Segmental Movement Compensations in Patients with Transtibial Amputation Identified Using Angular Momentum Separation

Patients with unilateral dysvascular transtibial amputation (TTA) adopt movement compensations that are required to maintain balance and achieve ambulation in the absence of ankle plantar flexion, and result in increased and asymmetric joint loading patterns. As a result, this population is at an increased risk of overuse injuries, such as low back pain (LBP). Clinical gait analysis is used to guide diagnostics in movement retraining following amputation, and is performed using instrumented (research based) or observational analyses (clinically based). However, instrumented analyses are currently impractical in most clinical settings due to expense and computational limitations. This dissertation presents the use of segmental angular momentum to describe movement compensations in patients with TTA, and assess their effects on the musculoskeletal system; which provides a potential platform applicable in both instrumented and observational settings. Ten patients with unilateral dysvascular TTA and two cohorts (patients with diabetes mellitus and healthy controls) completed one experimental study in which whole-body kinematics and core muscle demand were collected during walking and bilateral stepping tasks. Specific Aim 1 described the foundations of the separation of angular momentum into two components, translational (TAM) and rotational angular momentum (RAM) to describe movement coordination during healthy walking. Euler\u27s rotational laws were used to calculate segmental translational and rotational moments, which provide insight into the effort required to generate and arrest momentum by their relation to external forces and moments. Specific Aim 2 described trunk and pelvis movement compensations in patients with TTA during walking using TAM and RAM. Specific Aim 3 described the trunk translational and rotational moments in patients with TTA during step ambulation. Finally, Specific Aim 4 described the demand from the core musculature that supports trunk movement compensations in patients with TTA during step ambulation. The results from these Specific Aims indicate that patients with TTA generate larger amounts of TAM and RAM, which were caused by larger translational and rotational trunk moments and demand from core muscles, than healthy controls. These compensations alter the low back loading patterns, which may be reduced by targeted strengthening and retraining motor control compensations to better support trunk movements

Evaluation of Novel High-Density EMG Feedback Parameters on the Spatial Distribution of Trapezius Muscle Activity

Each year, 17.9% of adults working in a computer-dominated work environment develop an episode of chronic neck and shoulder pain. An effective treatment method for chronic pain is postural correction through therapist. The understanding of the relation between cervicoscapular posture and trapezius muscle activity is not fully understood because the anatomy of the scapula is not accessible for direct observation. Until recently, the spatial distribution of trapezius muscle activity could not be measured due to the limitation in size of detection zone in traditional bipolar electrodes. The primary goal of postural correction when treating cases of chronic neck and shoulder pain is to shift the distribution of trapezius muscle activity inferior. However, treatment methods of chronic musculoskeletal diseases are often inefficient due to the inability of the participant to permanently alter posture and activation patterns. The first goal of this project was to determine the relation between cervicoscapular posture and the distribution of trapezius muscle activity. To accomplish this, cervicoscapular posture and trapezius muscle activity were recorded while participants adopted three unique shoulder postures. Because scapular position cannot be measured ex vivo, the position of the acromion process relative to C7 was used as a surrogate. Finally, a biofeedback intervention using HDsEMG feedback parameter was developed for real-time postural correction during computer use. Biofeedback is an effective strategy for rehabilitation application to retrain muscle activation patterns through motor unit re-education. The HDsEMG biofeedback interface was developed to shift trapezius muscle activity inferior. This interface provides the opportunity to provide a more effective treatment to chronic neck pain by permanently shifting trapezius muscle activity inferiorly

Biomechanical Compensations of the Trunk and Lower Extremities during Stepping Tasks after Unilateral Transtibial Amputation

Background Lower extremity movement compensations following transtibial amputation are well-documented and are likely influenced by trunk posture and movement. However, the biomechanical compensations of the trunk and lower extremities, especially during high-demand tasks such as step ascent and descent, remain unclear. Methods Kinematic and kinetic data were collected during step ascent and descent tasks for three groups of individuals: diabetic/transtibial amputation, diabetic, and healthy. An ANCOVA was used to compare peak trunk, hip and knee joint angles and moments in the sagittal and frontal planes between groups. Paired t-tests were used to compare peak joint angles and moments between amputated and intact limbs of the diabetic/transtibial amputation group. Findings During step ascent and descent, the transtibial amputation group exhibited greater trunk forward flexion and lateral flexion compared to the other two groups (P \u3c 0.016), which resulted in greater low back moments and asymmetric loading patterns in the lower extremity joints. The diabetic group exhibited similar knee joint loading patterns compared to the amputation group (P \u3c 0.016), during step descent. Interpretation This study highlights the biomechanical compensations of the trunk and lower extremities in individuals with dysvascular transtibial amputation, by identifying low back, hip, and knee joint moment patterns unique to transtibial amputation during stepping tasks. In addition, the results suggest that some movement compensations may be confounded by the presence of diabetes and precede limb amputation. The increased and asymmetrical loading patterns identified may predispose individuals with transtibial amputation to the development of secondary pain conditions, such as low back pain or osteoarthritis

Identification of Trunk and Pelvis Movement Compensations in Patients with Transtibial Amputation using Angular Momentum Separation

Patients with unilateral dysvascular transtibial amputation (TTA) have a higher risk of developing low back pain than their healthy counterparts, which may be related to movement compensations used in the absence of ankle function. Assessing components of segmental angular momentum provides a unique framework to identify and interpret these movement compensations alongside traditional observational analyses. Angular momentum separation indicates two components of total angular momentum: (1) transfer momentum and (2) rotational momentum. The objective of this investigation was to assess movement compensations in patients with dysvascular TTA, patients with diabetes mellitus (DM), and healthy controls (HC) by examining patterns of generating and arresting trunk and pelvis segmental angular momenta during gait. We hypothesized that all groups would demonstrate similar patterns of generating/arresting total momentum and transfer momentum in the trunk and pelvis in reference to the groups (patients with DM and HC). We also hypothesized that patients with amputation would demonstrate different (larger) patterns of generating/arresting rotational angular momentum in the trunk. Patients with amputation demonstrated differences in trunk and pelvis transfer angular momentum in the sagittal and transverse planes in comparison to the reference groups, which indicates postural compensations adopted during walking. However, patients with amputation demonstrated larger patterns of generating and arresting of trunk and pelvis rotational angular momentum in comparison to the reference groups. These segmental rotational angular momentum patterns correspond with high eccentric muscle demands needed to arrest the angular momentum, and may lead to consequential long-term effects such as low back pain

Identification of Trunk and Pelvis Movement Compensations in Patients with Transtibial Amputation using Angular Momentum Separation

Patients with unilateral dysvascular transtibial amputation (TTA) have a higher risk of developing low back pain than their healthy counterparts, which may be related to movement compensations used in the absence of ankle function. Assessing components of segmental angular momentum provides a unique framework to identify and interpret these movement compensations alongside traditional observational analyses. Angular momentum separation indicates two components of total angular momentum: (1) transfer momentum and (2) rotational momentum. The objective of this investigation was to assess movement compensations in patients with dysvascular TTA, patients with diabetes mellitus (DM), and healthy controls (HC) by examining patterns of generating and arresting trunk and pelvis segmental angular momenta during gait. We hypothesized that all groups would demonstrate similar patterns of generating/arresting total momentum and transfer momentum in the trunk and pelvis in reference to the groups (patients with DM and HC). We also hypothesized that patients with amputation would demonstrate different (larger) patterns of generating/arresting rotational angular momentum in the trunk. Patients with amputation demonstrated differences in trunk and pelvis transfer angular momentum in the sagittal and transverse planes in comparison to the reference groups, which indicates postural compensations adopted during walking. However, patients with amputation demonstrated larger patterns of generating and arresting of trunk and pelvis rotational angular momentum in comparison to the reference groups. These segmental rotational angular momentum patterns correspond with high eccentric muscle demands needed to arrest the angular momentum, and may lead to consequential long-term effects such as low back pain

Biomechanical Compensations of the Trunk and Lower Extremities during Stepping Tasks after Unilateral Transtibial Amputation

Background Lower extremity movement compensations following transtibial amputation are well-documented and are likely influenced by trunk posture and movement. However, the biomechanical compensations of the trunk and lower extremities, especially during high-demand tasks such as step ascent and descent, remain unclear. Methods Kinematic and kinetic data were collected during step ascent and descent tasks for three groups of individuals: diabetic/transtibial amputation, diabetic, and healthy. An ANCOVA was used to compare peak trunk, hip and knee joint angles and moments in the sagittal and frontal planes between groups. Paired t-tests were used to compare peak joint angles and moments between amputated and intact limbs of the diabetic/transtibial amputation group. Findings During step ascent and descent, the transtibial amputation group exhibited greater trunk forward flexion and lateral flexion compared to the other two groups (P \u3c 0.016), which resulted in greater low back moments and asymmetric loading patterns in the lower extremity joints. The diabetic group exhibited similar knee joint loading patterns compared to the amputation group (P \u3c 0.016), during step descent. Interpretation This study highlights the biomechanical compensations of the trunk and lower extremities in individuals with dysvascular transtibial amputation, by identifying low back, hip, and knee joint moment patterns unique to transtibial amputation during stepping tasks. In addition, the results suggest that some movement compensations may be confounded by the presence of diabetes and precede limb amputation. The increased and asymmetrical loading patterns identified may predispose individuals with transtibial amputation to the development of secondary pain conditions, such as low back pain or osteoarthritis

Separation of Rotational and Translational Segmental Momentum to Assess Movement Coordination during Walking

This investigation presents an analysis of segmental angular momentum to describe segmental coordination during walking. Generating and arresting momentum is an intuitive concept, and also forms the foundation of Newton-Euler dynamics. Total segmental angular momentum is separated into separate components, translational angular momentum (TAM) and rotational angular momentum (RAM), which provide different but complementary perspectives of the segmental dynamics needed to achieve forward progression during walking. TAM was referenced to the stance foot, which provides insight into the mechanisms behind how forward progression is achieved through coordinated segmental motion relative to the foot. Translational and rotational segmental moments were calculated directly from TAM and RAM, via Euler’s 1st and 2nd laws in angular momentum form, respectively, and are composed of the effects of intersegmental forces and joint moments. Using data from 14 healthy participants, the effort required to generate and arrest momentum were assessed by linking the features of segmental angular momentum and the associated segmental moments to well-known spatiotemporal and kinetic features of the gait cycle. Segmental momentum provides an opportunity to explore and understand system-wide dynamics of coordination from an alternative perspective that is rooted in fundamentals of dynamics, and can be estimated using only segmental kinematic measurements