Paper 2: Biomechanical Alterations in Patients With Femoroacetabular Impingement

Abstract

SummaryBiomechanical testing of the pelvis, hip, and distal kinetic chain was carried out in patients with femoroacetabular impingement and compared with normal control subjects.DataIntroductionFemoroacetabular impingement (FAI) is a recently proposed pathomechanical process that has been implicated in the development of acetabular labral tears, articular cartilage injury, and early onset osteoarthritis. The spectrum of pathology among FAI patients is diverse. While some patients experience only subtle pain or functional deficiencies, others may have difficulty executing even simple tasks of daily living. A great deal of clinical and benchtop research has been devoted to improving surgical techniques and fostering a better understanding of the underlying morphologic conflict in patients with FAI. Despite advancements in such areas of study, biomechanical alterations in patients with FAI remain poorly understood. Furthermore, we are not aware of any studies that have examined the influence of FAI on biomechanics of the distal kinetic chain.Materials and MethodsIn this biomechanical study, 20 patients were recruited (10 age, sex, BMI matched control and 10 patients with unilateral FAI) to undergo biomechanical testing. A 5-task biomechanical analysis was conducted with a 3-D computer aided motion analysis system and high speed video monitoring. For each biomechanical task, motions at the pelvis, thigh, knee and foot were captured in the sagittal, frontal, and transverse planes. Kinematic and kinetic data was recorded using reflective markers and force plates.ResultsPatients with FAI demonstrated a statistically significant increase in pelvic contralateral rotation during running as well significant side-to-side differences in the frontal and sagittal planes at the hip. In addition, patients with FAI exhibited a significant increase in side-to-side knee valgus and tibial external rotation. When patients with FAI were compared with control subjects, variations were again observed at the pelvis, hip, and knee. These alterations were in concert with findings observed between the symptomatic and asymptomatic limbs of FAI patients.ConclusionsThis study uncovered a number of significant alterations in pelvic and hip kinematics. In addition, variations in knee kinematics were observed that reflect known risk factors for specific injury patterns. Changes in pelvis, hip, and knee kinematics were observed in a direct side-to-side comparison of involved and uninvolved limbs of FAI patients, as well as between FAI patients and control subjects. A global disynchrony in pelvi-femoral rhythm was also evident in patients with symptomatic FAI. It is unclear whether this finding is due to the characteristic morphologic abnormalities of FAI, or an overall deconditioning of the symptomatic limb that often accompanies this condition. As predicted, FAI patients sometimes utilized specific adaptive strategies to overcome abnormal morphology. SummaryBiomechanical testing of the pelvis, hip, and distal kinetic chain was carried out in patients with femoroacetabular impingement and compared with normal control subjects. Biomechanical testing of the pelvis, hip, and distal kinetic chain was carried out in patients with femoroacetabular impingement and compared with normal control subjects. DataIntroductionFemoroacetabular impingement (FAI) is a recently proposed pathomechanical process that has been implicated in the development of acetabular labral tears, articular cartilage injury, and early onset osteoarthritis. The spectrum of pathology among FAI patients is diverse. While some patients experience only subtle pain or functional deficiencies, others may have difficulty executing even simple tasks of daily living. A great deal of clinical and benchtop research has been devoted to improving surgical techniques and fostering a better understanding of the underlying morphologic conflict in patients with FAI. Despite advancements in such areas of study, biomechanical alterations in patients with FAI remain poorly understood. Furthermore, we are not aware of any studies that have examined the influence of FAI on biomechanics of the distal kinetic chain.Materials and MethodsIn this biomechanical study, 20 patients were recruited (10 age, sex, BMI matched control and 10 patients with unilateral FAI) to undergo biomechanical testing. A 5-task biomechanical analysis was conducted with a 3-D computer aided motion analysis system and high speed video monitoring. For each biomechanical task, motions at the pelvis, thigh, knee and foot were captured in the sagittal, frontal, and transverse planes. Kinematic and kinetic data was recorded using reflective markers and force plates.ResultsPatients with FAI demonstrated a statistically significant increase in pelvic contralateral rotation during running as well significant side-to-side differences in the frontal and sagittal planes at the hip. In addition, patients with FAI exhibited a significant increase in side-to-side knee valgus and tibial external rotation. When patients with FAI were compared with control subjects, variations were again observed at the pelvis, hip, and knee. These alterations were in concert with findings observed between the symptomatic and asymptomatic limbs of FAI patients.ConclusionsThis study uncovered a number of significant alterations in pelvic and hip kinematics. In addition, variations in knee kinematics were observed that reflect known risk factors for specific injury patterns. Changes in pelvis, hip, and knee kinematics were observed in a direct side-to-side comparison of involved and uninvolved limbs of FAI patients, as well as between FAI patients and control subjects. A global disynchrony in pelvi-femoral rhythm was also evident in patients with symptomatic FAI. It is unclear whether this finding is due to the characteristic morphologic abnormalities of FAI, or an overall deconditioning of the symptomatic limb that often accompanies this condition. As predicted, FAI patients sometimes utilized specific adaptive strategies to overcome abnormal morphology. IntroductionFemoroacetabular impingement (FAI) is a recently proposed pathomechanical process that has been implicated in the development of acetabular labral tears, articular cartilage injury, and early onset osteoarthritis. The spectrum of pathology among FAI patients is diverse. While some patients experience only subtle pain or functional deficiencies, others may have difficulty executing even simple tasks of daily living. A great deal of clinical and benchtop research has been devoted to improving surgical techniques and fostering a better understanding of the underlying morphologic conflict in patients with FAI. Despite advancements in such areas of study, biomechanical alterations in patients with FAI remain poorly understood. Furthermore, we are not aware of any studies that have examined the influence of FAI on biomechanics of the distal kinetic chain. Femoroacetabular impingement (FAI) is a recently proposed pathomechanical process that has been implicated in the development of acetabular labral tears, articular cartilage injury, and early onset osteoarthritis. The spectrum of pathology among FAI patients is diverse. While some patients experience only subtle pain or functional deficiencies, others may have difficulty executing even simple tasks of daily living. A great deal of clinical and benchtop research has been devoted to improving surgical techniques and fostering a better understanding of the underlying morphologic conflict in patients with FAI. Despite advancements in such areas of study, biomechanical alterations in patients with FAI remain poorly understood. Furthermore, we are not aware of any studies that have examined the influence of FAI on biomechanics of the distal kinetic chain. Materials and MethodsIn this biomechanical study, 20 patients were recruited (10 age, sex, BMI matched control and 10 patients with unilateral FAI) to undergo biomechanical testing. A 5-task biomechanical analysis was conducted with a 3-D computer aided motion analysis system and high speed video monitoring. For each biomechanical task, motions at the pelvis, thigh, knee and foot were captured in the sagittal, frontal, and transverse planes. Kinematic and kinetic data was recorded using reflective markers and force plates. In this biomechanical study, 20 patients were recruited (10 age, sex, BMI matched control and 10 patients with unilateral FAI) to undergo biomechanical testing. A 5-task biomechanical analysis was conducted with a 3-D computer aided motion analysis system and high speed video monitoring. For each biomechanical task, motions at the pelvis, thigh, knee and foot were captured in the sagittal, frontal, and transverse planes. Kinematic and kinetic data was recorded using reflective markers and force plates. ResultsPatients with FAI demonstrated a statistically significant increase in pelvic contralateral rotation during running as well significant side-to-side differences in the frontal and sagittal planes at the hip. In addition, patients with FAI exhibited a significant increase in side-to-side knee valgus and tibial external rotation. When patients with FAI were compared with control subjects, variations were again observed at the pelvis, hip, and knee. These alterations were in concert with findings observed between the symptomatic and asymptomatic limbs of FAI patients. Patients with FAI demonstrated a statistically significant increase in pelvic contralateral rotation during running as well significant side-to-side differences in the frontal and sagittal planes at the hip. In addition, patients with FAI exhibited a significant increase in side-to-side knee valgus and tibial external rotation. When patients with FAI were compared with control subjects, variations were again observed at the pelvis, hip, and knee. These alterations were in concert with findings observed between the symptomatic and asymptomatic limbs of FAI patients. ConclusionsThis study uncovered a number of significant alterations in pelvic and hip kinematics. In addition, variations in knee kinematics were observed that reflect known risk factors for specific injury patterns. Changes in pelvis, hip, and knee kinematics were observed in a direct side-to-side comparison of involved and uninvolved limbs of FAI patients, as well as between FAI patients and control subjects. A global disynchrony in pelvi-femoral rhythm was also evident in patients with symptomatic FAI. It is unclear whether this finding is due to the characteristic morphologic abnormalities of FAI, or an overall deconditioning of the symptomatic limb that often accompanies this condition. As predicted, FAI patients sometimes utilized specific adaptive strategies to overcome abnormal morphology. This study uncovered a number of significant alterations in pelvic and hip kinematics. In addition, variations in knee kinematics were observed that reflect known risk factors for specific injury patterns. Changes in pelvis, hip, and knee kinematics were observed in a direct side-to-side comparison of involved and uninvolved limbs of FAI patients, as well as between FAI patients and control subjects. A global disynchrony in pelvi-femoral rhythm was also evident in patients with symptomatic FAI. It is unclear whether this finding is due to the characteristic morphologic abnormalities of FAI, or an overall deconditioning of the symptomatic limb that often accompanies this condition. As predicted, FAI patients sometimes utilized specific adaptive strategies to overcome abnormal morphology.