Efectos biomecánicos de la vertebroplastia.

The natural upper limb is a coordinated, multi-articulated system, where the combined motion of each joint and element contributes to the overall functional capability (32). Its intricacy of movement is clearly demonstrated when attempts are made to replicate its many movement capabilities. Perry and Rosen (2006) produced a 7 degree of freedom upper limb robotic arm, which mirrored 99% of the ranges of motion required to perform daily living activities, but took considerable time and effort to produce (254). Acquiring knowledge of the upper limb joints and its design are essential for prostheses replacement; although upper limb activities are many and varied, studies into these movements are far less extensive than those that have been conducted for lower limb gait evaluations (63).

Historically, upper limb movement analysis has investigated specific movements that relate to daily living activities, particularly where the focus has been on prosthetic rehabilitation. Gilad (1983) performed micro-motion analysis with both able-bodied and prosthesis user subjects using ‘reach’, ‘grasp’, ‘movement’ and ‘positional’ motion evaluation elements (255). A task board was employed, in conjunction with frame-by-frame video analysis. Gilad also found that prosthesis users employed compensatory movements to achieve tasks, with movements of the back and shoulder used more predominantly than elbow movements (255).

In 1995, Doeringer & Hogan assessed the movement performance and output impedance of six transhumeral, prosthesis users (256). The subjects were observed performing ADL-based tasks, such as pointing, more slowly, and with less accuracy, with the prosthesis when compared to the same movements using the sound, natural limb (256). The body-powered prostheses used by the subjects were shown to be more consistent with normal usage patterns and ‘impedance to usage’ than myoelectric prostheses used by the same subjects. Although the act of ‘pointing’ was used as part of the assessment criteria, it was said that even quantifying this relatively simple movement was very difficult with regard to the trajectories of ADLs, due to the intricate balance and changeable nature of the various joint angles associated with the activity (256).

184 In 1998, Gilin used a single-subject study, again with a transhumeral level of limb absence and body-powered prosthesis, to evaluate daily living activities and movements associated with prosthesis wearing and the effect of limb absence (257). ADL screening, using a list of ADLs on a paper form, was used to assess the usefulness of the prosthesis when performing tasks including eating, working at a desk, housekeeping and general activities. The motion of the shoulder joint was also manually measured using a goniometer; the available shoulder flexion (135°), and abduction (140°), was lower than the standard figures quoted in chapter 2, figure 2.3a, although the other ranges of motion appeared to be at least on par with these standard ranges.

Murray and Johnson (2004) collected data from 10 male subjects using specific upper limb activities which included ‘reaching’, ‘raising objects’ and ‘hand to mouth movements’ (63). The subjects were asked to perform these activities at comfortable speeds during the assessment process, and a maximum additional load of 500g was added during some of the activities. Raising a large block produced the most forces in the joints, the amount of which was calculated using rigid body kinematics and inverse dynamics, with the associated movements being assessed using a system of cameras and reflective markers.

In 2008, Carey and Highsmith used a mixture of transradial prosthesis users and able- bodied subjects to investigate five different ADLs, which were ‘reaching’, ‘drinking from a cup’, ‘opening a door’, ‘turning a steering wheel’ and ‘lifting a box’ (32). Again, a system of cameras and reflective markers were used to acquire the data, and a bespoke testing apparatus was used to ensure that the tasks were employed effectively. A particular analysis was made of the movement pathways that were employed by each subject during the tasks, with the natural pathway (able-bodied subjects) being contrasted with the pathways used by the transradial prosthesis users. Greater motion around the torso was noted for the prosthesis user subjects with respect to the able-bodied subjects, and compensatory movements by the prosthesis user subjects using the elbow also occurred during each of the activities (32).

Bouwsema et al (2010) used a mixture of transradial and transhumeral prosthesis users and able-bodied subjects to compare forearm trajectories, using a similar camera and reflective marker-based methodology to that used by Carey and Highsmith (2008) (32, 258). Pointing and grasping activities were employed during this study, since it was stated that these had been used more often in previous studies. Forearm trajectories were seen to be

185 smoother for transradial prosthesis users than transhumeral prosthesis users, with grasp times being recorded as being higher for transhumeral users also (258). The authors also stated that the way a prosthesis used in ADLs has received little attention via investigative practice (258).

Again, in 2010, Butler et al observed ‘reach and grasp’ activities, as performed by children, the majority (90%) being able bodied, with the remaining subjects presenting with Cerebral Palsy (259). The authors’ stated that these (‘reach and grasp’ type) activities are essential for ADL completion and daily living. Quantifying these types of tests however, is very problematic, and activity outcomes, rather than the specific movement pathway elements associated with the movements, are more useful to acquire (259).

Although the methods of data collection have varied over recent years, the assessments have all attempted to classify upper limb movements and trajectories in terms of ADLs. Specific evaluations focusing on pure joint angles have been less important than the need to quantify upper limb movements in relatable trajectories that are relatively simple and repeatable, but are representative of daily movements and activities. As a result, this study used activities and movements that correlate to ADLs, and outcomes, rather than specific joint angles and other intricate data, which is relatively irrelevant to the aims of this study.