Clinical Resources for Assessing Mobility of People with Lower-Limb Amputation: Interviews with Rehabilitation Clinicians

Abstract

Introduction:

Mobility tests are increasingly used in prosthetic rehabilitation to evaluate patient outcomes. Knowledge of the space, equipment, and time resources available to clinicians who work in different settings can guide recommendations for which tests are most clinically-feasible and promote coordination of mobility testing among members of the rehabilitation team. The primary aim of this study was to characterize the different resources available to clinicians for measuring mobility of people with lower limb amputation. A secondary aim was to identify performance tasks that clinicians use to evaluate prosthetic mobility.

Materials and methods:

Semi-structured interviews were conducted with prosthetists, physical therapists, and physiatrists who treat people with lower limb amputation. Researchers used convenience and snowball sampling to identify participants. Interviews included questions about the resources available for conducting mobility tests, as well as questions about which tasks clinicians deemed valuable to assessing mobility of patients with lower limb amputation. Interviews were audio-recorded and transcribed. Summary and frequency statistics were calculated for quantitative data; explanatory comments were summarized.

Results:

Interviews were conducted with 25 clinicians (8 prosthetists, 9 physical therapists, and 8 physiatrists). Participants had access to multiple spaces and basic measurement equipment. The maximum time participants were willing to spend on performance tests varied. Physiatrists reported less time available (median=10 minutes, range 5-30 minutes) than prosthetists and physical therapists (median=30 minutes, range 5-60 minutes for both professions). Mobility tasks commonly used to evaluate patients with lower limb amputation included sit-to-stand, standing balance, walking, and varying speed. Participant comments suggested that mobility tests need to be quick, simple, and add value; existing mobility tests are beneficial but challenging to incorporate into practice; mobility tests should reflect real-world activities; and technological advancements could improve mobility testing.

Conclusions:

Clinicians generally had small-to-medium spaces, basic measurement equipment, and sufficient training to administer mobility tests in their clinics. A limiting factor was time, which can be addressed through selection of efficient measures and collaboration within the rehabilitation team.

INTRODUCTION

Rehabilitation clinicians often perform physical evaluations of mobility to assess patient status, guide the rehabilitation care plan, and inform details of the prosthetic prescription. For people with lower-limb amputation, mobility with a prosthesis is a primary determinant of key outcomes, including functional independence,¹ community reintegration,² employment,^{3, 4} and quality of life.^{5, 6} Mobility is also a criterion by which third-party payers determine individuals’ eligibility for prosthetic components and physical therapy. While a patient’s mobility classification can be based on observational clinical evaluation, some payers require justification of this determination using validated outcome measures.⁷ Further, standardized mobility assessment facilitates prescription of prosthetic or therapeutic intervention, evaluation of patient progress, communication between care providers, and documentation of intervention effectiveness. Therefore, use of standardized outcome measures to assess and document mobility in people with lower-limb amputation is increasingly critical to the provision of rehabilitation care.

Clinical assessments used to evaluate patients’ mobility include both patient-reported and performance-based outcome measures. Patient-reported outcome measures are surveys or questionnaires intended to evaluate health from the patient’s perspective.⁸ Performance-based outcome measures are tests of patient ability, typically administered and scored by a trained clinician or researcher.⁹ Performance-based tests require a patient to perform one or more tasks, such as walking a short distance or standing up from a chair.¹⁰ Both patient-reported surveys and performance-based tests provide distinct, valuable, and complementary information about patients’ health. Despite the recognized importance of outcomes measurement to prosthetic care,^{11, 12} only 38% of prosthetists¹³ and 48% of physical therapists¹⁴ previously reported routine use of standardized outcome measures in clinical practice. Rehabilitation professionals describe a number of barriers to outcomes measurement,^13–16 including lack of time^14–17 and training.^{15, 17} Further, some clinicians may not perceive the value of using standardized outcome measures for patient evaluation,¹⁸ which leads to prioritization of other activities.

In addition to these recognized barriers, many performance-based tests of mobility have spatial, equipment, and organizational requirements. Spatial requirements for measurement include environmental resources, such as large, open spaces or long corridors. Equipment requirements for measurement include physical resources, such as stairs, chairs, stopwatches, and tape measures. Organizational requirements for measurement include the administrative support and culture of the clinic. While some rehabilitation clinics are designed to accommodate performance-based outcomes measurement, others may be limited by small spaces, insufficient equipment, and a lack of organizational support.

Knowledge of resources available to clinicians who work in different types of rehabilitation settings will help organizations to identify standardized performance-based mobility tests that can be administered in most clinical environments. Such knowledge may also help to inform space and design decisions for new rehabilitation clinics that wish to include performance-based mobility testing as part of routine care. Lastly, information about resource constraints in clinics and perceived value of performance tasks could facilitate design of new performance-based tests for lower-limb prosthesis users. Therefore, the aim of this study was to collect descriptive information about the space, equipment, and time available to clinicians who regularly work with people who have lower-limb amputation. Information about the perceived clinical value of tasks and measures was also collected to identify outcomes that clinicians believe provide meaningful information about a patient’s mobility.

MATRIALS AND METHODS

Semi-structured telephone interviews were used to gather information about the clinical environments of rehabilitation professionals. Interview methods were selected in order to provide respondents opportunities to clarify and expand on their responses, thereby providing researchers with a better understanding of each individual’s setting and experiences measuring mobility outcomes. Researchers used an interview guide (Supplement 1) with open- and closed-ended questions to assess equipment and resources available, descriptions of valuable tasks, and perceptions of outcome measurement in prosthetic rehabilitation. A survey (Supplement 2) was used to characterize study participants based on demographic and clinical characteristics. Recruitment and data collection for this study occurred between August and October of 2017. The study protocol was reviewed by a University of Washington Institutional Review Board and determined to qualify for exempt status. Participants provided verbal consent prior to enrollment. All data were anonymized prior to analysis.

Participants

Prosthetists, physical therapists, and physiatrists who regularly worked with people with lower-limb amputation were sought to participate in this study. Because prosthetic rehabilitation is a relatively small field, a convenience sample of clinicians experienced in post-amputation rehabilitation was recruited through professional contacts. Referral (i.e., snowball) sampling was also used to identify participants. Study investigators were potentially known to the respondents, either through professional interaction or by reputation.

To be eligible for the study, participants had to be at least 18 years old, be certified and/or licensed in their state of practice, report clinical experience treating people with lower-limb amputation, and allow the interview to be recorded and transcribed. To solicit experiences from a range of clinical providers, at least five participants were sought from each of three disciplines (physiatry, prosthetics, and physical therapy), and from small (10 employees or less) and large (100 employees or more) facilities.

Procedures

A survey was sent to the participant via email in advance of the interview to collect demographic (e.g., race and ethnicity, sex, education) and practice characteristics (e.g., length of time in clinical practice, and employer type and size). Surveys also included items about the standardized outcome measures that participants use to assess people with lower-limb amputation. Study participants were then contacted via telephone at the scheduled meeting time to complete the interview.

Interviewers were researchers trained in clinical prosthetics, with backgrounds in outcome measure development. An interview guide was developed by an interdisciplinary team of investigators. The interview guide consisted of open- and closed-ended questions about clinicians’ access to resources that facilitate performance-based mobility testing, including space; supplies and equipment; time for collection, scoring, and interpretation; support from other staff; and training. The questions for the interview guide were developed based on known barriers and facilitators of outcome measurement^{13–15, 18, 19} and the requirements for administration of various performance-based tests.^{11, 12} Interviewers also asked clinicians about performance-based mobility tasks they used to evaluate patients with lower-limb amputation. Ad hoc follow-up questions were asked, when needed, to clarify responses or gather additional information. Field notes were taken throughout the interview.

Telephone interviews were audio recorded and transcribed by a Communications Access Realtime Translation (CART) reporter²⁰ to facilitate accurate data extraction and analysis. All participants consented to audio recording and were notified at the start of recording.

Analysis

Transcripts and field notes were independently reviewed by all investigators. Two investigators extracted data from the transcripts and field notes into a spreadsheet that organized clinicians’ responses regarding environment and space, equipment, time, application of performance-based tests, support and training, and performance-based tasks and activities. Additional interview data that characterized participants’ views and experiences with performance-based tests were also extracted. The spreadsheet was systematically checked for errors by a third investigator.

Extracted interview data were summarized and tabulated to compare results across and within professional groups. Summary statistics (e.g., means, standard deviations, ranges) were calculated for data that could be expressed quantitatively (e.g., number of minutes spent conducting performance-based assessments) as appropriate. Participant elaboration and spontaneous comments provided throughout the interviews were coded and organized into topics that captured participant experiences and perspectives.

RESULTS

Participants

Twenty-five participants from 12 U.S. states were interviewed, including eight physiatrists, eight prosthetists, and nine physical therapists. Clinicians worked in hospitals, outpatient clinics, or home health settings. Interviews lasted between 21.3 and 54.4 minutes (average length was 37.5 minutes). On average, participants had been practicing for 12.2 years (SD=7.5 years) and had been treating people with lower-limb amputation for 10.9 years (SD=7.6 years). Approximately two-thirds of participants worked for large facilities (i.e., those with over 100 employees) and over half of the participants identified their employer as a private facility (Table 1).

Table 1.

Participant demographics and characteristics.

	Mean	SD
Age (years)	39.6	7.4
Years in clinical practice (years)	12.2	7.5
Years in clinical practice treating patients lower limb amputation (years)	10.9	7.6
Proportion patients with lower limb amputation (%)	52%	30%
Number of patients with lower limb amputation (patients/month)	46	35
	N	%
Gender
Male	16	64%
Female	9	36%
Highest level of education
Bachelor’s degree	2	8%
Master’s degree	7	28%
Clinical professional doctorate (DPT)	7	24%
Medical or professional doctorate (MD, DO)	8	32%
Other (eg, post-baccalaureate clinical certificate)	1	8%
Formal training in outcomes measurement*
Continuing education	15	60%
Clinical residency	14	56%
Undergraduate or graduate courses	10	40%
Other (eg, self-taught, webinars, research activities)	10	40%
Area of clinical practice
Physical therapy	9	36%
Prosthetics	8	32%
Physiatry (physical medicine & rehabilitation)	8	32%
Facility size
≤10 employees	5	20%
11-99 employees	3	12%
≥ 100 employees	17	68%
Facility setting*
Out-patient hospital	17	68%
Out-patient clinic	13	52%
In-patient hospital	12	48%
Academic institution	4	16%
Other-home health	1	4%
Facility type*
Private	14	56%
Federal	5	20%
State	5	20%
Local	4	16%
Primary method of patient documentation
Electronic health record	25	100%
Person primarily responsible for outcomes assessment
Self	22	88%
Other clinician(s)	3	12%
Performance-based mobility measures used*
10mWT	11	44%
2MWT	14	56%
6MWT	13	52%
AMP	22	88%
CHAMP	5	20%
L Test	7	28%
TUG	23	92%

Acronyms: 10mWT, Ten-Meter Walk Test; 2MWT, Two-Minute Walk Test; 6MWT, Six-Minute Walk Test; AMP, Amputee Mobility Predictor; CHAMP, Comprehensive High-level Activity Mobility Predictor; L Test, L Test of Functional Mobility; TUG, Timed Up and Go.

^*Responses total more than 100% because more than 1 response may be selected.

Environment and space

Across disciplines, most participants stated that they had access to more than one room for patient evaluation. Rooms described by participants ranged from small examination rooms (~3 m²) to therapy gyms (~70-760 m²). The majority of physical therapists had access to a gym (n=8), whereas relatively few physiatrists (n=5) or prosthetists (n=2) had access to large indoor spaces.

All participants stated that their clinics had space available for patients to walk and turn around (e.g., long examination rooms, hallways, or indoor walking paths). Many of these spaces were common areas that were often occupied by other people and equipment. All participants had straight, indoor spaces that could accommodate walking distances of at least 8 m.

All participants identified at least one space where participants could run or jog. Four participants only had access to outdoor running spaces. All but one participant identified at least one outdoor space that was available for evaluating gait over a variety of surfaces, such as ramps, hills, uneven terrain, grass, stairs, long distances, and recreational spaces.

All participants identified at least one set of indoor stairs, with handrails, that could be used to assess patients’ performance in stair ascent and descent. Indoor stairs ranged from stand-alone therapy stairs with 3-4 steps to multiple-flight staircases. All but three participants reported access to at least one ramp, however, nine of the participants only had access to an outdoor ramp. Many participants reported that one or more of the ramps available to them did not have handrails (n=10).

Equipment

All participants had at least two chairs, and most had parallel bars (n=23). Approximately half of the participants had access to a treadmill (n=12). All participants reported that they had a stopwatch and a tape measure. Most had a meter or yard stick (n=16). The majority of participants stated that they had a tablet computer (n=19), and all participants reported that they had internet access in their clinic.

Time

Participants reported that they spend between 15-120 minutes (mean=50.3, median=47.5) in a patient evaluation appointment, depending on the complexity of the patient case and whether it was an initial or follow-up appointment. The typical amount of the total appointment time allocated to performance-based assessment varied by profession. Similar variation was seen in the maximum time participants reported that they were willing to allocate to performance-based assessment (Table 2). Participants stated that they usually spend between 1-20 minutes documenting and between a few seconds and 20 minutes scoring and interpreting performance-based assessments.

Table 2.

Typical and maximum time spent on performance measurement for rehabilitation professionals.

	Physiatrists (n=8)			Prosthetists (n=8)			Physical Therapists (n=9)
	Mean	Median	Range	Mean	Median	Range	Mean	Median	Range
Typical time allocated to performance measurement (minutes)	8.2	7.3	0-30	17.0	15.0	0-30	19.4	17.4	5-45
Maximum time willing to spend on performance measurement (minutes)	13.1	19	5-30	32.5	30.0	5-60	30.0	30.0	5-60

Application of performance-based test results

The majority (n=18) of participants used performance-based tests to document patient progress or compare outcomes over time, and nearly half (n=11) of participants used performance-based tests to determine functional level or justify services to payers. Other reported applications included determining the prosthetic or therapy plan of care (n=9) and communicating with patients (n=7) and/or other rehabilitation providers (n=6). Few participants (n=2) stated that they did not collect or use performance-based tests in their clinics (Figure 1).

Figure 1.

Number of study participants who endorsed various clinical uses or applications for results of performance-based outcome measures.

Support and training

The majority of physiatrists (n=7) and physical therapists (n=9) reported that they had received formal training to conduct performance-based tests. In contrast, only half of the prosthetists interviewed (n=4) reported receiving formal training. Almost all physical therapists (n=8) stated that outcomes measurement was required in their facilities, whereas approximately half of the physiatrists and prosthetists (n=4 and n=5, respectively) reported outcomes assessment was required. Members of all professions noted that employer support, technological features in electronic medical record systems, and permanent test set ups in their clinics facilitated performance-based patient assessment. Compared to prosthetists and therapists, more physiatrists reported that staff or other members of the rehabilitation team were available to conduct assessments for them.

Performance-based tasks and activities

All participants reported that they regularly asked their patients with lower-limb amputation to perform tasks such as walking in the hallway and moving from sit-to-stand. A majority of participants also asked their patients to walk in parallel bars (n=24). Other tasks and activities that were commonly used by participants to evaluate patients with lower-limb amputation included bed mobility, transfers, standing balance and weight shifting, walking tests, donning and doffing the prosthesis, varying gait speed, turning, navigating obstacles, negotiating stairs and ramps, and activities of daily living. Participants noted that they asked patients with low levels of mobility to do tasks and activities such as sit-to-stand, transfers, bed mobility, level ground walking, donning and doffing the prosthesis, standing balance and weight-shifting, turning, stairs, varying gait speed, and patient-specific goal-oriented tasks. For high-mobility patients, participants noted they asked them to perform standing balance and weight-shifting, walking long distances, stepping to the side and backwards, slopes and stairs, turning, walking while varying gait speed and jogging, walking on uneven surfaces, sports activities such as kicking a ball, and patient-specific vocational or avocational tasks.

Participants noted that the tasks that contribute most to their understanding of a patient’s mobility included sit-to-stand, transfers, standing balance, gait quality, stairs and ramps, walking speed and endurance, and navigating obstacles. Tests or tasks identified as contributing the least to participants’ understanding of a patient’s mobility included donning and doffing the prosthesis, straight line walking, walking on uneven terrain, running in the clinic, step tracking, and walking in the parallel bars. Walking tests (e.g., timed up and go [TUG], 2-minute walk test [2MWT], 6-Minute walk test [6MWT]), standardized tests that include variety of tasks (e.g., the Amputee Mobility Predictor [AMP]), as well as individual tasks (e.g., prosthetic single-limb stance, stair tasks that grade on handrail use, and use of assistive device) were indicated as both contributing the most and the least to the understanding of a patient’s mobility, depending on the respondent.

Perspectives on performance-based mobility testing

Participants described a range of considerations with respect to performance-based outcomes assessment in their clinics. These concepts were organized into four topics that described the clinician participants’ opinions on performance-based mobility testing: (1) standardized mobility tests need to be quick, easy to administer, and add value to the clinical appointment; (2) existing mobility tests are beneficial but challenging to incorporate into routine clinical practice; (3) ideally, mobility tests should include real-world activities patients need to perform; and (4) technological advancements could improve the ease and efficiency of standardized mobility testing.

Standardized mobility tests need to be quick, easy, and add value to the clinical appointment

The first topic was the need for quick, simple tests that add value to the appointment. Participants noted that both clinicians and patients have limited time for appointments. Because outcomes measurement is just one aspect of a comprehensive visit, performance-based tests need to be brief and easily administered. One physical therapist noted that a performance-based outcome measure “needs to be short, sweet, and to the point.” Some practitioners stated that scoring and interpretation should also be simple, with one physiatrist stating, “Scoring should be fast. So five minutes. You want to be able to do it quickly.” Others noted that they did not have enough time for standardized assessment. One prosthetist stated, “I would like to do more outcome measures myself, but you only have a limited time with the patient.” Further, participants noted that the time required for standardized assessment is worth spending if scores add value to the appointment, both in terms of information gained and the ability to justify services and devices. One physiatrist noted, “If it…helped me (counsel) with individual patients… and I feel like it makes a meaningful difference, then I would be willing to spend time doing it.” Participants from all disciplines mentioned that they would be especially receptive of measures that assist with justification for prosthetic care. One physical therapist said, “If I got really valuable data, like with the AMP, where it actually gives you a K-level, that’s helping me get a prosthesis for my patient. If I can get buy in that way, I would be far more willing to do more.” Further, participants explained that the outcomes assessment should add value and benefit to the appointment for both the clinician and the patient. Some participants commented that they would be willing to spend more time testing if the results were meaningful or motivating to patients, or if it was necessary or helpful in acquiring insurance approvals for prosthetic components.

Mobility tests are beneficial, but challenging to incorporate into routine clinical practice

Another topic identified was the benefits and challenges associated with clinical outcomes measurement. Participants reported that implementing a standardized set of outcome measures across similar patients would improve feasibility and allow facilities to better assess the effectiveness of their patient care plans. One prosthetist described an outcome measures “kit,” stating, “I will be very curious to see if somebody doesn’t say: Look, we need to just have a box that has all the parts in it. And the two chairs are there… we’ll see if we come together and standardize it. I think that’s the next step.” However, participants noted that a single set of tests may not always align with the abilities and goals of each individual patient. One physiatrist stated, ““So (for) individuals with low function, I have no interest in whether or not they can do uneven terrain, as you would imagine. The same is true of high functioning people getting up from a low seated position.” This finding suggests that standardized assessments could better target patients by general activity levels to increase the value of measurement activities.

Mobility tests should include real-world activities

Another topic was the desire for measures capable of informing the clinician about a patient’s functional abilities in real-life situations. Participants often saw value in performance-based tests that include a variety of tasks (e.g., AMP) and characterize different aspects of the construct being assessed. Measures that encompass a range of tasks were noted to provide broad information about a person’s functional mobility in different situations. One therapist noted, “it’s really helpful to have one outcome measure that will look at a lot of things. We try to… use something like the AMP, for example, because it integrates a lot of different aspects of mobility.” In addition, different aspects of each task (e.g., the way the task was completed and the distance covered) need to be assessed in order to determine the ability to perform the task and assess the patient’s quality of movement. A prosthetist stated, “a lot of people can successfully fulfill a requirement that I might ask them to do, but watching how they do it, and how smooth they do it, and how much effort that they put into doing that, maybe speaks more to me.”

Technological advancements could improve standardized mobility testing

The final topic described opportunities for technology to improve the efficiency of outcome measurement in the clinic (e.g., surveys and tests that could be integrated into electronic medical record systems would be quicker and easier to administer). Integration of outcome measures into a clinic’s health record system has the potential to facilitate routine outcomes assessment by walking a practitioner through the test administration, scoring the test automatically, and assisting the clinician to interpret the test using charts or graphs that contextualize the scores. One physiatrist noted that, “Ideally it would be nice to have something that could be graphed quickly,” to allow for comparisons to normative data.

DISCUSSION

The aim of this study was to collect information about the resources available to different rehabilitation clinicians to conduct performance-based assessments of mobility. A secondary objective was to determine mobility tasks or activities of value when performing such assessments. All participants had access to spaces and equipment for performance-based testing. The average and maximum time participants spend on performance-based assessment varied by profession, with physiatrists reporting less time than prosthetists and physical therapists. A majority of participants reported receiving training to conduct performance-based tests, and many reported that outcomes measurement was required in their clinic. The spontaneous comments and considerations that arose from open-ended interview questions offered useful insights when considering outcome measures best suited to assessment of lower-limb prosthesis users.

Knowledge of space, equipment, and time limitations can help match tasks and measures with appropriate clinical environments to maximize effective and efficient assessment of mobility. Table 3 details resources required for seven performance-based tests used in people with lower-limb amputation. Six of the tests (i.e., the 10mWT,²¹ TUG,²² L-Test,²³ 2MWT,²⁴ 6MWT,²⁴ and AMP²⁵) assess basic prosthetic mobility and were recommended by authors of recent reviews based on evidence of their measurement properties (e.g., reliability, validity, responsiveness, sensitivity) in lower-limb prosthesis users.^10–12 Another test, the CHAMP, has been recommended for assessing high-level mobility in a variety of healthy and clinical populations, including people with lower-limb amputation.²⁶ All seven tests have evidence of appropriate validity and reliability for clinical use, and are well-suited for mobility assessment in people with lower-limb amputation.^{10–12, 26, 27}

Table 3.

Number of clinicians with the resources^* available to administer common mobility performance tests in people with lower-limb amputation.

		Required resources			Number clinicians with required resources
Measure	Brief description	Equipment	Time**	Space***	Physiatrist	Prosthetist	Physical Therapist	Total	Limiting resource(s)
TUG	Time (s) required to stand up, walk 3 m, return to the chair, and sit down.	Stopwatch 1 chair Tape/cone Tape measure	<5 min.	4x1.5m room/hallway	8/8	8/8	9/9	25/25	n/a
L-Test	Time (s) required to stand up, walk 10 m in an “L” shape, return to the chair, and sit down.	Stopwatch 1 chair Tape/cone Tape measure	<5 min.	4x8m room or room+hallway	7/8	8/8	9/9	24/25	Space
10mWT	Time (s) or speed (m/s) required to walk a distance of 10 m.	Stopwatch Tape Tape measure	<5 min.	11m hallway	7/8	5/8	9/9	21/25	Space
2MWT	Distance (m) covered in two minutes of walking back and forth in a corridor.	Stopwatch Counter Tape/cones	<5 min.	31x1.5m room/hallway	3/8	2/8	8/9	13/25	Space
6MWT	Distance (m) covered in six minutes of walking back and forth in a corridor.	Stopwatch Counter Tape/cones	<10 min.	31x1.5m room/hallway	2/8	2/8	7/9	11/25	Time, space
AMP	Score based on observed ability to complete a series of tasks, which include seated and standing balance, typical and fast-paced walking, and stair negotiation.	Stopwatch Stairs (3 steps) Tape/cones Tape measure Ruler 2 chairs Obstacle Walker	<15 min.	5x1.5m room/hallway stairs	3/8	6/8	8/9	17/25	Time
CHAMP	Score based on observed ability and time required to complete a series of high-level tasks, which assess balance, agility, and sprinting.	Stopwatch Cones Tape measure	<15 min.	12x12m room/gym	0/8	1/8	6/9	7/25	Time, space

Acronyms: 10mWT, Ten-Meter Walk Test; 2MWT, Two-Minute Walk Test; 6MWT, Six-Minute Walk Test; AMP, Amputee Mobility Predictor; CHAMP, Comprehensive High-level Activity Mobility Predictor; L Test, L Test of Functional Mobility; TUG, Timed Up and Go.

^*Required resources were based on information provided in the development article or published instructions. In cases where resources were not described in sufficient detail, the investigators came to consensus on the equipment, time, and space required to administer all tasks in the test. The number of clinicians with required resources reflects the number of participants in each group that reported having the equipment, maximum time, and space necessary to conduct the designated test.

^**Time for set-up, scoring, and interpretation is not included. The maximum amount of time reported for performance-based assessment was used in this assessment.

^***One meter was added to each dimension of tests that involve walking, and two meters to tests that include running/ sprinting space to allow for equipment (e.g., a chair) and space near the borders of the test (e.g., turning around).

The clinicians interviewed reported access to various spaces, including small clinic rooms, long corridors for patients to walk, stairs, and indoor or outdoor spaces for patients to run. A subset of the sample, primarily therapists and physiatrists, had access to gymnasiums or other large spaces. All of the clinicians reported access to the space required for two (TUG, AMP) of the six recommended measures and the majority had the space required for the 10mWT and L-Test (n=21 and n=24, respectively). The recommended space requirements for the distance walk tests (2MWT, 6MWT) is a corridor or room that is at least 32 m in length (i.e., 30 m of walking distance, plus 1 m on each side for turning),^{28, 29} which was available for only 13 of the clinicians interviewed. However, the American Thoracic Society acknowledged that shorter walking distances can be used for within-person comparisons.²⁸ Clinicians could therefore use their longest corridor for the test, but could not compare recorded distances to published normative data.²⁹ The CHAMP has unique space requirements due to the 12 m by 12 m space required to conduct the T-Test (i.e., 10 m by 10 m, plus 1 m on each side for deceleration). The space requirements of the CHAMP prohibit its use for 16 participants (seven prosthetists, three therapists, and six physiatrists), who did not report having a large space. Because CHAMP is a measure of high-level mobility tasks that incorporate agility, speed, and balance,²⁶ it is appropriate to evaluate mobility in people who receive the top score on other measures, such as the AMP. While sufficiently large indoor spaces were limited in our sample, outdoor spaces can be used when available for this test if weather conditions are amenable.

Generally, equipment resources were not limited across disciplines; all participants reported having access to the basic equipment and supplies needed to conduct the seven recommended measures. However, some clinicians (particularly physiatrists) were limited in the amount of time that could be allocated to these tests. Time limitations have been identified as a barrier to implementation of outcome measures in clinical environments by both prosthetists¹³ and therapists.^{14, 15, 18} All clinicians interviewed in this study were willing to allocate enough time (<5 minutes) to conduct the TUG, L-Test, 10MWT, and 2MWT. However, three participants (one prosthetist, one therapist, and one physiatrist) did not have enough time (<10 minutes) to administer the 6MWT and eight participants (two prosthetists, one physical therapist, and five physiatrists) did not have enough time to administer the AMP or CHAMP (both <15 minutes).^{25, 26} Note that the time required to complete each measure (noted in Table 3) was reported by the test developers, and often reflects the minimum or optimal time required for measure administration due to the developers’ relative familiarity with the test. For example, the time required to conduct the AMP was reported as less than 15 minutes in the development paper,²⁵ but when prosthetists were asked how long the measure took them in daily practice, they reported a higher average administration time (19.5 minutes¹⁷). Increased time requirements for these tests may mean that even fewer participants would be able to allocate sufficient time for standardized assessments in their typical clinical practice.

Overall, most or all clinicians reported to having the space, equipment, and time resources available to conduct the TUG, L-Test, and 10mWT, tests of basic mobility. While these tests provide similar information about mobility, the L-Test is thought to better assess people with unilateral amputation as this test incorporates turns toward both the affected and non-affected sides.²³ Few have the resources available to conduct the CHAMP, a test of high-level mobility.²⁶ This result suggests that most rehabilitation clinics are currently able to accommodate assessment of basic prosthetic mobility, but these environments may be less optimal for measurement of people with lower-limb amputation at higher levels of mobility.

Of the rehabilitation medicine professionals interviewed, physical therapists most often had the space and equipment resources required to conduct both low- and high-level mobility assessments in their clinical environments. Physical therapists and prosthetists were most likely to have time for outcomes measurement. In contrast, physiatrists were generally limited in the time they could spend conducting performance-based outcomes assessment, likely due to the breadth of their scope of practice and short appointment times. This finding suggests that rehabilitation teams could streamline outcomes measurement of people with lower-limb amputation by having physical therapists and/or prosthetists conduct mobility assessments, given that they are most suited to assess outcomes for people with lower-limb amputation based on the time, space, and equipment available to them. Physical therapists may have the best opportunity to conduct performance-based tests in the early phases of rehabilitation, when clinical appointments are more frequent. However, prosthetists may be better positioned to administer performance-based tests in the long-term, given the lifelong relationship and routine follow-up that is typical between patients with amputation and their prosthetist. Other potential solutions include having a physical therapist and/or prosthetist present alongside a physiatrist in an amputation clinic to conduct assessments during routine follow-up appointments. Any of these approaches to interdisciplinary assessment would require established processes and good communication between team members, potentially facilitated by improved electronic medical record systems.³⁰ It is important to note that prosthetists are reimbursed for items (e.g., prosthetic components) they provide and cannot be specifically reimbursed for time spent in outcomes assessment, which may challenge their ability to allocate time for this activity during clinical appointments.

The majority of clinicians in this study used performance-based tests to document outcomes over time, assess functional level, and/or justify clinical services to payers. When clinicians were asked about the clinical value of individual performance-based tasks or tests, respondents differed on which ones they believed contributed to their understanding of a patient’s mobility. Clinicians may have reported inconsistent opinions about the value of particular tasks and tests because of their education and training, activity levels of their patient populations, or clinical settings in which they worked. For a clinic that treats mostly patients with low levels of mobility, tasks such as seated balance, straight-line walking, and use of an assistive device may be indicative of overall mobility, whereas those same tasks would not be informative to clinicians who treat patients with the potential for high-level mobility. This finding supports the idea of developing flexible or adaptive tests that can measure a wide range of people with lower-limb amputation.

Limitations and future directions

While results of this study can inform our understanding of the resources available to rehabilitation clinicians, generalization of these results is limited by the small sample and sampling strategy. For example, prosthetists included in this study may be considered as generalists in their field given that most prosthetists regularly treat people with lower-limb amputation. In contrast, the physiatrists and the physical therapists in the study specialize in the treatment of a small population (i.e., people with lower-limb amputation) in comparison to the general population of their potential clientele. Further, because participants were identified using a convenience sample, there is the potential for sampling bias.

Results of this study may also be affected by response bias. Investigators involved in this study were clinically trained in the rehabilitation of people with lower-limb amputation and/or experienced in the development of performance-based clinical tests. Given that participants may have been familiar with the investigators, they may have reported elevated amounts of time spent in measurement or reported administering performance-based tests more often than they routinely do because use of outcome measures is expected of those in their profession. Similarly, the availability of space and time resources was likely based on optimal conditions and may not reflect the realities of outcome measure assessment in most clinics. For example, corridors in busy clinics may be occupied by employees or other patients and may not be available for conducting walking tests, like the L-Test or 6MWT. Gyms may contain stationary exercise equipment or other large items that cannot be easily moved for performance-based tests with large footprints, such as the CHAMP. Development of a confidential survey based on results of this study and administration of the survey to a large representative sample of professionals may be needed to assess whether the resources available to clinicians included in this study are available to most clinicians who treat patients with lower-limb amputation. The target sample size of such a study would be calculated based on the number of total individuals in each profession, the sampling confidence level (95%), and the acceptable margin of error for the survey (5%).³¹

CONCLUSIONS

This study used interviews to ask prosthetists, therapists, and physiatrists about the space, equipment, and time resources available for standardized performance-based mobility assessment in their respective clinical environments. A majority of clinicians had small-to-moderate spaces, basic measurement equipment, and sufficient training to administer mobility tests in their clinics. Clinicians across disciplines reported limited available time for standardized assessment during patient appointments. This limitation can be addressed through selection of efficient measures and collaboration within the rehabilitation team.

Supplementary Material

Supplement 1

Supplement 1. Interview guide.

Supplement 2

Supplement 2. Participant questionnaire to describe sample characteristics.