Research Progress of Age Estimation in the Living by Knee Joint MRI / 法医学杂志

Bone development shows certain regularity with age. The regularity can be used to infer age and serve many fields such as justice, medicine, archaeology, etc. As a non-invasive evaluation method of the epiphyseal development stage, MRI is widely used in living age estimation. In recent years, the rapid development of machine learning has significantly improved the effectiveness and reliability of living age estimation, which is one of the main development directions of current research. This paper summarizes the analysis methods of age estimation by knee joint MRI, introduces the current research trends, and future application trend.

Study on the relationship between severe knee osteoarthritis and bone marrow edema / 中国骨伤

OBJECTIVE@#To investigate the relationship between bone marrow edema and pathological changes, symptoms and signs of severe knee osteoarthritis.@*METHODS@#From January 2020 to March 2021, 160 patients with severe knee osteoarthritis who underwrent MRI of the knee at the Department of Bone and Joint, Wangjing Hospital, China Academy of Chinese Medical Sciences were included. Eighty patients with bone marrow edema were selected as the case group, including 12 males and 68 females, aged from 51 to 80 years old with an average of (66.58±8.10) years old, the duration of disease 5 to 40 months with an average of (15.61±9.25) months. Eighty patients without bone marrow edema were selected as the control group, including 15 males and 65 females, aged from 50 to 80 years old with an average of (67.82±8.05) years old, the duration of disease 6 to 37 months with an average of (15.75±8.18) months, BMI was (28.26±3.13) kg·m-2 ranged from 21.39 to 34.46 kg·m-2. The degree of bone marrow edema was evaluated by knee whole oragan magnetic resonance imaging score (WORMS). The degree of knee osteoarthritis was evaluated by Kellgren- Lawrence(K-L) grade and Western Ontario and McMaster University Osteoarthritis Index (WOMAC). The degree of joint pain was evaluated by visual analogue scale(VAS) and WOMAC pain score, the joint signs were evaluated by tenderness, percussion pain, joint swelling and joint range of motion. To explore the relationship between bone marrow edema and knee osteoarthritis, the prevalence of bone marrow edema and K-L grade were compared between the two groups. Furthermore the WORMS score and WOMAC index, pain-related score, and sign-related score correlation coefficient were analyzed to further explore the relationship between bone marrow edema and knee osteoarthritis index, joint pain symptoms and signs.@*RESULTS@#There was 68.75% (55/80) of the patients in the case group were in K-L grade Ⅳ, and 52.5% (42/80) in the control group, indicating a higher proportion of patients with grade Ⅳ in the case group than the control group (χ2=4.425, P<0.05). In the case group, there was a strong correlation between bone marrow edema WORMS score and knee osteoarthritis WOMAC index. (r=0.873>0.8, P<0.001), a moderate correlation between WORMS score and VAS score and WOMAC pain score(r=0.752, 0.650>0.5, P<0.001), a moderate correlation between WORMS score and percussion pain score (r=0.784>0.5, P<0.001), and a weak correlation between WORMS score and VAS and tenderness score, joint swelling score and joint range of motion score (r=0.194, 0.259, 0.296<0.3, P<0.001).@*CONCLUSION@#Our study suggests that severe knee osteoarthritis is associated with an increased risk of bone marrow edema. Bone marrow edema can also lead to knee osteoarthritis joint pain, with percussion pain being a positive sign, but tenderness, joint swelling and limitation of activity are not significantly related to bone marrow edema.

Correlation between spatial inclination of Blumensaat line and anterior cruciate ligament injury based on EOS biplanar 3D imaging system / 中国骨伤

OBJECTIVE@#To explore correlation between femoral mechanical axis and Blumensaat line (FMBL) angle of knee joint (angle between Blumensaat line and femoral mechanical axis), α angle (angle between Blumensaat line and axis of distal femur in sagittal plane) on EOS biplane imaging and non-contact anterior cruciate ligament(ACL) injury, and evaluate angle for its accuracy in predicting the populations prone to non-contact ACL injury.@*METHODS@#From February 2018 to October 2020, EOS imaging and clinical data from 88 patients (176 knees) with unilateral non-contact ACL injury were retrospectively analyzed, including 53 males and 35 females, aged from 18 to 45 years old with an average of (30.3±6.2) years old, 48 patients on the left side and 40 patients on the right side. The patients were divided into ACL-affected group and ACL-health group according to side of ACL injuries, and 51 patients (51 knees) with non-ACL identified from EOS database were included in normal control group, including 28 males and 23 females, aged from 20 to 44 years old with an average of (31.6±5.5) years old, 26 patients on the left side and 25 patients on the right side. Full-length EOS imaging of skeleton extremitatis inferioris among three groups were reconstructed to 3D images of skeletal system with EOS software, and then FMBL angle and α angle were measured on the images. Univariate binary Logistic regression analysis was performed to determine the influence of the univariate(FMBL angle or α angle) on ACL status(normal or torn). And the angle cutoff value for univariate was selected based on receiver operating characteristics curve (ROC) to got the best accuracy.@*RESULTS@#There was no statistically significant difference in age, gender and side distribution between ACL-injured group and normal control group(P>0.05). Statistical analyses (one-way ANOVA) indicated no significant difference in FMBL angle between ACL-injured knee group (32.8±2.3)° and ACL-injured contralateral knee group(32.5±2.3)°(P>0.05), but the values between two groups were significantly lower than that in normal control group (37.0±2.0)°(P<0.001). There was no statistically significant difference in α angle among three groups (P>0.05). Univariate binary Logistic regression analysis demonstrated that FMBL angle was risk factor for non-contact ACL injury[OR=0.433, 95%CI(0.330, 0.569), P<0.001]. The area under ROC curve for FMBL angle was 0.909[95%CI(0.861, 0.958), P<0.001], and the sensitivity and specificity were 70.5% and 98.0% respectively, cut-off value was 33.7°.@*CONCLUSION@#FMBL angle formed by Blumensaat line and femoral mechanical axis is one of the risk factors for non-contact ACL injury and has good predictive accuracy. The general population with FMBL angle below 33.7° may be increased risk for ACL injury.

Diagnostic value of ultrasound in the discoid lateral meniscus of the knee / 中国骨伤

OBJECTIVE@#Based on the anatomical differences between discoid lateral meniscus(DLM) and normal lateral meniscus (NLM), this study aims to setting up the ultrasound examination parameters to distinguish DLM and NLM and explore the diagnostic value of these parameters on DLM.@*METHODS@#According to the inclusion, exclusion and matching criteria, 66 DLM patients(DLM group) and 132 NLM patients with other knee joint diseases(NLM group), hospitalized from October 2019 to June 2020, were included in this study. There were 18 males and 48 females in the DLM group, ranging in age from 3 to 60 years old, with a mean of (36.9±12.1) years old;36 males and 96 females in the NLM group, ranging in age from 3 to 60 years old, with a mean of (40.0±12.2) years old. Philips high frequency(3.0 to 12.0 MHz) linear array ultrasound probe was used to examine the lateral meniscus of all patients in two groups. Nine parameters including the thickness, width and the included angle of the anterior angle, body and posterior angle respectively in the lateral meniscus were measured. The included angke is formed by the chords of the upper and lower curved surfaces of the meniscus at the free edge. The independent t test was used to analyze the difference of the measured parameters between the DLM group and the NLM group. The receiver operating characteristic(ROC) curve was used to evaluate the cut-off value of each parameter for diagnosing DLM and the corresponding sensitivity, specificity, positive predictive value, negative predictive value, and area under the ROC curve(AUC).@*RESULTS@#The above 9 ultrasound measurement parameters between the DLM group and the NLM group had significant statistical differences(P<0.001). The ROC curve analysis method evaluated the cut-off value and diagnostic capabilities of these nine ultrasound parameters for DLM. The results showed that the cut-off value of the included angle of anterior part, body and posterior part were 25.85°, 24.85° and 29.15 °, respectively;and the sensitivity, specificity, negative predictive value, positive predictive value and AUC were significantly higher than other parameters, which were 88%, 91%, 79%, 95%, 0.94;89%, 94%, 82%, 97%, 0.96; 92%, 97%, 86%, 98%, 0.97, respectively.@*CONCLUSION@#Ultrasound diagnosis of DLM is feasible and reliable. The diagnostic ability of the included angle of the anterior part, body and posterior part in the lateral meniscus measured by ultrasound to diagnose DLM are significantly better than other ultrasound measurement parameters, and the sensitivity and specificity of those parameters are close to MRI. Therefore, ultrasound can be used as a reliable method for preliminary diagnosis of DLM.

Características morfométricas de los discos articulares de la rodilla en imágenes de resonancia magnética de mujeres colombianas / Morphometric features of the knee menisci in magnetic resonance images of Colombian female

RESUMEN: La población femenina de adultos mayores suele presentar daños de los discos o meniscos articulares de la rodilla (DAR) generalmente derivados de procesos degenerativos de cartílago ocurridos en osteoartritis. Conocer patrones morfológicos estándares de los DAR en una población demográfica específica permite tener claridad de las características autóctonas de dicha población. Una forma de caracterizar estos patrones es a través del diseño de Modelos de Elementos Finitos (MEF) que permiten predecir anormalidades clínicas y radiológicas. Hasta el momento es escasa la evidencia sobre las características morfométricas de los DAR en la población colombiana. Por esta razón, el objetivo del presente estudio fue describir la morfometría de DAR en imágenes por resonancia magnética (IRM) de mujeres colombianas saludables. En este estudio se tomaron 25 IRM de la rodilla de mujeres colombianas con normo-peso, sin antecedentes de patología de la rodilla, ni historia de trauma o cirugía de esta, y con edades entre los 18 y 60 años. El análisis del ancho del cuerno posterior del DAR medial (12,73 ± 2,42) comparado con el lateral (8,04 ± 1,52) arrojó diferencia estadísticamente significativa (p<0,05). Por otra parte, el DAR medial presentó un diámetro antero-posterior aumentado (38,52 ± 2,71) en comparación con el del DAR lateral (29,18 ± 2,75) cercano a la significancia estadística (p=0.051). De igual manera, la altura del cuerno anterior se encontró aumentada en el DAR medial (4,42 ± 0,79) en comparación con el lateral (3,66 ± 0,76), con tendencia a la significancia estadística (p=0,063). Anatómicamente se reconoce que los DAR medial y lateral se adaptan a la forma y tamaño de los cóndilos femorales, lo que concuerda con las medidas resultantes de la población estudiada, donde se evidencia un DAR medial más largo (diámetro antero-posterior) y menos alto que el lateral.

SUMMARY: The elderly female population usually presents damage to the articular discs or menisci of the knee (ADK), generally derived from degenerative cartilage processes that occur in osteoarthritis. Knowing the standard morphological patterns of ADKs in a specific demographic population allows clarity of the indigenous characteristics of that population. One way to characterize these patterns is through the design of Finite Element Models (FEM) that would enable predicting clinical and radiological abnormalities. So far, there is little evidence on the morphometric characteristics of ADKs in the Colombian population. Thus, the objective of the present study was to describe the morphometry of ADK in magnetic resonance imaging (MRI) of healthy Colombian women. In this study, 25 MRIs of the knee of Colombian women with normal weight were taken, with no history of knee pathology, trauma, or surgery, and with ages between 18 and 60 years. The analysis of the width of the posterior horn of the medial ADK (12.73 ± 2.42) compared to the lateral (8.04 ± 1.52) showed a statistically significant difference (p <0.05). On the other hand, the medial ADK presented an increased anteroposterior diameter (38.52 ± 2.71) compared to that of the lateral ADK (29.18 ± 2.75) close to statistical significance (p = 0.051). Similarly, the height of the anterior horn was found to be increased in the medial ADK (4.42 ± 0.79) compared to the lateral (3.66 ± 0.76), with a trend towards statistical significance (p = 0.063). Anatomically, it is recognized that the medial and lateral ADK adapt to the shape and size of the femoral condyles, which is in agreement with the results of the studied population where measurements show that medial ADK has a longer (anterior to posterior diameter) and a shorter height than the lateral ADK.

Difference of musculoskeletal ultrasound imaging of focus of knee joint tendon between patients with knee osteoarthritis and healthy subjects / 中国针灸

OBJECTIVE@#To observe the imaging features of focus of knee joint tendon in patients with knee osteoarthritis (KOA) by musculoskeletal ultrasound (MSUS) technique.@*METHODS@#One hundred KOA patients and 100 healthy subjects were included. All the KOA patients were palpated by the sequence of foot @*RESULTS@#The top-5 focus of knee tendon of KOA patients were located in medial inferior patella, medial tibial condyle, inferior patella, Zusanlici and Hedingci. The thickness of ligaments and tendons in extension and flexion positions in KOA patients were thicker than that in healthy subjects (@*CONCLUSION@#The focus of knee joint tendon in KOA patients shows significantly thickened musculoskeletal imaging features.

Correlation between cold pain of knee joint and subchondral bone marrow edema in patients with knee osteoarthritis / 中国骨伤

OBJECTIVE@#To investigate relationship between cold pain of knee joint and subchondral bone marrow edema (BME).@*METHODS@#From May 2018 to August 2019, 92 patients with knee osteoarthritis (KOA) associated with cold pain of knee were admitted, all patients were underwent MRI examination. The patients were divided into observation group (47 patients with BME) and control group(45 patients without BME). In observation group, there were 6 males and 41 females aged from 36 to 87 years old with an average of (63.2±12.3) years old. In control group, there were 10 males and 35 females, aged from 48 to 84 years old with an average of (62.7±8.3) years old. All patientswere treated with drugs. The degree of joint degeneration was evaluated by Kellgren-Lawrence (K-L) grading. Degree of cold pain of knee was evaluated by knee cold pain score, and degree of BME was evaluated according to WORMS. The correlation between cold pain of knee and K-L grading and BME was analyzed.@*RESULTS@#Score of cold pain in observation group (15.55±7.68) was higher than that of control group (9.42± 5.50), which had significant difference (@*CONCLUSION@#The cold pain of KOA patients is not related to K-L grading, but corelate with BME grading. The Cold pain of knee was more pronounced in KOA patients with BME, and the severity of BME is often related to degree of cold pain. It seemed to be a tendency:the more serious BME, the heavier coldpain.

Acoustic radiation force impulse (ARFI) elastography of the stifle joint of healthy beagles / [Elastografia acoustic radiation force impulse (ARFI) da articulação do joelho de beagles saudáveis]

The objective was to establish the reference standards for elastography of the main structures of the canine stifle joint. The medial meniscus, patellar and cruciate ligaments of thirty healthy beagles was evaluated by B-mode and ARFI elastography (n=60 joints). Analysis detected a positive correlation of the shear wave velocity (SWV) of structures according to age. Patellar ligament presented a gradual stiffness increase in relation to age, while medial meniscus and cruciate ligament were more rigid in puppies than in adults. However, greater stiffness of these structures was observed in elderly animals. Elasticity of each structure was evaluated according to gender and reproductive status. Females presented greater stiffness of all structures, with SWV differing 0.3 and 0.36m/s between genders. Only the medial meniscus was not stiffer in neutered animals when compared to intact animals, differing only 0.02m/s in menisci and 0.4 to 0.47m/s in ligaments between groups. These findings corroborate with literature data that states a higher prevalence of ligament insufficiency in elderly dogs, females and neutered animals. It was concluded that ARFI elastography of the canine stifle joint is feasible and its application can be potentially effective in early diagnosis of ligament and meniscal changes.(AU)

O objetivo foi estabelecer os padrões normais para elastografia das principais estruturas da articulação do joelho em cães. O menisco medial, ligamento patelar e cruzado de trinta beagles saudáveis foram avaliados pelo modo B e elastografia ARFI (n=60 articulações). A análise detectou uma correlação positiva da velocidade de cisalhamento (SWV) das estruturas com a idade. O ligamento patelar apresentou um aumento gradual da rigidez em relação à idade, enquanto o menisco medial e o ligamento cruzado foram mais rígidos em filhotes do que em adultos. Entretanto, observou-se maior rigidez dessas estruturas em idosos. A elasticidade de cada estrutura foi avaliada de acordo com o sexo e o estado reprodutivo. As fêmeas apresentaram maior rigidez em todas as estruturas, com SWV diferente de 0,3 e 0,36m/s entre os sexos. Somente o menisco medial não foi mais rígido nos animais castrados quando comparado não castrados, diferindo apenas 0,02m/s no menisco e 0,4 a 0,47m/s nos ligamentos entre os grupos. Esses achados corroboram com dados da literatura que afirmam maior prevalência de insuficiência ligamentar em cães idosos, fêmeas e animais castrados. Concluiu-se que a elastografia ARFI da articulação do joelho canino é viável e sua aplicação pode ser eficaz no diagnóstico precoce de alterações ligamentares e meniscais.(AU)

Rheumatoid arthritis combined with pigmented villonodular synovitis: A case report and literature review / 北京大学学报(医学版)

We reported a case of rheumatoid arthritis (RA) combined with pigmented villonodular synovitis (PVNS) from Peking University People's Hospital. The clinical data were introduced and the related literature was reviewed. The clinical features, treatment and prognosis of the disease were summarized to improve clinicians' understanding of this rare disease and avoid misdiagnosis and delayed diagnosis. A 45-year-old female, with 15 years of RA history and unregular treatment, was admitted to the hospital with the complaint of aggravating pain and swelling in the right knee for 3 months. The puncture of the right knee was performed and there was a large amount of bloody synovial fluid that could not be explained by her RA history. Moreover, the magnetic resonance imaging (MRI) of the right knee revealed hemosiderin deposition with low-intensity signals on both T1-weighted and T2-weighted images which suggested PVNS to us. Then, the patient underwent knee arthroscopy and biopsy to assist in diagnosis. The arthroscopic appearance and pathology were consistent with PVNS and the hyperplastic synovium was removed during arthroscopy. After the operation, she did active functional exercises and took disease-modifying antirheumatic drugs to control RA. She recovered well and remained asymptomatic after half a year of follow-up. Also, there was no recurrence of the right knee. As we all know, RA is a systemic autoimmune disease characterized by chronic synovitis and joint damage. And PVNS is characterized by synovial proliferation and infiltrative process. Both of them are synovial involvement and the clinical manifestations are quite similar. PVNS has occasionally been reported in association with RA. So it is difficult to make a clear diagnosis of RA combined with PVNS. Literature was searched with RA+PVNS in the WanFang Medical Network Database and China National Knowledge Infrastructure and there were no related Chinese cases. Then we searched literature from PubMed with RA+PVNS. The cases were still rare and eventually 2 related articles were yielded including 2 similar patients. It is necessary to fully understand the disease development, complicated MRI appearance and various pathological morpho-logy. They can contribute to making a correct diagnosis which is effective to guide the proper treatment.

Regression Algorithm of Bone Age Estimation of Knee-joint Based on Principal Component Analysis and Support Vector Machine / 法医学杂志

Objective To establish a regression algorithm model that applies to bone age estimation of Xinjiang Uygur adolescents with machine learning methods such as histogram of oriented gradient （HOG）, local binary patterns （LBP）, support vector machine （SVM）, principal component analysis （PCA）. Methods DR images of knee-joints from 275 male and 225 female subjects aged 12.0-<19.0 years old were collected, PCA method was used to reduce the dimensionality of the HOG and LBP features, and support vector regression （SVR） was used to establish a knee-joint bone age estimation algorithm model. Stratified random sampling method was used to select 215 male samples, 180 female samples for the model training set. K-fold cross validation method was used to optimize parameters of the model. The remaining samples as the independent test set was used to compare the sample's true age and model estimated age, and had an accuracy rate in the statistical error range of ±0.8 and ±1.0 years, respectively. Then the mean absolute error （MAE） and root mean square error （RMSE） were calculated. Results The accuracy rate of male in the statistical error range of ±0.8 and ±1.0 year was 80.67%, 89.33%, respectively. The MAE and RMSE were 0.486 and 0.606 years, respectively. The accuracy rate of female in the statistical error range of ±0.8 and ±1.0 years was 80.19%, 90.45%, respectively. The MAE and RMSE were 0.485 and 0.590 years, respectively. Conclusion Establishment of prediction model for bone age estimation by feature dimension reduction of HOG and LBP in DR images of knee-joint based on PCA and SVM has relatively high accuracy.

The diagnosis and treatment of tibial intercondylar chondroblastoma

OBJECTIVES: To investigate the diagnosis and treatment of tibial intercondylar chondroblastoma. METHODS: We retrospectively analyzed the diagnosis and treatment of 12 patients with tibial intercondylar chondroblastoma admitted to the orthopedics department from May 2011 to February 2016; among them were 4 males and 3 females aged 10-19 years, with an average age of 15.7 years. Tibial intercondylar chondroblastoma was on the left and right side in 7 and 5 cases, respectively. The preoperative average Lysholm score of the knee joint was 68 (42-87). A posteromedial approach was applied in all cases. The incisions were approximately 5-8 cm in length. Complete curettage and inactivation were performed after fenestration, and allogeneic bone grafts were transplanted. Then, the posterior cruciate ligament insertion was fixed with 5.0 suture anchors. All patients were followed up with regularly to monitor for tumor recurrence, observe bone graft healing, and reassess the Lysholm score of the knee. RESULTS: Patients were followed for 7-55 months, and the median follow-up time was 19 months. One patient experienced tumor relapse 4 months after the operation. Incision, inactivation and cementation were performed. Then, the bone was fixed with anchors. In the other 11 patients, the bone graft healed over an average period of 6.2 months (4-10 months), with good functional recovery postoperatively. The average postoperative Lysholm score of the knee was 91 (81-95). CONCLUSION: Tibial intercondylar chondroblastoma has unique clinical and imaging characteristics and can effectively be treated by curettage followed by the inactivation, transplantation and fixation of allogeneic bone grafts with suture anchors through a posteromedial approach.

El pedido de resonancia magnética de rodilla: ¿puede ser reducido por especialistas? / The order of knee magnetic resonance: can it be reduced by specialists?

Introducción: El dolor de rodilla es una de las consultas más comunes en el consultorio traumatológico. Es comúnencontrarnos con pacientes que llegan a la consulta con una Resonancia Magnetica Nuclear (RMN) diciendo que tienenun menisco roto y buscando un turno en el quirófano. La mayoría de estos pacientes son factibles de tratamientoortopédico y es suficiente realizar maniobras semiologicas correctas para determinarlo. A pesar de ello hay un númerocreciente de solicitud de RMN de rodilla por miembros del equipo de salud. La hipótesis de este trabajo postula quelas RMN solicitadas por los especialistas en ortopedia y traumatología ofrecen resultados positivos tanto para los diagnósticos como para los planes de tratamiento.Objetivos: El objetivo de este trabajo es comparar la utilidad en el diagnóstico y en la definición terapéutica de las RMNde rodillas solicitadas por especialistas médicos...

Introduction: Knee pain is one of the most common complications in the trauma clinic. It is common to find patients whocome to the office with a Nuclear Magnetic Resonance (MRI) who have a broken meniscus and who are looking for a lathe inthe operating room. The majority of these patients are feasible for orthopedic treatment and it is sufficient to perform correct semiological maneuvers to determine it. Although there is a growing demand for knee MRI by members of the health team.The hypothesis of this work postulates that the NMR requested by the specialists in orthopedics and traumatology offerpositive results both for the diagnoses and for the treatment plans.Objectives: The aim of this study is to compare the usefulness in diagnosis and in the therapeutic definition of knee MRIs requested by medical specialists...

Enfermedad de Osgood-Schlatter en un adolescente deportista: Caso clínico / Osgood-Schlatter disease in adolescent athlete: Case report

El dolor de rodilla es uno de los síntomas musculoesqueléticos más frecuentes en jóvenes físicamente activos y aparece, sobre todo, en adolescentes varones. Dentro del diagnóstico diferencial, hay que considerar entidades habituales de diagnóstico clínico, como la osteocondrosis apofisaria, y también otras en las que se precisan estudios complementarios. Se presenta el caso de un varón deportista de 12 años con dolor continuo en la rodilla derecha que se intensificaba con la actividad física y la presión directa. Se hizo el diagnóstico de enfermedad de Osgood-Schlatter mediante los datos exploratorios, reproducción del dolor ante la palpación a punta de dedo sobre la tuberosidad tibial anterior, y se confirmó mediante radiología. Se describe esta entidad y otras derivadas de la sobreutilización en la actividad física con las que hacer diagnóstico diferencial; se insiste en las medidas preventivas en cuanto a una correcta orientación en la actividad deportiva.

Knee pain is one of the most frequent musculoskeletal symptoms in young physically active males. Common entities of clinical diagnosis as osteochondritis/apophysitis and others that need complementary studies should be considered in the differential diagnosis. We present the case of a 12-year-old male athlete with continuous pain in his right knee that intensifies with physical activity and with direct pressure. Diagnosis of Osgood-Schlatter disease is made by exploratory data, pain-to-finger palpation on the anterior tibial tuberosity, and is confirmed by radiology. This entity is described as well as the main pathologies derived from overuse to make differential diagnosis and to stress preventive measures regarding a correct orientation in the sport activity.

Fixed-flexion knee radiography using a new positioning device produced highly repeatable measurements of joint space width: ELSA-Brasil Musculoskeletal Study (ELSA-Brasil MSK) / A radiografia do joelho em flexão fixa utilizando um novo posicionador produziu medidas da largura do espaço articular com alta repetibilidade: estudo ELSA-Brasil Musculoesquelético (ELSA-Brasil ME)

Abstract Objective: To describe the performance of a non-fluoroscopic fixed-flexion PA radiographic protocol with a new positioning device, developed for the assessment of knee osteoarthritis (OA) in Brazilian Longitudinal Study of Adult Health Musculoskeletal Study (ELSA-Brasil MSK). Material and methods: A test–retest design including 19 adults (38 knee images) was conducted. Feasibility of the radiographic protocol was assessed by image quality parameters and presence of radioanatomic alignment according to intermargin distance (IMD) values. Repeatability was assessed for IMD and joint space width (JSW) measured at three different locations. Results: Approximately 90% of knee images presented excellent quality. Frequencies of nearly perfect radioanatomic alignment (IMD ≤1 mm) ranged from 29% to 50%, and satisfactory alignment was found in up to 71% and 76% of the images (IMD ≤1.5 mm and ≤1.7 mm, respectively). Repeatability analyses yielded the following results: IMD [SD of mean difference = 1.08; coefficient of variation (%CV) = 54.68%; intraclass correlation coefficient (ICC) (95%CI) = 0.59 (0.34–0.77)]; JSW [SD of mean difference = 0.34–0.61; %CV = 4.48%–9.80%; ICC (95%CI) = 0.74 (0.55–0.85)–0.94 (0.87–0.97)]. Adequately reproducible measurements of IMD and JSW were found in 68% and 87% of the images, respectively. Conclusions: Despite the difficulty in achieving consistent radioanatomic alignment between subsequent radiographs in terms of IMD, the protocol produced highly repeatable JSW measurements when these were taken at midpoint and 10 mm from the medial extremity of the medial tibial plateau. Therefore, measurements of JSW at these locations can be considered adequate for the assessment of knee OA in ELSA-Brasil MSK.

Resumo Objetivo: Descrever o desempenho de um protocolo radiográfico em flexão fixa sem fluoroscopia em incidência PA com um novo posicionador, desenvolvido para a avaliação da osteoartrite de joelho (OA) no estudo ELSA-Brasil ME. Material e métodos: Fez-se um estudo de teste e reteste que incluiu 19 adultos (38 imagens de joelho). A viabilidade do protocolo radiográfico foi avaliada por meio de parâmetros de qualidade da imagem e presença de alinhamento radioanatômico de acordo com as medidas da distância intermarginal (DIM). Avaliaram-se a repetibilidade dos valores de DIM e do espaço articular (EA) em três locais diferentes. Resultados: Aproximadamente 90% das imagens de joelho apresentaram uma qualidade excelente. As frequências de imagens com alinhamento radioanatômico quase perfeito (DIM<1mm) variaram de 29% a 50%, e de alinhamento satisfatório (DIM<1,5mm e <1,7mm) de 71% a 76%, respectivamente. As análises de repetibilidade produziram os seguintes resultados: DIM [DP da média das diferenças = 1,08; coeficiente de variação (% CV) = 54,68%; coeficiente de correlação intraclasse (CCI) (IC 95%) = 0,59 (0,34 a 0,77)]; EA [DP da média das diferenças = 0,34 a 0,61; % CV = 4,48% a 9,80%; CCI (IC 95%) = 0,74 (0,55 a 0,85) a 0,94 (0,87 a 0,97]. Encontraram-se medidas adequadamente reprodutíveis de DIM e EA em 68% e 87% das imagens, respectivamente. Conclusões: Apesar da dificuldade de obter um alinhamento radioanatômico consistente entre radiografias repetidas em termos de DIM, o protocolo produziu medições de EA altamente repetíveis quando essas foram tomadas no ponto médio e a 10 mm da extremidade medial do platô tibial medial. Portanto, as medidas de EA nesses locais podem ser consideradas adequadas para a avaliação da OA de joelho no estudo ELSA-Brasil ME.

Evaluación con resonancia magnética de artroplastias totales de rodilla sintomáticas / MRI evaluation of symptomatic total knee arthroplasties

Introducción: Las artroplastias totales de rodilla sintomáticas con estudios normales resultan un desafío para el ortopedista. La resonancia magnética podría ser una alternativa para arribar al diagnóstico. El objetivo de este estudio fue evaluar la utilidad de la resonancia magnética con secuencias optimizadas en artroplastias totales de rodilla sintomáticas y también realizar un estudio interobservador para determinar qué estructuras anatómicas son evaluables. Materiales y Métodos: Se evaluaron retrospectivamente 15 pacientes con artroplastias totales de rodilla operados entre 2007 y 2012, con dolor periprotésico, y radiografía, centellograma y análisis de laboratorio normales, sometidos a una resonancia magnética. Se realizó un análisis interobservador utilizando los coeficientes de correlación intraclase y kappa entre cuatro profesionales, un residente de diagnóstico por imágenes y otro de Ortopedia, y dos médicos con 20 años de experiencia, uno en diagnóstico por imágenes y el otro en rodilla. Resultados: Se halló líquido articular aumentado en 14 pacientes, sinovitis en cuatro, un osículo infrarrotuliano y no se detectó osteólisis en ningún caso. En siete pacientes, fue posible evaluar correctamente los ligamentos colaterales. Los gemelos, el tejido celular subcutáneo y el aparato extensor se evaluaron sin dificultad. La resonancia magnética encontró causas de dolor en 12 casos. El coeficiente de correlación intraclase mostró concordancia para el ligamento colateral medial, el aparato extensor, los gemelos y el tejido celular subcutáneo. Conclusión: Este estudio demuestra la utilidad del método en la toma de decisiones. La concordancia interobservador fue estadísticamente significativa para el análisis del ligamento colateral medial, los gemelos y el tejido celular subcutáneo. Nivel de Evidencia: III

Introduction: Symptomatic total knee arthroplasties with normal studies are a challenge for the orthopedic surgeon. Nuclear magnetic resonance could be an alternative to reach a correct diagnosis. The objective of the study was to evaluate the usefulness of nuclear magnetic resonance using optimized sequences in symptomatic total knee arthroplasties, and to perform an interobserver study to determine which anatomical structures are evaluable. Methods: We retrospectively evaluated 15 patients operated on between 2007 and 2012 who had periprosthetic pain and normal radiographs, scintigraphy and laboratory values undergoing MRI. An interobserver analysis using intraclass correlation and kappa coefficients was performed among four professionals, a resident of diagnostic imaging and an advanced Orthopedic resident, and two physicians with 20 years of practice, one in diagnostic imaging and the other in knee surgery. Results: Joint fluid was increased in 14 patients; we detected synovitis in four cases and a case of infrapatellar ossicle, but osteolysis was not found in any of the patients. The collateral ligaments could be evaluated properly in seven cases. The gastrocnemius, the subcutaneous tissue and the extensor apparatus were evaluated without difficulty. MRI found causes of pain in 12 cases. The intraclass correlation coefficient showed concordance for the medial collateral ligament, the extensor apparatus, twins and subcutaneous tissue. Conclusion: This study demonstrates the usefulness of the method in the decision-making process. The interobserver agreement was statistically significant for the analysis of the medial collateral ligament, gastrocnemius and subcutaneous tissue. Level of Evidence: III

Radiologic Outcomes According to Varus Deformity in Minimally Invasive Surgery Total Knee Arthroplasty

PURPOSE: To identify the accuracy of postoperative implant alignment in minimally invasive surgery total knee arthroplasty (MIS-TKA), based on the degree of varus deformity. MATERIALS AND METHODS: The research examined 627 cases of MIS-TKA from November 2005 to December 2007. The cases were categorized according to the preoperative degree of varus deformity in the knee joint in order to compare the postoperative alignment of the implant: less than 5degrees varus (Group 1, 351 cases), 5degrees to less than 10degrees varus (Group 2, 189 cases), 10degrees to less than 15degrees varus (Group 3, 59 cases), and 15degrees varus or more (Group 4, 28 cases). RESULTS: On average, the alignment of the tibial implant was 0.2+/-1.4degrees, 0.1+/-1.3degrees, 0.1+/-1.6degrees, and 0.3+/-1.7degrees varus, and the tibiofemoral alignment was 5.2+/-1.9degrees, 4.7+/-1.9degrees, 4.9+/-1.9degrees, and 5.1+/-2.0degrees valgus for Groups 1, 2, 3, and 4, respectively, in the preoperative stage, indicating no difference between the groups (p>0.05). With respect to the accuracy of the tibial implant alignment, 98.1%, 97.6%, 87.5%, and 86.7% of Groups 1, 2, 3, and 4, respectively, had 0+/-3degrees varus angulation, demonstrating a reduced level of accuracy in Groups 3 and 4 (p0.05). CONCLUSION: Satisfactory component alignment was achieved in minimally invasive surgery in total knee arthroplasty, regardless of the degree of varus deformity.

Interposition of the Posterior Cruciate Ligament into the Medial Compartment of the Knee Joint on Coronal Magnetic Resonance Imaging

OBJECTIVE: The purpose of our study was to evaluate the overall prevalence and clinical significance of interposition of the posterior cruciate ligament (PCL) into the medial compartment of the knee joint in coronal magnetic resonance imaging (MRI). MATERIALS AND METHODS: We retrospectively reviewed 317 consecutive patients referred for knee MRI at our institution between October 2009 and December 2009. Interposition of the PCL into the medial compartment of the knee joint on proton coronal MRI was evaluated dichotomously (i.e., present or absent). We analyzed the interposition according to its prevalence as well as its relationship with right-left sidedness, gender, age, and disease categories (osteoarthritis, anterior cruciate ligament tear, and medial meniscus tear). RESULTS: Prevalence of interposition of PCL into the medial compartment of the knee joint was 47.0% (149/317). There was no right (50.0%, 83/166) to left (43.7%, 66/151) or male (50.3%, 87/173) to female (43.1%, 62/144) differences in the prevalence. There was no significant association between the prevalence and age, or the disease categories. CONCLUSION: Interposition of the PCL into the medial compartment of the knee joint is observed in almost half of patients on proton coronal MRI of the knee. Its presence is not associated with any particular factors including knee pathology and may be regarded as a normal MR finding.