Femoroacetabular impingement (FAI) is recognized as a pathomechanical process that leads to hip osteoarthritis (OA). It is hypothesized that mechanical stimuli are prominent at higher range of motions in hips with cam FAI (aspherical femoral head-neck deformity). Adverse loading conditions can impose elevated mechanical stimuli levels at the articulating surfaces and underlying subchondral bone, which plays a predominant mechanical role in early OA. The aim of this research was to determine the levels of mechanical stimuli within the hip, examining the effects of severe cam impingement on the onset of OA, using patient-specific biomechanics data, CT data, and finite element analysis (FEA). Patient-specific hip joint reaction forces were applied to two symptomatic patient models and two control-matched models, segmented from patient-specific CT data. The finite element models were simulated to compare the locations and magnitudes of mechanical stimuli during two quasi-static positions from standing to squatting. Maximum-shear stress (MSS) was analyzed to determine the adverse loading conditions within the joint and strain energy density (SED) was determined to examine its effect on the initiation of bone remodelling. The results revealed that peak mechanical stimuli concentrations were found on the antero-superior acetabulum during the squatting position, underlying to the cartilage. The MSS magnitudes were significantly higher and concentrated for the FAI patients (15.145 ± 1.715 MPa) in comparison with the MSS magnitudes for the control subjects (4.445 ± 0.085 MPa). The FAI group demonstrated a slight increase in peak SED values on the acetabulum from standing (1.005 ± 0.076 kPa) to squatting (1.018 ± 0.082 kPa). Insignificant changes in SED values were noticed for the control subjects. Squatting orients the femoral head into the antero-superior acetabulum, increasing the contact area with the cartilage and labral regions, thus resulting in higher peaks behind the cartilage on the acetabulum. The resultant location of the peak MSS and SED concentrations correspond well with the region of initial cartilage degradation and early OA observed during open surgical dislocation. Due to the relatively low elastic modulus of the articular cartilage, loads are transferred and amplified to the subchondral bone. This further suggests that elevated stimuli levels can provoke stiffening of the underlying subchondral plate, through bone remodelling, and consequently accelerating the onset of cartilage degradation. Since mechanical stimuli results are unique to their patient-specific loading parameters and conditions, it would be difficult to determine a patient-specific threshold to provoke bone remodeling at this stage.

Objetivo: determinar a prevalência dos sinais radiográficos de impacto femoroacetabular em adultos assintomáticos e correlacionar com dados do exame físico. Métodos: estudo transversal, realizado no Hospital de Clínicas de Porto Alegre, com 82 indivíduos, 164 quadris de pacientes entre 40 e 60 anos de idade assintomáticos. Foram submetidos à anamnese e exame clínico completo do quadril e exame radiográfico com três incidências, AP de bacia, Dunn a 45° e falso perfil de Lequesne de cada quadril, para mensuração das variáveis. Entre elas o ângulo alfa, offset anterior do colo femoral, ângulo cérvico diafisário, ângulo CE de Wiberg, índice acetabular, ângulo de Sharp, além dos sinais do cruzamento, da espinha isquiática e da parede posterior. Resultados: nossa amostra foi formada por 66% de mulheres, com média de idade de 50,4 anos. O ângulo alfa médio foi de 45.10º, DP = 8.6. 25% dos quadris apresentaram ângulo alfa maior ou igual a 50°; entre os homens esse número foi ainda maior, 34% e apenas 11% entre as mulheres. Encontramos sinais radiográficos indicativos de impacto femoroacetabular em 42,6% dos quadris, sejam eles femorais ou acetabulares. O aumento do alfa esteve relacionado com o decréscimo na rotação interna do quadril (p < 0,001). Conclusão: Os achados radiográficos de impacto femoroacetabular em pacientes assintomáticos são freqüentes e o aumento do ângulo alfa esteve relacionado com o decréscimo da rotação interna. / Objective: The objective of this research is to determine the prevalence of radiographic markers of femoroacetabular impingement in asymptomatic adults and correlate with data from physical examination. Methods: A cross-sectional study conducted at Hospital de Clinicas in Porto Alegre, with 82 individuals, 164 hips of asymptomatic individuals between 40 and 60 years old. They were subjected to a complete medical history and examination of the hip, three X-ray incidences, pelvis AP, Dunn 45° view and the Lequesne false profile of each hip, for the measurement of variables. The variables were the alpha angle, anterior femoral offset, neck shaft angle, CE angle of Wiberg, acetabular index, Sharp’s angle, in addition to crossover sign and the posterior ischial spine and the posterior wall sign. Results: the sample was made up of 66% women, average age of 50.4 years old. The average alpha angle was 45.10 º, SD = 8.6. 25% of the hips showed alpha angle greater than or equal to 50 °, among me n the figure was even higher, 34% and only 11% among women. We found radiographic signs indicative of femoroacetabular impingement in 42,6% of hips, whether femoral or acetabular. The increase in alpha angle was related to the decrease in hip internal rotation (p <0.001). Conclusion: The radiographic markers of femoroacetabular impingement were frequent in asymptomatic patients, and the increase in alpha angle was associated with decreased internal rotation of the hip.

Objetivo: determinar a prevalência dos sinais radiográficos de impacto femoroacetabular em adultos assintomáticos e correlacionar com dados do exame físico. Métodos: estudo transversal, realizado no Hospital de Clínicas de Porto Alegre, com 82 indivíduos, 164 quadris de pacientes entre 40 e 60 anos de idade assintomáticos. Foram submetidos à anamnese e exame clínico completo do quadril e exame radiográfico com três incidências, AP de bacia, Dunn a 45° e falso perfil de Lequesne de cada quadril, para mensuração das variáveis. Entre elas o ângulo alfa, offset anterior do colo femoral, ângulo cérvico diafisário, ângulo CE de Wiberg, índice acetabular, ângulo de Sharp, além dos sinais do cruzamento, da espinha isquiática e da parede posterior. Resultados: nossa amostra foi formada por 66% de mulheres, com média de idade de 50,4 anos. O ângulo alfa médio foi de 45.10º, DP = 8.6. 25% dos quadris apresentaram ângulo alfa maior ou igual a 50°; entre os homens esse número foi ainda maior, 34% e apenas 11% entre as mulheres. Encontramos sinais radiográficos indicativos de impacto femoroacetabular em 42,6% dos quadris, sejam eles femorais ou acetabulares. O aumento do alfa esteve relacionado com o decréscimo na rotação interna do quadril (p < 0,001). Conclusão: Os achados radiográficos de impacto femoroacetabular em pacientes assintomáticos são freqüentes e o aumento do ângulo alfa esteve relacionado com o decréscimo da rotação interna. / Objective: The objective of this research is to determine the prevalence of radiographic markers of femoroacetabular impingement in asymptomatic adults and correlate with data from physical examination. Methods: A cross-sectional study conducted at Hospital de Clinicas in Porto Alegre, with 82 individuals, 164 hips of asymptomatic individuals between 40 and 60 years old. They were subjected to a complete medical history and examination of the hip, three X-ray incidences, pelvis AP, Dunn 45° view and the Lequesne false profile of each hip, for the measurement of variables. The variables were the alpha angle, anterior femoral offset, neck shaft angle, CE angle of Wiberg, acetabular index, Sharp’s angle, in addition to crossover sign and the posterior ischial spine and the posterior wall sign. Results: the sample was made up of 66% women, average age of 50.4 years old. The average alpha angle was 45.10 º, SD = 8.6. 25% of the hips showed alpha angle greater than or equal to 50 °, among me n the figure was even higher, 34% and only 11% among women. We found radiographic signs indicative of femoroacetabular impingement in 42,6% of hips, whether femoral or acetabular. The increase in alpha angle was related to the decrease in hip internal rotation (p <0.001). Conclusion: The radiographic markers of femoroacetabular impingement were frequent in asymptomatic patients, and the increase in alpha angle was associated with decreased internal rotation of the hip.

Objetivo: determinar a prevalência dos sinais radiográficos de impacto femoroacetabular em adultos assintomáticos e correlacionar com dados do exame físico. Métodos: estudo transversal, realizado no Hospital de Clínicas de Porto Alegre, com 82 indivíduos, 164 quadris de pacientes entre 40 e 60 anos de idade assintomáticos. Foram submetidos à anamnese e exame clínico completo do quadril e exame radiográfico com três incidências, AP de bacia, Dunn a 45° e falso perfil de Lequesne de cada quadril, para mensuração das variáveis. Entre elas o ângulo alfa, offset anterior do colo femoral, ângulo cérvico diafisário, ângulo CE de Wiberg, índice acetabular, ângulo de Sharp, além dos sinais do cruzamento, da espinha isquiática e da parede posterior. Resultados: nossa amostra foi formada por 66% de mulheres, com média de idade de 50,4 anos. O ângulo alfa médio foi de 45.10º, DP = 8.6. 25% dos quadris apresentaram ângulo alfa maior ou igual a 50°; entre os homens esse número foi ainda maior, 34% e apenas 11% entre as mulheres. Encontramos sinais radiográficos indicativos de impacto femoroacetabular em 42,6% dos quadris, sejam eles femorais ou acetabulares. O aumento do alfa esteve relacionado com o decréscimo na rotação interna do quadril (p < 0,001). Conclusão: Os achados radiográficos de impacto femoroacetabular em pacientes assintomáticos são freqüentes e o aumento do ângulo alfa esteve relacionado com o decréscimo da rotação interna. / Objective: The objective of this research is to determine the prevalence of radiographic markers of femoroacetabular impingement in asymptomatic adults and correlate with data from physical examination. Methods: A cross-sectional study conducted at Hospital de Clinicas in Porto Alegre, with 82 individuals, 164 hips of asymptomatic individuals between 40 and 60 years old. They were subjected to a complete medical history and examination of the hip, three X-ray incidences, pelvis AP, Dunn 45° view and the Lequesne false profile of each hip, for the measurement of variables. The variables were the alpha angle, anterior femoral offset, neck shaft angle, CE angle of Wiberg, acetabular index, Sharp’s angle, in addition to crossover sign and the posterior ischial spine and the posterior wall sign. Results: the sample was made up of 66% women, average age of 50.4 years old. The average alpha angle was 45.10 º, SD = 8.6. 25% of the hips showed alpha angle greater than or equal to 50 °, among me n the figure was even higher, 34% and only 11% among women. We found radiographic signs indicative of femoroacetabular impingement in 42,6% of hips, whether femoral or acetabular. The increase in alpha angle was related to the decrease in hip internal rotation (p <0.001). Conclusion: The radiographic markers of femoroacetabular impingement were frequent in asymptomatic patients, and the increase in alpha angle was associated with decreased internal rotation of the hip.

Bibliographic identification DINDA, Ondřej. Kinematic analysis of patients wiht femoroacetabular impingement syndrome. Prague: Charles University, 2nd Faculty of medicine, Department of Rehabilitation and Sports Medicine, 2017. 82 pages. Supervisor: Mgr. Petra Valouchová, Ph.D. Abstract The purpose of this master thesis was to find out, if there are objective changes in biomechanics of the gait and upstairs gait by objectives with diagnosed femoroacetabular impingement syndrome and by healthy objectives. The data were acquired using kinematic analysis Qualisys and processed using software Qualisys track manager and Visual3D. The subject of research was the range of motion in hip joint in frontal and sagittal plane, than the movement of pelvis in frontal plane, movement of pelvis against thorax in transversal plane and deviation of the axis of spine in frontal plane. These parameters were documented using angular deviation of the segments, deviation of the segments in the plane or shifting of the markers in coordinate system. The conclusions were than statistically evaluated. There were 20 objects with diagnosed femoroacetabular impingement syndrome in the age from 23 to 47 years of age included in the study. In the gait research, a significant difference in angular deviation of the pelvis against thorax in...

Femoroacetabular impingement syndrome (FAI) is a hip impairment, which is according to recent studies significant contributor to hip osteoarthritis. Current research is dedicated to evaluate movement patterns of hip, pelvis and spine in patients with FAI using a motion analysis capture system. Biomechanics and kinesiology relations between spino-pelvic complex and lower limb joints led us to choose the topic of this thesis. The goal of this study was to define the movements of ankle and foot in patients with FAI syndrome and to compare with asymptomatic control group. To measure the parameters during gait we used Qualisys motion capture system and then the data were processed in Qualisys Track Manager 2020.03. We assessed the movements of ankle, rearfoot and the progression foot angle during the stance phase of gait cycle. Moreover, we measured the step length, gait speed and passive range of motion of the hip in both exploratory groups. In total we examinated 30 subjects, 15 with FAI syndrome and 15 asymptomatic volunteers with physiologic hip condition. We demonstrated three significant between group changes in average ankle range of motion in sagittal plane, foot progression angle and passive range of motion of the hip.

Femoroacetabular impingement (FAI) is recognized as a pathomechanical process that leads to hip osteoarthritis (OA). It is hypothesized that mechanical stimuli are prominent at higher range of motions in hips with cam FAI (aspherical femoral head-neck deformity). Adverse loading conditions can impose elevated mechanical stimuli levels at the articulating surfaces and underlying subchondral bone, which plays a predominant mechanical role in early OA. The aim of this research was to determine the levels of mechanical stimuli within the hip, examining the effects of severe cam impingement on the onset of OA, using patient-specific biomechanics data, CT data, and finite element analysis (FEA). Patient-specific hip joint reaction forces were applied to two symptomatic patient models and two control-matched models, segmented from patient-specific CT data. The finite element models were simulated to compare the locations and magnitudes of mechanical stimuli during two quasi-static positions from standing to squatting. Maximum-shear stress (MSS) was analyzed to determine the adverse loading conditions within the joint and strain energy density (SED) was determined to examine its effect on the initiation of bone remodelling. The results revealed that peak mechanical stimuli concentrations were found on the antero-superior acetabulum during the squatting position, underlying to the cartilage. The MSS magnitudes were significantly higher and concentrated for the FAI patients (15.145 ± 1.715 MPa) in comparison with the MSS magnitudes for the control subjects (4.445 ± 0.085 MPa). The FAI group demonstrated a slight increase in peak SED values on the acetabulum from standing (1.005 ± 0.076 kPa) to squatting (1.018 ± 0.082 kPa). Insignificant changes in SED values were noticed for the control subjects. Squatting orients the femoral head into the antero-superior acetabulum, increasing the contact area with the cartilage and labral regions, thus resulting in higher peaks behind the cartilage on the acetabulum. The resultant location of the peak MSS and SED concentrations correspond well with the region of initial cartilage degradation and early OA observed during open surgical dislocation. Due to the relatively low elastic modulus of the articular cartilage, loads are transferred and amplified to the subchondral bone. This further suggests that elevated stimuli levels can provoke stiffening of the underlying subchondral plate, through bone remodelling, and consequently accelerating the onset of cartilage degradation. Since mechanical stimuli results are unique to their patient-specific loading parameters and conditions, it would be difficult to determine a patient-specific threshold to provoke bone remodeling at this stage.

Current research suggests that femoroacetabular impingement can be a cause of osteoarthritis. Femoroacetabular impingement is a condition that can affect both the femur and the pelvis of an individual. Femoroacetabular impingement can cause damage to the hip joint and its surrounding tissues. The articular cartilage and the labrum are both affected by this condition. A cam impingement is where a bony protrusion develops at the femoral head/neck junction. A pincer impingement is where a bony protrusion develops at the acetabular rim. Often, patients are seen with a combination of both impingements. The main goal of this study was to computationally model and analyze acetabular stresses in a healthy hip, a hip with a cam impingement, a hip with a pincer impingement, and a hip with a combination of the two impingements. The bone models were taken from CT scans. The impingements were created by using Autodesk Maya to modify the surfaces of the models. The hip models were set up to model the single-leg stance phase of the walking cycle. For the most part, the impingements reduce the stress experienced by the femur. The only exception to this is that the cam femur paired with the pincer pelvis experienced the highest maximum principal stress in the proximomedial region. The pincer impingements increase both the maximum and minimum principal stresses experienced in the acetabulum. Overall, the two types of femoroacetabular impingement change the stress experienced by both the femur and the pelvis. The results of this study demonstrate that acetabular stresses can increase as a result of femoroacetabular impingements. These increased stresses can lead to damage in the hip joint which presents a clinical problem.

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Le conflit fémoro-acétabulaire (femoroacetabular impingement, FAI) est une pathologie mécanique de la hanche qui peut causer des douleurs et limitations fonctionnelles. Le but de cette thèse était d’étudier la fonction musculaire au niveau de la hanche chez des patients présentant un FAI symptomatique. La fonction musculaire de la hanche a été évaluée, dans un premier temps, chez des patients avant qu’ils ne subissent une opération. Ces patients démontraient un déficit de force qui pourrait être expliqué par de l’inhibition musculaire. Cependant, ce déficit de force n’était pas associé à une plus grande fatigabilité musculaire. Dans un deuxième temps, les altérations de force musculaire ont été évaluées chez des patients ayant subi une arthroscopie de la hanche. Après l’opération, les patients récupéraient un niveau de force normal au niveau de tous les groupes musculaires de la hanche excepté les fléchisseurs. Le cas d’un joueur de hockey sur glace ayant subi une chirurgie ouverte aux deux hanches pour traiter un FAI bilatéral a aussi été décrit. On a démontré que la déhiscence de la bandelette iléo-tibiale pouvait survenir après chirurgie, empêcher l’augmentation de force musculaire des abducteurs de la hanche, et retarder la reprise du sport. Enfin, un protocole d’évaluation du taux de développement de la force normalisé, variable permettant d’estimer l’inhibition musculaire de la hanche, a été proposé chez des sujets sains. La fiabilité et reproductibilité des résultats ont été montrées au niveau des adducteurs, rotateurs externes, et fléchisseurs de la hanche. Ces résultats montrent que ces patients ont une fonction musculaire altérée au niveau de la hanche, qui est toutefois récupéré après une opération. / Femoroacetabular impingement (FAI) is a pathomechanical process of the hip joint, which could lead to hip pain and functional disability. Aim of this thesis was to investigate hip muscle function in patients with a symptomatic FAI. Hip muscle function was first investigated before patients underwent any surgical treatment for managing FAI. It was shown that they present with reduced hip muscle strength (i.e., muscle weakness), probably due to hip muscle inhibition. Nevertheless, hip muscle weakness was not associated with exaggerated hip muscle fatigue. Hip muscle strength recovery was then evaluated in a series of patients after hip arthroscopy to treat FAI. These patients demonstrated a good recovery for all hip muscle groups, except for hip flexors. The case of a professional ice hockey player who underwent bilateral hip open surgeries for treating bilateral FAI was also documented. This report showed that iliotibial band dehiscence could occur after hip open surgery, thereby preventing hip abductor strength increase during rehabilitation and delaying the return to sport. In addition, the assessment of the rate of force development scaling factor for the hip muscles was evaluated in a group of healthy adults. This parameter seems to be promising for the evaluation of hip muscle inhibition. The testing protocol was feasible and reproducible for hip adductors, external rotators and flexors. Taken as a whole, these findings show that patients with symptomatic FAI demonstrate an impaired hip muscle function, which is however mainly resolved after surgical treatment.