Translation, cross-cultural adaptation and validation of the Norwich Patellar Instability score for use in Brazilian Portuguese

ABSTRACT BACKGROUND: The Norwich Patellar Instability (NPI) score is a tool for evaluating the impact of patellofemoral instability on joint function. It has not been translated or culturally adapted for the Brazilian population before. OBJECTIVE: This study had the aims of translating and culturally adapting the NPI score for use in Brazilian Portuguese and subsequently assessing its validity for this population. DESIGN AND SETTING: Translation, cross-cultural adaptation and validation study conducted at the State Public Servants' Institute of São Paulo, Brazil. METHODS: Sixty patients of both sexes (aged 16-40 years) with diagnoses of patellar dislocation were recruited. The translation and cultural adaptation were undertaken through translation into Brazilian Portuguese and back-translation to English by an independent translator. Face validity was assessed by a committee of experts and by 20 patients. Concurrent validity was assessed through comparing the Brazilian Portuguese NPI score with the Brazilian Portuguese versions of the Lysholm knee score and the Kujala patellofemoral disorder score among the other 40 patients. Correlation analysis between the three scores was performed using Pearson correlation coefficients with significance levels of P < 0.05. RESULTS: The Brazilian Portuguese version of the NPI score showed moderate correlation with the Brazilian Portuguese versions of the Lysholm score (r = -0.56; 95% confidence interval, CI: -0.74 to -0.30; P < 0.01) and Kujala score (r = -0.57; 95% CI: -0.75 to -0.31; P < 0.01). CONCLUSION: The Brazilian Portuguese version of the NPI score is a validated tool for assessing patient-reported patellar instability for the Brazilian population.

Test de Zohlen y su relación con el ángulo Q en población sin dolor patelofemoral / Zohlen's test and its relation to the Q angle in a population without patellofemoral pain

Determinar qué porcentaje de una población sin dolor anterior de rodilla tiene un test de Zohlen positivo, además determinar el ángulo Q de esta población y buscar si existe alguna relación entre la positividad del test de Zohlen y alteraciones en el ángulo Q. Material y método: Estudio descriptivo-prospectivo observacional. Aplicación del test de Zohlen y medición del ángulo Q. La población se dividió en 2 grupos: test de Zohlen positivo y test de Zohlen negativo. Cuantificación y comparación de medias del ángulo Q en los dos grupos. Resultados: 90 sujetos evaluados, promedio de edad 20,18 años (18-40). Veinte sujetos (22,2 por ciento) con test de Zohlen positivo. Ángulo Q promedio en los sujetos con test de Zohlen negativo: 14,95°; ángulo Q promedio en los sujetos con test de Zohlen positivo: 16,9° (p < 0,05). Ángulo Q promedio en hombres con test de Zohlen negativo 13,4°; ángulo Q promedio en hombres con test de Zohlen positivo: 16° (p < 0,05). Ángulo Q promedio en mujeres con test de Zohlen negativo: 16,5°; ángulo Q promedio en mujeres con test de Zohlen positivo: 18°, sin diferencias estadísticamente significativas entre ambos grupos. Conclusiones: El test de Zohlen tiene una correlación positiva con el ángulo Q en sujetos de sexo masculino. Dada la correlación entre un ángulo Q alterado y la presencia de dolor anterior de rodilla, en los pacientes que presentan un test de Zohlen positivo sin haber consultado por dolor anterior de rodilla, la prevención primaria de dolor anterior de rodilla puede ser de utilidad...

To determine the percentage of a population without anterior knee pain with a positive Zohlen test, and also to determine the Q angle of this population and to determine if there is any relationship between the Zohlen test and Q angle anomalies. Methods:A prospective observational study was conducted in which Zohlen¿s test was applied and the Q angle was measured. The population was divided into 2 groups: Zohlen¿s positive and Zohlen¿s negative. Q angle was compared in the 2 groups. Results: The study included 90 subjects, with a mean age 20.18 years (18-40), of whom 20 subjects (22.2 percent) had positive Zohlen¿s test. The mean Q angle in subjects with negative Zohlen¿s test was 14.95°, and the mean Q angle in subjects with positive Zohlen¿s test was 16,9° (p<.05). The mean Q angle in men with negative Zohlen¿s test was 13.4°, and the mean Q angle in men with positive Zohlen¿s test was 16° (p < .05). The mean Q angle in women with negative Zohlen¿s test was 16.5°, with a mean Q angle of 18° in women with positive Zohlen¿s test, with no statistically significant differences found between groups. Conclusions: Zohlen¿s test has a positive correlation with the Q angle in male subjects. Given the correlation between the Q angle and the presence of anterior knee pain in patients who have a positive test without symptoms, primary prevention of anterior knee pain can be achieved...

Biomechanics of Hyperflexion and Kneeling before and after Total Knee Arthroplasty

The capacity to perform certain activities is frequently compromised after total knee arthroplasty (TKA) due to a functional decline resulting from decreased range of motion and a diminished ability to kneel. In this manuscript, the current biomechanical understanding of hyperflexion and kneeling before and after TKA will be discussed. Patellofemoral and tibiofemoral joint contact area, contact pressure, and kinematics were evaluated in cadaveric studies using a Tekscan pressure measuring system and Microscribe. Testing was performed on intact knees and following cruciate retaining and posterior stabilized TKA at knee flexion angles of 90degrees, 105degrees, 120degrees, and 135degrees. Three loading conditions were used to simulate squatting, double stance kneeling, and single stance kneeling. Following TKA with double stance kneeling, patellofemoral contact areas did not increase significantly at high knee flexion angle (135degrees). Kneeling resulted in tibial posterior translation and external rotation at all flexion angles. Moving from double to single stance kneeling tended to increase pressures in the cruciate retaining group, but decreased pressures in the posterior stabilized group. The cruciate retaining group had significantly larger contact areas than the posterior stabilized group, although no significant differences in pressures were observed comparing the two TKA designs (p < 0.05). If greater than 120degrees of postoperative knee range of motion can be achieved following TKA, then kneeling may be performed with less risk in the patellofemoral joint than was previously believed to be the case. However, kneeling may increase the likelihood of damage to cartilage and menisci in intact knees and after TKA increases in tibiofemoral contact area and pressures may lead to polyethyelene wear if performed on a chronic, repetitive basis.

Patellofemoral Crepitus after Total Knee Arthroplasty: Etiology and Preventive Measures

Patellofemoral crepitus and clunk syndrome are infrequent, yet troublesome complications of total knee arthroplasty with a reported incidence of 0%-18%. They are primarily associated with implantation of posterior cruciate substituting designs. These entities are the result of peripatellar fibrosynovial hyperplasia at the junction of the superior pole of the patella and the distal quadriceps tendon which becomes entrapped within the superior aspect of the intercondylar box of the femoral component during knee flexion. When the knee extends, a crepitant sensation occurs as the fibrosynovial tissue exits the intercondylar box. Numerous etiologies have been proposed such as femoral component designs with a high intercondylar box ratio, previous knee surgery, reduced patellar tendon length, thinner patellar components, reduced patella-patellar component composite thickness, and smaller femoral components. Preventative measures include choice of femoral components with a reduced intercondylar box ratio, use of thicker patellar components, avoidance of over-resection of the patella, and debridement of the fibrosynovial tissue at the time of knee arthroplasty. Most patients with crepitus are unaware of the problem or have minimal symptoms so that no treatment is required. If significant disability is incurred, symptoms can be eliminated in a high percentage of patients with arthroscopic debridement of the fibrosynovial hyperplasia.

Angulo Q extendido: un nuevo signo clínico para decidir técnica de realineación distal de aparato extensor / Extended Q angle: a new sign for the physical exam for deciding distal realignement

Los trastornos patelofemorales son una de las causas más frecuentes de consulta en ortopedia, y múltiples son los factores etiológicos descriptos en la fisiopatogenia. Un examen físico completo es imprescindible para detectar él o los factores influyentes en cada paciente para realizar un tratamiento “a la carta”. En la bibliografía se suele considerar a la realineación distal del aparato extensor como sinónimo de transposición de la TAT, sin embargo este concepto no contempla el factor rotacional generador de grandes fuerzas desestabilizantes en esta articulación. En este trabajo se describe un signo semiológico muy útil para decidir la realineación distal del aparato extensor, donde se agrega un vector más al ángulo Q clásico, desde el polo inferior de la rótula y paralelo a la diáfisis tibial y su relación con la posición del pie. Este signo se mide con rodilla en 30° de flexión, rótulas al cenit. Se describen 2 tipos de ángulo Q aumentado, contemplando la posición del pie que es fundamental para detectar trastorno rotacional con intrarotación de rodilla durante la marcha. También se describe y fundamenta la necesidad de diferenciar los 2 tipos de ángulo Q extendido para un tratamiento de realineación distal que respeta la biomecánica patelofemoral.

Patellofemoral problems are one of the most common cause of consult in orthopaedic practice. Multiple etiologic factors have been described in the genesis of the pathology. A complete physical exam is very important for the detection of factors that affect each patient, so that we can make a “a la carte” treatment. In the literature the distal realignement is consider as sinonym of transfer of the tibial tuberosity, but this concept not consider the rotational influence that generate grate forces at the articulation. Here we describe a new sign for the physical exam, useful for deciding distal realignement, where we add and other vector from the distal pole of the patella and paralel to the tibial diafisis and the relantionship with the foot. The sign must be taken in 30° of knee flexion, patellas facing straight to the cenit . We find that there is two types of extended Q angles considering the position of the foot and the presence of a rotational problem wich produce an inward knee. We describe the importance of different type of treatment for each extended Q angles in distal realignement procedures considering more physiological and anatomic treatment for patellofemoral problems.

Avaliação dos fatores predisponentes nas instabilidades femoropatelares / Avaliation of predisposing factors in patellofemoral instabilities

OBJETIVO: Avaliar a prevalência dos fatores predisponentes à instabilidade femoropatelar (displasia de tróclea, patela alta, TAGT, báscula patelar) em um grupo de pacientes acompanhados em nível ambulatorial. MÉTODOS: Avaliou-se 70 pacientes, sendo 52 do sexo feminino (74,28 por cento) e 18 (25,72 por cento) do sexo masculino, num total de 127 joelhos, com uma média de idade de 17,71 anos. A avaliação por imagem foi realizada através de radiografias e tomografia computadorizada. As instabilidades femoropatelares foram classificadas seguindo-se a classificação de Henri Dejour (instabilidade maior, objetiva e potencial). Enquadraram-se as displasias trocleares de acordo com a classificação de David Dejour (tipo A, B, C, D). RESULTADOS: Observou-se displasia troclear em 118 (92,91 por cento) joelhos, sendo 91 (77,11 por cento) joelhos dos tipos A e B. A altura patelar apresentou uma média de 1,23, com 44 (34,64 por cento) consideradas patela alta e 83 (65,36 por cento) normais. A báscula patelar alterada foi encontrada em 92 (72,44 por cento) joelhos e a elevação da TAGT em 63 (49,60 por cento) joelhos. Obteve-se predominância de instabilidades objetivas 89 (70,07 por cento) joelhos, Quanto a associação de fatores predisponentes,, 117 (92,13 por cento) joelhos apresentaram mais quem um fator. CONCLUSÕES: A instabilidade femoropatelar é uma doença multifatorial, os distúrbios trocleares são mais prevalentes e há uma forte associação entre 2 ou mais fatores predisponentes.

OBJECTIVE: To evaluate the prevalence of predisposing factors for femoropatelar instability (dysplasia of the trochlea, high patella, TTTG, and patellar tilt) in a group of patients in outpatient follow-up. METHODS: 70 patients were evaluated; 52 (74.28 percent) female and 18 (25.72 percent) male, with an average age of 17.71 years and a total of 127 knees. The evaluation by imaging was carried out through radiologic examination and computerized tomography. The femoropatelar instabilities were classified according to Henri Dejour's classification (major, objective and potential instability). The trochlear dysplasia was classified according to David Dejour's classification (type A, B, C, D). RESULTS: Trochlear dysplasia was observed in 118 knees (92.91 percent), with 91 knees (77.11 percent) being of type A and B. The average for patellar height was 1.23, with 44 (34.64 percent) considered high patellas and 83 (65.36 percent) within the normal range. Abnormal patellae tilt was found in 92 knees (72.44 percent) and an elevation of TTTG in 63 knees (49.60 percent). The was a prevalence of objective instabilities with 89 knees (70.07 percent). In relation to the association of predisposing factors, 117 knees (92.13 percent) presented more than one factor. CONCLUSIONS: Femoropatelar instability is a multifactorial disease, with trochlear disorders being the most frequent, and there is a strong association between two or more predisposing factors.