Biology subjects

Rainbow, M.

Publications and source records attributed to Rainbow, M..

2 recordsLinked to original sources

bioRxiv2024

The influence of talus size and shape on in vivo talocrural hopping kinematics

Talus implants often come in standard sizes and shapes; however, humans vary in their bone size and shape. Consequently, patient-specific implants are becoming available. Understanding how shape changes alter function in a healthy cohort may help designers determine how much specificity is required in talocrural implants. Nine participants (5 females) hopped on one leg while biplanar video radiography and force plate data were collected. 3D bone models were created from computed tomography scans. Helical axes of motion were calculated for the talus relative to the tibia (rotation axes) and a cylinder was fit through the talar dome (morphological axis). Bland-Altman plots and spatial angles tested whether the rotation and morphological axes agree. A shape model of 36 (15 females) participants was established and a cylinder fit was morphed through the range of {+/-}3 standard deviations. The rotation and morphological axes largely agree regarding their orientation and location during hopping. The morphological axis consistently overestimates the orientation-component in anterior-posterior direction. Some shape components affect talar dome orientation and curvature independent of size. This suggests that besides size, the shape of the talar dome might affect the movement pattern during locomotion. Our findings are important to inform talocrural joint arthroplasty design.

bioengineering↗

bioRxiv2023

It is all about the talus - In vivo tarsal joint complex kinematics during walking, running, and hopping

The interaction among joints of the midtarsal complex and subtalar joint is essential role for locomotor function; however, its complexity poses substantial challenges in quantifying their motions. We determine the mobility of these joints across locomotion tasks and investigate their alignment with individual talus morphology. Utilizing highly accurate biplanar videoradiography, three-dimensional bone kinematics were captured during walking, running, and hopping. We calculated the axis of rotation of each midtarsal and subtalar joint for the landing and push-off phases, respectively. A comparison was made between these rotation axes and the morphological subtalar axis. Measurement included total rotation about, the orientation of the rotation axes in the direction of the subtalar joint and its deviation via spatial angles for both phases. The rotation axes of all three bones relative to the talus closely align with the morphological subtalar axis. This suggests that the midtarsal and subtalar joints motions might be described by one commonly oriented axis. Despite having such axis, the location of axes and ranges of motion differed among the bones. Our results provide a novel perspective of healthy foot function across different sagittal plane-dominant locomotion tasks underscoring the importance of midtarsal and subtalar motion with respect to subject-specific talus morphology.

bioengineering↗