Effects of realistic sheep elbow kinematics in inverse dynamic simulation

Abstract

Looking for new opportunities in mechanical design, we are interested in studying the kinematic behaviour of biological joints. The real kinematic behaviour of the elbow of quadruped animals (which is submitted to high mechanical stresses in comparison with bipeds) remains unexplored. The sheep elbow joint was chosen because of its similarity with a revolute joint. The main objective of this study is to estimate the effects of elbow simplifications on the prediction of joint reaction forces in inverse dynamic simulations. Rigid motions between humerus and radius-ulna were registered during full flexion-extension gestures on five cadaveric specimens. The experiments were initially conducted with fresh specimens with ligaments and repeated after removal of all soft tissue, including cartilage. A digital image correlation system was used for tracking optical markers fixed on the bones. The geometry of the specimens was digitized using a 3D optical scanner. Then, the instantaneous helical axis of the joint was computed for each acquisition time. Finally, an OpenSim musculoskeletal model of the sheep forelimb was used to quantify effects of elbow joint approximations on the prediction of joint reaction forces. The motion analysis showed that only the medial-lateral translation is sufficiently large regarding the measuring uncertainty of the experiments. This translation assimilates the sheep elbow to a screw joint instead of a revolute joint. In comparison with fresh specimens, the experiments conducted with dry bone specimens (bones without soft tissue) provided different kinematic behaviour. From the results of our inverse dynamic simulations, it was noticed that the inclusion of the medial-lateral translation to the model made up with the mean flexion axis does not affect the predicted joint reaction forces. A geometrical difference between the axis of the best fitting cylinder and the mean flexion axis (derived from the motion analysis) of fresh specimens was highlighted. This geometrical difference impacts slightly the prediction of joint reactions.

Low elbow mobility indicates unique forelimb posture and function in a giant extinct marsupial

“…Therefore, low FE values within our envelopes are probably less likely to represent in vivo ROM than higher values. Additionally, passive muscle forces, capsular and extracapsular ligaments of the elbow have all been shown to limit LAR and ABAD in cadaveric sheep elbows (Poncery et al, 2019), and while these factors would unquestionably limit ROM modelled here, whether this would affect positive and negative rotations equally is unknown.…”

“…The extent of this effect could be further investigated in the future via cadaveric XROMM or marker‐based motion capture approaches. Such iterative ex vivo testing, where soft tissue layers are progressively removed while sampling extreme elbow poses in cadaveric specimens as in recent work on sheep forelimbs (Poncery et al, 2019) and archosaur elbows (Hutson & Hutson, 2012), may prove fruitful both in our understanding of the effects of soft tissues on elbow mobility and in parameterising future biomechanical models of extinct mammals.…”

Wear Behavior of a Bio-inspired Bearing for off-center Loads

“…Secondly, lamb parts are particularly easy to obtain for analysis purposes. Thirdly, studies show that the kinematics of its elbows are similar to a pivot link [20,21]. Besides, its humerus is comparable to a revolution shape which facilitates its mimicking.…”

“…In this paper, the source of inspiration for the design of a bio-inspired bearing was the lamb elbow. Firstly, the lamb was chosen as a member of unguligrade quadruped animal as it can bear high mechanical stresses [20]. Secondly, lamb parts are particularly easy to obtain for analysis purposes.…”

Load bearing performance of mechanical joints inspired by elbow of quadrupedal mammals

“…These studies have motivated the design and the development of prosthetic knee (Russell et al, 2018;Sathasivam and Walker, 1994), ankle (Au et al, 2008) and elbow (Cil et al, 2008;Prasad et al, 2016). Some other works have studied load transmission in animal joints, for example on horse (Becker et al, 2019;Harrison et al, 2010;Panagiotopoulou et al, 2016;Praet et al, 2012), sheep (Lerner et al, 2015;Picault et al, 2018;Poncery et al, 2019) and seahorse (Praet et al, 2012).…”