Pascal Madeleine1, Rasmus Elbæk Andersen2, Jesper Bie Larsen2, Lars Arendt-Nielsen3, Afshin Samani4. 1. Sport Sciences - Performance and Technology, Department of Health Science and Technology, School of Medicine, Aalborg University, Niels Jernes vej 12, 9220 Aalborg East, Denmark. Electronic address: pm@hst.aau.dk. 2. Sport Sciences - Performance and Technology, Department of Health Science and Technology, School of Medicine, Aalborg University, Niels Jernes vej 12, 9220 Aalborg East, Denmark; SMI®, Department of Health Science and Technology, School of Medicine, Aalborg University, Fredrik Bajers vej 7, 9229 Aalborg East, Denmark. 3. SMI®, Department of Health Science and Technology, School of Medicine, Aalborg University, Fredrik Bajers vej 7, 9229 Aalborg East, Denmark. 4. Sport Sciences - Performance and Technology, Department of Health Science and Technology, School of Medicine, Aalborg University, Niels Jernes vej 12, 9220 Aalborg East, Denmark.
Abstract
BACKGROUND: Variations in the internal pressure distribution applied to cartilage and synovial fluid explain the spatial dependencies of the knee vibroarthrographic signals. These spatial dependencies were assessed by multi-channel recordings during activities of daily living in patients with painful knee osteoarthrosis. METHODS: Knee vibroarthrographic signals were detected using eight miniature accelerometers, and vibroarthrographic maps were calculated for the most affected knee of 20 osteoarthritis patients and 20 asymptomatic participants during three activities: (i) sit to stand, (ii) stairs descent, and (iii) stairs ascent in real life conditions. Vibroarthrographic maps of average rectified value, variance of means squared, form factor, mean power frequency, % of recurrence and, % of determinism were obtained from the eight VAG recordings. FINDINGS: Higher average rectified value and lower % of recurrence were found in knee osteoarthritis patients compared with asymptomatic participants. All vibroarthrographic parameters, except for % of recurrence, differentiated the type of activity. Average rectified value, variance of means squared, form factor, and % of determinism were lowest while mean power frequency was highest during sit-to-stand compared with stairs ascent and descent. INTERPRETATION: Distinct topographical vibroarthrographic maps underlined that the computed parameters represent unique features. The present study demonstrated that wireless multichannel vibroarthrographic recordings and the associated topographical maps highlighted differences between (i) knee osteoarthritis patients and asymptomatic participants, (ii) sit to stand, stairs descent and ascent and (iii) knee locations. The technique offers new perspectives for biomechanical assessments of physical functions of the knee joint in ecological environment.
BACKGROUND: Variations in the internal pressure distribution applied to cartilage and synovial fluid explain the spatial dependencies of the knee vibroarthrographic signals. These spatial dependencies were assessed by multi-channel recordings during activities of daily living in patients with painful knee osteoarthrosis. METHODS: Knee vibroarthrographic signals were detected using eight miniature accelerometers, and vibroarthrographic maps were calculated for the most affected knee of 20 osteoarthritispatients and 20 asymptomatic participants during three activities: (i) sit to stand, (ii) stairs descent, and (iii) stairs ascent in real life conditions. Vibroarthrographic maps of average rectified value, variance of means squared, form factor, mean power frequency, % of recurrence and, % of determinism were obtained from the eight VAG recordings. FINDINGS: Higher average rectified value and lower % of recurrence were found in knee osteoarthritispatients compared with asymptomatic participants. All vibroarthrographic parameters, except for % of recurrence, differentiated the type of activity. Average rectified value, variance of means squared, form factor, and % of determinism were lowest while mean power frequency was highest during sit-to-stand compared with stairs ascent and descent. INTERPRETATION: Distinct topographical vibroarthrographic maps underlined that the computed parameters represent unique features. The present study demonstrated that wireless multichannel vibroarthrographic recordings and the associated topographical maps highlighted differences between (i) knee osteoarthritispatients and asymptomatic participants, (ii) sit to stand, stairs descent and ascent and (iii) knee locations. The technique offers new perspectives for biomechanical assessments of physical functions of the knee joint in ecological environment.