Effectiveness and Cost-effectiveness of Lower Limb Prostheses

The SQUASH is a questionnaire to measure physical activity [29]. The list is based on the Dutch Standard for Healthy Exercise [30]. This questionnaire contains 11 items to be completed by the participant. The SQUASH measures the frequency, duration and intensity of four different physical activities, namely: physical activity to and from work; household activities; activities at work; and physical activities performed in leisure time. The higher the score, the more time is spent on physical activities.

The Timed Up \& Go test (TUG) measures the time it takes the participant to get up from a chair, walk 3 meters comfortably, turn around, walk back and sit down. Participants are allowed to use their walking aids, but no physical assistance or encouragement should be given.

The Activities-Specific Balance Confidence (ABC) Scale is a questionnaire consisting of 16 items. For each item/activity, the patient should indicate how much confidence he/she has in not falling or losing balance when performing them. Each question is scored from 0% to 100% confidence. The activities described take place both indoors and outdoors and are diverse. A high score corresponds to a lot of confidence to perform the activity.

To get insight in the costs, two existing questionnaires were combined: the Productivity Cost Questionnaire (iPCQ) and the Medical Consumption Questionnaire (iMCQ).

The iMCQ is used to measure medical consumption. It includes questions related to the number of appointments with health care providers. The iPCQ measures and values productivity losses. It looks at absenteeism, presenteeism, productivity losses and unpaid work. As this study focussed on costs related to lower limb prostheses, questions about appointments with a dietician and speech therapist, and trips to the emergency room were replaced with questions about the type of prosthesis and the number of appointments with their prosthetist. Finally, questions about personal costs related to the acquisition and repairs of the prosthesis, as well as personal expenses were added.

The PEQ is a reliable and valid self-report questionnaire to evaluate prosthesis and prosthesis-related quality of life. Questions are divided into nine subscales (ambulation, perceived response, sounds, appearance, residual limb health, utility, frustration, social burden and well-being) and several separate questions related to pain, satisfaction, transfers, prosthetic care, self-efficacy and importance. Most questions are scored on a visual analogue scale (VAS) from 0-100. Some questions about the frequency of certain problems (e.g. pain in residual limb or back) are multiple choice. A higher score on this questionnaire is linked to a more positive outcome.

This questionnaire is used to rate objective and subjective participation. It is composed of 31 items, divided over three scales: 1) frequency: 1a. how much time the participant spends on work, study and household per week, rated on a scale from 0 (not at all) up to 5 (36 hours or more) and 1b. how often the participant partakes in certain activities per week, scored from 0 (not at all) up to 5 (19 times or more); 2) restrictions: whether the participant experiences limitations in daily life and whether they could do certain activities with or without help, scored from 0 (not possible at all) to 3 (independent without difficulty); and 3) satisfaction: how satisfied the participant is with different aspects of daily life, scored on a range from 0 (very dissatisfied) to 4 (very satisfied).

The Active 8 professional activity monitor was used to register walking during one full week. The activity monitor was placed by the physical therapist on the thigh of the non-affected side of the participant. During the week, the participant was asked to fill out a short diary with the time they got up and went to bed; whether they had worn the monitor for the full 24 hours; whether they had done any physical activity that wasn't in their usual day-to-day routine; and if so during what time that activity was performed.