Resultados obtenidos

Temporal-spatial parameters describe many variables such as speed and step length, providing an initial assessment of gait. In LLA gait, temporal-spatial variables were found to differ between the intact and prosthetic limb (Isakov et al., 1992; 2000) and also varied depending on individual characteristics such as level of amputation as well as prosthetic components. The self-selected walking speed of individuals with LLA tends to be lower relative to that of able-bodied individuals. However, different average results have been reported across studies for individuals with UTTA and individuals with UTFA as illustrated in Figures 2.4 and 2.5.

Chapter 2: Review of Literature

13 Figure 2.4 Average walking speed (m/s) of individuals with UTTA. The solid black line indicates the average speed of able-bodied individuals. Error bars show standard deviation. In all studies, speeds were identified from over ground walking except for Schmalz et al. (2002). The majority of the cohorts in these studies had undergone an amputation due to trauma, and their choice of prosthetic components were elastic response feet and microprocessor knee joints with some exceptions. Figure adapted from Jarvis et al. (2017).

Figure 2.5 Average walking speed (m/s) of individuals with UTFA. The solid black line indicates the average speed of able-bodied individuals. Error bars show standard deviation. In all studies, speeds were identified from over ground walking except for Schmalz et al. (2002). The majority of the cohorts in these studies had undergone an amputation due to trauma, and their choice of prosthetic components were elastic response feet and microprocessor knee joints with some exceptions. Figure adapted from Jarvis et al. (2017).

Chapter 2: Review of Literature

14 Isakov et al. (2000) found the average speed of fourteen individuals with UTTA using patellar tendon bearing (PTB) sockets and solid ankle cushion heel (SACH) feet to be 1.25 m/s. They also found significantly larger step time and swing time on the prosthetic limb (step time 0.582±0.04s; swing time 0.438±0.04s) relative to the intact limb (step time 0.569±0.04s; swing time 0.407±0.03s). Furthermore, larger stance time and single support time on the intact limb (stance time 0.774±0.06s, single support time 0.438±0.04s) relative to the prosthetic limb (stance time 0.708±0.05s, single support time 0.407±0.03s) was found (Isakov et al., 2000). The shorter single support time on the prosthetic limb was attributed to the prosthetic foot, since the rigid ankle mechanism of the SACH foot leads to quicker weight transfer from the heel to the forefoot, i.e. resulting in shorter stance duration on the prosthetic limb and shorter swing time on the intact limb. Breakey (1976) found similar results regarding the stance duration on the prosthetic limb. Highsmith et al. (2010) reported similar results for individuals with UTFA in step time on the prosthetic limb (0.70±0.05s) relative to the intact limb (0.60±0.06s), however, in individuals with UTTA they found step time to be shorter on the prosthetic limb (58±0.03s) relative to the intact limb (0.60±0.05s). Jarvis et al. (2017) also reported significantly shorter step time on the prosthetic limb (60-62% of the gait cycle) relative to the intact limb (62-66% of the gait cycle). Longer stance time on the intact limb relative to the prosthetic limb (Board et al., 2001; Breakey, 1976; Isakov et al., 2000; McNealy and Gard, 2008; Sanderson and Martin, 1997; Schmid et al., 2005; van der Linden et al., 1999) was described as a control mechanism and was attributed to the lack of confidence in the prosthetic limb (Sanderson & Martin, 1997). It has also been identified as an attempt to protect the prosthetic limb from increased loads and forces (Hurley et

al., 1990; Nolan et al., 2003; Powers et al., 1998; Sanderson & Martin, 1997). Jarvis et al. (2017)

however, reported that walking speed, stride length and cadence of high functioning individuals with UTTA and individuals with UTFA, who use state of the art prosthetic devices, was comparable to able-bodied individuals (Table 2.1). Rábago and Wilken (2016) used prevalence to describe gait deviations of individuals with UTTA. The measure of prevalence is described as a percentage outside normative reference ranges, where the reference range was calculated using the mean and standard deviation of a group of able-bodied individuals. Individuals with UTTA were found to have the greatest prevalence, i.e. differed from the normative reference ranges, in step time and length measurements of the intact limb, however, these deviations were not significant.

Chapter 2: Review of Literature

15 Table 2.1 Temporal-spatial variables of individuals with UTTA and individuals with UTFA of both prosthetic (PROS) and intact (NONPROS) limbs, and able-bodied individuals of both right and left limbs. Table adopted from Jarvis et al. (2017).

Parameter Individuals with UTTA

Individuals with UTFA

Able-bodied Individuals PROS NONPROS PROS NONPROS Right Left

Speed (m/s) 1.36+5% 1.22-5% 1.29 Stride length (m) 1.46-1% 1.42-3% 1.47 Stride width (m) 0.13+9% 0.18+54% 0.12 Cadence (steps/min) 112+6% 103-3% 106 Step length 0.73+0% 0.73+1% 0.71-3% 0.72-3% 0.74 0.73 Step time (% cycle) 60.9-3% 63.8+1% 62.3-1% 64.0+1% 63.1 62.9

Temporal-spatial parameters are often used to investigate the process of rehabilitation in individuals with LLA. Baker and Hewison (1990) used speed as a performance index, demonstrating that it increases by almost 55% within the initial 15 days of rehabilitation. Barnett

et al. (2009) also demonstrated that temporal-spatial asymmetry reduces between limbs during

the rehabilitation process. Analysing temporal-spatial parameters, Isakov et al. (1996) found these variables to be symmetrical between the limbs of individuals with UTTA, unlike knee kinematic data which was found to be asymmetrical. During loading response, knee flexion increased during fast speed (1.4 m.s-1_{) relative to ‘normal’ speed (0.9 m.s}-1_{) on the intact limb, but not in the} prosthetic limb. Also, during toe-off, larger knee flexion was reported on the prosthetic limb relative to the intact limb due to the lack of dorsiflexion of the prosthetic foot. Schmid et al. (2005) found that the duration of double-support phase prior to the prosthetic limb was prolonged relative to double support prior to the intact limb, which was attributed to balance and comfort issues. However, not all studies have found this asymmetry in double-support phases (Isakov et al., 1996). The temporal differences between intact and prosthetic limbs tend to reduce as walking velocity increases (Nolan et al., 2003) but increase with higher prosthetic limb mass (Donker and Beek 2002; Mattes et al., 2000; Nolan et al., 2003).

Although individuals with UTTA and able-bodied individuals were found to have similar stance time and double support time, able-bodied individuals spend only 12% of the gait cycle having heel only contact whilst UTTA spend 20% of the gait cycle having heel only contact (Powers et

al., 1998). The inability of individuals with UTTA to lower the foot much more rapid after initial

Chapter 2: Review of Literature

16 ankle (Isakov et al., 2000), which can be improved with better prosthetic foot devices (van der Linden et al., 1999; 2004). Temporal-spatial parameters vary depending on the prosthetic foot. During the analysis of ten participants using five prosthetic feet (Carbon Copy II, Seattle, Quantum, SACH and Flex foot) at self-selected speeds, Powers et al. (1994) found that irrespective of the prosthetic used, the foot cadence was similar between intact and prosthetic limbs of individuals with LLA, as well as control limbs of able-bodied individuals. However, stride length was found to be larger in the Flex foot stride (1.5 m) relative to SACH (1.44 m) and Quantum (1.44 m), while the other feet were similar (Carbon Copy II = 1.46 m, Seattle = 1.47 m and control foot = 1.51 m). The Flex foot also had larger dorsiflexion (23.2º) relative to the Quantum, while the Quantum had larger dorsiflexion (19.5º) relative to the other feet (Carbon Copy II = 12.1º, Seattle = 15.1º and SACH = 12.0º). Prince et al. (1998) suggested that a prosthetic foot should be selected, depending on the time it takes to reach foot flat, the amount of energy recovered by the foot and other objective criteria such as maintenance.