Functional and radiological outcomes of total knee arthroplasty using posterior-stabilized U2 knee system: A retrospective study in 560 cases at five years of follow-up.

PURPOSE: The purpose of this study was to assess clinical and functional outcomes as well as the prosthesis survival rates of the U2 Knee system in primary total knee arthroplasty (TKA) with a minimum follow-up of four years. METHODS: We retrospectively analyzed 560 consecutively primary TKA performed between 2015 and 2019 due to osteoarthritis with a mean follow-up of 5.4 ± 1.1 years. The clinical outcomes were assessed using the knee society score (KSS) and the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC). Radiographic outcomes were assessed using the American knee society's roentgenographic evaluation system. Prosthetic survival was calculated using the Kaplan-Meier method. RESULTS: Postoperative KSS showed significant improvement at one year (Clinical: 37.4 ± 4.1 vs. 91.9 ± 3.7; p < 0.01; Functional: 41.2 ± 3.3 vs. 90.6 ± 4.8; p = < 0.01), with these improvements maintained throughout the follow-up period. The WOMAC score improved from 60 ± 10.1 preoperatively to 10.9 ± 8.3 (p = 0.02) at the end of the follow-up. There were 20 (3.7%) knees with radiolucent lines around the implant (< 2 mm), and none showed evidence of loosening. There were six (1.1%) revisions-four due to prosthetic joint infections and two due to periprosthetic femur fracture. The prosthetic survival was 97.8% at the study closure. CONCLUSION: The U2 knee system demonstrates effective and safe performance for primary TKA with significant improvements in functional scores, patient-reported outcomes, and a promising prosthesis survival rate at mid-term follow-up. We will continue with the series analysis to assess the long-term outcomes.

[Intraosseous vancomycin in total knee arthroplasty]. / Vancomicina intraósea en artroplastía total de rodilla.

INTRODUCTION: intravenous antibiotic prophylaxis has significantly reduced the incidence of periprosthetic joint infection (PJI) in knee surgeries. However, for patients colonized with methicillin-resistant Staphylococcus aureus (MRSA) or those at risk of colonization, prophylaxis should include vancomycin. Intraosseous (IO) administration of vancomycin could enhance its effectiveness in total knee arthroplasty (TKA). MATERIAL AND METHODS: a retrospective review was conducted, including 143 patients at risk of PJI scheduled for TKA who received IO vancomycin along with intravenous (IV) cefazolin, referred to as group I (GI), between May 2021 and December 2022. The occurrence of complications in the first three postoperative months was evaluated. Results were compared with 140 patients without risk factors who received standard IV prophylaxis, designated as group II (GII). RESULTS: in GI, 500 mg of IO vancomycin was administered, injected into the proximal tibia, in addition to standard IV prophylaxis. In GII, patients received only IV cefazolin. The incidence of complications was 1.64% in GI and 1.4% in GII. The PJI rate at 90 postoperative days was 0.69% in GI and 0.71% in GII. CONCLUSIONS: IO vancomycin administration, along with standard IV prophylaxis, provides a safe and effective alternative for patients at risk of MRSA colonization. This approach minimizes complications associated with IV vancomycin use and addresses logistical challenges of timely administration.

INTRODUCCIÓN: la profilaxis antibiótica intravenosa ha reducido significativamente la incidencia de infección articular periprotésica (IAP) en cirugías de rodilla. No obstante, para pacientes colonizados con Staphylococcus aureus resistente a meticilina (SARM) o aquellos con riesgo de colonización, la profilaxis debe incluir vancomicina. La administración intraósea de vancomicina podría potenciar su efectividad en la artroplastía total de rodilla. MATERIAL Y MÉTODOS: se realizó una revisión retrospectiva que incluyó a 143 pacientes en riesgo de IAP programados para artroplastía total de rodilla que recibieron vancomicina intraósea junto a cefazolina intravenosa (IV), a quienes denominamos grupo I (GI), entre mayo de 2021 y diciembre de 2022. Se evaluó la aparición de complicaciones en los primeros tres meses postoperatorios. Los resultados se compararon con 140 pacientes sin factores de riesgo que recibieron profilaxis intravenosa estándar, denominados grupo II (GII). RESULTADOS: en el GI, se administraron 500 mg de vancomicina intraósea, inyectados en la tibia proximal, además de la profilaxis intravenosa estándar. En el GII, los pacientes recibieron sólo cefazolina intravenosa. La incidencia de complicaciones fue de 1.64% en el GI y de 1.4% en el GII. La tasa de IAP a los 90 días postoperatorios fue de 0.69% en el GI y de 0.71% en el GII. CONCLUSIONES: la administración de vancomicina intraósea, junto con la profilaxis intravenosa estándar, ofrece una alternativa segura y eficaz para pacientes con riesgo de colonización por SARM. Este enfoque minimiza las complicaciones asociadas con el uso intravenoso de vancomicina y soluciona los desafíos logísticos de la administración oportuna.

Synovial fluid NMR-based metabolomics in septic and aseptic revision total knee arthroplasty: Implications on diagnosis and treatment.

Periprosthetic joint infection (PJI) is one of the most challenging complications following total knee arthroplasty. Despite its importance, there is a paucity of reports in the literature regarding its pathogenesis. Recently, cellular metabolic reprogramming has been shown to play an important role in the progression and outcome of infectious diseases. Therefore, the aim of this study was to evaluate the metabolites composition of the synovial fluid from patients with PJI or aseptic failure of total knee arthroplasties. The synovial fluids from 21 patients scheduled for revision total knee arthroplasty (11 with the diagnosis of PJI and 10 with aseptic failures) were analyzed using 1D 1H NMR spectroscopy. Univariate and multivariate statistical analyzes were used to identify metabolites that were differentially abundant between those groups. A total of 28 metabolites were identified and five of them found to be differentially abundant between infected and non-infected synovial fluids. Lactate, acetate and 3-hydroxybutyrate were found to be in a higher concentration, and glucose and creatine were found reduced in the synovial fluid from PJI patients. Synovial fluid from patients with PJI exhibit a distinct metabolic profile, possibly reflecting metabolic adaptation that occurs in the infected periprosthetic microenvironment. Further research and studies are warranted to gain a broader insight into the metabolic pathways engaged by both pathogen and immune cells in the context of a PJI.

Prognostic value of perioperative high sensitivity troponin in patients undergoing hip and knee arthroplasty.

The authors conducted a prospective observational study to investigate the prognostic value of high-sensitivity Troponin I (hs-TnI) in the short- and long-term periods after orthopedic surgery, including Total Hip and Knee Arthroplasty (THA and TKA, respectively), in a tertiary orthopedic center in Brazil. Perioperative Myocardial Injury (PMI) was defined as an absolute increase in hs-TnI of ≥ 26 ng/L above preoperative values. The primary endpoint was all-cause mortality assessed at 30 days and 18 months after surgery. The secondary endpoint consisted of a composite outcome: cardiovascular death, acute myocardial infarction, angina requiring revascularization, and/or stroke. The authors compared Relative Risks (RR) of all-cause mortality and composite outcomes in patients with or without PMI at 30 days and 18 months. A Cox proportional hazards model for long-term outcomes was calculated and adjusted for age > 70 years, gender, and Revised Cardiac Risk Index (RCRI) class ≥ 2. PMI occurred in 3.4 % of all surgeries. At 30-days, 6.6 % of patients with PMI had died versus none without PMI. At 18 months, 20.0 % of PMI versus 4.7 % without PMI had died (RR = 5.0; 95 % Confidence Interval [95 % CI 1.3-19.3]). Based on composite outcomes in short and long-term periods, the RRs were 16.2 (95 % CI 2.7-96.5) and 7.7 (95 % CI 2.2-26.6), respectively. PMI was associated with all-cause mortality after 18 months and increased risk for a composite outcome (Hazard Ratio [HR = 3.97], 95 % CI 1.13-13.89 and HR = 5.80, 95 % CI 1.93-17.45, respectively). Patients with PMI who underwent THA or TKA presented worse short- and long-term prognoses compared to those without PMI.

Development of a Machine-Learning Model for Anterior Knee Pain After Total Knee Arthroplasty With Patellar Preservation Using Radiological Variables.

BACKGROUND: Anterior knee pain (AKP) following total knee arthroplasty (TKA) with patellar preservation is a common complication that significantly affects patients' quality of life. This study aimed to develop a machine-learning model to predict the likelihood of developing AKP after TKA using radiological variables. METHODS: A cohort of 131 anterior stabilized TKA cases (105 patients) without patellar resurfacing was included. Patients underwent a follow-up evaluation with a minimum 1-year follow-up. The primary outcome was AKP, and radiological measurements were used as predictor variables. There were 2 observers who made the radiological measurement, which included lower limb dysmetria, joint space, and coronal, sagittal, and axial alignment. Machine-learning models were applied to predict AKP. The best-performing model was selected based on accuracy, precision, sensitivity, specificity, and Kappa statistics. Python 3.11 with Pandas and PyCaret libraries were used for analysis. RESULTS: A total of 35 TKA had AKP (26.7%). Patient-reported outcomes were significantly better in the patients who did not have AKP. The Gradient Boosting Classifier performed best for both observers, achieving an area under the curve of 0.9261 and 0.9164, respectively. The mechanical tibial slope was the most important variable for predicting AKP. The Shapley test indicated that high/low mechanical tibial slope, a shorter operated leg, a valgus coronal alignment, and excessive patellar tilt increased AKP risk. CONCLUSIONS: The results suggest that global alignment, including sagittal, coronal, and axial alignment, is relevant in predicting AKP after TKA. These findings provide valuable insights for optimizing TKA outcomes and reducing the incidence of AKP.

Incidence of vascular injury associated with knee arthroplasty: series of cases.

INTRODUCTION: The incidence of vascular injury associated with knee arthroplasty is scarce, but, when they occur, the consequences are serious. OBJECTIVES: Describe the incidence of vascular lesions in our center and evaluate time to diagnosis, resolution and follow-up. MATERIALS AND METHODS: Retrospective cohort during the 2010-2019 period of primary arthroplasties and knee revision. The incidence of vascular lesions and their demographic characteristics were analyzed. Type of lesion, diagnostic method and treatment were recorded. It was evaluated in distant follow-up of pain and functionality. RESULTS: 7.940 primary total knee arthroplasty and revision surgeries were recorded, and a report of 7 emergency cases for vascular lesions was also recorded, with an incidence of 0.088%. 3 vascular lesions were caused by direct laceration of the popliteal artery, 1 case of thrombosis of the popliteal artery and 3 cases of pseudoaneurysmal lesion of the superior genicular artery. Three vascular lesions that occurred in primary arthroplasty were immediately repaired by a vascular surgeon. Pseudoaneurysm lesions and thrombosis were resolved by angiographic procedure. DISCUSSION: Vascular complications around the knee are rare. Time to diagnosis and treatment is essential. Digital angiography is a diagnostic and therapeutic tool. There are various repair techniques, whether it's embolization, cauterization, stenting or endoprosthesis; therefore, digital angiography is a safe method with a low complication rate. CONCLUSION: The incidence of vascular lesions in knee arthroplasty in our center is very low. The cases were diagnosed and resolved early, without registering subsequent complications with good functional results in distant follow-up.

Effects of amino acid supplementation on muscle mass, muscle performance and functional capacity in subjects undergoing total knee arthroplasty: a systematic review of randomized clinical trials.

The aim of the present study was to summarize the effectiveness of amino acid supplementation on muscle strength, muscle volume, and functional capacity in patients undergoing total knee arthroplasty. For this, in November 2022, a search was carried out in the PubMed, Cochrane Library, and EMBASE databases, identifying a total of 2182 documents, of which only 4 were included in the present review. The included studies had 148 participants (47 men and 101 women), with a minimum age of 53 and a maximum of 92 years, and supplementation times of 13 to 30 days (1 to 3 times a day). For the results, in relation to muscle performance, when comparing the control and experimental groups, greater muscle atrophy was observed in the pre- and post-moments of the control group, in relation to the experimental group. In addition, studies suggest a good tendency for muscle mass gain, and improvement in the functional capacities of patients who used supplementation. Therefore, the use of amino acids after TKA surgery reduces muscle atrophy, which preserves muscle mass and leads to better performance in tests of strength and functional capacity, when compared to the use of a placebo.

Neutrophil Extracellular Trap-related Biomarkers Are Increased in the Synovial Fluid of Patients With Periprosthetic Joint Infections.

BACKGROUND: The diagnosis of periprosthetic joint infection (PJI) is a major challenge in clinical practice. The role of neutrophils in fighting infection has been increasingly understood, and one mechanism of action of these cells is neutrophil extracellular traps. However, little is known about this process in PJI. QUESTIONS/PURPOSES: (1) Are the biomarkers of neutrophil extracellular trap formation (citrullinated histone H3 [H3Cit], cell-free DNA [cf-DNA], and myeloperoxidase [MPO]) increased in the synovial fluid of patients with PJI? (2) What is the diagnostic accuracy of biomarkers of neutrophil extracellular trap formation for PJI? METHODS: Between May 2020 and March 2021, 43 patients who underwent revision THA or TKA were enrolled in this study. Eleven patients were excluded and 32 patients were categorized into the PJI group (n = 16) or non-PJI group (n = 16) according to the 2018 Second International Consensus Meeting on Musculoskeletal Infection criteria. There were 15 men and 17 women in this study, with a median (range) age of 70 years (60 to 80 years). Twenty-seven patients had TKA and five had THA. We measured cf-DNA, MPO, and H3Cit in synovial fluid. The sensitivity, specificity, and receiver operating characteristic curve were calculated for each biomarker using the Musculoskeletal Infection Society criteria as the gold standard for diagnosis and considering a clinical surveillance of 2 years for patients in the non-PJI group. RESULTS: Patients with PJI had higher levels of synovial fluid cf-DNA (median [range] 130 ng/µL [18 to 179] versus 2 ng/µL [0 to 6]; p < 0.001), MPO (1436 ng/µL [55 to 3996] versus 0 ng/µL [0 to 393]; p < 0.001), and H3Cit (2115 ng/µL [5 to 2885] versus 3 ng/µL [0 to 87]; p < 0.001) than those in the non-PJI group. In receiver operating characteristic curve analyses, we observed near-perfect performance for all biomarkers evaluated, with an area under the curve of 1 (95% CI 0.9 to 1), 0.98 (95% CI 0.9 to 1), and 0.94 (95% CI 0.8 to 0.99) for cf-DNA, MPO, and H3Cit, respectively. The sensitivity for detecting PJI using synovial fluid was 100% for cf-DNA, 94% for MPO, and 88% for H3Cit. The specificity was 100% for cf-DNA and MPO, and 88% for H3Cit. CONCLUSION: Our results show that neutrophils in the periprosthetic microenvironment release neutrophil extracellular traps as part of the bactericidal arsenal to fight infection. These results allow a better understanding of the cellular and molecular processes that occur in this microenvironment, enabling the design of more assertive strategies for identifying new biomarkers and improving the available ones. Novel studies are needed to define whether and how neutrophil extracellular trap-related biomarkers can be useful for diagnosing PJI. LEVEL OF EVIDENCE: Level II, diagnostic study.

[Results and complications of knee arthroplasty in patients with obesity]. / Resultados y complicaciones de la artroplastía de rodilla en pacientes con obesidad.

Introduction: In México, many patients undergoing total knee arthroplasty (TKA) are obese, which has medical and financial consequences. The functional outcomes and the incidence of complications of these patients remain uncertain due to the inconsistency between studies. Objective: To determine the association between obesity, complications and functional results of patients undergoing TKA. Material and methods: Descriptive, cross-sectional, prospective, observational, cohort study in which patients who underwent TKA between September 1, 2021, and August 30, 2022, were studied. Patients were divided by their body mass index (BMI) in < 30kg/m2 and > 30kg/m2 and their demographic characteristics, Oxford Knee Score (OKS), and incidence of complications were compared. Results: Out of the 102 patients, 59 presented a BMI < 30 kg/m2 and 43 a BMI > 30 kg/m2. No difference was found in their postoperative OKS (p = 0.12) and delta OKS (p = 0.07). A significant increase in trans-surgical (p = 0.02) and post-surgical (p = 0.04) complications was found in the group with BMI > 30 kg/m2, presenting a risk 5.03 times higher. Conclusion: A BMI > 30kg/m2 does not affect the functional results after a TKA; however, it is associated with a risk 5.03 times higher of suffering complications during and after surgical intervention.

Introducción: en México un gran número de pacientes sometidos a artroplastía total de rodilla (ATR) padecen obesidad, situación que genera grandes implicaciones médicas y financieras. Los resultados funcionales y la incidencia de complicaciones de estos pacientes permanecen inciertos debido a la gran incongruencia entre los diferentes estudios. Objetivos: determinar la asociación entre obesidad, complicaciones y resultados funcionales de los pacientes sometidos a una ATR. Material y métodos: estudio descriptivo, transversal, prospectivo, observacional, de cohorte en el que se estudiaron los pacientes a los que se les realizó una ATR primaria entre el 1 de septiembre de 2021 y el 30 de agosto de 2022. Se dividió a los pacientes con base en su índice de masa corporal (IMC) en < 30kg/m2 y > 30 kg/m2 y se compararon según sus características demográficas, el Oxford Knee Score (OKS) y la incidencia de complicaciones. Resultados: de los 102 pacientes, 59 presentaron un IMC < 30 kg/m2 y 43 un IMC>30kg/m2. No se encontró diferencia significativa en el OKS postquirúrgico (p = 0.12) y el OKS delta (p = 0.07); sin embargo, sí se encontró un aumento significativo en las complicaciones transquirúrgicas (p = 0.02) y postquirúrgicas (p = 0.04) en el grupo de IMC > 30 kg/m2, pues presentó un riesgo 5.03 veces mayor. Conclusión: un IMC > 30 kg/m2 no afecta los resultados funcionales posteriores a una ATR; sin embargo, sí se asocia con un riesgo 5.03 veces mayor de sufrir complicaciones durante y después de la intervención quirúrgica.

Determinants of High Facility Costs in Total Joint Arthroplasty Patients: A Time-driven Activity-based Costing Analysis.

INTRODUCTION: Although several studies identify risk factors for high-cost patients in an episode of care for total hip (THA) and knee arthroplasty (TKA), few have looked at cost outliers from a facility perspective. The purpose of this study was to use time-driven activity-based costing (TDABC) to identify characteristics of high-cost patients. METHODS: We reviewed a consecutive series of primary THA and TKA patients by 22 different surgeons at two hospitals between 2015 and 2020. Facility costs were calculated using a TDABC algorithm for their entire hospital stay. Patients in the top decile of costs were considered to be high-cost patients. Multivariate regression was done to identify independent patient factors that predicted high costs. RESULTS: Of the 8,647 patients we identified, 60.5% underwent THA and 39.5% underwent TKA. Implant purchase price accounted for 49.5% of total inpatient costs (mean $2,880), followed by intraoperative (15.9%, mean $925) and postoperative personnel costs (16.8%, mean $980). Implant price demonstrated the highest variation between high-cost and low-cost groups (4.4 times). Patient-related factors associated with high costs were female sex (OR = 1.332), Hispanic ethnicity (OR = 1.409), American Society of Anesthesiology score (OR = 1.658), need for transfusion (OR = 2.008), and lower preoperative HOOS/KOOS Jr (OR = 1.009). CONCLUSION: This study identifies several variables for patients at risk to have high facility costs after primary THA and TKA. From the hospital's perspective, efforts to reduce implant purchase prices may translate into substantial cost savings. At the patient level, multidisciplinary initiatives to optimize medical comorbidities, decrease transfusion risk, and control medication expenses in high-risk patients may narrow the existing variation in costs.

Mark Coventry Award: Human Knee Has a Distinct Microbiome: Implications for Periprosthetic Joint Infection.

BACKGROUND: Pathogens causing prosthetic joint infection (PJI) are thought to gain access to the knee during surgery or from a remote site in the body. Recent studies have shown that there is a distinct microbiome in various sites of the body. This prospective study, and first of its kind, was set up to investigate the presence of possible microbiome in human knee and compare the profile in different knee conditions. METHODS: We obtained synovial fluid from 65 knees (55 patients) with various conditions that included normal knee, osteoarthritis (OA), aseptic revision, and those undergoing revision for PJI. The contralateral knee of patients who had a PJI were also aspirated for comparison. A minimum of 3 milliliters of synovial fluid was collected per joint. All samples were aliquoted for culture and next-generation sequencing analysis. RESULTS: The highest number of species was found in native osteoarthritic knees (P ≤ .035). Cutibacterium, Staphylococcus, and Paracoccus species were dominant in native nonosteoarthritic knees, and meanwhile a markedly high abundance of Proteobacteria was observed in the osteoarthritic joints. Moreover, the contralateral and aseptic revision knees showed a similar trend in bacterial composition (P = .75). The sequencing analysis of patients who had PJI diagnosis, confirmed the culture results. CONCLUSION: Distinct knee microbiome profiles can be detected in patients who have OA and other knee conditions. The distinct microbiome in the knee joint and the close host-microbe relationships within the knee joint may play a decisive role in the development of OA and PJI.

The role of SPECT/CT in painful, noninfected knees after knee arthroplasty: a systematic review and meta-analysis-a diagnostic test accuracy review.

PURPOSE: The aim of this systematic review was to present the current evidence on the clinical use of single-photon emission computed tomography/computed tomography (SPECT/CT) in the evaluation of noninfected painful knees after knee arthroplasty. METHODS: Embase, PubMed, Google Scholar, Ovid, Scopus, Science Direct and the Cochrane Database of Systematic Reviews were searched from database inception to May 2022 following the PRISMA guidelines. As a primary outcome, we defined the role of SPECT/CT in the diagnostic approach to noninfected painful knee arthroplasty; as a secondary objective, we described the noninfection-related factors linked to painful knee arthroplasty. Pooled sensitivity, specificity, positive likelihood ratio, negative likelihood ratio, diagnostic odds ratio values and other indicators were calculated; receiver operating characteristic (ROC) curve analysis results and a summary of the areas under the curve (AUCs) from the included studies were reported. A Fagan plot, likelihood ratio plot and Deeks' funnel plot were generated and analysed. Methodological quality was assessed using the QUADAS-2 tool, and the certainty of evidence was assessed by the GRADE approach. RESULTS: A total of 493 publications were identified, of which eight met the inclusion criteria, with a final pooled sample size of 308 patients. The pooled sensitivity and specificity of SPECT/CT in diagnosing the source of pain in painful knee prostheses were 0.86 (95% CI: 0.75-0.93) and 0.90 (95% CI: 0.79-0.96), respectively, with pooled +LR and -LR values of 8.9 (95% CI: 4.11-19.19) and 0.15 (95% CI: 0.09-0.28). The pooled diagnostic odds ratio was 57.35, and the area under the curve was 0.94. SPECT/CT highly accurately identified different sources of pain, such as loosening of the prosthetic components, patellofemoral overloading, instability, malalignment of the components and degeneration of the patellofemoral compartment. The confidence of the estimates was moderate according to the GRADE approach. CONCLUSION: With demonstrated high sensitivity and specificity, as a diagnostic tool, SPECT/CT can identify the source of pain in painful knees after knee arthroplasty, particularly in cases of loosening, patellofemoral disorders and component malalignment (level of evidence III). These findings have significant clinical repercussions, such as in changing the initial diagnosis, identifying or excluding different causes of painful knee arthroplasties, guiding subsequent treatment and positively impacting the final clinical outcome. We moderately recommend the use of SPECT/CT for identifying the source of pain after knee arthroplasty according to the GRADE assessment. This review was preregistered in Prospero under code CRD42022320457.

Short-to Mid-Term Survivorship of a Patient-specific Unicompartmental Knee Arthroplasty Implant Cast from a Three-Dimensional Printed Mold.

The purpose of this study was to determine early survivorship and complication rates associated with the implantation of a new patient-specific unicompartmental knee implant cast from a three-dimensional (3D) printed mold, introduced in 2012. We retrospectively reviewed 92 consecutive patients who underwent unicompartmental knee arthroplasty (UKA) with a patient-specific implant cast from a 3D printed mold between September 2012 and October 2015. The early results of a patient-specific UKA implant were favorable in our cohort, with survivorship free from reoperation of 97% at an average 4.5 years follow-up. Future studies are necessary to investigate the long-term performance of this implant. Survivorship of a patient-specific unicompartmental knee arthroplasty implant cast from a 3D printed mold.

Extensor mechanism injury, infection, and an extended time between trauma and surgical approach are related to the need for total knee arthroplasty removal after traumatic dehiscence.

BACKGROUND: Surgical wound-related traumatic complications are rarely reported in the literature. Traumatic dehiscence is unpredictable because of the trauma magnitude and the potential of associated injuries. This study aims to report the clinical outcomes and complications of a case series due to traumatic dehiscence after total knee arthroplasty (TKA) and establish possible criteria for prognosis for maintaining the implant. METHODS: Patients admitted to an emergency room due to traumatic dehiscence after TKA were retrospectively evaluated. Patient data was analyzed and patients who maintained or not the arthroplasty were compared to establish prognosis factors. RESULTS: Thirty-two patients with traumatic dehiscence after TKA were evaluated. The trauma occurred on a mean of 14.3 +/- 25.0 days after the surgical procedure, and debridement in the operating room was performed on a mean of 6.2 +/- 4.9 hours after the trauma. Twenty patients maintained the arthroplasty until the end of follow-up and did not require revision. Factors related to arthroplasty removal were associated extensor mechanism injury (p = 0.026), time from trauma to surgical debridement (p = 0.035), and infection (p = 0.0001) CONCLUSION: Traumatic dehiscence after total knee arthroplasty is an event with a high rate of complications. Extensor mechanism Injury, infection, and extended time between trauma and surgical intervention were poor prognostic factors for arthroplasty maintenance.

Gonyautoxins 2/3 Local Periarticular Injection for Pain Management after Total Knee Arthroplasty: A Double-Blind, Randomized Study.

The purpose of this study was to compare the efficacy of periarticular infiltration of gonyautoxin 2/3 (GTX 2/3) and a mixture of levobupivacaine, ketorolac, and epinephrine for pain management after total knee arthroplasty (TKA). Forty-eight patients were randomly allocated to receive periarticular infiltration of 40 µg GTX 2/3 (n = 24) diluted in 30 mL of sodium chloride 0.9% (study group) or a combination of 300 mg of levobupivacaine, 1 mg of epinephrine, and 60 mg ketorolac (n = 24) diluted in 150 mL of sodium chloride 0.9% (control group). Intraoperative anesthetic and surgical techniques were identical for both groups. Postoperatively, all patients received patient-controlled analgesia (morphine bolus of 1 mg; lockout interval of 8 minutes), acetaminophen, and ketoprofen for 72 hours. A blinded investigator recorded morphine consumption, which was the primary outcome. Also, the range of motion (ROM) and static and dynamic pain were assessed at 6, 12, 36, and 60 hours after surgery. The incidence of adverse events, time to readiness for discharge, and length of hospital stay were also recorded. The median of total cumulative morphine consumption was 16 mg (range, 0-62 mg) in the GTX 2/3 group and 9 mg (range, 0-54 mg) in control group, which did not reach statistical difference (median test, p = 0.40). Furthermore, static and dynamic pain scores were similar at all time intervals. GTX 2/3 was inferior in range of motion at 6 and 12 hours; nevertheless, we noted no difference after 36 hours. No differences between groups were found in terms of complications, side effects, or length of hospital stay. No significant differences were found between groups in terms of breakthrough morphine requirement. However, local anesthetic use resulted in an increased ROM in the first 12 hours. This prospective randomized clinical trial shows that GTX 2/3 is a safe and efficient drug for pain control after TKA; nevertheless, more studies using GTX 2/3 with larger populations are needed to confirm the safety profile and efficiency. This is level 1 therapeutic study, randomized, double-blind clinical trial.

Total knee replacement in octogenarians, Is age a determining factor in predicting complications? a retrospective cohort study.

INTRODUCTION: Given the increase in life expectancy in the general population of our country, there is an exponential increase since the last decades of functional older adults who undergo total knee replacement (TKR). There is a direct relationship between the increase in age and the prevalence of both functional and cognitive disabling chronic diseases, however, little we know about whether age is an independent factor in predicting worse functional outcomes and readmissions after TKR. The objective of this study was to evaluate the clinical-functional results and unplanned readmissions within the first 90 postoperative days in patients older than 80 years compared with a control group of patients younger than 80 years. METHODS: From our institutional patient database, 450 patients who underwent TKR between 2016 and 2019 were retrospectively analyzed. All patients had the medical assurance of Hospital Italiano (Plan de Salud), for which none of these was lost on the follow-up nor were treated in another hospital. Patients were divided in two groups: Group A with 186 patients over 80 years and a control group B with 264 patients between 70 and 80 years. The fragility of these was defined according to the Charlson Comorbidity Index and the Simple Frail Score. Comorbidities were divided in eight groups to define which were the most influential in the final results. RESULTS: No significant differences were observed in terms of unplanned readmissions, pain or in functional scores within 90 days between both groups. There was a significant difference in the length of postoperative hospital stay in favor of group A (A: 2.56 SD + - 0.76, B: 4.08 SD = - 2.23; p = 0.00001). The Charlson score was higher in the group of patients older than 80 years (p = 0.02) as well as the Simple Frail Score (p = 0.004). The ASA score did not show significant differences between both groups. CONCLUSION: Age as an independent factor proved not to be a predictor by itself of unplanned readmissions or worse clinical-functional results in a period of 90 postoperative days between both groups. We believe that the preoperative evaluation of octogenarian patients should be multidisciplinary, with special attention to the identification of comorbidities that can influence the fragility of a patient and the optimization of the pathology.

Optimized Tourniquet Use in Primary Total Knee Arthroplasty: A Comparative, Prospective, and Randomized Study.

BACKGROUND: The results of recent studies investigating tourniquet (TNQ) use for knee arthroplasty are controversial. Therefore, this study aimed to compare patients undergoing total knee arthroplasty who did not have a TNQ to those in whom an optimized TNQ protocol was applied. METHODS: We prospectively evaluated 127 patients who had knee osteoarthritis who had undergone total knee arthroplasty and randomized them into two groups: "without TNQ" and "optimized TNQ" (TNQ inflation before skin incision, deflation after cementing, with pressure one hundred millimeters of mercury above the systolic blood pressure, and without articular suction drain usage). The means of surgery and TNQ duration, blood loss, number of blood transfusions, degree of pain, edema, range of motion (ROM), functional score over time, and postoperative complications were compared between the groups. Statistical significance was set at P < .05. RESULTS: No significant differences were found in terms of surgical timing, blood loss, thigh and knee pain, edema, ROM, functional scores, and complications between the "without TNQ" and "optimized TNQ" groups. CONCLUSION: The use of an optimized TNQ in primary total knee arthroplasty presents similar clinical results to surgery without a TNQ and did not increase the incidence of postoperative complications. Its use allowed surgery to occur with the benefits of a clean and dry surgical field provided by TNQ without increasing procedure-related comorbidities.

Microbiología de las infecciones periprotésicas de rodilla en Hospital Regional de Talca / Microbiology of periprosthetic knee infections in Regional Hospital

Introduction: Periprosthetic infection (PPI) is one of the most devastating complications of total knee arthroplasty (TKA). The incidence described in the literature is 2.4% and the most frequently isolated bacteria are Staphylococcus Aureus and Staphylococcus Coagulase-Negative (Gram positive). Polymicrobial infections represent between 10 to 37% and negative cultures between 7 to 15%. Methodology: Descriptive and retrospective study that consisted of reviewing the TKA database of the Regional Hospital of Talca during the 2018-2020 period, where knee PPIs were identified according to the diagnostic criteria validated in 2018. The cultures of patients diagnosed with PPI were reviewed, analyzing the antibiogram and resistance profile. Results: During 2018-2020, 459 TKAs were performed in our center, diagnosing 30 PPIs of the knee. 47% of PPIs were acute and 53% chronic. The results of the cultures were negative in 26.6%, 23.3% Methicillin Sensitive Staphylococcus Aureus; 13.3% Methicillin Resistant Staphylococcus Epidermidis and 13.3% of the cultures were polymicrobial. Discussion: Highlights the high resistance to methicillin, especially of Staphylococcus Epidermidis. This opportunistic pathogen has the ability to form a biofilm and, thanks to its genomic flexibility, rapidly acquires resistance to antibiotics. Polymicrobial infections have a synergistic effect that favors the persistence of the infection, which is why they will require a greater number of surgeries and prolonged antibiotic therapy. Pruebas especiales como la sonicación podrían aumentar las posibilidad de identificar al microorganismo. Conclusion: In these three years of follow-up, the PPI rate has been higher than reported annually in the literature. Gram-positive microorganisms continue to predominate, but with an increase in the rate of resistant to methicillin. Also, highlight the number of negative cultures. There would be a possible benefit theoretical in optimizing antibiotic prophylaxis in view of the large percentage of methicillin resistance and in seeking new ways to reduce negative cultures.

Single-level Lumbar Fusion Versus Total Joint Arthroplasty: A Comparison of 1-year Outcomes.

INTRODUCTION: Primary hip and knee arthroplasty represent two of the most successful orthopaedic surgical interventions in the past century. Similarly, lumbar fusion (LF) remains a valuable, evidence-based option to relieve pain and disability related to spinal degenerative conditions. This study evaluates the relative improvements in 1-year health-related quality of life (HRQOL) measures among patients undergoing primary single-level LF, primary total hip arthroplasty (THA), and primary total knee arthroplasty (TKA). METHODS: Patients older than 18 years who underwent primary single-level posterior LF (posterolateral decompression and fusion with or without transforaminal lumbar interbody fusion, involving any single lumbar level), TKA, and THA at a single academic institution were retrospectively identified. Patient demographics and surgical characteristics were collected. HRQOL measures were collected preoperatively and at 1-year postoperative time point including Short-Form 12 Physical Component Score (PCS) and Mental Component Score (MCS) along with subspecialty-specific outcomes. RESULTS: A total of 2,563 patients were included (346 LF, 1,035 TKA, and 1,182 THA). Change in MCS-12 and PCS-12 after LF did not vary markedly by preoperative diagnosis. LF patients had a significantly lower preoperative MCS-12 (LF: 50.8, TKA: 53.9, THA: 52.9, P < 0.001), postoperative MCS-12 (LF: 52.5, TKA: 54.8, THA: 54.5, P < 0.001), postoperative PCS-12 (LF: 40.1, TKA: 44.0, THA: 43.9, P < 0.001), ΔPCS-12 (LF: 7.9, TKA: 10.8, THA: 11.9, P < 0.001), and PCS-12 recovery ratio (LF: 10.7%, TKA: 15.1%, THA 16.6%, P < 0.001) compared with TKA and THA patients. In regression analysis, both TKA and LF were found to be independently associated with a smaller ΔPCS-12 improvement (TKA: ß = -1.36, P = 0.009; LF: ß = -4.74, P < 0.001) compared with THA. TKA (ß = -1.42, P = 0.003) was also independently associated with a smaller ΔMCS-12 improvement compared with THA. CONCLUSIONS: Patients undergoing single-level LF, TKA, and THA demonstrate notable improvements in HRQOL outcomes at 1 year postoperatively compared with preoperative baseline scores. The greatest improvements were found among THA patients, followed subsequently by TKA and LF patients. Both LF and TKA were independently associated with markedly less improvement in physical disability at 1 year postoperatively compared with THA. STUDY DESIGN: Retrospective Cohort Study.