1.1

Introduction

Gait efficiency can be defined as the percentage of energy input that is transformed into useful work. Physiologic work during level walking also called as gait efficiency can also be defined as the amount of oxygen consumed per kilogram body weight per unit distance traveled (mL/kg/m) . Previous studies have established that the lower limb amputees spend more energy as compared to the normal subjects . In a study, Gailey et al. noticed that the metabolic cost (VO ₂ ), heart rate (HR) at self-selected speed of ambulation of transtibial amputees (TTAs) were 16% greater, and the ambulation pace 11% slower than the non-amputee controls . Many studies have shown the effect of different types of crutches on energy efficiency with different crutch gaits. McBerth et al. found that use of a cane or crutches with two-point alternating and three points partial weight bearing gaits required about 33% more energy than normal walking. The swing through and three-points non-weight bearing gaits required about 73% more energy than normal walking . In a comparison between underarm axillary crutches and elbow crutches, Fisher and Patterson had found no significant difference between them . In another study, Lee noticed that oxygen consumption was less for axillary crutches than elbow crutches .

Waters et al. in a direct comparison of walking in unilateral amputees with and without a prosthesis utilizing a three-point crutch-assisted gait pattern revealed that prosthesis had a lower rate of energy expenditure (EE), HR, and O ₂ cost . Bryan et al. directly compared the walking in unilateral traumatic and dysvascular amputees at the symes, transtibial or transfemoral level using prosthesis or a swing through crutch assisted gait without a prosthesis found that almost all amputees have a lower rate of EE, HR and O ₂ cost when using prosthesis . In a comparison of mechanical efficiency, Datta et al. noticed that the below-knee rehabilitees and the crutch users needed 20.5 and 48.5% more energy, respectively, than the normal subjects while ascending stairs . In another study, Waters et al. found that a well-fitted prosthesis results in a satisfactory gait not requiring crutches significantly reduces the physiologic energy demand. The rate of oxygen consumption, HR, respiratory quotient was significantly increased in all groups of amputees when using crutches and without prosthesis. This increase ranges from 1.3 ml/kg/min in vascular symes amputation to 6.9 ml/kg/min in traumatic below knee amputation .

Although there is a considerable body of literature on the physiologic EE of amputee gait in different prosthetic components or different types of crutches, a direct comparison of the results of the different studies is difficult for the following reasons. First, many comparison had been done for young or usually traumatic amputees with older or usually vascular amputees, and there are significant differences between these two groups with respect to gait performance. Secondly, there is often no distinction between amputees who use upper-limb assistive devices and those who do not. Although the oxygen uptake method has been shown to be a reliable method and is used by many, the previous instruments are cumbersome, more patient unwillingness, and not available in many clinics . Other disadvantages include no breath by breath data can be obtained and therefore rapid changes in ventilation or VO ₂ cannot be studied and secondly the method is time consuming due to the requirement of sampling and analysis after collection . Many of the past studies used calculating the physiological cost index (PCI) as one of the methods of assessing metabolic energy cost but there is controversy over validity and reliability of the PCI as an outcome measure for the assessment of EE . Hence there is a requirement for analyzing exact quantification of EE between “prosthesis” and “crutches without prosthesis” among subjects with little variation of age and clinical conditions. It is also required for clinical practice for prescription of aids and diet control. Therefore we made an attempt to compare the gait efficiency between two most commonly used assistive devices (patellar tendon bearing [PTB] exoskeletal prosthesis & axillary crutch) in Indian conditions by using portable and highly reliable Respiratory Analyser System Cosmed ^® K4 b ² based on automated on line breath by breath gas analysis system .

1.2

Material & methods

A sample of convenience of 30 unilateral TTA took part in this study. They were advised to walk in level ground surface using “prosthesis” and “crutches without prosthesis” individually. The environmental conditions were maintained the same throughout the study. No data was taken in rainy or extreme hot and humid environmental conditions. The patients were normal psychologically with no anxiety, stress, fear etc. They were taught to walk with their own self-selected walking speed for either prosthesis or crutch walking. They were advised to take their normal diet at least 2 days before the test.

Our inclusion criteria include:

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  transtibial amputee with minimum muscle strength of Grade 3+ around the knee joint;

  
  
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  only unilateral amputees of either side will be considered;

  
  
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  origin of amputation: traumatic;

  
  
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  the amputee must be a prosthetic user for a minimum period of one month;

  
  
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  type of prosthesis: transtibial exoskeletal prosthesis with PTB socket with cuff suspension with sach foot fabricated and fitted by same CPO;

  
  
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  age range: 25–45 yrs;

  
  
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  full ROM in knee and hip joints;

  
  
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  adequate upper extremity strength (minimum Grade-4 as per Manual Muscle Testing);

  
  
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  stump length: minimum 8 cms from tibial plateau;

  
  
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  no contracture in the proximal joints (knee and hip, etc.);

  
  
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  no neuroma or edema;

  
  
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  must be a community ambulatory (at least K2 level);

  
  
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  they should be ready to participate in this study on their own.

Similarly we have excluded:

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  TTA with contracture and weak (less than grade 3) knee power;

  
  
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  complicated stump (pain, wound, etc.);

  
  
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  cause of amputation: peripheral vascular disease (PVD);

  
  
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  patient with inadequate ROM and strength in contra lateral limb;

  
  
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  patients with neurologic disorders, or other related psychological problems;

  
  
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  patients with cardiovascular and respiratory problems;

  
  
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  musculoskeletal disorder that might alter gait characteristics.

1.3

Results

The demographic data of the amputees included in the study are presented in Table 1 . The VO ₂ uptake and EE comparisons were highly significant for both prosthesis and crutches without prosthesis walking ( P < 0.025). The VO ₂ uptake data showed more symmetry in prosthesis walking compared to crutch walking without prosthesis ( Fig. 3 ). The EE/min data showed more symmetry in prosthesis walking compared to crutch walking without prosthesis ( Fig. 4 ). The results for HR indicate that, the patients were in a comfortable range throughout this study ( Table 2 ).

Line graph of VO ₂ uptake rate for Crutch and Prosthesis walking.

Line graph of EE/min for Crutch and Prosthesis walking.

1.4

Discussion

The purpose of the study was to compare the gait efficiency and the effectiveness of the transtibial prosthesis over the crutches without prosthesis in patients with unilateral transtibial amputation for walking activities. The study included the unilateral TTA of either side with no consideration of sex. The other physical factors like height and weight were also not considered except the stump length. In results it was observed that VO ₂ uptake and EE/min comparisons were highly significant for both prosthesis and crutches without prosthesis walking ( P < 0.025). This suggests that the change in VO ₂ uptake can directly affects the EE/min values and vice versa. This well-established fact had been employed in many previous studies of the energy costs of both crutch-walking without prosthesis and prosthesis walking .

Bryan et al. suggested that direct comparison in walking in unilateral traumatic and dysvascular amputees at the symes, transtibial or transfemoral level using prosthesis or a swing through crutch assisted gait without a prosthesis revealed that almost all amputees have a lower rate of EE, O ₂ cost than using a prosthesis. In another study, Waters et al. found that the rate of oxygen consumption, HR, respiratory quotient was significantly increased in all group of amputees when using a crutches and without prosthesis. Tachycardia was found to be increased in all patients using crutches. All the amputee subgroups averaged between 120 and 125 heartbeats per minute. The results of this study also revealed the same findings in oxygen consumption only but not for HR. We found that throughout our study whether using prosthesis or crutches without prosthesis, the patients were within the comfortable range. (Mean HR for prosthesis walking and crutch walking was 82 and 91 beats/min respectively). This indicates that in comparison to previous reports, the patients were in a comfortable range throughout this study. The difference of this result with respect to the previous studies is may be due to the fact that, prior to the test the initial resting phase was meant for the accommodation to the system and in between the two tests the patients were rested for 30 minutes. By this time the patient’s normal resting HR comes to a baseline level. However in a comparison between prosthesis and crutch walking, it was observed that the prosthesis walking was 6% more stable in regards to HR than crutch walking. In another study by Jessie , the authors concluded that the energy cost of walking with prosthesis is less than that expended when walking without it using crutches or a walker. Our study also revealed the same findings. In comparing the VO ₂ uptake for both prosthesis and crutches, significant differences were observed ( P < 0.005). The comparison for EE/min values also showed a significant difference ( P < 0.00001). It was observed that the prosthesis walking in self selected velocities in level surface is 21% more efficient in terms of VO ₂ uptake and 92% more efficient in terms of EE/min as compared to crutch walking in case of unilateral TTA.

The above findings clearly suggest that prosthesis walking is much more efficient than crutch walking without prosthesis in case of unilateral TTA. This may be due to the fact that the prosthesis not only replaced the lost anatomical part from cosmetic point of view but also replaced the weight of the lost part of the limb to maximum extent. It requires no extra exertions of upper limb muscles and lifting the body, etc. The prosthetic limb motion is symmetrical, and the displacement of the center of gravity of the head, arms, and trunk (HAT) in the vertical direction is of low-amplitude as because it is like the normal walking. The results may be due to the fact that most patients were the prosthetic users for at least six months, by which they acquainted themselves in its use. As the amputee group choose the swing-through crutch locomotion, which requires a high rate of physical effort in comparison to normal and other means of crutch walking. The arms and shoulder girdle musculature must lift and then swing the entire body weight forward with each step. The metabolic energy demands of supporting the body weight with the arms and shoulders were more significant.

The results of this study can be clinically applied in view that, the crutches without prosthesis should not be used as a permanent rehabilitative measure in case of patients with unilateral transtibial amputations. Crutch walking without prosthesis with a three-point gait pattern (as it requires less effort as compared to swing through crutch assisted gaits) in unilateral amputees may be a primary or secondary means of transportation when an adequate prosthesis is unavailable or inadequate. Crutches may be considered for times when the amputees choose not to wear their prosthesis or for occasions when they are unable to wear their prosthesis secondary to edema, skin irritation, or poor prosthetic fit. In addition it may only be used for the purpose of extra stability or security if needed by some amputees due to various pathological conditions. Whereas in all the case of patients with unilateral transtibial amputations, the below knee prosthesis should be considered as a permanent rehabilitative measure as it is more efficient in terms of energy consuming gait in comparison with the crutches without prosthesis.

The hypothesis of this study that prosthesis is more effective in conserving energy in case of unilateral Trans tibial amputees than crutches without prosthesis for walking activities is well supported by the results of this study. The data on oxygen consumption, HR, and EE per minute clearly indicated that all below knee amputee groups walk with less effort by using prosthesis. We found that the amputee gait was 21% more efficient in terms of VO ₂ uptake and 92% more efficient in terms of EE/min as compared to crutch walking in self-selected walking speed on level surface. So it can easily be concluded that a well-fitted prosthesis results in a satisfactory gait, which significantly reduces the physiologic energy demand when compared their EE while using crutches only. Instead of this also, the use of either crutch or prosthesis cannot be fully neglected. While some amputee may prefer to use the crutch for indoor activities where the increased EE can be compromised for small distance walking, the use of prosthesis can be undertaken for activities requiring long distance walking. Because crutch walking requires more exertion than walking with prosthesis, patients with unilateral transtibial amputations should not be required to attempt to crutch walk without prosthesis as a permanent prescription, rather both of them can be prescribed together.

Some of the limitations of the study are as follows:

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  a proper gait training with both the assistive devices should be have been imparted to the participants to quantify the real and exact EE as different gait pattern may alter the energy cost;

  
  
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  the test was performed for 10 minutes only in three occasions, which can be increased to a week or so for better results.

Disclosure of interest

The authors declare that they have no conflicts of interest concerning this article.

Acknowledgement

This study was undertaken at the Department of R&D and MPO training Section at National Institute for the Orthopaedically Handicapped, Kolkata with financial and technical support from the Institute.

2.1

Introduction

L’efficience de la marche peut être définie comme le pourcentage de consommation d’énergie transformé en travail utile. Le travail physiologique effectué pendant la marche à plat également appelé efficience de la marche peut aussi être défini comme la quantité d’oxygène consommée par kilo de poids du corps par unité de distance parcourue (ml/kg/m) . De précédentes études ont établi que les amputés des membres inférieurs dépensent plus d’énergie par rapport aux sujets normaux . Dans leur étude, Gailey et al. ont remarqué que le coût métabolique (VO ₂ ) et la fréquence cardiaque des amputés transtibiaux (ATT) à vitesse de marche choisie par eux-mêmes étaient plus élevés de 16 %, et le rythme de marche plus lent de 11 % que dans le groupe témoin des non-amputés . De nombreuses études ont montré l’effet de différents types de béquilles sur le rendement énergétique selon les différentes démarches données par les béquilles. McBerth et al. ont montré que l’utilisation d’une canne ou de béquilles avec une marche à deux points d’appui alternés et trois points avec décharge partielle du poids du corps exigeait près de 33 % d’énergie de plus que la marche normale. La marche pendulaire et la marche en décharge avec trois points d’appui exigeaient près de 73 % d’énergie en plus que la marche normale . En comparant les béquilles axillaires (sous-aisselles) et les cannes à appui antébrachial, Fisher et Patterson n’ont pas trouvé de différence significative . Dans une autre étude, Lee a remarqué que la consommation d’oxygène était inférieure pour les béquilles axillaires que pour les canne à appui natébrachial .

Waters et al. dans une comparaison directe de la marche chez des amputés unilatéraux avec et sans prothèse utilisant un modèle de marche à trois points d’appui avec béquilles, ont révélé que l’utilisation de la prothèse s’accompagnait d’un taux plus faible de dépense énergique, de fréquence cardiaque et de consommation d’oxygène . Bryan et al., en comparant directement la marche chez des amputés unilatéraux traumatiques et vasculaires de type Syme, transtibial ou transfémoral qui utilisaient une prothèse ou marchaient en pendulaire avec des béquilles et sans prothèse, ont trouvé que presque tous les amputés ont un taux plus faible de dépense d’énergie (DE), de fréquence cardiaque et de consommation d’O ₂ avec l’utilisation d’une prothèse . En comparant la DE, Datta et al. ont noté que les patients rééduqués après amputation sous le genou et les utilisateurs de béquilles dépensaient 20,5 % et 48,5 % plus d’énergie, respectivement, que les sujets normaux pour monter des escaliers . Dans une autre étude, Waters et al.ont montré qu’une prothèse bien ajustée permettait une démarche satisfaisante sans recourir à des béquilles et diminuait de façon significative la demande physiologique d’énergie. L’augmentation du taux de consommation d’énergie, de fréquence cardiaque, du quotient respiratoire, était significative dans tous les groupes d’amputés lorsqu’ils utilisaient des béquilles sans prothèse. Cette augmentation va de 1,3 mL/kg par minute chez les amputés vasculaires de type Syme à 6,9 mL/kg par minute chez les amputés traumatiques sous le genou .

Bien qu’il y ait une littérature considérable sur la DE physiologique au cours de la marche chez les amputés avec différents composants de prothèses ou différents types de béquilles, une comparaison directe des résultats des différentes études est difficile pour les raisons suivantes : premièrement, de nombreuses comparaisons ont été faites entre des amputés jeunes ou généralement traumatiques et des amputés plus âgés ou généralement vasculaires, et les différences sont significatives entre ces deux groupes en termes de performance de marche. Secondement, il n’y a souvent pas de distinction entre les amputés qui utilisent des dispositifs d’assistance des membres supérieurs et ceux qui n’en utilisent pas. Bien que la méthode de consommation d’oxygène ait montré sa fiabilité et soit fréquemment utilisée, les instruments utilisés préalablement sont encombrants, rencontrent plus de refus des patients et ne sont pas disponibles dans de nombreuses cliniques . Cette méthode comporte d’autres inconvénients, tels que l’impossibilité d’obtenir des données en continu, et par conséquent d’étudier des changements rapides de ventilation ou de VO ₂ , ou encore la consommation en temps de, la méthode à cause des conditions de prélèvement des échantillons et de leur analyse après recueil . De nombreuses études anciennes ont utilisé le calcul de l’indice de coût physiologique (ICP) comme l’une des méthodes d’évaluation du coût d’énergie métabolique, mais il existe une controverse sur la validité et la fiabilité de l’ICP comme mesure des données pour l’évaluation de la DE . Il y a donc un vrai besoin d’analyse exacte de la quantification de DE entre « prothèse » et « béquilles sans prothèse » chez des sujets présentant peu de variations d’âge et de conditions cliniques. Par ailleurs, il faut aussi qu’en pratique clinique des aides et un contrôle alimentaire soient prescrits. Nous avons donc essayé de comparer l’efficacité de la marche entre les deux dispositifs d’assistance les plus fréquemment utilisés (prothèses exosquelettiques PTB & béquilles axillaires) dans le contexte Indien en utilisant le système d’analyse respiratoire portable et hautement fiable Respiratory Analyser System Cosmed ^® K4 b ² fondé sur le système d’analyse de gaz automatisé en ligne et en continu .

2.2

Matériel et méthodes

Un échantillon disponible de 30 amputés unilatéraux transtibiaux a pris part dans cette étude. Il a été demandé aux sujets de marcher sur une sol plat, à l’aide d’une « prothèse » et de « béquilles sans prothèse » individuellement. L’environnement devait être maintenu à l’identique tout au long de l’étude. En cas de pluie ou d’extrême chaleur et d’humidité, aucune donnée n’était recueillie. Les patients étaient en état psychologique normal, sans anxiété, stress, peur, etc. Il leur a été demandé de marcher à la vitesse de leur choix, que ce soit avec la prothèse ou les béquilles. Ils devaient prendre leur régime alimentaire normal au moins deux jours avant le test.