A Guide to Trials for Prosthetic Component Selection

STEPS Prosthetics offers cutting-edge products sourced from the world’s leading manufacturers. As the largest independent clinical provider of prosthetics in the UK, we are completely independent from prosthetic product manufacturers and can supply the full spectrum of products that are available in the market.

When it comes to selecting the most appropriate prosthetic component for amputee clients, there are often several products that might be suitable. To help decide on the optimal prescription, it can be beneficial to conduct a trial to assess which product best meets the client’s individual needs. STEPS Prosthetics clinician’s follow a consistent approach when trialling products, to give each product a fair trial and to provide an objective comparison using subjective feedback from the client, outcome measures and photographic and video evidence.

In this article, we’ll outline the trial process at STEPS Prosthetics which enables us to select the most suitable products tailored to each client’s individual needs to optimise their mobility and independence. Of course, personal preference plays a major role, but other factors need to be considered in an objective way.

Component Selection

Typically, trials are required to differentiate between the more expensive, advanced prosthetic components such as microprocessor-controlled feet (MPFs), microprocessor-controlled knees (MPKs), powered feet and knees, and powered upper limb components including pattern recognition control systems and multi-grip hands.

There are many factors to consider when selecting which components to trial including the available space distal to the residual limb to fit in the available products, the client’s weight, their lifestyle including employment, hobbies, and activities they enjoy, and their need for the components to be weatherproof or fully waterproof.

Our clinicians take time to get to know each of our clients to truly understand their goals to ensure that each product selected to be trialled is well matched to their needs.

Methodology

For established amputees, we begin by recording baseline outcome measures with the client’s current prosthesis. This helps to set the scene by establishing their current level of mobility, subjective feedback, restrictions to their mobility or gait deviations that may present.

We ensure they have a well-fitting, comfortable socket that can be used for the duration of the trial process to avoid any socket fitting issues during the trial and to minimise variation for each product trialled. The order in which the products are trialled is randomised, usually dictated by availability of products from each manufacturer. We ensure each product is trialled for a consistent time frame, usually 2-weeks for micro-processor feet, and around 4-weeks or longer for microprocessor and powered knees and for powered upper limb components due to the additional complexity and need for additional training.

At the end of each product trial, outcome measures are recorded to be included in a final report once all the products have been trialled, along with photo and video evidence.

Outcome Measures

There are a number of validated outcome measures available that can be used in amputee rehabilitation, we have found that the following outcome measures and PROMS (patient reported outcome measures) provide a good overview of how well the patient performs with each product, comparing the results between components and against evidenced literature to help inform definitive prescription recommendations.

Lower Limb Outcome Measures

• L-Test: The L-Test is a modified version of the Timed Up and Go (TUG) incorporating 4 turns, of which at least 1 would be to the opposite side. The total distance covered is 20-metres. The patient is timed to stand from sitting, walk 5 metres, turn 90^o, walk a further 5 metres, turn 180^o and then return to a seated position.
• 2 Minute Walk Test (2MWT): A 2-minute walking test where the patient walks as far as possible on a 10-metre course over 2 minutes with the distance walked recorded.
• 6 Minute Walk Test (6MWT): A continuation of the 2MWT where the patient walks over the same 10 metre course for 6 minutes and the distance walked is recorded. The 6MWT has been seen to be responsive to change in lower limb amputees.
• 4-Square Step Test: A test of the patients’ ability to step forward, sideways (left and right) and backwards in a square pattern. Modified T-Test: The T-Test is a test of the patients’ ability to walk forwards, side-step left and right and walk backwards over a set distance as quickly as possible.

Upper Limb Outcome Measures

• Box and Block Test (BBT): The BBT is used to assess and monitor unilateral upper extremity manual dexterity. It has been found to be a valid and reliable outcome measure in a variety of populations including traumatic upper limb amputation. Clients are asked to transfer as many 1” cubes as possible of from one side of a box, over a wooden partition, to the other side, one at a time in 60 seconds.
• Assessment of Capacity for Myoelectric Control (ACMC): The ACMC is an observational assessment developed to assess the ability of a prosthesis user to control a myoelectric prosthetic hand. Each item in the ACMC is an observable prosthetic hand movement, such as timing during grasping, or an observable prosthetic hand movement in relation to other body parts, such as using the prosthesis over the shoulder. The ACMC assesses how skilful a prosthesis hand user performs different prosthetic hand movements when performing a bimanual activity and therefore an ACMC assessment is often carried out during the client’s performance of an everyday activity.
• Timed Tasks: Five tasks are performed with each task performed twice and the average time reported.
  • Stacking 3 large beakers and 1 small beaker in a pyramid,
  • Opening a small bottle and a square jar,
  • Folding a towel,
  • Bag pack – unzipping and packing a bag with items, rezipping the bag, carrying it to the door and opening the door,
  • Chopping food.

Patient Reported Outcome Measures

• Plus-M: A self-reported measure of how challenging patients find set activities gradually increasing in difficulty. PLUS-M™ questions assess respondents’ perceived ability to carry out actions that require use of both lower limbs, ranging from household ambulation to outdoor recreational activities. It is important to note that PLUS-M™ questions assess respondents’ reported abilityto perform activities rather than individuals’ actual performance of that activity. A higher Plus-M T-score corresponds to greater mobility. It can therefore be used to assess differences in how patients perceive they can complete activities with different prosthetic componentry.
• The Trinity Amputation and Prosthesis Experiences Scales (TAPES): This aims to measure both physical and psychosocial aspects of adjustment to a prosthetic limb, specific demands of wearing a prosthesis and potential sources of maladjustment. The scale is split into 6 subscales: general adjustment, social adjustment, adjustment to limitations, activity restriction, aesthetic satisfaction, and functional satisfaction. There is also an overall satisfaction rating out of 10. Quick DASH (DASH): This is a shortened version of the DASH outcome measure. It is a self-reported questionnaire and uses 11 items to measure physical function and symptoms in people with any musculoskeletal disorders of the upper limb. The questionnaire was designed to help describe the disability experienced by people with upper limb disorders and to monitor changes in symptoms and function over time. It is therefore well suited to assessing differences between different prosthetic hands. It is scored out of 100 with a higher score indicating greater disability, therefore a lower score indicating better function.

 

Photograph and video evidence

Finally, we record photograph and video evidence, showing the client walking for lower limb amputees including steps and slopes, and in performing different activities for upper limb amputees including opening a range of jars, stacking cups, folding a towel, and packing a bag. Video evidence can help to demonstrate visually whether any gait deviations or compensatory movements can be observed whilst walking, improvements in gait pattern and progression of walking aids and patient’s ability when performing different tasks.

Final Report

Once all these products have been trialled, a final report will be prepared, detailing the trial findings, outcome measures and subjective feedback and making recommendations for definitive prescription for the product(s) that best suit each client’s needs.

If you’d like to find out more about trialling different prosthetic components, please contact us:

Email: clinic@stepsprosthetics.com
Tel: 0114 4000 232

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