Measuring residual limb health in persons with upper limb amputation: Modifications of the Prosthetic Evaluation Questionnaire residual limb health scale.

BACKGROUND

Assessing the user perspective on residual limb health problems is particularly important for amputation care, given the relationship between residual limb health and prosthetic satisfaction. Only 1 measure, the Residual Limb Health scale of the Prosthetic Evaluation Questionnaire (PEQ) has been validated for use in lower limb amputation, but not examined in persons with upper limb amputation (ULA).

OBJECTIVES

The objective of this study was to examine the psychometric properties of a modified PEQ Residual Limb Health scale in a sample of persons with ULA.

STUDY DESIGN

The study involved a telephone survey of 392 prosthesis users with ULA, with a 40-person retest sample.

METHODS

The PEQ item response scale was modified to a Likert scale. The item set and instructions were refined in cognitive and pilot testing. Descriptive analyses characterized the prevalence of residual limb issues. Factor analyses and Rasch analyses evaluated unidimensionality, monotonicity, item fit, differential item functioning, and reliability. Test-retest reliability was assessed by an intraclass correlation coefficient.

RESULTS

Sweating and prosthesis odor were prevalent at 90.7% and 72.5%, respectively; blisters/sores (12.1%) and ingrown hairs (7.7%) were the least prevalent problems. Response categories were dichotomized for 3 items and trichotomized for 3 items to improve monotonicity. After adjusting for residual correlations, confirmatory factor analyses showed acceptable fit (comparative fit index = 0.984, Tucker-Lewis index = 0.970, and root mean square error approximation = 0.032). Person reliability was 0.65. No items had moderate-to-severe differential item functioning by age or sex. Intraclass correlation coefficient for test-retest reliability was 0.87 (95% CI, 0.76-0.93).

CONCLUSIONS

The modified scale had excellent structural validity, fair person reliability, very good test-retest reliability, and no floor or ceiling effects. The scale is recommended for use with persons with wrist disarticulation, transradial amputation, elbow disarticulation, and above-elbow amputation.