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.

Similar Patient Satisfaction and Quality of Life Improvement Achieved with TKA and THA According to the Goodman Scale: A Comparative Study.

Background: Total knee arthroplasty (TKA) and total hip arthroplasty (THA) are effective treatments for severe knee and hip osteoarthritis. Historically, TKA has been associated with lower satisfaction than THA, but recent advances in knee surgery have led to lower dissatisfaction rates. This study aimed to compare the satisfaction and self-reported improvement in the quality of life of two cohorts of patients who underwent TKA and THA, respectively. Methods: This observational study compared two previously published cohorts of patients who underwent THA and TKA in a single university center. The Goodman scale was used to assess satisfaction and self-perception of improved quality of life after TKA and THA at a minimum one-year follow-up. Propensity score matching was used to balance age, gender, and follow-up between groups. Significance was set at 0.05. Results: The study included a total of 105 THAs and 131 TKAs. Both groups had high levels of satisfaction with pain relief, ability to do house/yard work, and overall satisfaction, with above 90% satisfaction rates. Regarding improvement in quality of life, both groups had 86% of patients reporting improvement as "much better." After propensity score matching, no significant difference was found between THA and TKA for any of the comparisons made using the Goodman scale. Conclusions: The study showed that both TKA and THA resulted in high levels of satisfaction and improvement in quality of life. There was no significant difference in satisfaction rates between TKA and THA, contrary to the historical trend of lower satisfaction rates for TKA.

Anterior knee pain and sit-up tests predicts patients' satisfaction and improvement in quality of life after anterior stabilized total knee replacement without patellar resurfacing.

PURPOSE: The purpose of this study was to assess patient satisfaction and identify risk factors for dissatisfaction after anterior stabilised conventional total knee arthroplasty (TKA) without patellar resurfacing, using the Goodman score. METHODS: We conducted a cross-sectional study using data from our institutional database from 1 January 2018 to 1 March 2021. Patients who underwent TKA with the Vanguard® Cruciate Retaining Anterior Stabilized Knee System (Zimmer Biomet, Warsaw, Indiana, USA) without patellar replacement were included. Patients with other bearing surfaces (posterior stabilised or medial congruent) or diagnosed with infection or instability were excluded. Patients' reported outcomes, body mass index (BMI), passive range of motion, the timed up-and-go test, sit-up test, and algometry were assessed. Patients were also asked if they had anterior knee pain. Satisfaction was assessed using the Goodman scale, and logistic multivariate regression was used to identify variables associated with dissatisfaction and perceived improvement in quality of life. RESULTS: A total of 131 TKA patients were included in the study. The median satisfaction score was 100 (interquartile range [IQR], 87.5 to 100), with the 75-point threshold at the 90th percentile according to Section A of Goodman. Section B of Goodman showed that 113 TKA patients (86.26%) reported "great improvement" or "more than I ever dreamed." Multivariate logistic regression revealed that anterior knee pain (OR 5.16, 95% CI 1.24 to 21.39), the sit-up test (OR 0.63, 95% CI 0.49 to 0.81), and BMI (OR 0.84, 95% CI 0.70 to 0.99) were significantly associated with patient dissatisfaction and a worse perceived improvement in quality of life. The receiver operating characteristics curve for the models had areas under the curve of 0.83 (95% CI 0.69 to 0.97) and 0.82 (95% CI 0.70 to 0.94), respectively. CONCLUSION: Anterior stabilised TKA without patellar resurfacing can achieve 90% satisfaction and 86% improvement in quality of life. To improve these results, it is essential to prevent and treat anterior knee pain and enhance quadriceps strength. LEVEL OF EVIDENCE: Level III (retrospective cohort study).

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.

Cohorte histórica de artroplastia unicompartimental de rodilla en un hospital universitario chileno / Historical cohort of unicompartmental knee arthroplasty in a Chilean university hospital

OBJETIVO Describir el resultado funcional informado por el paciente de una cohorte de pacientes sometidos a artroplastia unicompartimental de rodilla (AUR) en un hospital universitario chileno. MÉTODOS Se diseñó un estudio de cohorte histórica. Se incluyeron todos los pacientes que se sometieron a AUR de platillo fijo entre 2003 y 2019. Un evaluador independiente se puso en contacto con los pacientes en junio de 2020. Se utilizó el índice de artritis de las universidades de Western Ontario y McMaster (WOMAC) para comparar los procedimientos de AUR (medial o lateral), la edad (mayor o menor de 70 años), y el seguimiento (más o menos de 5 años). RESULTADOS Se incluyeron 78 pacientes, en un total de 94 AURs. La mediana de edad fue de 64 años (rango: 43 a 85 años). Hubo 72 (76,6%) casos de AUR medial. Un paciente necesitó revisión para artroplastia total de rodilla (ATR). Un total de 60 pacientes (76,9%), correspondientes a 72 AURs (76,7%), fueron contactados con éxito por teléfono para el seguimiento final. La mediana del puntaje en los dominios del WOMAC fue: dolor ­ 1 (rango: 0 a 12); rigidez ­ 0 (rango: 0 a 4); y función física ­ 2 (rango: 0 a 29). La mediana del puntaje total en el WOMAC fue de 4 (rango: 0 a 44). Los pacientes sometidos a AUR lateral lograron mejores puntuaciones funcionales (p » 0,0432), y el puntaje total en el WOMAC fue similar en pacientes mayores o menores de 70 años (p » 0,3706). CONCLUSIONES La AUR es un tratamiento eficaz y reproducible para pacientes con artrosis de rodilla unicompartimental. La edad parece no afectar los resultados funcionales, y la AUR es un tratamiento eficaz en pacientes mayores de 70 años. Estos resultados deberían animar a los cirujanos de rodilla a aprender esta técnica y a los responsables de las políticas de salud pública a considerar la AUR para la osteoartritis de rodilla.

PURPOSE To describe the patient-reported functional outcome of a cohort of patients undergoing unicompartmental knee arthroplasty (UKA) in a Chilean university hospital. METHODS A historical cohort study was designed. All patients who underwent fixedbearing UKA between 2003 and 2019 were included. An independent evaluator contacted the patients in June 2020. The Western Ontario and McMaster Universities Arthritis Index (WOMAC) was used to compare UKA procedures (medial or lateral), age (over or under 70 years), and follow up (longer or shorter than 5 years). RESULTS A total of 78 patients, corresponding to 94 UKAs, were included. The median age was 64 years (range: 43 to 85 years). There were 72 (76.6%) cases of medial UKA. One patient needed revision to total knee arthoplasty (TKA). A total of 60 patients (76.9%), corresponding to 72 UKAs, were successfully contacted by phone for the final follow-up. The median scores on the WOMAC domains were: pain ­ 1 (range: 0 to 12); stiffness ­0 (range: 0 to 4); and physical function ­ 2 (range: 0 to 29). The median total score on the WOMAC was 4 (range: 0 to 44). Patients submitted to lateral UKA had better functional scores (p » 0.0432), and the total WOMAC score was similar among patients older or younger than 70 years of age (p » 0.3706). CONCLUSIONS For patients with unicompartmental knee osteoarthritis, UKA is an effective and reproducible treatment. Age does not seem to affect the functional results, and UKA is an effective treatment in patients over 70 years old. These results should encourage knee surgeons to learn this technique and those responsible for public health policies to consider UKA for knee osteoarthritis

The Distance between Tibial Tubercle and Trochlear Groove Correlates with Knee Articular Torsion.

This study aims to correlate the tibial tubercle to trochlear groove (TT-TG) distance with knee axial alignment. The hypothesis is that as internal torsion of the distal femur or external torsion of the proximal tibial increases, the TT-TG distance increases. We designed a cross-sectional study approved by our institutional ethics review board. We reviewed 32 computed tomography angiographies of patients that have nonjoint or bone-related symptoms. Distal femoral torsion, proximal tibial torsion, knee articular torsion (AT), and TT-TG distance were measured. A regression analysis between the TT-TG distance and the AT was performed. A positive correlation between the TT-TG distance and the AT was found. An increase in external torsion of the proximal tibial or an increase in internal torsion of the distal femur increases the TT-TG distance. For a correct interpretation of the TT to trochlear groove distance, we propose that the axial alignment should be included in the regular analysis of patellofemoral disease.

Mortality after hip or knee arthroplasty for osteoarthritis in Chile: A survival analysis.

BACKGROUND: The purpose of this study is to determine if patients with osteoarthritis that undergo hip or knee arthroplasty jeopardize their life expectancy in Chile. METHODS: A survival analysis study was designed and approved by our institutional ethics review board. Patients were included if they underwent surgery for hip or knee osteoarthritis and were 50 years or older at the time of surgery. Patients were excluded if arthroplasty was performed for fracture, hemophilia arthropathy, or tumor. A multiparametric Weibull regression was estimated, and the hazard ratio was reported. For internal validity, a bootstrap of 200 repetitions was performed. RESULTS: A total of 4 094 arthroplasties were included. The Kaplan-Meier curve estimates a higher survival than the general population up to 12 years, after which the median survival is less than the general population. The bootstrap multiparametric Weibull regression estimated a hazard ratio of 1.53 (95% confidence interval: 1.27 to 1.84) for women, 1.09 (1.08 to 1.10) for every year older, and 1.29 (1.07 to 1.53) for hip arthroplasty patients. CONCLUSION: Mortality after hip and knee arthroplasty in Chile follows a bimodal behavior similar to reports from the United States and Europe. At first, mortality is lower than the general population but worsens after 12 to 15 years of surgery.

INTRODUCCIÓN: El propósito de este estudio es determinar si los pacientes con artrosis severa intervenidos con artroplastia de rodilla o cadera ponen en riesgo su expectativa de vida. MÉTODO: Se diseñó un estudio de sobrevida el cual fue aprobado por el comité de ética de nuestra institución. Los pacientes fueron incluidos si fueron intervenidos de artroplastia de rodilla y cadera por artrosis severa y tenían más de 50 años. Los pacientes fueron excluidos si la artroplastia se realizó por fractura, hemofilia o un tumor. Una regresión multiparamétrica de Weibull fue estimada, siendo reportado el hazard ratio. Un bootstrap de 200 repeticiones fue realizada para validación interna. RESULTADOS: Un total de 4094 artroplastias fueron incluidos. La curva de Kaplan-Meier estima una mayor sobrevida que la población general hasta los 12 años, luego de lo cual la mediana de sobrevida es menor que la de la población general. La regresión multiparamétrica de Weibull estimó hazard ratios de 1,53 (intervalo de confianza 95%: 1,27 a 1,84) en mujeres, de 1,09 (1,08 a 1,10) por cada año de edad y de 1,29 (1,07 a 1,53) en artroplastia de cadera. CONCLUSIÓN: La mortalidad después de una intervención de artroplastia de rodilla o cadera sigue un comportamiento bimodal respecto a la población general similar a series reportadas en Estados Unidos y Suecia. Inicialmente la sobrevida es mayor que la población general, pero es menor luego de 12 a 15 años.

Periacetabular osteotomy with concomitant hip arthroscopy: A case series with 24 months minimum follow-up.

PURPOSE: To describe patient-reported outcomes, radiological results, and revision to total hip replacement in patients with hip dysplasia that underwent periacetabular osteotomy as isolated treatment or concomitant with hip arthroscopy. METHODS: Case series study. Between 2014 and 2017, patients were included if they complained of hip pain and had a lateral center-edge angle ≤ of 20°. Exclusion criteria included an in-maturate skeleton, age of 40 or older, previous hip surgery, concomitant connective tissue related disease, and Tönnis osteoarthritis grade ≥ 1. All patients were studied before surgery with an anteroposterior pelvis radiograph, false-profile radiograph, and magnetic resonance imaging. Magnetic resonance imaging was used to assess intraarticular lesions, and if a labral or chondral injury was found, concomitant hip arthroscopy was performed. The non-parametric median test for paired data was used to compare radiological measures (anterior and lateral center-edge angle, Tönnis angle, and extrusion index) after and before surgery. Survival analysis was performed using revision to total hip arthroplasty as a failure. Kaplan Meier curve was estimated. The data were processed using Stata. RESULTS: A total of 15 consecutive patients were included; 14 (93%) were female patients. The median follow-up was 3.5 years (range, 2 to 8 years). The median age was 20 (range 13 to 32). Lateral center-edge angle, Tönnis angle, and extrusion index correction achieved statistical significance. Seven patients (47%) underwent concomitant hip arthroscopy; three of them (47%) were bilateral (10 hips). The labrum was repaired in six cases (60%). Three patients (15%) required revision with hip arthroplasty, and no hip arthroscopy-related complications are reported in this series. CONCLUSION: To perform a hip arthroscopy concomitant with periacetabular osteotomy did not affect the acetabular correction. Nowadays, due to a lack of conclusive evidence, a case by case decision seems more appropriate to design a comprehensive treatment.

OBJETIVO: Describir los resultados funcionales, radiológicos y la tasa revisión a artroplastia total de cadera en una cohorte de pacientes con displasia de cadera que requirió osteotomía periacetabular como tratamiento aislado o concomitante con artroscopia de cadera. MÉTODO: Estudio de series de casos. Fueron incluidos pacientes intervenidos quirúrgicamente entre 2014 y 2017. Los criterios de inclusión fueron dolor en la cadera y un ángulo lateral de centro borde ≤ 20°. Los criterios de exclusión fueron esqueleto maduro, edad de 40 años o más, cirugía previa de cadera, enfermedad concomitante relacionada con el tejido conectivo y coxartrosis grado ≥ 1 de Tönnis. Todos los pacientes fueron estudiados antes de la cirugía con una radiografía anteroposterior de pelvis, radiografía de falso perfil y resonancia magnética. En caso de pesquisar una lesión intrarticular en resonancia magnética se realizó una artroscopia concomitante a osteotomía periacetabular. La prueba mediana no paramétrica para datos no pareados se utilizó para comparar medidas radiológicas (ángulo del borde central anterior y lateral, ángulo de Tönnis e índice de extrusión) antes y después de la cirugía. El análisis de sobrevida se realizó utilizando la revisión de la artroplastia total de cadera como fracaso. Se estimó la curva de Kaplan Meier. Los datos se procesaron con Stata. RESULTADOS: Fueron incluidos un total de 15 pacientes consecutivos; Siete pacientes (47%) se sometieron a artroscopia de cadera concomitante, tres de ellos (47%) fueron bilaterales (10 caderas). La mediana de seguimiento fue de 3.5 años (rango, 2 a 8 años). La mediana de edad fue de 20 (rango 13 a 32). El ángulo de cobertura lateral preoperatorio era de 12° (rango, -29° a 19°) y posterior a la cirugía fue de 25° (rango, 8° a 34°), logrando una mediana de corrección de 16° (rango, 7° a 53°). El labrum fue reparado en seis casos (60%). Tres pacientes (15%) requirieron revisión con artroplastia de cadera, y no se informan complicaciones relacionadas con la artroscopia en esta serie. CONCLUSIÓN: Realizar una artroscopia concomitante con osteotomía periacetabular no afectó la corrección acetabular, ni el resultado clínico. Hoy en día, debido a la falta de evidencia concluyente, el realizar una artroscopía es una decisión que debe ser tomada caso a caso para un tratamiento integral.

Mortalidad de los pacientes intervenidos de artroplastia de rodilla y cadera en Chile: análisis de sobrevida / Mortality after hip or knee arthroplasty for osteoarthritis in Chile: a survival analysis

Introducción El propósito de este estudio es determinar si los pacientes con artrosis severa intervenidos con artroplastia de rodilla o cadera ponen en riesgo su expectativa de vida. Método Se diseñó un estudio de sobrevida el cual fue aprobado por el comité de ética de nuestra institución. Los pacientes fueron incluidos si fueron intervenidos de artroplastia de rodilla y cadera por artrosis severa y tenían más de 50 años. Los pacientes fueron excluidos si la artroplastia se realizó por fractura, hemofilia o un tumor. Una regresión multiparamétrica de Weibull fue estimada, siendo reportado el hazard ratio. Un bootstrap de 200 repeticiones fue realizada para validación interna. Resultados Un total de 4094 artroplastias fueron incluidos. La curva de Kaplan-Meier estima una mayor sobrevida que la población general hasta los 12 años, luego de lo cual la mediana de sobrevida es menor que la de la población general. La regresión multiparamétrica de Weibull estimó hazard ratios de 1,53 (intervalo de confianza 95%: 1,27 a 1,84) en mujeres, de 1,09 (1,08 a 1,10) por cada año de edad y de 1,29 (1,07 a 1,53) en artroplastia de cadera. Conclusión La mortalidad después de una intervención de artroplastia de rodilla o cadera sigue un comportamiento bimodal respecto a la población general similar a series reportadas en Estados Unidos y Suecia. Inicialmente la sobrevida es mayor que la población general, pero es menor luego de 12 a 15 años.

Background The purpose of this study is to determine if patients with osteoarthritis that undergo hip or knee arthroplasty jeopardize their life expectancy in Chile. Methods A survival analysis study was designed and approved by our institutional ethics review board. Patients were included if they underwent surgery for hip or knee osteoarthritis and were 50 years or older at the time of surgery. Patients were excluded if arthroplasty was performed for fracture, hemophilia arthropathy, or tumor. A multiparametric Weibull regression was estimated, and the hazard ratio was reported. For internal validity, a bootstrap of 200 repetitions was performed. Results A total of 4 094 arthroplasties were included. The Kaplan-Meier curve estimates a higher survival than the general population up to 12 years, after which the median survival is less than the general population. The bootstrap multiparametric Weibull regression estimated a hazard ratio of 1.53 (95% confidence interval: 1.27 to 1.84) for women, 1.09 (1.08 to 1.10) for every year older, and 1.29 (1.07 to 1.53) for hip arthroplasty patients. Conclusion Mortality after hip and knee arthroplasty in Chile follows a bimodal behavior similar to reports from the United States and Europe. At first, mortality is lower than the general population but worsens after 12 to 15 years of surgery.

Periacetabular osteotomy with concomitant hip arthroscopy: a case series with 24 months minimum follow-up

PURPOSE To describe patient-reported outcomes, radiological results, and revision to total hip replacement in patients with hip dysplasia that underwent periacetabular osteotomy as isolated treatment or concomitant with hip arthroscopy. METHODS Case series study. Between 2014 and 2017, patients were included if they complained of hip pain and had a lateral center-edge angle ≤ of 20°. Exclusion criteria included an in-maturate skeleton, age of 40 or older, previous hip surgery, concomitant connective tissue related disease, and Tönnis osteoarthritis grade ≥ 1. All patients were studied before surgery with an anteroposterior pelvis radiograph, false-profile radiograph, and magnetic resonance imaging. Magnetic resonance imaging was used to assess intraarticular lesions, and if a labral or chondral injury was found, concomitant hip arthroscopy was performed. The non-parametric median test for paired data was used to compare radiological measures (anterior and lateral center-edge angle, Tönnis angle, and extrusion index) after and before surgery. Survival analysis was performed using revision to total hip arthroplasty as a failure. Kaplan Meier curve was estimated. The data were processed using Stata. RESULTS A total of 15 consecutive patients were included; 14 (93%) were female patients. The median follow-up was 3.5 years (range, 2 to 8 years). The median age was 20 (range 13 to 32). Lateral center-edge angle, Tönnis angle, and extrusion index correction achieved statistical significance. Seven patients (47%) underwent concomitant hip arthroscopy; three of them (47%) were bilateral (10 hips). The labrum was repaired in six cases (60%). Three patients (15%) required revision with hip arthroplasty, and no hip arthroscopy-related complications are reported in this series. CONCLUSION To perform a hip arthroscopy concomitant with periacetabular osteotomy did not affect the acetabular correction. Nowadays, due to a lack of conclusive evidence, a case by case decision seems more appropriate to design a comprehensive treatment.

Successful Selective Embolization for Recurrent Hemarthrosis after Knee Arthroplasty.

Knee replacement has demonstrated to be a cost-effective treatment for severe knee osteoarthritis. Nevertheless, perioperative complications may occur, including recurrent hemarthrosis reaching an incidence between 0.3 and 1.6%. Success rate after conservative treatment has been reported to be above 80%, but in case of recurrence, computed tomography angiography, magnetic resonance angiography, and Doppler ultrasound have been used to conduct the diagnosis. Arthroscopy or selective embolization is used for treatment depending on the etiology of the bleeding. Open surgery is performed in the rare cases of failure of the above alternatives. The patient consulted seven months after total knee arthroplasty with sudden pain in the medial side of the knee. Infection was ruled out, and arthrocentesis shows hemarthrosis. Successful selective embolization of medial superior and lateral superior genicular artery was performed. After two years, the patients report 92 points in the Forgotten joint score, 0 in Womac pain, 1 in Womac stiffness, and 3 in Womac functional score.

A Novel Approach to Lower-limb Axial Alignment Analysis: A CT Study.

To analyze the torsion of the lower extremities in a healthy cohort and to determine the contribution of different segments of the femur and tibia to the torsion of both bones. METHODS: In this cross-sectional study, 32 patients with nonjoint or bone-related symptoms were analyzed by CT angiography. Lower-limb torsion, femoral torsion, proximal femoral torsion, femoral shaft torsion, distal femoral torsion, tibial torsion, proximal tibial torsion, and distal tibial torsion were measured. RESULTS: The median total limb torsion was 25° external torsion, with the median femoral torsion being -9° and the median tibial torsion 30°. Both femoral metaphyses had internal torsion, with the internal torsion of the proximal metaphysis being approximately three times greater than that of the distal femoral metaphysis. The shaft was found to compensate with an external torsion of approximately two-thirds of the internal torsion of both femoral metaphyses. The proximal metaphysis of the tibia accounted for approximately one-third of the external torsion, with the segment from the distal to the tibial tubercle accounting for the remaining two-thirds of the tibial torsion. CONCLUSIONS: The diaphysis and distal metaphysis are the major contributors to external torsion of the tibia, whereas the proximal metaphysis is the major contributor to the internal torsion of the femur.

Retrograde Intramedullary Nail Fixation for Derotational Femoral Osteotomy for Recurrent Femoropatellar Instability.

Axial alignment of the femur and tibia is often misdiagnosed in patients with patellofemoral stability problems. Femoral torsion is critical for patellofemoral biomechanics, so it must be evaluated in every patient before the plan of surgery is decided. This case describes a femoral derotational osteotomy due to excessive internal torsion of the femur fixed with a retrograde femoral nail. This type of fixation provides a biomechanical advantage compared to plates. At the two-year follow-up, the patient achieved excellent results, reaching a functional score of 91 points on the Lysholm scale. Derotational femoral osteotomy should be considered in patellofemoral pathology, and a retrograde femoral nail is a valid fixation method for this surgery.

Treatment of Osteochondritis Dissecans of the Knee with Autologous Iliac Bone Graft and Hyaluronic Acid Scaffold.

Osteochondritis dissecans (OCD) is a condition that corresponds to an idiopathic focal lesion affecting the subchondral bone with possible compromise of the stability of the adjacent cartilage. Treatment depends on the size of the lesion, cartilage stability, and the physeal status. The case reported is about an 18-year-old male patient who complained of suffering from knee pain for a period of ten months. Magnetic resonance imaging (MRI) revealed a lesion of 2 cm2 in the medial femoral condyle that compromised the subchondral bone, compatible with OCD. He underwent surgery that consisted of filling the subchonral defect with an iliac crest autograft and sealing the defect with a hyaluronic acid scaffold. At the 12-month follow-up, the MRI shows complete healing and the patient has resumed sports activities. Management with autologous iliac crest graft and hyaluronic acid scaffold represents an effective alternative treatment for OCD.

Primary Meningococcal Type C Arthritis: A Case Report and Literature Review.

Acute septic arthritis is a common clinical problem in emergency departments. Primary meningococcal arthritis (PMA) is very rare and few cases are reported in literature. D. B. M. consulted the emergency department for knee pain and fever; analysis showed that the cause was a Neisseria meningitidis type C infection. He received a treatment consisting of 2 arthroscopies and 5 weeks of antibiotics. At five weeks he returned to work and at 2 months he resumed sports (jogging and soccer) without complaints. Primary arthritis of the knee caused by Neisseria meningitidis is very rare. It has a very good response to antibiotics and arthroscopy procedure. Short-term follow-up and functional results are often good or excellent.

Is there a pathological alpha angle for hip impingement? A diagnostic test study.

The normal value of alpha angle is controversial. The aim of this study was to compare the alpha angle in asymptomatic volunteers versus patients who had undergone surgery for symptomatic cam-type femoroacetabular impingement (FAI) and determine a diagnostic cut-off value for symptomatic cam impingement. This is a diagnostic test study. Cases were defined as those patients who had undergone surgery for symptomatic cam or mixed type FAI. Controls were defined as asymptomatic volunteers, with no history of hip pain who had undergone a computed tomography (CT) scan of the abdomen and pelvis for a non-joint or bone-related reason. In both groups, the alpha angle was measured in an oblique axial CT reconstruction of the femoral neck. A logistic regression model was first estimated and a receiver operating characteristics (ROC) curve was then calculated. The diagnostic cut-off value selected was the one that maximizes sensitivity and specificity. Data were analysed from 38 consecutive cases of cam or mixed FAI and 101 controls. The average alpha angle was 67°(±12°) among cases and 48°°(±5°) among controls. An odds ratio of 1.28 [1.18-1.39] was obtained. A ROC curve of 0.96 [0.93-0.99] was calculated, and using an alpha angle of 57° as the diagnostic cut-off value, provided a sensitivity of 92% and a specificity of 95%. If a patient complains of hip pain and an alpha angle of 57° is found in CT, strongly suggest that cam impingement is causing the pain.

Gonyautoxins: First evidence in pain management in total knee arthroplasty.

Improvements in pain management techniques in the last decade have had a major impact on the practice of total knee arthroplasty (TKA). Gonyautoxin are phycotoxins, whose molecular mechanism of action is a reversible block of the voltage-gated sodium channels at the axonal level, impeding nerve impulse propagation. This study was designed to evaluate the clinical efficacy of Gonyautoxin infiltration, as a long acting pain blocker in TKA. Fifteen patients received a total dose of 40 µg of Gonyautoxin during the TKA operation. Postoperatively, all patients were given a standard painkiller protocol: 100 mg of intravenous ketoprofen and 1000 mg of oral acetaminophen every 8 hours for 3 days. The Visual Analog Scale (VAS) pain score and range of motion were recorded 12, 36, and 60 hours post-surgery. All patients reported pain of 2 or less on the VAS 12 and 36 hours post-surgery. Moreover, all scored were less than 4 at 60 hours post-surgery. All patients achieved full knee extension at all times. No side effects or adverse reactions to Gonyautoxin were detected in the follow-up period. The median hospital stay was 3 days. For the first time, this study has shown the effect of blocking the neuronal transmission of pain by locally infiltrating Gonyautoxin during TKA. All patients successfully responded to the pain control. The Gonyautoxin infiltration was safe and effective, and patients experienced pain relief without the use of opioids.

Fluid Extravasation Related to Hip Arthroscopy: A Prospective Computed Tomography-Based Study.

BACKGROUND: Complications related to hip arthroscopy are rare, with a current rate of <2%. Some complications are related to fluid extravasation, which has been associated with life-threatening conditions such as abdominal compartment syndrome, cardiopulmonary arrest, hypothermia, and atelectasis. PURPOSE: To identify risk factors for fluid volume extravasation in hip arthroscopy and to determine the relationship between anatomical location on computed tomography (CT) and extravasated volume. STUDY DESIGN: Case series; Level of evidence, 4. METHODS: We performed a prospective cohort study of 40 consecutive arthroscopies for femoroacetabular impingement. Patient demographics and procedures performed (ie, acetabuloplasty and its size, femoral osteoplasty, and psoas tenotomy) were recorded. The extravasated volume was estimated by the difference between the infused volume and the intraoperatively collected volume. Within 12 hours after the procedure, the pelvis was scanned by CT. We created a 3-stage radiological classification based on progressive involvement of anatomical structures attributed to liquid extravasation. Statistical analyses were performed with a 95% CI and a significance level of 5%. RESULTS: No relevant clinical symptoms related to fluid extravasation were recorded. The mean extravasated volume was 3.06 L at a rate of 1.05 L/h, corresponding to nearly 10% of the infused volume. There was a trend toward greater extravasated volume with longer operative time and longer time in the peripheral compartment (without axial traction); however, there was no statistical significance. The anatomical classification on CT imaging was directly related to the extravasated volume and compromised the thigh, gluteus, and retroperitoneum and intraperitoneal spaces. There was a 6-fold greater probability of female patients having an advanced stage extravasation on CT classification. CONCLUSION: In our series, 10% of the infused volume was extravasated in uncomplicated hip arthroscopy. Risk factors for extravasation were related to operative time, particularly during peripheral compartment intervention (ie, without traction). The anatomical classification proposed in this study reflects the progressive involvement of the thigh, gluteus, iliopsoas, and retroperitoneal and intraperitoneal spaces after increase in extravasated volume. Compared with males, females were associated with more severe anatomical compromise for the same extravasated volume.

Effect of active versus passive recovery on performance during intrameet swimming competition.

BACKGROUND: During competition, high-performance swimmers are subject to repeated physical demands that affect their final performance. Measurement of lactate concentration in blood seeks to indirectly gauge physiologic responses to the increase in physical exercise. Swimmers face multiple maximal-exertion events during competition. Strenuous physical exercise leads to fatigue and, thus, a decrease in sports performance. HYPOTHESIS: Regeneration exercises in swimming increase the clearance of blood lactate and therefore improve athletic performance within a single day of competition. STUDY DESIGN: Crossover study. LEVEL OF EVIDENCE: Level 1. METHODS: Of 25 swimmers, 21 were included, with a mean age of 17 years. They performed exercises that increased blood lactate on 2 days. The protocol was a warm-up, followed by a 100-m freestyle workout at full speed. Swimming exercises followed that were increasingly demanding, during which serial lactatemia measurements were taken. On the first day, regeneration exercises were performed; on the second day, the swimmers rested. Next, lactatemia was measured, and a timed 100-m freestyle workout was performed at maximum speed. RESULTS: The stress exercises increased the mean lactate concentration by 4.6 mmol/L, which corresponds to 78% of the initial basal level. The postregeneration lactatemia level was lower than that after resting (mean, 2.76 vs 6.51 mmol/L). The time to swim 100 m after regeneration was 68.11 seconds, while that after rest was 69.31 seconds. CONCLUSION: Blood lactate levels rose by up to 78% after the intensity of the training sessions was progressively increased. Regeneration exercises increased the rate in which blood lactate dissipated, in comparison with passive recuperation. The rate of lactate dissipation for regeneration exercises was 68%. This factor may have improved the physical performance of swimmers. CLINICAL RELEVANCE: Regeneration exercises improved the performance of swimmers in maximal-exertion competition in a single day. The blood lactate level correlated with physical exercise load.

Hip Morphology Characterization: Implications in Femoroacetabular Impingement in a Chilean Population.

BACKGROUND: Femoroacetabular impingement (FAI) is the result of a mechanical conflict in the hip joint, and its diagnosis is based on clinical and radiological parameters. To our knowledge, there are no published studies describing the radiologic characteristics of FAI in Latin American populations. PURPOSE: To describe the radiological features associated with FAI in an asymptomatic Chilean population. STUDY DESIGN: Cross-sectional study; Level of evidence, 3. METHODS: We prospectively recruited asymptomatic patients with no history or symptoms of hip pathology who underwent abdomen-pelvis computed tomography (CT) for a nonorthopaedic indication. The acetabular and femoral parameters related to FAI were measured. RESULTS: We studied 101 subjects (202 hips) with a mean age of 36.8 ± 14.4 years. The mean center-edge angle was 39.4° ± 7.2°. The crossover sign was present in 34 cases (33.7%). The mean alpha angle was 49.7° ± 8.3°. Depending on the cut points chosen for FAI-related parameters, between 39.6% and 69.3% of an asymptomatic Chilean population were found to have morphological features related to FAI. CONCLUSION: Our findings suggest that the proposed pathological threshold values in the literature cannot be extrapolated to a Chilean population, and this must be taken into consideration when evaluating Latin American patients with hip pain.