Response to: Comments regarding: Mobility Analysis of AmpuTees (MAAT I): quality of life and satisfaction are strongly related to mobility for patients with a lower limb prosthesis by Wurdeman et al.

Dear Editor

Thank you for providing the opportunity to respond to the comments directed at our recently published manuscript, ‘Mobility Analysis of AmpuTees (MAAT I): Quality of life and satisfaction are strongly related to mobility for patients with a lower limb prosthesis’.

We appreciate the comments regarding the advancement of outcomes collection and reporting in lower limb prosthetics as this represents a shift in common practice within care facilities that provide lower limb prostheses. In order to fully address the question posed at the end of the letter which starts, ‘as long as the patient is present’, it is imperative to keep in mind this shift in common practice. Implementation of routine outcomes collection within care facilities is not as simple as a mandate that can be passed down. There are multiple barriers to implementation which have been previously identified.^1,2 These barriers fall within the domains of clinician and administration running the clinics, but also includes the patient. Specifically, perceived value is a barrier to both clinician and patient, where value can be represented as reward or results divided by effort or cost. These can be either real or perceived. And, while the burden of time to administer physical performance tests such as sit-to-stand and stair climb test, is debatable, these tests increase the effort for the patient and the clinician. Thus, the increased effort decreases the perceived value, which increases this barrier unless such effort is offset with increased reward or results, both to the patient and the clinician. Unfortunately, the perceived rewards to the patients and clinicians are lacking. However, we believe that the continued efforts of the scientific community to highlight the rewards of doing physical performance measures are growing. This will be beneficial in future efforts to implement routine physical performance measures in prosthetics rehabilitation care facilities. As such we would argue the mere presence of a patient in the clinic, which is markedly different from a research subject in a laboratory, does not always represent an ‘opportunity’ to collect physical performance measures.

We should not confuse or diminish the value of self-report measures of mobility such as the Prosthetic Limb Users Survey of Mobility (PLUS-M). The reference to ‘better applicability’ within the letter denotes a higher level of importance on what the authors have noted as physical capacity or activity performance monitors. Notably, the labelling of questionnaires, physical tests and activity monitors as perception, capacity and performance, respectively, is uncertain and is not drawn from the referenced study. Physical performance measures and self-report measures quantify different constructs, the value of one construct over another should not be assumed. It seems somewhat paradoxical to suggest increased value of physical performance measures over self-report measures in the same letter that refers to the use of goal attainment scaling (GAS) as having identified mobility as a primary concern.

When a self-report instrument is used to identify the most valuable domain within rehabilitation, it would seem appropriate to place at least equal value on the results of a self-report instrument used to measure that domain. Furthermore, Kayes and McPherson ³ elegantly outline that the nature of physical performance measures has wrongly led to the misguided belief that such measures are superior when in reality they face as many and sometimes more limitations. One such limitation aligns with comments from Bussman and Stam ⁴ noting the various levels of outcome measures, remarking that physical performance measures may have weak relationships with complex activity and role fulfilment, both of which can however be explored through self-report questionnaires such as PLUS-M.

Thus, while we agree that there is likely a wealth of information yet to be explored from the additional collection of physical performance measures or perhaps activity monitors, this should not take away from the value of the findings of this study or any study investigating mobility captured via self-report instruments. The commenters surmise the findings to be ‘unsurprising’. Respectfully, although rehabilitation professionals are historically trained to place emphasis on the restoration of mobility following lower limb amputation, changes in healthcare dynamics are placing increased emphasis on the limb loss patient’s quality of life and general satisfaction. Unfortunately, the relationship between these constructs and mobility in the patient with lower limb loss has attracted little scholarly attention.