Early Postoperative Results in Robotic-Arm-Assisted Total Knee Replacement versus Conventional Technique: First Latin American Experience.

Early results with robotic-arm-assisted total knee arthroplasty (TKA) are encouraging; nevertheless, literature might be unrepresentative, as it comes mostly from American, European, and Asian countries. There is limited experience and no comparative clinical reports in Latin America, a region of mainly low- and middle-income countries with limited access to these promising technologies. This study aims to compare the early postoperative results of the first Latin American experience with robotic-arm-assisted TKA versus conventional TKA. A cohort study was performed, including 181 consecutive patients (195 knees) with advanced symptomatic knee osteoarthritis (OA) undergoing primary TKA between March 2016 and October 2019. The cohort included 111 consecutive patients (123 knees) undergoing conventional TKA, followed by 70 consecutive patients (72 knees) undergoing robotic-arm-assisted TKA. The same surgical team (surgeon 1 and surgeon 2) performed all procedures. Patients with previous osteotomy, posttraumatic OA, and revision components were not considered. The same anesthetic and rehabilitation protocol was followed. The investigated clinical outcomes (for the first 60 postoperative days) were: surgical tourniquet time, time to home discharge, time to ambulation, postoperative daily pain (Visual Analog Scale), opioid use, range of motion, blood loss, complications, and postoperative mechanical axis. The early clinical postoperative results of this first Latin American comparative experience of robotic-arm-assisted TKA versus conventional technique showed lower opioids requirements and faster functional recovery of ambulation in those patients operated with the robotic system; nevertheless, surgical times were higher, without differences in total postoperative complications and other clinical outcomes.

Over 50% of self-reported burnout among Latin American orthopaedic surgeons: A cross-sectional survey on prevalence and risk factors.

OBJECTIVE: Assess the prevalence of self-reported burnout and identify risk and protective factors based on demographic and life quality aspects, among Latin American orthopaedic surgeons. METHODS: This study employed a cross-sectional analytical design. An original design survey was developed using multiple-choice and Likert-scale questions to gather self-reported burnout, demographic, work-related, social, personal, and mood-related data. The survey was electronically distributed to the Chilean Orthopaedic Surgery Society and the Latin American Society of Arthroscopy, Knee Surgery, and Sports Medicine members. Statistical analysis included Chi-square and Fisher's exact tests to determine associations between self-reported burnout and other variables. Subsequently, a multivariate logistic regression was carried out to identify key risk and protective factors (p â€‹< â€‹0.05). RESULTS: The survey's response rate was 20 â€‹% (n â€‹= â€‹358) out of the 1779 invitations that were sent. The most representative age range was 41-60 years (50 â€‹%) and 94 â€‹% were men. Of those surveyed, 50 â€‹% reported a burnout episode more than once per year, 60 â€‹% depersonalization when treating patients at least yearly, 13 â€‹% anhedonia, 11 â€‹% a depressive mood more than half of the month or almost every day, and 61 â€‹% weariness at the end of a working day. Burnout was statistically associated with age under 40 years old (p â€‹= â€‹0.012), fewer years as a specialist (p â€‹= â€‹0.037), fear of lawsuits (p â€‹< â€‹0.001), a non-healthy diet (p â€‹= â€‹0.003), non-doing recreational activities (p â€‹= â€‹0.004), depersonalization when treating their patients (p â€‹< â€‹0.001), weariness (p â€‹< â€‹0.001), anhedonia (p â€‹< â€‹0.001), depressive mood (p â€‹< â€‹0.001), and career dissatisfaction (p â€‹< â€‹0.001). The logistic regression demonstrated that fear of lawsuits (p â€‹< â€‹0.001), weariness at the end of a workday (p â€‹= â€‹0.016), and anhedonia (p â€‹= â€‹0.019) were those variables with stronger direct associations with self-reported burnout. A healthy diet was the strongest protective variable (p â€‹< â€‹0.001). CONCLUSION: Over 50 â€‹% of the Latin American orthopaedic surgeons who participated in the survey reported experiencing burnout episodes more than once a year, along with depersonalization when treating their patients at least once a year. Additionally, nearly 10 â€‹% of respondents experienced weekly depressive symptoms. Among the noteworthy risk factors for self-reported burnout were fear of lawsuits, weariness at the end of the workday, and anhedonia. Conversely, maintaining a healthy diet emerged as the most potent protective factor. LEVEL OF EVIDENCE: Level III.

Isolated Medial Patellofemoral Ligament Reconstruction in Patellar Instability: Does the Distance Between Tibial Tuberosity-Trochlear Groove Make a Difference?

Introduction: Medial patellofemoral ligament reconstruction (MPFLR) is used in most patellar instability surgeries, there is controversy on adding a tibial tuberosity osteotomy (TTO). Objective: To describe the results of isolated MPFLR in patellar instability according to the Tibial Tuberosity-Trochlear Groove distance (TT-TG). Methods: Retrospective study of patients with patellar instability with a mature skeleton in one center between 2016 and 2021, using isolated MPFLR. Patients with incomplete clinical and/or radiological records and less than one year follow-up were excluded. Pre-surgical demographic and radiological data (TT-TG, Caton-Deschamps (CD) index, patellar tilt, trochlear dysplasia) were recorded. Patients were divided into three groups according to TT-TG distance (Group 1: < 17 mm, Group 2: 17-19, Group 3: ≥ 20 mm). A pre and post-surgical Kujala score was performed. Local complications, satisfaction, recurrence and/or reintervention were recorded. Pre-surgical variables between groups, intra and inter-group Kujala differences were compared using Bartlett's test. Consent from the patients and approval from the local ethics committee were obtained. Results: 67 patients met the selection criteria, mean age of 23 years, 70% were women. There were no pre surgical, radiological nor follow-up differences between the groups (average 27 months). Pre and post-surgical Kujala score, respectively: Group 1: 37-78, Group 2: 37-78, Group 3: 39-79. All groups had a significant improvement (p < 0.05), there were no significant differences in improvement between groups (p > 0.05). There were three patients with a redislocation episode, all in group 1. One patient had a mobilization under anesthesia due to an arthrofibrosis (Group 2). 97% of all cases reported being satisfied. Conclusion: Isolated MPFLR in patellar instability presents a functional improvement, with a low rate of complications and failure, regardless of the pre surgical TT-TG. Supplementary Information: The online version contains supplementary material available at 10.1007/s43465-023-00906-6.

¿Existen discrepancias entre la planificación preoperatoria y la evaluación intraoperatoria realizada por el cirujano en la artroplastia total de rodilla con asistencia robótica? / Are there discrepancies between preoperative planning and intraoperative evaluation by the surgeon in robotically assisted total knee arthroplasty?

Introducción: Existe poca evidencia respecto de la concordancia entre el plan preoperatorio mediante artroplastia total de rodilla asistida por robot y el plan posterior al balance protésico realizado por el cirujano. El objetivo de este trabajo es evaluar el grado de concordancia entre la planificación preoperatoria de la artroplastia total de rodilla con asistencia robótica semiactiva (Mako) y la planificación efectuada por el traumatólogo durante la cirugía. Materiales y métodos: estudio retrospectivo y descriptivo de prótesis primarias instaladas entre octubre de 2018 y junio de 2019 con planificación preoperatoria realizada por el software MAKOplasty®. Se excluyeron las prótesis no colocadas por el sistema robótico o con información clínica incompleta. Esto se comparó con la planificación intraoperatoria del traumatólogo. Variables analizadas: alineación coronal y sagital, rotación y tamaño de los componentes e inserto. Los datos se analizaron con el softwareSTATA v.16.0. Se realizó un análisis descriptivo univariante cualitativo, con un intervalo de confianza del 95%. Resultados: se incluyeron cincuenta y una rodillas operadas de cuarenta y nueve pacientes, el 69% fueron mujeres. El nivel de concordancia para el componente femoral fue: axial 86.3% (IC = 73.7 - 94.2), coronal 88.2% (IC = 76.1 - 95.5), sagital 88.2% (IC = 76.1 - 95.5). Componente tibial: axial 98% (IC = 89.5 ­ 99.9), coronal 96.1% (IC = 86.5 ­ 99.5), sagital 96.1% (IC = 86.5 ­ 99.5). Tamaño del componente: fémur 94.1% (IC = 83.7 ­ 98.7), tibia 84.3% (IC = 71.4 ­ 92.9), inserto 27.4% (IC = 15.8 ­ 41.7). Conclusión: la planificación preoperatoria mediante el uso de la asistencia robótica semiactiva de Mako presenta un buen nivel de concordancia con la planificada intraoperatoriamente, a excepción del tamaño del inserto. El traumatólogo es determinante en la modificación del plan preoperatorio. Nivel de Evidencia: III

Introduction: There is little evidence regarding the concordance between the preoperative plan using robotic-assisted total knee arthroplasty and that after the prosthetic balance by the surgeon. Our aim is to evaluate the level of agreement between the preoperative planning of total knee arthroplasty with semiactive robotic assistance (Mako) and the planning made by the orthopedic surgeon during the surgery. Materials and methods: descriptive study of prostheses installed between October 2018 and June 2019 with preoperative planning performed by the MAKOplasty® software. This was compared with intraoperative planning by the Orthopedic Surgeon. Variables analyzed: coronal and sagittal alignment, rotation and size of the components and insert. The data was analyzed with the STATA v.16.0 software. A qualitative univariate descriptive analysis was performed, with a 95% confidence interval. Results: fifty-one operated knees from forty-nine patients were included, 69% were women. The level of agreement was: Femoral component: axial 86.3% [CI = 73.7 - 94.2], coronal 88.2% [CI = 76.1 - 95.5], sagittal 88.2% [CI = 76.1 - 95.5]. Tibial component: axial 98% [CI = 89.5 - 99.9], coronal 96.1% [CI = 86.5 - 99.5], sagittal 96.1% [CI = 86.5 - 99.5]. Component size: femur 94.1% [CI = 83.7 - 98.7], tibia 84.3% [CI = 71.4 - 92.9], insert 27.4% [CI = 15.8 - 41.7]. Conclusion: preoperative planning through the use of Mako semiactive robotic assistance presents a good level of agreement with that planned intraoperatively, with the exception of the insert size. The orthopedic surgeon is decisive in modifying the preoperative plan. Level of Evidence: III

Vancomycin Presoaking of the Graft Appears to Prevent Infection After Anterior Cruciate Ligament Reconstruction: A Systematic Review and Meta-analysis.

Background: Vancomycin presoaking of the graft has been shown to decrease infection rates in some case series of anterior cruciate ligament (ACL) reconstruction. Purpose: We sought to substantiate the efficacy of vancomycin presoaked grafts for the prevention of infection after ACL reconstruction. Methods: We performed a systematic review of Medline and OVID to assess the incidence of postoperative infection in studies comparing patients undergoing ACL reconstruction with the use of vancomycin presoaked ACL grafts and a control group of patients undergoing ACL reconstruction without the use of presoaked grafts. The efficacy of vancomycin presoaking was calculated using the Agresti-Coull confidence interval. Relative risk (RR) was calculated for every study and the total sample. Results: The 11 studies that met inclusion criteria comprised 24,298 patients. In patients with vancomycin presoaking of the graft, 1 infection was reported in 8764 cases (0.01% rate). In the studies with control groups that did not have vancomycin presoaked grafts, there were 125 infections in 15,534 ACL reconstructions (0.8% rate). The efficacy of vancomycin presoaking in preventing infection after ACL reconstruction was 99.9% (0.999%-1.000% CI). The overall RR obtained was 0.07 (0.03-0.16 CI). All included studies were retrospective cohort studies (level III). Conclusions: Vancomycin presoaking of the graft has been shown to decrease infection rates after ACL reconstruction in studies of low evidence level. This suggests the need for prospective randomized controlled trials addressing this issue so that recommendations on the routine use of vancomycin presoaking of ACL grafts can be made with confidence.

Alineamiento en prótesis total de rodilla: cuestionando los paradigmas / Alignment in knee prosthesis

La artroplastia total de rodilla (ATR) es un procedimiento altamente exitoso, sin embargo, podemos encontrar pacientes insatisfechos. Aunque la insatisfacción posterior a una ATR es un problema multifactorial, existe un interés creciente en el alineamiento como causa modificable del problema. El alineamiento ideal en ATR aún sigue siendo motivo de controversia y se describen muchas técnicas. La técnica clásica y más utilizada es el alineamiento mecánico, pero existen otros como el anatómico, mecánico ajustado, cinemático, cinemático reverso y el recientemente descripto alineamiento funcional. En esta revisión narrativa se detallan las técnicas de alineamiento más utilizadas, sus beneficios y problemas, y se comentan cuáles podrían ser los nuevos lineamientos que podrían guiar las técnicas de alineamiento en los próximos años

Total knee arthroplasty (TKA) is a highly successful procedure; however, we can find dissatisfied patients. Although post-TKA dissatisfaction is a multifactorial problem, there is growing interest in alignment as a modifiable cause of the problem. The ideal alignment in TKA is still controversial and many techniques are described. The classic and most used technique is mechanical alignment, but there are others such as anatomical, adjusted mechanical, kinematic, reverse kinematic alignment and the recently described functional alignment. This narrative review details the most used alignment techniques, their benefits and problems, and comments on what could be the new guidelines that could guide alignment techniques in the coming years

Medial femoral condyle fracture during an Oxford unicompartmental knee replacement surgery: case report.

Oxford unicompartmental knee arthroplasty has been used as a good alternative for medial unicompartmental osteoarthritis due to its association with early rehabilitation and a low rate of intraoperative complications. This case describes a rare complication during the procedure of an intraoperative fracture of the medial condyle that was treated with osteosynthesis with 6.5 mm cannulated screws and a compression technique. The patient followed a non-weight-bearing protocol for 6 weeks and reached full range of motion at 3 months. Complete radiological fusion and good functional outcome were observed. Intraoperative fractures can benefit from stable osteosynthesis that allows free range of motion and does not jeopardise the final surgical result.

Treatment of Patellofemoral Chondral Lesions Using Microfractures Associated with a Chitosan Scaffold: Mid-Term Clinical and Radiological Results.

OBJECTIVE: To assess the clinical and radiological results of patellofemoral osteochondral lesions treated with microfractures associated with a chitosan scaffold. DESIGN: A retrospective observational analytical study was performed. Fifteen patients with full-thickness patellofemoral osteochondral lesions were included. Quantity and quality of the reparation cartilage was assessed with the MOCART 2.0 score on a postoperative magnetic resonance imaging (MRI), and clinical outcomes were evaluated with pre- and postoperative Kujala score tests. Shapiro-Wilk test for normality was applied as well as Wilcoxon's signed rank test and Kruskal-Wallis H test for clinical scores within subjects and patella versus trochlea subgroups comparisons. Analysis of variance test was used for imaging subgroups comparison, with P < 0.05 defined as statistical significance. RESULTS: Mean follow-up was 33.36 months (range 24-60 months). Postoperative Kujala scores improved an average of 19 points compared with the preoperative state (SE = 17.6; P < 0.001). No statistical difference was found through the clinical location assessment (P = 0.756), as well as the cartilage imaging assessment (P = 0.756). The mean MOCART 2.0 scale was 67.67 (range 50-85). CONCLUSIONS: Treating full-thickness patellofemoral osteochondral lesions with microfractures associated with a chitosan scaffold proved to be effective regarding defect filling and symptomatic improvement.

Vancomycin presoaking of hamstring autografts to prevent infection in anterior cruciate ligament reconstruction: a narrative review.

Hamstring autograft use has been linked to an increased risk of infection after anterior cruciate (ACL) reconstruction compared to other grafts. The absolute reason for this remains unclear, with contamination after harvesting and preparation of the graft being the most accepted hypothesis.Using the rationale that a contaminated graft could be the main factor in postoperative septic arthritis and in an effort to maximize the antibiotic efficacy of the graft, the Vancomycin presoaking technique was developed. It has shown success in decreasing the infection rate in ACL reconstruction. In recent years, an important number of research articles using this protocol have appeared, but the technique is still not widely implemented.Recent literature shows that Vancomycin presoaking of the graft has shown a successful decrease in the infection rate after hamstring autograft ACL reconstruction. It has also shown efficacy decreasing the infection rate in other types of grafts (patellar tendon, quadriceps tendon, allograft) and also in patients with concomitant ligament procedures or open surgeries.Despite the positive effects of Vancomycin presoaking reducing the infection rate after ACL reconstruction, the lack of prospective randomized control trials and the heterogeneity of the different studies mean it is not feasible to recommend Vancomycin presoaking of the graft universally for every ACL reconstruction patient. Cite this article: EFORT Open Rev 2021;6:211-216. DOI: 10.1302/2058-5241.6.200059.

Meniscal polyurethane scaffold plus cartilage repair in post meniscectomy syndrome patients without malalignment improves clinical outcomes at mid-term follow-up.

BACKGROUND: The aim of this study is to report the mid-term follow-up results of a prospective cohort of patients who underwent a polyurethane (PU) meniscal scaffold implantation for post meniscectomy syndrome (PMS), without limb realignment procedures. METHODS: Prospective study in patients with PU meniscal scaffolds implanted during 2014-2016. Limb realignment procedures excluded. Clinical outcomes were prospectively evaluated pre-operatively and every year post-operatively using patient-reported outcome scores (KOOS, VAS, Lysholm and IKDC). Post-operative radiologic evaluation was done using 3.0 T magnetic resonance imaging (MRI). Meniscal scaffold extrusion, signal intensity, tibio-femoral cartilage degeneration progression and complications were analyzed. RESULTS: Fourteen patients with an average age of 25.8 years (range: 17-47) received a PU scaffold (8 lateral and 6 medial). Associated procedures were done in all patients, with an osteochondral allograft transplantation (OAT) being the most common. Mean follow up was 51.6 (range: 39-66) months. Post-operative mean clinical outcomes scores showed significantly improved results compared to the pre-operative scores. Lysholm scores increased from 62.4 to 80.2 (P = 0.0023), KOOS from 68.9 to 80 (P = 0.0083) and VAS for pain decreased from 5.3 to 3.1 (P = 0.0024). Average post-operative IKDC score was 67.7. There were 8 cases of complete extrusion (>3 mm). The mean extrusion value was 4.0 mm (range: 3-6 mm). Three patients showed signs of a ruptured meniscal scaffold. One patient showed progression of the cartilage degenerative process. CONCLUSION: The use of a PU scaffold, associated with other surgical procedures in the knee, especially chondral repair, had a significant improvement in clinical outcomes compared to the baseline status, at an average of 51.6 months follow-up in patients suffering from PMS. Although imaging results show a high proportion of implant extrusion, this does not appear to imply a worsening in clinical outcomes in the short term. LEVEL OF EVIDENCE: IV. Case series.

Factores determinantes del rango de movimiento postoperatorio en artroplastia total de rodilla primaria / Identify determinants for postoperative range of motion after primary total knee arthroplasty

Introducción: El objetivo de este trabajo es describir e identificar variables determinantes de la progresión del rango de movilidad articular (RMA) postoperatorio en artroplastia total de rodilla primaria (ATRp). Materiales y métodos: estudio prospectivo de pacientes con gonartrosis, operados de ATRp por un mismo equipo quirúrgico, implante y protocolo de rehabilitación. Se excluyeron pacientes con seguimiento menor a seis meses. Se midió el RMA (extensión-flexión) preoperatorio, durante la hospitalización y al primer, tercer y sexto mes postoperatorio. Se definió RMA funcional y satisfactorio como 5-95º y 0-120º, respectivamente. El análisis estadístico incluyó modelos mixtos, buscando relación entre la progresión del RMA postoperatorio y variables demográficas, pre, intra y postoperatorias externas a la técnica quirúrgica (p < 0.05).Resultados: cincuenta pacientes (53 ATRp), edad mediana 68 (49-91), 75.5% mujeres. Al sexto mes, el 100% presentó un RMA funcional y un 72.2% un RMA satisfactorio. Un umbral de 105º de flexión al tercer mes fue significativo para discriminar aquellos pacientes que alcanzaron un RMA favorable al sexto mes (sensibilidad = 97.1%; especificidad = 75%). Conclusión: la progresión del RMA postoperatorio de ATRp fue determinante del RMA satisfactorio (0-120º) a los seis meses. Un umbral de 105º de flexión al tercer mes postoperatorio posee una excelente capacidad de identificar aquellos pacientes que no lograrán el RMA apropiado. Nivel de Evidencia: Estudio pronóstico Nivel I

Introduction: This study aims to describe and identify determinants for the postoperative RMA progression after a primary total knee arthroplasty (pTKA).Materials and methods: prospective study in patients with knee osteoarthritis who underwent pTKA. Patients were operated by the same surgical team, implant, and followed the same rehabilitation protocol. Exclusion criteria included a follow-up of less than six months. The RMA (extension-flexion) was evaluated preoperatively, during the hospital stay, and postoperatively (first, third and sixth months). Functional and satisfactory RMA were established as 5-95º and 0-120º, respectively. Statistical analysis included mixed models for association between postoperative RMA and demographic, pre, intra, and postoperative non-related surgical technique variables (p < 0.05).Results: fifty patients (53 pTKA), median age 68 (49-91), 75.5% females. At six months, 100% of patients presented with functional RMA, and 72.2% with satisfactory RMA. A threshold of 105º of flexion at the third postoperative month, was statistically significant for identifying patients who achieved an acceptable RMA at six months (sensitivity = 97.1%; specificity = 75%).Conclusions: the postoperative RMA progression was determinant for a satisfactory RMA at six months after pTKA. A threshold of 105º of flexion at the third postoperative month has an excellent accuracy to identify patients who will not achieve an acceptable RMA. Level of Evidence: Prognostic study Level I

Is the Clinician's Eye a Valid and Reproducible Tool for Diagnosing Patella Alta on a Lateral Knee Radiography?

INTRODUCTION: Validity and reproducibility of the clinician's eye (CE) to diagnose patella alta (PA) on a lateral knee radiography (radiograph) is unknown. METHODS: Cross-sectional study of 46 lateral knee x-rays. Three blind observers used CE, Insall-Salvati (IS), modified Insall-Salvati (mIS), and Caton-Deschamps (C-D) to determine patellar height. Sensitivity and specificity of each observer was compared with the musculoskeletal radiologist's C-D measurements. Intraobserver and interobserver agreement were assessed with intraclass correlation coefficient and Fleiss κ, respectively. Time needed to estimate patellar height for every method was recorded in seconds. Statistical differences between observers were calculated with a generalized estimating equation. Analysis of variance and post hoc Bonferroni test compared duration of each method (P < 0.05). Data were analyzed using Stata 15 (StataCorp). RESULTS: CE, IS, mIS, and C-D's sensitivity and specificity values are as follows: 77%, 92%; 94%, 52%; 67%, 58%; and 53%, 89%, respectively. Intraclass correlation coefficient and Fleiss κ of CE, IS, mIS, and C-D values are as follows: 0.66 and 0.43, 0.88 and 0.68, 0.54 and 0.09, and 0.68 and 0.59, respectively. CE was the second most sensitive and most specific method for diagnosis of PA, with moderate intraobserver and interobserver agreement. IS was the most sensitive method with good intraobserver and interobserver agreement. CE was significantly faster (P < 0.05) than all other conventional radiographic ratios. CONCLUSION: CE's sensitivity increases with observer's experience and is highly specific. If normal patellar height is diagnosed, no other ratios are necessary, even in the less experienced clinician. Intraobserver and interobserver reproducibilities were moderate and only inferior to the IS ratio. In case patellar height is uncertain with the CE, the IS ratio is the most sensitive and reproducible method to confirm the diagnosis of PA.

Graft choice in combined anterior cruciate ligament and medial collateral ligament reconstruction.

There is a concern regarding which grafts should be used in combined anterior cruciate ligament (ACL) and medial collateral ligament (MCL) reconstructions, with a paucity of recommendations focused on this specific topic.Expert opinions suggest the use of allograft-only reconstructions to limit donor-site morbidity or using at least one allograft and one autograft.When a hamstring tendon autograft is harvested, techniques that maintain both the integrity of the sartorius fascia and the gracilis are recommended because of the role that the ST-G-S (semitendinosus-gracilis-sartorius) complex plays in valgus stability in the setting of an MCL-deficient knee. Cite this article: EFORT Open Rev 2020;5:221-225. DOI: 10.1302/2058-5241.5.190049.

Exchange couplings and quantum phases in two dissimilar arrays of similar copper dinuclear units.

To investigate the magnetic properties and the spin entanglement of dinuclear arrays, we prepared compounds [{Cu(pAB)(phen)H2O}2·NO3·pABH·2H2O], 1, and [Cu2(pAB)2(phen)2pz]n, 2 (pABH = p-aminobenzoic acid, phen = 1,10-phenanthroline and pz = pyrazine). The structure of 1 is known and we report here that of 2. They contain similar dinuclear units of CuII ions with 1/2-spins S1 and S2 bridged by pairs of pAB molecules, with similar intradinuclear exchange and fine interactions , but different 3D crystal arrays with weak interdinuclear exchange J', stronger in 2 than in 1. To investigate the magnetic properties and the spin entanglement produced by J', we collected the powder spectra of 1 and 2 at 9.4 GHz and T between 5 and 298 K, and at 34.4 GHz and T = 298 K and single-crystal spectra at room T and 34.4 GHz as a function of magnetic field (B0) orientation in three crystal planes, calculating intradinuclear magnetic parameters J(1)0 = (-75 ± 1) cm-1, J(2)0 = (-78 ± 2) cm-1, |D(1)| = (0.142 ± 0.006) cm-1, |D(2)| = (0.141 ± 0.006) cm-1 and E(1) ∼ E(2) ∼ 0. Single crystal data indicate a quantum entangled phase in 2 around the crossing between two fine structure EPR absorption peaks within the spin triplet. This phase also shows up in powder samples of 2 as a U-peak collecting the signals of the entangled microcrystals, a feature that allows estimating |J'|. Transitions between the two quantum phases are observed in single crystals of 2 changing the orientation of B0. We estimate interdinuclear exchange couplings |J'(1)| < 0.003 cm-1 and |J'(2)| = (0.013 ± 0.005) cm-1, in 1 and 2, respectively. Our analysis indicates that the standard approximation of a spin Hamiltonian with S = 1 for the dinuclear spectra is valid only when the interdinuclear coupling is large enough, as for compound 2 (|J'(2)/J(2)0| ∼ 1.7 × 10-4). When J' is negligible as in 1, the real spin Hamiltonian with two spins 1/2 has to be used. Broken-symmetry DFT predicts correctly the nature and magnitude of the antiferromagnetic exchange coupling in 1 and 2 and ferromagnetic interdinuclear coupling for compound 2.

Assessment of Cell Viability of Fresh Osteochondral Allografts in N-Acetylcysteine-Enriched Medium.

OBJECTIVE: The purpose of this study was to evaluate the effect of N-acetylcysteine (NAC)-enriched storage medium on fresh osteochondral viability at 4°C. Our hypothesis was that the cell viability of chondrocytes obtained from human osteochondral tissue and stored at 4°C significantly improves in the presence of NAC. DESIGN: Controlled laboratory study. For this study, 8 samples of femoral condyle osteochondral tissue were obtained from patients undergoing total knee replacement. The samples were stored at either 4°C in phosphate-buffered saline (PBS) or at 3 different concentrations of NAC (NAC 1, 2, and 5 mM). Cell viability was analyzed at time 0 and 4 weeks by flow cytometry. The results of cell viability (median) were analyzed statistically using analysis of variance and Tukey's post hoc test. P values <0.05 were considered statistically significant. RESULTS: The viability at time 0 was 95.5% ± 3.7%. At 4 weeks, the cell viability was 56.8% ± 20.1% in the control group (PBS), 83.8% ± 11.9% in the group stored with NAC 1 mM, 73.4% ± 13.6% in the group stored with NAC 2 mM, and 66.4% ± 27.7% in the group stored with NAC 5 mM. A statistically significant difference from the baseline viability (time 0) was observed in the PBS control group (P = 0.0018) but not in the other groups. A statistically significant difference was observed in the NAC 1 mM group compared with the PBS group (P = 0.0255). CONCLUSION: The use of NAC at 1 mM concentration improves cell viability after 4 weeks of storage in chondrocytes obtained from human osteochondral tissue.

Sutura meniscal en niños. ¿En qué hemos avanzado? / Meniscal repair in children

La real incidencia de las lesiones meniscales en niños y adolescentes sigue siendo desconocida, aunque se estima que estas han aumentado en los últimos años. En este grupo de pacientes, tanto el examen físico como la resonancia magnética han reportado un menor rendimiento, por lo que la sospecha clínica debe ser alta. Aunque la literatura es escasa en niños y las bases del manejo de estas lesiones se extrapolan del manejo en adultos, la tendencia actual es la preservación meniscal. Dado el alto potencial de cicatrización y la mayor vascularización del menisco pediátrico, se extiende la indicación de sutura meniscal a toda aquella lesión reparable, independiente del patrón, extensión o tiempo de evolución en este grupo étareo. La literatura reporta buenos resultados tras la reparación meniscal en pacientes pediátricos, con tasas de cicatrización promedio por sobre el 70%, que son al menos comparable a lo reportado en adultos. A la fecha, la técnica todo-dentro es la más utilizada por su fácil utilización y menor tiempo quirúrgico. Sin embargo, debemos ser especialmente cuidadosos para evitar una lesión neurovascular iatrogénica dado el menor tamaño y proximidad del paquete neurovascular en rodillas pediátricas. La principal complicación es la falla de la sutura, reportándose tasas comparables a la población adulta a pesar de su indicación extendida en niños y adolescentes. Se han identificado como factores protectores para la reparación meniscal la menor edad, la fisis abierta, roturas de patrones simples y la reconstrucción concomitante de ligamento cruzado anterior. En el presente artículo realizamos una detallada revisión de la literatura disponible sobre reparación meniscal en niños y adolescentes, enfatizando las diferencias versus población adulta. También presentamos nuestra experiencia y protocolo de rehabilitación para sutura meniscal en pacientes pediátricos

The true incidence of meniscal injuries in children and adolescents remains unknown, though estimated to have increased during the last years. Clinical suspicion must remain high since physical examination and magnetic resonance imaging have reported less accuracy for meniscal tears in pediatric patients. Although literature is scarce in children and adolescents and the basis for managing these lesions is extrapolated from adult population, the current trend is meniscal preservation. Considering the greater healing potential and vascularization of the pediatric meniscus, indications for meniscal suture are extended to all those tears amenable to repair in spite of their size, tear pattern and time to repair. Literature has demonstrated good outcomes for meniscal repair in children, with healing rates above 70%, comparable to those reported for adults. To date, the all-inside technique is the most frequently used for meniscal repair thanks to its simplicity and shorter operative time. However, we must be especially careful to avoid iatrogenic neurovascular injury given the smaller size and proximity of the neurovascular package in the pediatric knee. Suture failure is the main complication, with rates comparable to adult population despite widespread indication of repair in children. Younger age, open physis, simple tear patterns and simultaneous anterior cruciate ligament reconstruction appear to benefit meniscal repair in children. This article summarizes the available literature regarding meniscal repair in children and adolescents, emphasizing the differences with adult population. We also present our experience in the treatment of these injuries and our preferred rehabilitation protocol

Encuesta sobre el manejo de injertos del ligamento cruzado anterior contaminados accidentalmente / Survey on management of accidentally contaminated anterior cruciate ligament grafts

OBJETIVO: Encuestar a cirujanos de rodilla en Chile, sobre su conducta en contaminaciones accidentales del injerto, en reconstrucciones de ligamento cruzado anterior (LCA). MÉTODOS: Se realizó una encuesta anónima en relación a la incidencia, tratamiento y resultados clínicos de los injertos de LCA contaminados, a todos los médicos pertenecientes al área de traumatología y ortopedia asistentes al congreso Ateneo de rodilla 2015. RESULTADOS: Se encuestaron 54 médicos, 33 (61%) especialistas en cirugía de rodilla y 21 (39%) médicos en formación. De los cirujanos de rodilla, 15 (45%) reportaron al menos un caso de contaminación, de los cuales 12 (80%) informaron un único evento, 3 (20%) indicaron la eventualidad en 2, 3 y 5 ocasiones respectivamente, para un total de 22 injertos contaminados. De los cirujanos que reportaron injertos contaminados, 11 (73%) realizan 50 o más reconstrucciones al año. La decisión tomada en los casos de contaminación fue en 13 oportunidades (59%), lavar el injerto y utilizarlo de acuerdo al plan inicial; en 6 casos (27%), utilizar aloinjerto; en 2 ocasiones (9%), utilizar autoinjerto alternativo; y en 1 oportunidad (5%); triplicar el semitendinoso. Ninguno de los casos de contaminación reportó infecciones. CONCLUSIONES: En casos de una contaminación accidental, la mayoría de los cirujanos encuestados prefieren optar por la descontaminación del injerto y su utilización en la reconstrucción de acuerdo al plan inicial; para lo cual la clorhexidina y antibióticos sería la solución a usar de preferencia. NIVEL DE EVIDENCIA: Nivel V, opinión de experto.

OBJECTIVE: To survey knee surgeons who perform anterior cruciate ligament (ACL) reconstruction in Chile, about the management when ACL graft contamination occurs. METHODS: An anonymous survey was conducted to all physicians belonging to the area of traumatology and orthopedics who attended the 2015 annual Chilean Knee Society meeting. The survey questioned the incidence, treatment, and outcomes of ACL graft contaminations. RESULTS: Fifty-four physicians were surveyed, of which 33 (61%) where knee surgeons and 21 (39%) physicians in training. Of the 33 knee surgeons, 15 (45%) reported at least one contamination during their career. Of those 15, 12 (80%) had one event, and three surgeons (20%) informed having 2, 3, and 5 episodes respectively, for a total of 22 reported contaminated grafts. Of the surgeons who reported a contaminated graft, 11 (73%) performed 50 or more ACL reconstructions annually. In 13 opportunities (59%) the management for a contaminated graft was cleansing the graft and proceeding as planned. In 6 cases (27%) an allograft was used, in 2 occasions (9%) a different graft was harvested, and in 1 opportunity (5%) a semitendinosus graft triplication was performed. No infections in any of the contaminated grafts were reported. CONCLUSIONS: In case of accidental graft contamination during an ACL reconstruction, knee surgeons most often preferred disinfecting the graft and using it as the initial plan. LEVEL OF EVIDENCE: Level V, expert opinion.

Presoaking of Hamstring Autografts in Vancomycin Decreases the Occurrence of Infection Following Primary Anterior Cruciate Ligament Reconstruction.

BACKGROUND: Postoperative septic arthritis is an uncommon but potentially devastating complication after anterior cruciate ligament (ACL) reconstruction. Our group started presoaking grafts with vancomycin to decrease this risk. PURPOSE: To compare the rate of septic arthritis in primary hamstring autograft ACL reconstruction with and without vancomycin-presoaked grafts. STUDY DESIGN: Cohort study; Level of evidence, 3. METHODS: Consecutive periods were studied, inclusive of April 2013 through October 2015 (pre-vancomycin protocol) and November 2015 through May 2018 (vancomycin protocol). A total of 490 patients were included in the study: 230 in the pre-vancomycin protocol and 260 in the vancomycin protocol. All patients who underwent a primary hamstring autograft ACL reconstruction by 2 senior surgeons during the periods studied were included. The final outcome studied was occurrence of highly probable postoperative septic arthritis in both groups. Diagnosis of probable septic arthritis was made by clinical diagnosis as well as cytological analysis of joint aspiration (cell count >50,000/µL and >90% neutrophils). Statistical analysis was performed with the Fisher exact test. Significance was set at P < .05. RESULTS: Four cases of probable postoperative septic arthritis were noted in the pre-vancomycin protocol (1.7%; 2 cases per surgeon), while no cases of septic arthritis were noted in the vancomycin protocol during the study period (P < .05). Diagnosis was made at a mean 21.7 days (range, 16-25 days). Staphylococcus epidermidis was isolated in 2 cases, and in the other 2 cases, no organism was isolated. CONCLUSION: Presoaking of hamstring autografts in vancomycin for primary ACL reconstruction prevented the occurrence of postoperative septic arthritis during the study period as compared with no soaking of the grafts.

Clinical and functional outcomes of primary total knee arthroplasty: a South American perspective.

BACKGROUND: The aim of this study was to report the clinical and functional outcomes as well as complications after primary total knee arthroplasty in a cohort of Chilean patients. METHODS: We retrospectively reviewed 191 total knee arthroplasties performed in 182 patients over an 8-year period, with a minimum follow-up of 2 years. The primary outcome measure was the rate of major complications. Secondary outcomes were minor complications, residual symptoms, level of satisfaction, and the Knee Injury and Osteoarthritis Outcome Score. RESULTS: Global complication rate was 15.5%, reintervention rate was 9.2%, and revision rate was 2.5%. Major and minor complications were seen in 9.2% and 5.1% of patients, respectively. Average Knee Injury and Osteoarthritis Outcome Score was 77 points (14-100), and 90% of patients reported satisfaction with the procedure. At 2-year follow-up, 45.8% of patients had some degree of range of motion limitations. CONCLUSIONS: Our results show a medium-term follow-up complication rate comparable to those described in the literature. This is the first series to report on the clinical and functional outcomes after primary total knee arthroplasty in a Chilean population.

Meniscus allograft transplantation: indications, techniques and outcomes.

New indications for meniscal allograft transplantation (MAT) are being added, but the general expert opinion is that it is still a procedure reserved for symptomatic meniscal loss.Lateral MAT has better clinical outcomes and less failure risk compared to medial MAT.Ideal conditions (low-grade chondral lesions) make MAT a more survivable and successful procedure.Meniscal extrusion after MAT is common and does not seem to alter results.Midterm survivorship of a MAT is reported to be 85-90%, while long-term survivorship decreases to 50-70% depending on chondral status and concomitant procedures.Even if the procedure is a success, there are high possibilities of not being able to resume sports activities. Cite this article: EFORT Open Rev 2019;4:115-120. DOI: 10.1302/2058-5241.4.180052.