Enhancing the clinical practice of prosthetists: gait analysis methods
Although walking poses little challenge to individuals who are healthy, those with gait pathologies or lower-limb amputations can find it tiring and difficult [4]. Gait analysis is a well-established tool for the quantitative assessment of gait disturbances providing functional diagnosis, assessment for treatment planning, and monitoring of disease progress [1]. Ultimately, the goal of clinical gait analysis is to optimize the kinematic pattern of gait so that the patient walks with as little energy expenditure and more comfort as possible [9].
In what concerns lower-limb amputation rehabilitation, gait analysis allows the comparison of different prosthetic designs or different alignments of the same prosthesis, for example, along with the optimization of the patient’s gait and diminishment of the negative influence the prosthesis will have in their mobility. It is crucial for a successful O&P practice, so is the prosthetist's interest to gather information on how to conduct this analysis. Data aids the clinician and prosthetist in uncovering specific problems experienced by the amputee and in pinpointing the causes. In this post, we’ll take a deeper look into this process and let you know what practices can be applied in gait analysis for lower-limb amputees, as well as let you know how Adapttech’s INSIGHT can help improve patient outcomes.
The human gait and lower-extremity amputation
Human gait is a series of alternating movements of the trunk and limbs which define a forward displacement of the center of mass of the body. Gait is the most important method of human locomotion for mobility and independence, characterized by periods of loading and unloading of the limbs to move around [1]. Saunders and colleagues and Inman and colleagues define the functional task of walking as the translation of the center of gravity through space in a manner that requires the least energy expenditure, and it considers three functional tasks that need to be carried out for it to be considered successful: weight acceptance, single limb support, and limb advancement [7].
The gait is said to be healthy, considering standards, when the movements of the segments involved in each event of the gait cycle are within the limits considered normal for individuals of the same sex and age [11]. These normal limits will be mentioned below the headline “Basics of gait analysis”.
According to Saunders et al., there are six mechanisms to solve this gait optimization problem, biomechanical patterns that can be considered pivotal to minimize the center of gravity displacement. These mechanisms are pelvic rotation, pelvic tilt, lateral displacement of the pelvis, early knee flexion, foot and ankle mechanisms, and late knee flexion [8].
The gait cycle can be considered in a dual division of stance and swing, respectively when the limb in analysis is in contact with the ground and when it’s not. Step length, stride length, cadence, and velocity are important quantitative, interrelated kinematic measures of gait.
To adequately evaluate the gait characteristics of people with lower-extremity amputations, the clinician must understand the normal gait as well as the “typical gait deviations” frequently exhibited by individuals with limb amputation [2]. Gait quality and its velocity can be used as outcome measures in this population.
The Basics of Gait Analysis
Conventional gait analysis generally assumes a repeatable gait pattern [3]. The non-pathological gait cycle accounts for 60% stance and 40% swing. In males (41-60 years old) the average duration of the gait cycle is 1.6 seconds, but, for functional analysis, extra granularity is needed.
According to RLA (Rancho Los Amigos National Rehabilitation Center) terminology, the gait cycle (100%) can be further divided in 8 consecutive phases:
Initial contact (IC, 0%)
Loading response (LR, 0-10%)
Midstance (MSt, 10-30%)
Terminal stance (TSt, 30-50%)
Pre-swing (PSw, 50-60%)
Initial swing (ISw, 60-73%)
Midswing (MSw, 73-87%)
Terminal swing (TSw, 87-100%)
The phases involving single support are midstance and terminal stance, while initial contact, loading response, and pre-swing will correspond to double support.
At Adapttech, after some previous work and requirements gathered with prosthetists, is suggested a modified version of RLA contemplating five stages: initial contact, loading response, midstance terminal stance, and swing, with pre, initial, mid and terminal swing being merged into the single swing phase. Initial contact is traditionally selected as the starting and completing event of a single cycle of gait [7].
There are several deviations, either at stance phase or swing phase, differently caused, that need to be taken into consideration. According to Murphy [5], Table 1 and Table 2 represent the main gait deviations of lower-limb amputees in the stance phase and swing phase, respectively. Musculoskeletal causes were mostly filtered out.
Table 1 - Main gait deviations of lower-limb amputees in the stance phase
Table 2 - Main gait deviations of lower-limb amputees in the swing phase
In an individual with lower-limb amputation, optimizing their gait characteristics can enhance the cosmetic qualities of the gait pattern, influence residual limb comfort, affect the efficiency of ambulation, and reduce compensatory movements that over time may prove harmful to the individual [10].
Precautions and common issues
When doing gait analysis, patient-reported feedback is commonly taken into consideration. However, there are several variants in that feedback. For example, a child is much less likely to report pain effectively than an adult individual, as well as perspiration-related discomfort, is also much lower in children than adults [12]. As the reader might acknowledge, patient feedback will condition the evaluation made by the clinician.
When performing gait analysis, a number of difficulties must be taken into consideration. The amputee population is largely diverse with the amputations resulting from many causes, with different anatomic levels and the clinician encounters an array of individuals with a wide range of functional goals and expectations. Another difficulty is the functional outcome, which is related to numerous variables, such as medical status, age, rehabilitation care, social status, prosthetic fit, and function. A prosthetist needs to assess if limitations of function are related to the underlying disease process (plus secondary complications), the rehabilitation process, or the prosthetic devices.
How INSIGHT System can help improve your practice
The human eye is highly sensitive to detecting deviations from normal gait but not necessarily to identifying primary problems or compensatory strategies [1]. INSIGHT System is a device that can acquire quantitative pressure data, either along with dynamic gait acquisitions or static acquisitions (in which the patient is not moving).
A dynamic acquisition made and recorded by the INSIGHT App provides a real-time view of what is happening inside the prosthetic socket while the individual is moving, meaning that it provides quantitative pressure data during the gait cycle and shows the spatial distribution of pressure. As you can see in the image below, when one plays back the acquisition, the patient is represented by an animated figure in the App, and the clinicians can observe the evolution of the pressure map according to the patient's gait phases and when turning, as well as obtain an average pressure per gait phase.
This acquired data will help the clinicians come up with the best solution and contribute to the understanding of the perceived needs of the amputee, improving the rehabilitation process of the amputee and influencing the prosthetic design and manufacture. For example, by understanding the balance between time spent in single and double support, the prosthetist can determine how comfortable the patient feels wearing their prosthesis. It has been suggested that longer double support may be caused by amputees’ reluctance in placing the prosthetic foot on the ground and supporting their body weight in it [6, 13].
Besides the prementioned benefits, there are plenty of other benefits regarding INSIGHT that cover healthcare providers, patients, prosthetists, and prosthetic centers. There is access to patient history and digitally stored patient sockets, a more accurate fitting process (breaking the trial-and-error process) which leads to each patient requiring less time from the prosthetist. It also creates the opportunity to monitor patients more closely, as well as making the training of younger prosthetists a lot easier once the experience of mentors is translated into objective data and concepts.
INSIGHT System leads to a more efficient and cost-effective workflow. Learn more about INSIGHT workflow here.
See you in our next blog post!
References
[1] Baker R, Esquenazi A, Benedetti MG, Desloovere K. Gait analysis: clinical facts. Eur J Phys Rehabil Med. 2016 Aug;52(4):560-74. PMID: 27618499.
[2] Esquenazi A. Analysis of prosthetic gait. In: Esquenazi A, editor. Physical medicine and rehabilitation. State of the art reviews, vol. 8, No. 1. Philadelphia: Henley & Belfus, Inc; 1994. p. 201–20.
[3] Esquenazi A. & Talaty M. (2011). Gait analysis, technology and clinical applications. Physical Medicine and Rehabilitation. 99-116.
[4] Gonzalez EG, Corcoran PJ. Energy expenditure during ambulation. In: Downey JA, Myers SJ, Gonzalez EG, Lieberman JS. eds. The Physiological Basis of Rehabilitation Medicine Boston, MA: Butterworth-Heinemann; 1994:413–446
[5] D. Murphy. Fundamentals of Amputation and Prosthetics. 2014.Cited on pages v, ix, xiii, xiv, 1, 10,11, 12, 13, 14, and 16.
[6] M. E. Chamberlin, B. D. Fulwider, S. L. Sanders, and J. M. Medeiros, “Does fear of falling influence spatial and temporal gait parameters in elderly persons beyond changes associated with normal aging?,” Journals Gerontol. - Ser. A Biol. Sci. Med. Sci., vol. 60, no. 9, 2005.
[7] PhD Pt, M. L. M., Jorge, M., & PhD, C. N. C. (2012). Orthotics and Prosthetics in Rehabilitation (3rd ed.). Saunders.
[8] Saunders JBD, Inman VT, Eberhart HD. The major determinants in normal and pathological gait. J Bone Joint Surg Am 1953;35:543–558
[9] Talaty M. & Esquenazi A. Determination of dynamic prosthetic alignment using forceline Visualization. J prosth orth 2013;25:15-21
[10] Treweek sp, Condie ME. Three measures of functional outcome for lower limb amputees: a retrospective view. prosth orth int 1998;22:178-85
[11] Whittle, M. W. (2007). "Gait Analysis an Introduction" (4th ed.). Elsevier Ltd.
[12] W. M. Vannah, J. R. Davids, D. M. Drvaric, Y. Setoguchi, B. J. “A survey of function in children with lower limb deficiencies” (1999), Oxley 10.3109/03093649909071640 Prosthetics & Orthotics International
[13] X. Zhang, G. Fiedler, and Z. Liu, “Evaluation of gait variable change over time as transtibial amputees adapt to a new prosthesis foot,” Biomed Res. Int., vol. 2019, 2019.
