Osteoarthritis (OA) is a degenerative disease which affects articulations. Tibiofemoral malalignment leads to a worsening of the OA. It consists in a deviation of the mechanical axis of the leg, resulting in modified loads distributions between medial and lateral compartments of the knee. In this field, High Tibial Osteotomy (HTO) represents an ideal option, especially for young patients. This surgical technique modifies the limb alignment with a consequent unloading of the damaged compartment, reducing the pain and the progression of osteoarthritis. The aim of this thesis was to evaluate the correlation between the tibiofemoral malalignment angle in the target limb and the hip contact forces in the contralateral limb, in patients with unicompartmental knee osteoarthritis during daily activities. This project is the continuation of a previous work carried out by the colleague Nicolò Caredda, which focused on the correlation between tibiofemoral angle and knee contact loads, by distinguishing the medial and lateral components. Both of them are part of a bigger study, which is carried out at Rizzoli Orthopaedic Institute of Bologna whose aim is to evaluate how an accurately planned HTO affects the progression of knee osteoarthritis by analysing the quality of cartilage and subchondral bone in people with varus tibiofemoral alignment, by combining biomechanical and medical imaging approach. Nineteen patients with early-stage medial osteoarthritis, who were indicated for HTO, were studied within this thesis. Subjects were randomly divided into a control and an operation group, characterized by conservative therapies and surgery, respectively, and for each of them gait analysis data were collected from 3 motor activities (walking, stair ascent and stair descent) through a stereophotogrammetric system, a set of markers, 2 force platforms and 8 EMG sensors for each limb. First, by using subject-specific anthropometric data, a generic musculoskeletal (MSK) model was scaled within OpenSim, which is an open-source software that permits to create and analyse MSK models, and then simulate different motor activities. The tibiofemoral malalignment angle was calculated by processing RX images through the software HTO-Rplus, specifically created to plan this type of surgery. Within OpenSim, an inverse dynamic problem based on optimization was solved to compute the internal joints contact forces and muscle activations. In the post-processing phase, the relationship between tibiofemoral malalignment and contralateral hip contact forces was evaluated through a linear correlation analysis. Then, statistical parametric mapping in a nonparametric two-tailed unpaired t-tests (α = 0.05), and Mann-Whitney U-test (α = 0.05) were used to study the differences between the contralateral and target limbs, throughout the gait cycles and on the force peaks, respectively. The last part of this thesis evaluates the ground reaction forces recorded during the gait analysis sessions using the force platforms, and validates the results through a comparison between muscle activations computed via OpenSim, and EMG signals across the activity cycle. The analysis of the results reported a weak correlation between tibiofemoral malalignment in the target limb and hip contact loads in the contralateral limb, although some significant correlations were found if considering the two limbs separately. Moreover, peak force distribution and contact forces analysis highlighted a statistically significant difference between target and contralateral limbs, in favor of the latter, which was emphasized in more demanding tasks. This could be due to an antalgic compensation strategy adopted to relieve the pain in the target limb. Muscle activations showed good matching with EMG signals, except on few occasions.

Effect of tibiofemoral malalignment on the contralateral hip forces in patients with unicompartmental osteoarthritis during daily motor activities: a musculoskeletal modeling analysis

MEGGIOLARO, MATTIA
2021/2022

Abstract

Osteoarthritis (OA) is a degenerative disease which affects articulations. Tibiofemoral malalignment leads to a worsening of the OA. It consists in a deviation of the mechanical axis of the leg, resulting in modified loads distributions between medial and lateral compartments of the knee. In this field, High Tibial Osteotomy (HTO) represents an ideal option, especially for young patients. This surgical technique modifies the limb alignment with a consequent unloading of the damaged compartment, reducing the pain and the progression of osteoarthritis. The aim of this thesis was to evaluate the correlation between the tibiofemoral malalignment angle in the target limb and the hip contact forces in the contralateral limb, in patients with unicompartmental knee osteoarthritis during daily activities. This project is the continuation of a previous work carried out by the colleague Nicolò Caredda, which focused on the correlation between tibiofemoral angle and knee contact loads, by distinguishing the medial and lateral components. Both of them are part of a bigger study, which is carried out at Rizzoli Orthopaedic Institute of Bologna whose aim is to evaluate how an accurately planned HTO affects the progression of knee osteoarthritis by analysing the quality of cartilage and subchondral bone in people with varus tibiofemoral alignment, by combining biomechanical and medical imaging approach. Nineteen patients with early-stage medial osteoarthritis, who were indicated for HTO, were studied within this thesis. Subjects were randomly divided into a control and an operation group, characterized by conservative therapies and surgery, respectively, and for each of them gait analysis data were collected from 3 motor activities (walking, stair ascent and stair descent) through a stereophotogrammetric system, a set of markers, 2 force platforms and 8 EMG sensors for each limb. First, by using subject-specific anthropometric data, a generic musculoskeletal (MSK) model was scaled within OpenSim, which is an open-source software that permits to create and analyse MSK models, and then simulate different motor activities. The tibiofemoral malalignment angle was calculated by processing RX images through the software HTO-Rplus, specifically created to plan this type of surgery. Within OpenSim, an inverse dynamic problem based on optimization was solved to compute the internal joints contact forces and muscle activations. In the post-processing phase, the relationship between tibiofemoral malalignment and contralateral hip contact forces was evaluated through a linear correlation analysis. Then, statistical parametric mapping in a nonparametric two-tailed unpaired t-tests (α = 0.05), and Mann-Whitney U-test (α = 0.05) were used to study the differences between the contralateral and target limbs, throughout the gait cycles and on the force peaks, respectively. The last part of this thesis evaluates the ground reaction forces recorded during the gait analysis sessions using the force platforms, and validates the results through a comparison between muscle activations computed via OpenSim, and EMG signals across the activity cycle. The analysis of the results reported a weak correlation between tibiofemoral malalignment in the target limb and hip contact loads in the contralateral limb, although some significant correlations were found if considering the two limbs separately. Moreover, peak force distribution and contact forces analysis highlighted a statistically significant difference between target and contralateral limbs, in favor of the latter, which was emphasized in more demanding tasks. This could be due to an antalgic compensation strategy adopted to relieve the pain in the target limb. Muscle activations showed good matching with EMG signals, except on few occasions.
2021
Effect of tibiofemoral malalignment on the contralateral hip forces in patients with unicompartmental osteoarthritis during daily motor activities: a musculoskeletal modeling analysis
malalignment
osteoarthritis
musculoskeletal
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/20.500.12608/30827