Development of a core outcome set for lower limb orthopaedic surgical interventions in ambulant children and young people with cerebral palsy
Keywords: lower limb
surgery
outcome measures
core outcome set
cerebral palsy

Background: The literature on lower limb orthopaedic surgery for ambulant children with cerebral palsy (CP) demonstrates significantly heterogenous outcomes and outcome measures and evidence of selective outcome reporting. This limits evidence synthesis and undermines research findings through outcome reporting bias. Although several outcomes are commonly measured and reported, these do not always capture the needs and expectations of children and families.
Purpose: The aims of this project were to (1) develop a minimum set of important and relevant outcomes, a “Core Outcome Set” for use in future clinical studies evaluating lower limb orthopaedic surgery for ambulant children with CP, and (2) develop a recommendation of optimal outcome measures, a “Core Outcome Measurement Set”, to assess each outcome within the core outcome set.
Methods: The project was designed in four parts. (1) potential outcomes were identified through systematic reviews; (2) interviews with stakeholders (healthcare professionals, researchers, children and families) were undertaken; (3) an international two-round e-Delphi consensus survey was used to gain agreement between stakeholders as to which outcomes were “core”; (4) outcomes selected through the Delphi process were brought forward to a consensus meeting to agree on the final core outcome set. Target stakeholders from relevant national and international networks were approached to contribute to this selection.
The selection of core outcome measurement instruments was designed in four parts. (1) conceptual considerations; (2) identification of existing outcome measures; (3) quality assessment; and (4) development of generic recommendations on the selection of outcome measurement instruments for a COS.
Results: The literature review and stakeholder interviews initially identified 99 outcome domains. These were grouped into 41 outcomes for prioritisation in the Delphi survey. A total of 197 participants from 13 countries were surveyed. The findings were brought forward to the consensus meetings with 21 international stakeholders. Consensus was achieved on eight outcome domains: (1) pain and fatigue; (2) lower limb structure; (3) motor function; (4) daily life activities; (5) gait-related outcomes; (6) physical activity; (7) independence; and (8) quality of life. An adverse event domain was agreed as an essential part of any study documentation.
The outcome measures recommended by the consensus group were a combination of clinician-driven objective measures: (1) Three-Dimensional Gait Analysis (3-DGA); (2) Edinburgh Visual Gait Score (EVGS); (3) 10-Meter Walk Test (10-MWT); and (4) Gross Motor Functional Measure (GMFM-66), and patient-reported outcome measures (PROMs): (5) Gait Outcomes Assessment List (GOAL); (6) Gillette Functional Assessment Questionnaire (Gillette FAQ); (7) Patient-Reported Outcomes Instruments System (PROMIS); and (8) Cerebral Palsy - Quality of Life (CP- QoL).
Conclusions: This project has developed an evidence-based, internationally endorsed core outcome set for lower limb orthopaedic surgery in ambulant children with CP. It is recommended that these core sets be implemented into future clinical studies. The use of these core sets would enhance the consistency and quality of studies in orthopaedic surgery for children with CP.