgeons should consider NS data as an important clinical decision-making tool to assess risk for postoperative complications to minimize complications following TKA.

Empiric antibiotic treatment for periprosthetic joint infections: a national survey in The Netherlands

Early periprosthetic joint infection (PJI) is generally treated by means of debridement, antibiotics and implant retention (DAIR). Subsequently, empiric antibiotic therapy is commenced directly after surgery which is important for the successful treatment of PJI. The aim of this study is to evaluate current nationwide empiric antibiotic treatment regimens for PJI in the Netherlands. An electronic 15-question survey addressing the empiric antibiotic treatment strategy for PJI following THA or TKA was sent to orthopaedic surgeons in all Dutch hospitals in April 2019. Orthopaedic surgeons active in every single Dutch orthopaedic hospital (n=69) were approached. At least one surgeon in every hospital completed the survey (100% response rate). A protocol dictating the empiric antibiotic treatment following DAIR was used in 87% (60 hospitals). Among all hospitals, 72% (50 hospitals) used antibiotic monotherapy and 28% (19 hospitals) used combination therapy. Cefazolin was the most commonly used regimen in centres opting for monotherapy (42%, 29 hospitals). Similar regimens were used for the empiric treatment of suspected early PJI after revision surgery and for acute hematogenous PJI. In septic patients, combination therapy was preferred (64%). 81% (56 hospitals) incubated tissue biopsies for a minimum of 10 days whereas 16% (9 hospitals) indicated an incubation period of 7 days or less. Even in a small country such as the Netherlands there seems to be no uniformity regarding empiric antibiotic treatment for PJI. Increased uniformity regarding empiric treatment could be an important first step in improving PJI treatment.

Association of Acute Kidney Injury With Antibiotic Loaded Cement Used for Treatment of Periprosthetic Joint Infection

BACKGROUND

Antibiotic-loaded bone cement (ALBC) is commonly used in the treatment of periprosthetic joint infections (PJIs) to increase the local concentration of antibiotic at the site of infection. Use of ALBC has been associated with rare instances of acute kidney injury (AKI) despite low systemic absorption of the nephrotoxic antibiotics; however, the incidence of AKI is unknown. The purpose of this study was to determine the incidence of and risk factors for AKI associated with ALBC.

METHODS

This single-site, retrospective cohort study compared 162 PJI patients who underwent Stage 1 revision to a spacer with ALBC to 115 PJI patients who underwent debridement, antibiotics, and implant retention (DAIR) without the use of ALBC. Both groups received similar systemic antibiotics postoperatively. Descriptive statistics and multivariable logistic regressions were used to analyze risk factors for AKI.

RESULTS

There was no statistically significant difference in the rate of AKI: 29 patients (17.9%) in the ALBC group and 17 (14.7%) in DAIR group developed AKI (odds ratio 1.43; 95% CI 0.70 to 2.93). There was a trend toward increased severity of AKI in the ALBC group. Chronic kidney disease, systemic vancomycin, and diuretic use were independent factors associated with the risk of AKI.

CONCLUSION

An AKI occurred in 17% of PJI patients receiving either a spacer with ALBC or a DAIR. The use of ALBC was not associated with a significant increased risk of AKI. However, the use of systemic vancomycin and diuretic use were independent predictors of AKI in this patient population.

Sequential repeated tibial tubercle osteotomy in a two-stage exchange strategy: a superior approach to treating a chronically infected knee arthroplasty?

PURPOSE

Surgical approach can impact the reliability of the debridement after a chronic total knee periprosthetic joint infection (PJI), a factor of utmost importance to eradicate the infection. The most adequate knee surgical approach in cases of PJI is a matter of debate. The purpose of this study was to determine the influence of performing a tibial tubercle osteotomy (TTO) in a two-stage exchange protocol for knee PJI treatment.

METHODS

Retrospective cohort study examining patients managed with two-stage arthroplasty due to chronic knee PJI (2010-2019). Performance and timing of the TTO were collected. Primary end-point was infection control with a minimum FU of 12 months and according to internationally accepted criteria. Correlation between TTO timing and reinfection rate was reviewed.

RESULTS

Fifty-two cases were finally included. Overall success (average follow-up: 46.2 months) was 90.4%. Treatment success was significantly higher among cases addressed using TTO during the second stage (97.1% vs. 76.5%, p value 0.03). Only 4.8% of the patients relapsed after performing a sequential repeated TTO, that is, during both first and second stages, compared to 23.1% cases in which TTO was not done (p value 0.28). No complications were observed among patients in the TTO group with a significant decrease in soft tissue necrosis (p: 0.052).

CONCLUSION

Sequential repeated tibial tubercle osteotomy during a two-stage strategy is a reasonable option and offers high rates of infection control in complex cases of knee PJI with a low rate of complications.

Next-generation Sequencing Results Require Higher Inoculum for Cutibacterium acnes Detection Than Conventional Anaerobic Culture

BACKGROUND

Cutibacterium acnes has been described as the most common causative microorganism in prosthetic shoulder infections. Conventional anaerobic culture or molecular-based technologies are usually used for this purpose, but little to no concordance between these methodologies (k = 0.333 or less) has been observed.

QUESTIONS/PURPOSES

(1) Is the minimum C. acnes load for detection higher for next-generation sequencing (NGS) than for anaerobic conventional culture? (2) What duration of incubation is necessary for anaerobic culture to detect all C. acnes loads?

METHODS

Five C. acnes strains were tested for this study: Four strains were causing infection and were isolated from surgical samples. Meanwhile, the other was a reference strain commonly used as a positive and quality control in microbiology and bioinformatics. To create inoculums with varying degrees of bacterial load, we began with a standard bacterial suspension at 1.5 x 10 8 colony-forming units (CFU)/mL and created six more diluted suspensions (from 1.5 x 10 6 CFU/mL to 1.5 x 10 1 CFU/mL). Briefly, to do so, we transferred 200 µL from the tube with the highest inoculum (for example, 1.5 x 10 6 CFU/mL) to the following dilution tube (1.5 x 10 5 CFU/mL; 1800 µL of diluent + 200 µL of 1.5 x 10 6 CFU/mL). We serially continued the transfers to create all diluted suspensions. Six tubes were prepared per strain. Thirty bacterial suspensions were tested per assay. Then, 100 µL of each diluted suspension was inoculated into brain heart infusion agar with horse blood and taurocholate agar plates. Two plates were used per bacterial suspension in each assay. All plates were incubated at 37°C in an anaerobic chamber and assessed for growth after 3 days of incubation and daily thereafter until positive or Day 14. The remaining volume of each bacterial suspension was sent for NGS analysis to identify bacterial DNA copies. We performed the experimental assays in duplicate. We calculated mean DNA copies and CFUs for each strain, bacterial load, and incubation timepoint assessed. We reported detection by NGS and culture as a qualitative variable based on the identification or absence of DNA copies and CFUs, respectively. In this way, we identified the minimum bacterial load detected by NGS and culture, regardless of incubation time. We performed a qualitative comparison of detection rates between methodologies. Simultaneously, we tracked C. acnes growth on agar plates and determined the minimum incubation time in days required for CFU detection in all strains and loads examined in this study. Growth detection and bacterial CFU counting were performed by three laboratory personnel, with a high intraobserver and interobserver agreement (κ > 0.80). A two-tailed p value below 0.05 was considered statistically significant.

RESULTS

Conventional cultures can detect C. acnes at a load of 1.5 x 10 1 CFU/mL, whereas NGS can detect bacteria when the concentration was higher, at 1.5 x 10 2 CFU/mL. This is represented by a lower positive detection proportion (73% [22 of 30]) for NGS than for cultures (100% [30 of 30]); p = 0.004). By 7 days, anaerobic cultures were able to detect all C. acnes loads, even at the lowest concentrations.

CONCLUSION

When NGS is negative and culture is positive for C. acnes , there is likely a low bacterial load. Holding cultures beyond 7 days is likely unnecessary.

CLINICAL RELEVANCE

This is important for treating physicians to decide whether low bacterial loads necessitate aggressive antibiotic treatment or whether they are more likely contaminants. Cultures that are positive beyond 7 days likely represent contamination or bacterial loads even below the dilution used in this study. Physicians may benefit from studies designed to clarify the clinical importance of the low bacteria loads used in this study at which both methodologies' detection differed. Moreover, researchers might explore whether even lower C. acnes loads have a role in true periprosthetic joint infection.

Zucker Diabetic-Sprague Dawley Rats Have Impaired Peri-Implant Bone Formation, Matrix Composition, and Implant Fixation Strength

An increasing number of patients with type 2 diabetes (T2DM) will require total joint replacement (TJR) in the next decade. T2DM patients are at increased risk for TJR failure, but the mechanisms are not well understood. The current study used the Zucker Diabetic-Sprague Dawley (ZDSD) rat model of T2DM with Sprague Dawley (SPD) controls to investigate the effects of intramedullary implant placement on osseointegration, peri-implant bone structure and matrix composition, and fixation strength at 2 and 10 weeks post-implant placement. Postoperative inflammation was assessed with circulating MCP-1 and IL-10 2 days post-implant placement. In addition to comparing the two groups, stepwise linear regression modeling was performed to determine the relative contribution of glucose, cytokines, bone formation, bone structure, and bone matrix composition on osseointegration and implant fixation strength. ZDSD rats had decreased peri-implant bone formation and reduced trabecular bone volume per total volume compared with SPD controls. The osseointegrated bone matrix of ZDSD rats had decreased mineral-to-matrix and increased crystallinity compared with SPD controls. Osseointegrated bone volume per total volume was not different between the groups, whereas implant fixation was significantly decreased in ZDSD at 2 weeks but not at 10 weeks. A combination of trabecular mineral apposition rate and postoperative MCP-1 levels explained 55.6% of the variance in osseointegration, whereas cortical thickness, osseointegration mineral apposition rate, and matrix compositional parameters explained 69.2% of the variance in implant fixation strength. The results support the growing recognition that both peri-implant structure and matrix composition affect implant fixation and suggest that postoperative inflammation may contribute to poor outcomes after TJR surgeries in T2DM patients. © 2023 The Authors. JBMR Plus published by Wiley Periodicals LLC on behalf of American Society for Bone and Mineral Research.

Increased Risk of In-Hospital Complications and Costs After Total Hip Arthroplasty for Primary and Secondary Osteonecrosis

BACKGROUND

An increasing proportion of patients are undergoing total hip arthroplasty (THA) for osteonecrosis (ON). Comorbid conditions and surgical risk factors are known to be greater in ON patients compared with patients who have osteoarthritis (OA) alone. The purpose of our study was to quantify the specific in-hospital complications and resource utilization associated with patients undergoing THA for ON versus OA.

METHODS

A large national database was queried to identify patients undergoing primary THA from January 1, 2016 to December 31, 2019. A total of 1,383,880 OA, 21,080 primary ON, and 54,335 secondary ON patients were identified. Demographics, in-hospital complications, costs, lengths of stay, and discharge dispositions for primary and secondary ON cohorts were compared to OA only. Age, race, ethnicity, comorbidities, Medicaid, and income status were controlled with binary logistic regression analyses.

RESULTS

The ON patients were often younger, African American or Hispanic, and had more comorbidities. Those undergoing THA for primary and secondary ON had a significantly higher risk of perioperative complications, including myocardial infarction, postoperative blood transfusion, and intraoperative bleeding. Total hospital costs and lengths of stay were significantly higher for both primary ON and secondary ON and both cohorts were less likely to be discharged home.

CONCLUSION

While rates of most complications have decreased over recent decades in ON patients undergoing THA, the ON patients still have worse outcomes even when controlling for comorbidity differences. Bundled payment systems and perioperative management strategies for these different patient cohorts should be considered separately.

Robotic-assisted mechanically aligned total knee arthroplasty does not lead to better clinical and radiological outcomes when compared to conventional TKA: a systematic review and meta-analysis of randomized controlled trials

PURPOSE

Robotic-assisted total knee arthroplasty (R-TKA) has emerged as an alternative to improve the results of the conventional manual TKA (C-TKA). The aim of this study was to analyse the high-level studies comparing R-TKA and C-TKA in terms of clinical outcomes, radiological results, perioperative parameters, and complications.

METHODS

The literature search was conducted on three databases (PubMed, Cochrane, and Web of Science) on 1 February 2023 according to the guidelines for Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA). Inclusion criteria were: randomized controlled trials (RCTs), written in English language, published in the last 15 years, focusing on the comparison of C-TKA and R-TKA results. The quality of each article was assessed using the Cochrane risk-of-bias tool for randomized trials version 2 (RoB 2). The statistical analysis was carried out using random effects (DerSimonian & Laird) for weighted mean difference (MD) of the continuous variables and Peto method for odds ratios of the dichotomous variables.

RESULTS

Among the 2905 articles retrieved, 14 RCTs on 12 series of patients treated with mechanically aligned implants were included. A total of 2255 patients (25.1% males and 74.9% females; mean age 62.9 ± 3.0; mean BMI 28.1 ± 1.3) were analysed. The results of this systematic review and meta-analysis showed that R-TKA did not provide overall superior results compared to C-TKA in mechanically aligned implants in terms of clinical and radiological outcomes. R-TKA showed longer operative time (MD = 15.3 min, p = 0.004) and similar complication rates compared to C-TKA. A statistically significant difference in favour of R-TKA was found in the posterior-stabilized subgroup in terms of radiological outcomes (hip-knee-ankle angle MD = 1.7, p < 0.001) compared to C-TKA, although without resulting in appreciable difference of clinical outcomes.

CONCLUSION

R-TKA did not provide overall superior results compared to C-TKA in terms of clinical and radiological outcomes, showing longer operative time and similar complication rates.

LEVEL OF EVIDENCE

Level I.

Rank-Ordered List of Cost-effective Strategies for Preventing Prosthetic Joint Infection in Total Joint Arthroplasty in an Academic US Hospital

Although the overall rate of prosthetic joint infection (PJI) is low, it remains a major complication associated with total joint arthroplasty (TJA). PJI represents a significant economic burden to the health care system that is projected to increase commensurate with increasing joint replacement volumes. This review provides a rank-ordered list of cost-effective strategies that are performable intraoperatively and have data supporting their efficacy at preventing PJI after TJA. This study may be helpful in assisting surgeons, ambulatory surgery center owners, and hospital acquisition committees to make reasonable and cost-conscious decisions in the face of changing reimbursement. [Orthopedics. 2023;46(6):327-332.].

"Single-use peripheral" vs "conventional" reaming in total hip arthroplasty: how to respect native centre of rotation and acetabular offset? A CT study

PURPOSE

The respect of native hip offset represents a mainstay for satisfying results in total hip arthroplasty (THA). Historically, a great interest has been focused on restoration of femoral offset, while only in recent years, acetabular offset (AO) has been considered. The purpose of the current study was to compare the "single-use peripheral" reaming technique with the "conventional" one for the maintenance of the native COR of the hip and AO in patients undergoing to primary THA.

METHODS

Eighty patients affected from primary hip osteoarthritis were prospectively enrolled in the study and were divided in two groups (Group A "single-use peripheral" and Group B "conventional" reaming technique). Pre- and post-operatively, AO, acetabular floor distance (AFd) and acetabular version (AV) were assessed through a CT scan. A comparison between groups for the radiological parameters, surgical time and complications was performed.

RESULTS

The demographic data were similar in both groups. The complications rate and the AV did not differ statistically between groups. Group A presented a statistically significant shorter surgical time and lower variation between pre- and post-operative AO and AFd. Statistical significance was defined as p < 0.05.

CONCLUSIONS

The "single-use peripheral" reaming technique demonstrated to be more reliable in reproducing the native COR and AO of patients undergoing to primary THA than the "conventional" one. The operative time was significantly reduced, and it may lead to a reduction in the infection risk even though it was not observed in the current study. Further research could be useful to validate such findings and to assess clinical impact and long-term survival of the implant.

Fabrication and Characterization of a Multifunctional Coating to Promote the Osteogenic Properties of Orthopedic Implants

Titanium-based alloys are used in orthopedic applications as fixation elements, hard tissue replacements in artificial bones, and dental implants. Despite their wide range of applications, metallic implant defects and failures arise due to inadequate mechanical bonding, postoperative clotting problems, aseptic loosening, and infections. To improve the surface bioactivity and reduce the corrosion rate of the Ti6Al4V alloy, multi-layered coatings (HAp, BG, Cs, and Hep) were applied via electrophoretic deposition (EPD). XRD images showed the presence of HAp within the coating. In vitro investigation: cell line NIH-3T3 fibroblasts were seeded on the non-coated and coated Ti6Al4V substrates, and their cellular behavior was evaluated. The results indicated that the HApBGCsHep coating could enhance the adhesion and proliferation of NIH 3T3 cells. In addition, the potentiodynamic polarization results are compatible with the in vitro outcome.

Local Administration of Antibiotics in Orthopedics and Traumatology

2022 marks the 50th anniversary of the development of the antibiotic loaded PMMA chain. The loading of bone cements with antibiotics was a major advance in the treatment of musculoskeletal infections and is still a proven standard today. The research and use of novel antibiotic carriers continues to be an important part of research in the context of musculoskeletal infections. The article provides an overview of the various local antibiotics available and their specifics. In addition, current adapted treatment concepts are discussed.