F. Temporiti1,2, C. Cescon3, P. Adamo1, F. Natali1, F. De Capitani1, M. Barbero3, R. Gatti1,2
1Humanitas Clinical and Research Center - IRCCS, Milan, Italy, 2Humanitas University, Milan, Italy, 3University of Applied Sciences and Arts of Southern Switzerland, Manno, Switzerland
Background: The knee has poor congruence among its articular surfaces. This feature leads to continuous displacement of joint rotation center during movements, assigning a key role to passive and active structures surrounding the knee. The knee joint rotation center displacement can be estimated in vivo through the analysis of helical axis (HAs) dispersion, which depends on degeneration of joint surfaces, as those described in elderly, and differences in neuromuscular control, as those reported in dominant versus non-dominant lower limb. In addition to simple movements, HAs dispersion can be analyzed during functional tasks such as walking, providing information on joint stability.
Purpose: The study aim was to describe knee HAs dispersion during walking in dominant and non-dominant legs of young and elderly healthy subjects.
Methods: Twenty young (YG: age 23.3±2.4 years) and twenty elderly (EG: age 69.3±4.6 years) healthy subjects were asked to walk on a treadmill at a self-selected speed with reflective markers placed bilaterally on thighs and shanks to detect HAs dispersion and knee kinematics with an optoelectronic system. HAs dispersion was described during four phases of gait cycle: 1) knee flexion from 95% of the previous gait cycle to 10% of the subsequent gait cycle, 2) knee extension from 10% to 40%, 3) knee flexion from 40% to 75% and 4) knee extension from 75% to 95% of the gait cycle. Mean Distance (MD - cm) and Mean Angle (MA - degrees) were used as HAs dispersion indexes during each gait phase.
Results: EG revealed higher MD (YG: 3.2±1.0; EG: 4.4±1.5; p=0.001) and MA (YG: 13.7±4.4; 18.1±4.9; p<0.001) during the first phase and higher MA (YG: 10.3±2.6; 13.5±3.3; p=0.001) during the fourth phase on the sagittal plane. Non-dominant limb revealed higher MD during the second (dominant: 3.0±1.4; non-dominant: 3.8±1.3; p=0.016) and fourth phases (dominant: 2.5±1.3; non-dominant: 3.5±1.2; p<0.001) on transverse plane. Moreover, higher MA was found for non-dominant limb during the first (dominant: 14.2±6.9; non-dominant: 20.2±4.9; p<0.001) and fourth phases (dominant: 14.4±5.8; non-dominant: 17.5±4.5; p=0.010) on transverse plane and during the second phase (dominant: 12.4±6.4; non-dominant: 15.5±5.3; p=0.022) on sagittal plane. Finally, participants showed greater MD and MA on sagittal and frontal planes during the first and second phases.
Conclusion(s): Higher knee HAs dispersion was found in elderly with respect to young healthy subjects, whereas greater HAs dispersion was found in the non-dominant compared to the dominant limb. These findings could be explained through lower neuromuscular control during walking in elderly, especially when the transversal component of the articular forces is greater, and by mean of joint degeneration described in elderly.
Implications: HAs parameters can be a promising non-invasive technique to analyze knee kinematics during walking. Our results could be used as reference in further studies aimed at investigating the knee rotation center displacement after rehabilitation or surgery. Moreover, this approach may help clinicians to monitor an elderly population or subjects at high risk of developing a degenerative condition at knee joint.
Funding, acknowledgements: The authors did not receive any funding.
Keywords: Knee joint, Helical axes, Neuromuscular control
Topic: Musculoskeletal: lower limb
Did this work require ethics approval? Yes
Institution: Humanitas Clinical and Research Center - IRCCS
Committee: Internal Ethical Committee of the Humanitas Clinical and Research Center
Ethics number: CLF19/04
All authors, affiliations and abstracts have been published as submitted.
