Lower Limb Differences are a group of heterogeneous conditions where one lower limb differs in shape, length, or position from the other. These differences present as a spectrum of disorders that may include leg length difference, complete or partial absence of one or more segments of the lower limb or angular or rotational deformities. Lower Limb Differences can arise from a spectrum of disorders, which can be either congenital (e.g. fibular hemimelia, tibial hemimelia, congenital femoral deficiency, Genu valgum, Genu varus) or acquired from conditions such as trauma, infections, tumors, and Perthes disease, Blount’s disease, and rickets. There is currently no rigorously developed and internationally applicable PROM for children with lower limb differences. The development of the LIMB-Q Kids has the following three aims:
- To identify concepts for LIMB-Q Kids in an international qualitative study
- To establish content validity for the LIMB-Q Kids through cognitive debriefing interviews with children and obtaining expert opinion
- To finalize the scales and determine psychometric properties of the LIMB-Q Kids via an international field-test study
To develop LIMB-Q Kids, our team followed a mixed-method, multiphase approach based on international guidelines for PROM development. Briefly, in phase 1, using qualitative methods, a conceptual framework to be measured was defined, and an exhaustive pool of items was generated. This item pool was developed into scales, which were shown to patients and experts to establish content validity (i.e., the content is relevant, comprehensive, and comprehensible to patients). Our team received funding from the department of orthopedics at the University of British Columbia and the Canadian Orthopedic Foundation for phase 1 of the development of LIMB-Q Kids.
At this time, LIMB-Q Kids is being field-tested in a large international sample of children from 22 orthopedic clinics across 11 countries. Using the data from the field test, the questions that represent the best indicators of outcome will be retained based on their performance against a set of psychometric criteria using Rasch analysis (a modern psychometric approach). Additionally, translation and cultural adaptation are underway for Arabic, Danish, Finnish, Hindi, Luganda and Swahili versions with German translation completed already.
LIMB-Q KIDS FRAMEWORK