Combined three-dimensional gait and plantar pressure analyses detecting significant functional deficits in children with juvenile idiopathic arthritis

Publication date: Available online 9 September 2018

Source: Gait & Posture

Author(s): Josephine Merker, Matthias Hartmann, Johannes-Peter Haas, Ansgar Schwirtz

Abstract

Background

Children suffering from juvenile idiopathic arthritis (JIA), a heterogeneous group of chronic inflammatory joint diseases, adapt to individual gait patterns to avoid loading of inflamed, swollen and painful joints. As the interpretability of previous studies is limited, this study aims to assess the functional capacity, loads and plantar pressure distribution in the gait of a homogeneous JIA group.

Research question

Does a symmetrical lower limb joint involvement influence the gait dynamics in JIA patients, and how are the results of three-dimensional gait analysis (3DGA) and pedobarography related?

Methods

Fifty JIA patients with symmetrical hip, knee and ankle joint arthritis and 27 healthy controls performed 3DGA and pedobarography at self-selected walking speeds. Kinematics and kinetics of lower limb joints were retrospectively compared in range of motion and in time-normalized waveforms. Plantar load was evaluated by measuring peak pressure, pressure-time integral and maximum force of the whole foot and ten selected foot regions. 1D-SPM analysis, parametric and non-parametric statistical significance tests and correlation coefficients were used for statistical analysis.

Results

JIA patients had a significantly slower walking speed with an anteriorly tilted pelvis and a reduced extension motion of all joints of the lower limb. The horizontal ground reaction forces and generated hip and ankle power during propulsion phase were small. Patients experienced reduced loading at toe regions, which correlated with limited ankle plantarflexion motion in the push-off phase. The total peak pressure was significantly increased and loads at lateral midfoot and metatarsal regions were higher in patients.

Significance

Symmetrical lower limb arthritis is linked to crouch-like gait and restricted gait dynamics with increased total peak pressure. The results confirm earlier results of 3DGA and provide new insights regarding waveform analysis and plantar loading in JIA patients. The used methods help to design individualized functional treatment of JIA patients.

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Coordination and variability during anticipated and unanticipated sidestepping

Publication date: Available online 9 September 2018

Source: Gait & Posture

Author(s): Gillian Weir, Richard van Emmerik, Carl Jewell, Joseph Hamill

ABSTRACT

Background

Numerous investigations have attempted to link the incidence and risk of non-contact anterior cruciate ligament injuries to specific intrinsic and extrinsic mechanisms. However, these are often measured in isolation.

Research Question

This study utilizes a dynamical systems approach to investigate differences in coordination and coordination variability between segments and joints in anticipated and unanticipated sidestepping, a task linked to a high risk of non-contact anterior cruciate ligament injuries.

Methods

Full body, three-dimensional kinematics and knee kinetic data were collected on 22 male collegiate soccer players during anticipated and unanticipated sidestepping tasks. A modified vector coding technique was used to quantify coordination and coordination variability of the trunk and pelvis segments and the hip and knee joints.

Results

Sagittal and frontal plane trunk-pelvis coordination were more in-phase during unanticipated sidestepping. Sagittal plane hip-knee and hip (rotation)-knee (flexion/extension) coordination were more in-phase with the knee dominating the movement during unanticipated sidestepping (P <  0.05). Coordination variability was greater in unanticipated sidestepping for trunk (flexion)-pelvis (tilt), trunk (lateral flexion)-pelvis (obliquity), hip (flexion/extension)-knee (flexion/extension) and hip (rotation)-knee (flexion/extension) (P <  0.05). In unanticipated sidestepping where there is limited time to pre-plan the movement, multiple kinematic solutions and high coordinative variability is required to achieve the task.

Significance

Our results suggest that coordination becomes more in-phase and the variability of this coordination increases as a function of task complexity and reduced planning time as that which occurs in unanticipated sporting task scenarios. Consequently, injury prevention programs must incorporate perceptual components in order to optimise planning time and coordinate appropriate postural adjustments to reduce external knee joint loading and subsequent injury risk in sport.

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Combined three-dimensional gait and plantar pressure analyses detecting significant functional deficits in children with juvenile idiopathic arthritis

Publication date: Available online 9 September 2018

Source: Gait & Posture

Author(s): Josephine Merker, Matthias Hartmann, Johannes-Peter Haas, Ansgar Schwirtz

Abstract

Background

Children suffering from juvenile idiopathic arthritis (JIA), a heterogeneous group of chronic inflammatory joint diseases, adapt to individual gait patterns to avoid loading of inflamed, swollen and painful joints. As the interpretability of previous studies is limited, this study aims to assess the functional capacity, loads and plantar pressure distribution in the gait of a homogeneous JIA group.

Research question

Does a symmetrical lower limb joint involvement influence the gait dynamics in JIA patients, and how are the results of three-dimensional gait analysis (3DGA) and pedobarography related?

Methods

Fifty JIA patients with symmetrical hip, knee and ankle joint arthritis and 27 healthy controls performed 3DGA and pedobarography at self-selected walking speeds. Kinematics and kinetics of lower limb joints were retrospectively compared in range of motion and in time-normalized waveforms. Plantar load was evaluated by measuring peak pressure, pressure-time integral and maximum force of the whole foot and ten selected foot regions. 1D-SPM analysis, parametric and non-parametric statistical significance tests and correlation coefficients were used for statistical analysis.

Results

JIA patients had a significantly slower walking speed with an anteriorly tilted pelvis and a reduced extension motion of all joints of the lower limb. The horizontal ground reaction forces and generated hip and ankle power during propulsion phase were small. Patients experienced reduced loading at toe regions, which correlated with limited ankle plantarflexion motion in the push-off phase. The total peak pressure was significantly increased and loads at lateral midfoot and metatarsal regions were higher in patients.

Significance

Symmetrical lower limb arthritis is linked to crouch-like gait and restricted gait dynamics with increased total peak pressure. The results confirm earlier results of 3DGA and provide new insights regarding waveform analysis and plantar loading in JIA patients. The used methods help to design individualized functional treatment of JIA patients.

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Coordination and variability during anticipated and unanticipated sidestepping

Publication date: Available online 9 September 2018

Source: Gait & Posture

Author(s): Gillian Weir, Richard van Emmerik, Carl Jewell, Joseph Hamill

ABSTRACT

Background

Numerous investigations have attempted to link the incidence and risk of non-contact anterior cruciate ligament injuries to specific intrinsic and extrinsic mechanisms. However, these are often measured in isolation.

Research Question

This study utilizes a dynamical systems approach to investigate differences in coordination and coordination variability between segments and joints in anticipated and unanticipated sidestepping, a task linked to a high risk of non-contact anterior cruciate ligament injuries.

Methods

Full body, three-dimensional kinematics and knee kinetic data were collected on 22 male collegiate soccer players during anticipated and unanticipated sidestepping tasks. A modified vector coding technique was used to quantify coordination and coordination variability of the trunk and pelvis segments and the hip and knee joints.

Results

Sagittal and frontal plane trunk-pelvis coordination were more in-phase during unanticipated sidestepping. Sagittal plane hip-knee and hip (rotation)-knee (flexion/extension) coordination were more in-phase with the knee dominating the movement during unanticipated sidestepping (P <  0.05). Coordination variability was greater in unanticipated sidestepping for trunk (flexion)-pelvis (tilt), trunk (lateral flexion)-pelvis (obliquity), hip (flexion/extension)-knee (flexion/extension) and hip (rotation)-knee (flexion/extension) (P <  0.05). In unanticipated sidestepping where there is limited time to pre-plan the movement, multiple kinematic solutions and high coordinative variability is required to achieve the task.

Significance

Our results suggest that coordination becomes more in-phase and the variability of this coordination increases as a function of task complexity and reduced planning time as that which occurs in unanticipated sporting task scenarios. Consequently, injury prevention programs must incorporate perceptual components in order to optimise planning time and coordinate appropriate postural adjustments to reduce external knee joint loading and subsequent injury risk in sport.

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Air- and Bone-Conducted Sources of Feedback With an Active Middle Ear Implant

Objectives: Active middle ear implants (AMEI) have been used to treat hearing loss in patients for whom conventional hearing aids are unsuccessful for varied biologic or personal reasons. Several studies have discussed feedback as a potential complication of AMEI usage, though the feedback pathway is not well understood. While reverse propagation of an acoustic signal through the ossicular chain and tympanic membrane constitutes an air-conducted source of feedback, the implanted nature of the device microphone near the mastoid cortex suggests that bone conduction pathways may potentially be another significant factor. This study examines the relative contributions of potential sources of feedback during stimulation with an AMEI. Design: Four fresh-frozen, hemi-sectioned, human cadaver specimens were prepared with a mastoid antrostomy and atticotomy to visualize the posterior incus body. A Carina active middle ear implant actuator (Cochlear Ltd., Boulder, CO) was coupled to the incus by two means: (1) a stereotactic arm mounted independently of the specimen and (2) a fixation bracket anchored directly to the mastoid cortical bone. The actuator was driven with pure-tone frequencies in 1/4 octave steps from 500 to 6000 Hz. Acoustic sound intensity in the ear canal was measured with a probe tube microphone (Bruel & Kjær, Nærum, Denmark). Bone-conducted vibration was quantified with a single-axis laser Doppler vibrometer (Polytec Inc., Irvine, CA) from both a piece of reflective tape placed on the skin overlying the mastoid and a bone-anchored titanium screw and pedestal (Cochlear Ltd., Centennial, CO) implanted in the cortical mastoid bone. Results: Microphone measurements revealed ear-canal pressures of 60–89 dB SPL, peaking in the frequency range below 2 kHz. Peak LDV measurements were greatest on the mastoid bone (0.32–0.79 mm/s with mounting bracket and 0.21–0.36 mm/s with the stereotactic suspension); peak measurements on the skin ranged from 0.05 to 0.15 mm/s with the bracket and 0.03 to 0.13 mm/s with stereotactic suspension. Conclusion: AMEI produce both air- and bone-conducted signals of adequate strength to be detected by the implanted device microphone, potentially resulting in reamplification. Understanding the relative contribution of these sources may play an important role in the development of targeted mitigation algorithms, as well as surgical techniques emphasizing acoustic isolation. RMBH was funded by NIH NIDCD T32 DC-012280. The authors have no conflicts of interest to disclose. Received September 27, 2017; accepted June 27, 2018. Address for correspondence: Renee M. Banakis Hartl, MD, AuD, Department of Otolaryngology, University of Colorado School of Medicine, 12631 E. 17th Ave, MS B205, Aurora, CO 80045, USA. E-mail: Renee.BanakisHartl@ucdenver.edu Copyright © 2018 Wolters Kluwer Health, Inc. All rights reserved.

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Air- and Bone-Conducted Sources of Feedback With an Active Middle Ear Implant

Objectives: Active middle ear implants (AMEI) have been used to treat hearing loss in patients for whom conventional hearing aids are unsuccessful for varied biologic or personal reasons. Several studies have discussed feedback as a potential complication of AMEI usage, though the feedback pathway is not well understood. While reverse propagation of an acoustic signal through the ossicular chain and tympanic membrane constitutes an air-conducted source of feedback, the implanted nature of the device microphone near the mastoid cortex suggests that bone conduction pathways may potentially be another significant factor. This study examines the relative contributions of potential sources of feedback during stimulation with an AMEI. Design: Four fresh-frozen, hemi-sectioned, human cadaver specimens were prepared with a mastoid antrostomy and atticotomy to visualize the posterior incus body. A Carina active middle ear implant actuator (Cochlear Ltd., Boulder, CO) was coupled to the incus by two means: (1) a stereotactic arm mounted independently of the specimen and (2) a fixation bracket anchored directly to the mastoid cortical bone. The actuator was driven with pure-tone frequencies in 1/4 octave steps from 500 to 6000 Hz. Acoustic sound intensity in the ear canal was measured with a probe tube microphone (Bruel & Kjær, Nærum, Denmark). Bone-conducted vibration was quantified with a single-axis laser Doppler vibrometer (Polytec Inc., Irvine, CA) from both a piece of reflective tape placed on the skin overlying the mastoid and a bone-anchored titanium screw and pedestal (Cochlear Ltd., Centennial, CO) implanted in the cortical mastoid bone. Results: Microphone measurements revealed ear-canal pressures of 60–89 dB SPL, peaking in the frequency range below 2 kHz. Peak LDV measurements were greatest on the mastoid bone (0.32–0.79 mm/s with mounting bracket and 0.21–0.36 mm/s with the stereotactic suspension); peak measurements on the skin ranged from 0.05 to 0.15 mm/s with the bracket and 0.03 to 0.13 mm/s with stereotactic suspension. Conclusion: AMEI produce both air- and bone-conducted signals of adequate strength to be detected by the implanted device microphone, potentially resulting in reamplification. Understanding the relative contribution of these sources may play an important role in the development of targeted mitigation algorithms, as well as surgical techniques emphasizing acoustic isolation. RMBH was funded by NIH NIDCD T32 DC-012280. The authors have no conflicts of interest to disclose. Received September 27, 2017; accepted June 27, 2018. Address for correspondence: Renee M. Banakis Hartl, MD, AuD, Department of Otolaryngology, University of Colorado School of Medicine, 12631 E. 17th Ave, MS B205, Aurora, CO 80045, USA. E-mail: Renee.BanakisHartl@ucdenver.edu Copyright © 2018 Wolters Kluwer Health, Inc. All rights reserved.

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