Prosthetic Fit Assessment in Transtibial Amputees Secondary to Trauma

Specific Aim 1: To test the reliability of the ProFit.

Patients enrolled in the TAOS trial returning for their eighteen month final visit will
undergo radiographic, video, and photographic assessment. A blinded prosthetist panel (PP)
will view these remotely and complete a 42 item assessment based on x-ray, photo and video.
We will examine two aspects of reliability for the ProFit, inter-rater reliability and
internal consistency.

Specific Aim 2: To examine the validity and responsiveness of the ProFit.

This study aims to examine the validity of the ProFit by specifically evaluating factor
validity, construct validity and discriminant validity. This will be accomplished by
correlating ProFit scores with measures of self-reported pain (Brief Pain Inventory),
function (Short Musculoskeletal Functional Assessment), and satisfaction (Orthotics and
Prosthetics User's Survey). Moreover, a subset of subjects will undergo quantitative
measurement of fit and alignment using a novel prosthesis-mounted socket reaction moment
sensor. Responsiveness of the ProFit will be based on repeated measurements at 6 and 18
months.

Specific Aim 3: To develop a shorter version of the ProFit.

Based on findings from Aim 1 and 2 at the individual item level, we will remove items that:
1) have poor inter-rater agreement; 2) demonstrate weak relationships with clinician and
patient report of overall fit; or 3) exhibit strong ceiling or floor effects.

Study design: The ProFit study is a prospective validation study of an assessment of
prosthetic fit and alignment among patients with a transtibial amputation.

Study duration: 3 years Sample size: 120 TAOS patients will provide adequate power to detect
important differences in fit and alignment 18 months following amputation. A subset of 60
patients is necessary to detect significant differences in alignment using the Smart Pyramid.

Number of study sites: Up to 35 centers including 24 Core METRC sites, 4 MTFs, and 7 METRC
satellite sites.

Study population: Patients enrolled in the METRC TAOS study.

Outcome measure: This ancillary project to the TAOS trial is designed to study the validity
reliability and validity of the ProFit, a 42-item tool for assessing prosthetic fit and
alignment among patients with a transtibial amputation.

Statistical analysis: Inter-rater reliability and internal consistency will be examined to
test the reliability of the ProFit. The validity of this assessment will be evaluated using a
variety of construct validity tests. Based on findings from the reliability and validity
analysis, a shorter version of the ProFit will be developed. The performance of the shorter
version will be determined based on correlation with the original assessment.

Randomization: Not applicable

Safety monitoring: Not applicable

Inclusion Criteria:

- Must be enrolled in the TAOS study

Exclusion Criteria:

- Patients weighing <300 lbs.

- Patient requires an LAR

- Women who are breastfeeding or pregnant