No description available.

Parmi les blessures sportives reliées au genou, 20 % impliquent le ligament croisé antérieur (LCA). Le LCA étant le principal stabilisateur du genou, une lésion à cette structure engendre une importante instabilité articulaire influençant considérablement la fonction du genou. L’évaluation clinique actuelle des patients ayant une atteinte au LCA présente malheureusement des limitations importantes à la fois dans l’investigation de l’impact de la blessure et dans le processus diagnostic. Une évaluation biomécanique tridimensionnelle (3D) du genou pourrait s’avérer une avenue innovante afin de pallier à ces limitations. L’objectif général de la thèse est de démontrer la valeur ajoutée du domaine biomécanique dans (1) l’investigation de l’impact de la blessure sur la fonction articulaire du genou et dans (2) l’aide au diagnostic. Pour répondre aux objectifs de recherche un groupe de 29 patients ayant une rupture du LCA (ACLD) et un groupe contrôle de 15 participants sains ont pris part à une évaluation biomécanique 3D du genou lors de tâches de marche sur tapis roulant. L’évaluation des patrons biomécaniques 3D du genou a permis de démontrer que les patients ACLD adoptent un mécanisme compensatoire que nous avons intitulé pivot-shift avoidance gait. Cette adaptation biomécanique a pour objectif d’éviter de positionner le genou dans une condition susceptible de provoquer une instabilité antérolatérale du genou lors de la marche. Par la suite, une méthode de classification a été développée afin d’associer de manière automatique et objective des patrons biomécaniques 3D du genou soit au groupe ACLD ou au groupe contrôle. Pour cela, des paramètres ont été extraits des patrons biomécaniques en utilisant une décomposition en ondelettes et ont ensuite été classifiés par la méthode du plus proche voisin. Notre méthode de classification a obtenu un excellent niveau précision, de sensibilité et de spécificité atteignant respectivement 88%, 90% et 87%. Cette méthode a donc le potentiel de servir d’outil d’aide à la décision clinique. La présente thèse a démontré l’apport considérable d’une évaluation biomécanique 3D du genou dans la prise en charge orthopédique de patients présentant une rupture du LCA; plus spécifiquement dans l’investigation de l’impact de la blessure et dans l’aide au diagnostic. / The anterior cruciate ligament (ACL) is involved in approximately 20% of all sports-related knee injuries. An injury to the ACL, the primary stabilizer of the knee, will lead to knee joint instability and functional impairment. Unfortunately, current clinical assessments of ACL-deficient patients present limitations with respect to the investigation of the impact of the injury on knee function. A 3D knee biomechanical assessment could provide innovative information to overcome these drawbacks. The main objective of the doctoral theses is to demonstrate the role of biomechanics in (1) the investigation of the impact of the injury on knee function and in (2) the diagnostic process. Twenty-nine ACL-deficient patients and a control group of fifteen healthy participants took part in a 3D knee biomechanical assessment during treadmill walking. By assessing the 3D knee biomechanical patterns of each group we observed that ACL-deficient patients adopted a gait compensatory mechanism: the Pivot-shift avoidance gait. The explanation for this adaptative strategy is to avoid placing the knee in a position biomechanically favorable to anterolateral rotatory instability during gait. Furthermore, an automatic classification method capable of distinguishing ACL deficient patients from an asymptomatic population was developed. Features were extracted from the 3D knee biomechanical patterns using a wavelet decomposition method and then classified by the nearest neighbour rule. The proposed classification method obtained a level of accuracy, sensitivity and specificity of 88%, 90% and 87% respectively. This method shows great potential as a diagnostic aid in a clinical setting. This thesis demonstrates that biomechanics plays a substantial role in the management of ACL injuries by improving the understanding of the impact of the injury on knee function and by its capacity to serve as a diagnostic aid.

A instabilidade patelar é uma patologia comum dentro da especialidade da cirurgia do joelho. O principal fator estabilizador dessa articulação é o ligamento patelofemoral medial, sendo esta a principal estrutura a ser reconstruída no tratamento cirúrgico da instabilidade patelar. Apesar de sua reconstrução apresentar excelentes resultados clínicos, não se sabe ao certo o real efeito in vivo desse procedimento no movimento da patela ao redor do fêmur. A avaliação da articulação patelofemoral tradicionalmente é feita através de exames de imagem estáticos. Com a evolução dos aparelhos de tomografia computadorizada, se tornou possível realizar esse exame durante movimento ativo, técnica ainda pouco utilizada para estudo de articulações como o joelho. O objetivo deste estudo foi padronizar o uso da tomografia de 320 fileiras de detectores para estudo dinâmico da articulação patelofemoral em pacientes com instabilidade patelar recidivante pré e pós-reconstrução do ligamento patelofemoral medial, analisando o efeito da cirurgia no trajeto da patela ao longo do arco de movimento. Foram selecionados 10 pacientes com instabilidade patelar e indicação de reconstrução do ligamento patelofemoral medial isolada, que foram submetidos à tomografia antes e após um mínimo de 6 meses da cirurgia. Os parâmetros anatômicos avaliados foram os ângulos de inclinação da patela e distância da patela ao eixo da tróclea através de um programa de computador desenvolvido especificamente para esse fim. Foram aplicados os escores clínicos de Kujala e Tegner e calculada a radiação dos exames. O protocolo escolhido para aquisição de imagens na tomografia foi: potencial do tubo de 80 kV, carga transportável de 50 mA, espessura de corte de 0,5 mm e tempo de aquisição de 10 segundos, o que gerou um DLP (dose length product) de 254 mGycm e uma dose efetiva estimada de radiação de 0,2032 mSv. O paciente realizava uma extensão ativa do joelho contra a gravidade. Os resultados não mostraram mudança do trajeto da patela após a reconstrução do ligamento patelofemoral medial, apesar de não ter havido nenhuma recidiva da instabilidade e os escores clínicos apresentarem melhora média de 22,33 pontos no Kujala (p=0,011) e de 2 níveis no Tegner (p=0,017) / Patellar instability is a common pathology in the practice of knee surgeons. The most important stabilizing structure in the patellofemoral joint is the medial patellofemoral ligament. This ligament is the main structure to be reconstructed during surgery for patellofemoral instability. Although clinical results for this procedure are excellent, the real in vivo effect of medial patellofemoral ligament reconstruction on patellar tracking is unknown. The study of this joint is usually made with static imaging. With the recent evolution of tomographers, it is now possible to analyze anatomical structures moving during active range of motion. This technique (dynamic computerized tomography) has not been routinely used to study joints as the knee. This study had the purpose of standardizing the use of 320-detector row computerized tomography for the patellofemoral joint, analyzing patients before and after surgical reconstruction of medial patellofemoral ligament. We selected 10 patients with patellofemoral instability referred to isolated medial patellofemoral ligament reconstruction surgery, and submitted them to a dynamic computerized tomography before and at a minimum of 6 months after surgery. Patellar tilt angles and shift distance were analyzed using a computer software specifically designed for this purpose. Kujala and Tegner scores were applied and the radiation of the exams was recorded. The protocol for imaging acquisition was: tube potential of 80 kV, 50 mA, slice thickness of 0.5 mm and 10 seconds of acquisition duration. This produced a DLP (dose length product) of 254 mGycm and a radiation effective estimated dose of 0.2032 mSv. There were no changes in patellar tracking after medial patellofemoral ligament reconstruction. There was no instability relapse. Clinical scores showed an average improvement of 22.33 points for Kujala (p=0.011) and of 2 levels for Tegner (p=0.017)

Conselho Nacional de Desenvolvimento Científico e Tecnológico / The upper limbs are constituted by the shoulder, arm, forearm and hand. The shoulder consists of the sternoclavicular, acromioclavicular and shoulder joints. The acromioclavicular joint is stabilized by ligaments and deltoid and trapezius muscles. The ligaments which constitute this joint are the acromioclavicular, coracoacromial and coracoclavicular, which is divided into trapezoid and conoid. The joint can be injured due to the direct fall on shoulder or on extended upper limb and are common in sports with hard contact. The acromioclavicular dislocation is classified into different types and there are specific treatments for each one. The Weaver-Dunn technique is one of the most common and consists in removing the intact coracoacromial ligament of the acromion, followed by its direct attachment to the structure of the clavicle. This technique has disadvantages when compared with others that do not require the transfer of the ligament. This occurs because it is an invasive procedure, require longer surgical time and require a longer period of healing. In this study, the techniques of Weaver-Dunn and coracoclavicular sling were evaluated. In both procedures, sutures are used to replace the coracoclavicular ligaments that have been injured. The analysis of the influence of coracoacromial ligament transfer was performed using three-dimensional models by the finite element method. Here is also investigated the tensile strength of some commercial sutures. Sutures composed by polyblend, as Fiberwire® and HiFi®, showed higher tensile strength than polyester sutures, as Ethibond®. In intact acromioclavicular joint, considering the proposed conditions, the trapezoid ligament showed higher stress values. The distance between the clavicle and the coracoid process showed similar behavior among the techniques evaluated. Thus, considering the simplifications of the models, it was concluded that there would not be a positive influence in the implementation of the transfer of the coracoacromial ligament to stabilize the acromioclavicular joint. To verify the results of this study, it is important the development of new numerical models and clinical research related to surgical techniques assessed. / Os membros superiores são constituídos pelo ombro, o braço, o antebraço e a mão. O ombro é composto pelas articulações esternoclavicular, acromioclavicular e do ombro. A articulação acromioclavicular se estabiliza através dos ligamentos e dos músculos deltóide e trapézio. Os ligamentos que constituem a articulação são o acromioclavicular, o coracoacromial e os coracoclaviculares, trapezóide e conóide. As lesões mais comuns ocorrem devido à queda sobre o ombro ou sobre o membro superior estendido, sendo comuns em esportes de contato. A luxação acromioclavicular é classificada em diferentes tipos e existem tratamentos específicos para cada um deles. A técnica de Weaver-Dunn é uma das mais utilizadas e consiste na retirada do ligamento coracoacromial intacto do acrômio, seguida pela sua fixação direta na estrutura da clavícula. Essa técnica apresenta desvantagens em relação a outras que não necessitam da transferência do ligamento, por ser um procedimento invasivo, demandar maior tempo cirúrgico e necessitar de um maior período de cicatrização. Nesse estudo, foram avaliadas as técnicas de Weaver-Dunn e dos amarrilhos coracoclaviculares. Em ambos os procedimentos, usam-se os fios de sutura para substituir os ligamentos coracoclaviculares rompidos. Analisou-se a influência da transferência do ligamento coracoacromial através de modelos tridimensionais de elementos finitos. Além disso, verificou-se a resistência à tração de alguns fios de sutura comerciais. Os fios constituídos de polimistura, como o FiberWire® e o HiFi®, apresentaram maiores valores de resistência à tração do que os fios de poliéster, como o Ethibond®. Para as condições propostas, o ligamento trapezóide apresentou os maiores níveis de tensão na articulação acromiclavicular intacta. A distância entre a clavícula e o processo coracóide apresentou comportamento semelhante entre as técnicas avaliadas. Assim, considerando as simplificações dos modelos, conclui-se que não há influência positiva na realização da transferência do ligamento coracoacromial para a estabilização da articulação acromioclavicular. Para a comprovação dos resultados deste estudo, é importante a realização de novas modelagens numéricas e pesquisas clínicas relacionadas com as técnicas cirúrgicas abordadas. / Mestre em Engenharia Mecânica

Background: Patient reports of pain and function are used to inform the need for and timing of total knee replacement (TKR) and evaluate TKR outcomes. This dissertation compared measurement properties of commonly-used patient surveys in TKR and explored ways to develop more efficient knee-specific function measures. Methods: 1,179 FORCE-TJR patients (mean age=66.1, 61% female) completed questionnaires before and 6 months after TKR. Patient surveys included the knee-specific Knee injury and Osteoarthritis Outcome Score (KOOS) and Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) and generic SF-36 Health Survey. Tests of KOOS and WOMAC measurement properties included evaluations of scaling assumptions and reliability. Item response theory methods were used to calibrate 22 KOOS function items in one item bank; simulated computerized adaptive tests (CAT) then were used to evaluate shorter function scores customized for each patient. Validity and responsiveness of measures varying in attributes (knee-specific versus generic, longer versus shorter, CAT versus fixed-length) were compared. Results: KOOS and WOMAC scales generally met tests of scaling assumptions, although many pain items were equally strong measures of pain and physical function. Internal consistency reliability of KOOS and WOMAC scales exceeded minimum levels of 0.70 recommended for group-level comparisons across sociodemographic and clinical subgroups. Function items could be calibrated in one item bank. CAT simulations indicated that reliable knee-specific function scores could be estimated for most patients with a 55-86% reduction in respondent burden, but one-third could not achieve a reliable (≥ 0.95) CAT score post-TKR because the item bank did not include enough items vi measuring high function levels. KOOS and WOMAC scales were valid and responsive. Short function scales and CATs were as valid and responsive as longer KOOS and WOMAC function scales. The KOOS Quality of Life (QOL) scale and SF-36 Physical Component Summary discriminated best among groups evaluating themselves as improved, same or worse at 6 months. Conclusions: Results support use of the KOOS and WOMAC in TKR. Improved knee-specific function measures require new items that measure higher function levels. TKR outcomes should be evaluated with a knee-specific quality of life scale such as KOOS QOL, as well as knee-specific measures of pain and function and generic health measures.

No description available.

Parmi les blessures sportives reliées au genou, 20 % impliquent le ligament croisé antérieur (LCA). Le LCA étant le principal stabilisateur du genou, une lésion à cette structure engendre une importante instabilité articulaire influençant considérablement la fonction du genou. L’évaluation clinique actuelle des patients ayant une atteinte au LCA présente malheureusement des limitations importantes à la fois dans l’investigation de l’impact de la blessure et dans le processus diagnostic. Une évaluation biomécanique tridimensionnelle (3D) du genou pourrait s’avérer une avenue innovante afin de pallier à ces limitations. L’objectif général de la thèse est de démontrer la valeur ajoutée du domaine biomécanique dans (1) l’investigation de l’impact de la blessure sur la fonction articulaire du genou et dans (2) l’aide au diagnostic. Pour répondre aux objectifs de recherche un groupe de 29 patients ayant une rupture du LCA (ACLD) et un groupe contrôle de 15 participants sains ont pris part à une évaluation biomécanique 3D du genou lors de tâches de marche sur tapis roulant. L’évaluation des patrons biomécaniques 3D du genou a permis de démontrer que les patients ACLD adoptent un mécanisme compensatoire que nous avons intitulé pivot-shift avoidance gait. Cette adaptation biomécanique a pour objectif d’éviter de positionner le genou dans une condition susceptible de provoquer une instabilité antérolatérale du genou lors de la marche. Par la suite, une méthode de classification a été développée afin d’associer de manière automatique et objective des patrons biomécaniques 3D du genou soit au groupe ACLD ou au groupe contrôle. Pour cela, des paramètres ont été extraits des patrons biomécaniques en utilisant une décomposition en ondelettes et ont ensuite été classifiés par la méthode du plus proche voisin. Notre méthode de classification a obtenu un excellent niveau précision, de sensibilité et de spécificité atteignant respectivement 88%, 90% et 87%. Cette méthode a donc le potentiel de servir d’outil d’aide à la décision clinique. La présente thèse a démontré l’apport considérable d’une évaluation biomécanique 3D du genou dans la prise en charge orthopédique de patients présentant une rupture du LCA; plus spécifiquement dans l’investigation de l’impact de la blessure et dans l’aide au diagnostic. / The anterior cruciate ligament (ACL) is involved in approximately 20% of all sports-related knee injuries. An injury to the ACL, the primary stabilizer of the knee, will lead to knee joint instability and functional impairment. Unfortunately, current clinical assessments of ACL-deficient patients present limitations with respect to the investigation of the impact of the injury on knee function. A 3D knee biomechanical assessment could provide innovative information to overcome these drawbacks. The main objective of the doctoral theses is to demonstrate the role of biomechanics in (1) the investigation of the impact of the injury on knee function and in (2) the diagnostic process. Twenty-nine ACL-deficient patients and a control group of fifteen healthy participants took part in a 3D knee biomechanical assessment during treadmill walking. By assessing the 3D knee biomechanical patterns of each group we observed that ACL-deficient patients adopted a gait compensatory mechanism: the Pivot-shift avoidance gait. The explanation for this adaptative strategy is to avoid placing the knee in a position biomechanically favorable to anterolateral rotatory instability during gait. Furthermore, an automatic classification method capable of distinguishing ACL deficient patients from an asymptomatic population was developed. Features were extracted from the 3D knee biomechanical patterns using a wavelet decomposition method and then classified by the nearest neighbour rule. The proposed classification method obtained a level of accuracy, sensitivity and specificity of 88%, 90% and 87% respectively. This method shows great potential as a diagnostic aid in a clinical setting. This thesis demonstrates that biomechanics plays a substantial role in the management of ACL injuries by improving the understanding of the impact of the injury on knee function and by its capacity to serve as a diagnostic aid.

This systematic review investigates the biomechanical risk factors associated with femoroacetabular impingement (FAI) in female athletes. Using a particular methodology, the review synthesizes relevant sources to comprehensively analyze multi-factorial contributions to FAI, including load distribution, forces, strain, and sport-related mechanisms. By critically evaluating existing literature, this study aimed to provide a nuanced understanding of the intricate biomechanical aspects influencing the development of FAI in female athletes. A thorough examination of the literature encompassed articles spanning the years 2000 to 2024. Intentional sampling techniques were employed to guarantee the inclusion of female athletes across a diverse array of sports disciplines, including but not limited to soccer, ice hockey, running, and competitive dance. This approach aimed to provide a holistic view of biomechanical factors across different athletic activities. Data extraction systematically collected information from the selected studies, including study characteristics, participant profiles, methodology, and relevant outcomes pertaining to biomechanical factors linked to FAI in female athletes. A comprehensive literature review was performed, and articles that met the inclusion criteria were identified. The Downs and Black tool was subsequently used to evaluate the methodological quality of each study, recognizing the importance of considering factors such as reporting clarity, external validity, bias, confounding, and statistical power. Common themes were synthesized, and it was found that specific biomechanical factors, such as hip joint mechanics during dynamic movements and abnormal loading patterns, played significant roles in the development and progression of FAI in female athletes.

La scoliose idiopathique de l’adolescent (SIA) est le type de déformation musculosquelettique le plus fréquent dans la population pédiatrique, pour une prévalence d’environ 2,0%. Depuis l’arrêt des programmes scolaires de dépistage de la SIA dans les années 1980 au Canada, nous ne disposions d’aucune donnée sur l’utilisation des services de santé par les patients présentant une SIA suspectée. En l’absence de tels programmes, des changements dans les patrons d’utilisation des services spécialisés d’orthopédie pédiatrique sont anticipés. La thèse a donc pour but d’étudier la pertinence de la référence dans ces services des jeunes avec SIA suspectée. Elle est structurée autour de trois principaux objectifs. 1) Valider un instrument de mesure de la morbidité perçue (perception des symptômes) dans la clientèle d’orthopédie pédiatrique; 2) Étudier la relation entre la morbidité perçue par les profanes (le jeune et le parent) et la morbidité objectivée par les experts; 3) Caractériser les itinéraires de soins des patients avec SIA suspectée, de façon à en élaborer une taxonomie et à analyser les relations entre ceux-ci et la pertinence de la référence. En 2006-2007, une vaste enquête a été réalisée dans les cinq cliniques d’orthopédie pédiatrique du Sud-Ouest du Québec : 831 patients référés ont été recrutés. Ils furent classés selon des critères de pertinence de la référence (inappropriée, appropriée ou tardive) définis en fonction de l’amplitude de la courbe rachidienne et de la maturité squelettique à cette première visite. La morbidité perçue par les profanes a été opérationnalisée par la gravité, l’urgence, les douleurs, l’impact sur l’image de soi et la santé générale. L’ensemble des consultations médicales et paramédicales effectuées en amont de la consultation en orthopédie pédiatrique a été documenté par questionnaire auprès des familles. En s’appuyant sur le Modèle comportemental de l’utilisation des services d’Andersen, les facteurs (dits de facilitation et de capacité) individuels, relatifs aux professionnels et au système ont été considérés comme variables d’ajustement dans l’étude des relations entre la morbidité perçue ou les itinéraires de soins et la pertinence de la référence. Les principales conclusions de cette étude sont : i) Nous disposons d’instruments fidèles (alpha de Cronbach entre 0,79 et 0,86) et valides (validité de construit, concomitante et capacité discriminante) pour mesurer la perception de la morbidité dans la population adolescente francophone qui consulte en orthopédie pédiatrique; ii) Les profanes jouent un rôle important dans la suspicion de la scoliose (53% des cas) et leur perception de la morbidité est directement associée à la morbidité objectivée par les professionnels; iii) Le case-mix actuel en orthopédie est jugé non optimal en regard de la pertinence de la référence, les mécanismes actuels entraînant un nombre considérable de références inappropriées (38%) et tardives (18%) en soins spécialisés d’orthopédie pédiatrique; iv) Il existe une grande diversité de professionnels par qui sont vus les jeunes avec SIA suspectée ainsi qu’une variabilité des parcours de soins en amont de la consultation en orthopédie, et v) La continuité des soins manifestée dans les itinéraires, notamment via la source régulière de soins de l’enfant, est favorable à la diminution des références tardives (OR=0,32 [0,17-0,59]). Les retombées de cette thèse se veulent des contributions à l’avancement des connaissances et ouvrent sur des propositions d’initiatives de transfert des connaissances auprès des professionnels de la première ligne. De telles initiatives visent la sensibilisation à cette condition de santé et le soutien à la prise de décision de même qu’une meilleure coordination des demandes de consultation pour une référence appropriée et en temps opportun. / Adolescent Idiopathic Scoliosis (AIS) is the type of musculoskeletal deformity most frequently encountered in the pediatric population with a prevalence of approximately 2.0%. Since the Canadian school screening programs were discontinued in the 1980s, data detailing health service utilization or typical reference patterns for patients with suspected AIS are no longer available. Without such programs, changes in the utilization patterns of pediatric orthopedic specialized services are anticipated. The thesis therefore aims to study the appropriateness of referral of youths with suspected AIS. It comprises three main objectives: 1) To validate a measurement tool based on perceived morbidity (perception of the symptoms) in the orthopedic pediatric patient population, 2) To study the relationships between morbidity perceived by lay persons (the young patient and his parent), and the objective morbidity determined by medical professionals, 3) To characterize the healthcare service pathways of suspected AIS cases upstream of their first orthopedic consultation in order to define a taxonomy of the pathways and analyse their relationships with the appropriateness of referral. In 2006-2007, an extensive survey conducted in the five clinics serving southwest Quebec recruited 831 patients. They were categorized using criteria for the appropriateness of referral (inappropriate, appropriate or late) based on the amplitude of the main spinal curve and skeletal maturity at the first visit. Lay perceived morbidity was operationalized according to the seriousness, urgency, pain, self-image and general perceived health. Medical and paramedical visits upstream of the pediatric orthopedic consultation were documented with questionnaires to the families. Based on Andersen’s Health Behavior Model, the individual (facilitating and enabling), professional and systemic factors were considered as control variables in the study of associations between perceived morbidity or healthcare trajectories, and appropriateness of referral. The main conclusions of the thesis are: i) Reliable (Cronbach alpha between 0.79 and 0.86) and valid (construct, concurrent and discriminant validity) measurement tools are available to evaluate the perceived morbidity in the French-speaking adolescent population that consults in pediatric orthopedics, ii) Lay stakeholders play an important role in the suspicion of scoliosis (53% of cases) with their perceived morbidity directly related to the objective morbidity, and therefore associated to the appropriateness of referral, iii) The current orthopedic casemix is considered suboptimal with regards to the appropriateness of referral, and the actual mechanisms for reference are in fact responsible for a large number of inappropriate (38%) and late (18%) referrals to specialized pediatric orthopedic services, iv) Adolescents with suspected AIS consult with a wide range of health specialists resulting in a large variety of healthcare pathways upstream of the orthopedic consultation, and v) Continuity of healthcare services, mainly through a regular source of care for the child, is favourable to a reduction in late referrals (OR=0.32 [0.17-0.59]). This thesis is intended to contribute to the advancement of conceptual, empirical and applied knowledge leading to a series of knowledge translation initiatives targeting primary health care providers. Such initiatives have the potential to increase awareness of the condition, to support decision-making as well as to improve the coordination of consultation requests, thus promoting appropriateness and timeliness of referrals.

O plasma rico em plaquetas (PRP) tem sido utilizado na ortopedia como método para melhorar a cicatrização tecidual. Existem poucos estudos com alto nível de evidência sobre o seu efeito no reparo do manguito rotador e os resultados são conflitantes, não havendo consenso sobre sua eficácia. O objetivo primário deste estudo foi avaliar o efeito do uso do PRP em pacientes submetidos ao reparo do manguito rotador por via artroscópica através da escala da University of California at Los Angeles (UCLA). A avaliação clínica através da escala de Constant-Murley, de dor através da escala visual analógica (EVA), a presença de rerroturas na análise da ressonância magnética (RM) e a ocorrência de complicações foram considerados desfechos secundários. Estudo prospectivo, randomizado, duplo-cego. Dois grupos com 27 pacientes (Grupo PRP e Grupo Controle) foram submetidos ao reparo artroscópico em fileira simples de âncoras, sendo que, no Grupo PRP, foi aplicado o concentrado de plaquetas ao final do procedimento. O PRP foi obtido por aférese, aplicado na consistência líquida, com adição de trombina autóloga. Foram incluídas apenas roturas de espessura completa do supraespinal com retração inferior a 30 mm. Os procedimentos foram realizados pelo mesmo cirurgião, entre setembro de 2008 e abril de 2012. Os desfechos foram avaliados através das escalas da UCLA, de Constant-Murley, EVA e pela RM, pré-operatoriamente e aos 3, 6 e 12 meses. A EVA foi aplicada adicionalmente no primeiro e sétimo dia. O nível de significância empregado foi de 5%. Os pacientes apresentaram melhora clínica significativa com o procedimento nos dois grupos (p < 0,001). Evoluíram de 13,63 ± 3,639 para 30,04 ± 4,528 no Grupo Controle e de 13,93 ± 4,649 para 32,30 ± 3,506 no Grupo PRP aos 12 meses (p = 0,046) de acordo com a escala da UCLA, com um poder de 84% e tamanho do efeito de 0,56. De acordo com a escala de Constant-Murley, os pacientes evoluíram de 47,37 ± 11,088 para 76,89 ± 13,198 no Grupo Controle e de 46,96 ± 11,937 para 83,26 ± 11,141 no Grupo PRP aos 12 meses (p=0,061). A avaliação aos 3 e 6 meses não demonstrou diferença significativa. A avaliação pela EVA não demonstrou diferença estatística em nenhum dos tempos de seguimento, evoluindo de 7,00 ± 1,939 no Grupo Controle e de 6,67 ± 1,617 no Grupo PRP no pré-operatório para 1,70 ± 2,127 e 1,04 ± 1,808, respectivamente, aos 12 meses (p = 0,220). Na análise pela RM, o Grupo Controle apresentou uma rerrotura completa e quatro parciais, enquanto o Grupo PRP apresentou duas rerroturas parciais (p = 0,42). Ocorreu um caso de rigidez articular em cada grupo (p = 1). O PRP obtido por aférese, aplicado na consistência líquida e com adição de trombina propiciou melhores resultados pela escala da UCLA aos 12 meses de pós-operatório / Platelet-rich plasma (PRP) has been used in orthopedics as a method to enhance tissue healing. There are few studies with a high level of evidence about its effect on rotator cuff repair, and the results are conflicting, with no consensus about its effectiveness. Clinical assessment as measured by the UCLA (University of California at Los Angeles) shoulder rating scale was established as the primary outcome. The secondary outcomes included clinical assessment on the Constant-Murley scale, pain as measured by a visual analog scale (VAS), the retear rate assessed by magnetic resonance imaging (MRI) and the complication rate. A prospective, randomized, doubleblind trial was conducted. Two groups of 27 patients (PRP Group and Control Group) were subjected to arthroscopic single-row repair. Liquid PRP prepared by apheresis was applied to the PRP Group at the end of the surgical procedure, with autologous thrombin. Complete supraspinatus tears with retraction less than 30 mm were included. The procedures were performed by the same surgeon between September 2008 and April 2012. Outcomes were assessed using UCLA and Constant-Murley scales, VAS and magnetic resonance imaging preoperatively and at 3, 6 and 12 months. The VAS was also applied on days one and seven. The significance level was 5%. The two groups of patients exhibited significant clinical improvement (p < 0.001). The score on the UCLA scale increased from 13.63 ± 3.639 to 30.04 ± 4.528 and from 13.93 ± 4.649 to 32.30 ± 3.506 in the Control and PRP groups, respectively, between the preoperative assessment and after 12 months (p=0.046), with a 84% power and a 0.56 effect size. The score on Constant-Murley scale increased from 47.37 ± 11.088 to 76.89 ± 13.198 in the Control Group and from 46.96 ± 11.937 to 83.26 ± 11.141 in the PRP Group (p = 0.061). Assessment at 3 and 6 months did not identify significant differences. The VAS did not statistically differ at any investigated timepoint and varied from 7.00 ± 1.939 and 6.67 ± 1.617 before surgery to 1.70 ± 2.127 and 1.04 ± 1.808 at the 12-month assessment in the Control and PRP groups, respectively (p = 0.220). The Control Group exhibited one case of complete and four of partial retears, and the Group PRP exhibited two cases of partial retears (p = 0.42). PRP prepared by apheresis, applied in the liquid state with thrombin, promoted better results on the UCLA scale 12 months after surgery