ASSESSMENT OF SELECT KINEMATIC AND KINETIC GAIT OUTCOMES ACROSS THREE STANDARD SINGLE-EVENT MULTILEVEL SURGERY GROUPS

Abstract

Single-event multilevel surgery (SEMLS) is commonly performed in ambulatory children with cerebral palsy (CP) to address musculoskeletal deformities contributing to pathological gait. Although instrumented gait analysis (IGA) is widely used to evaluate postoperative outcomes, uncertainty remains regarding the sensitivity, specificity, and clinical interpretability of commonly reported gait metrics across heterogeneous surgical protocols and patient presentations. The objective of this dissertation was to explore the behavior of kinematic, spatiotemporal, kinetic, and frontal-plane knee loading outcomes following three standardized SEMLS protocols and to evaluate how these outcomes respond to surgical context, developmental factors, and postoperative recovery.Retrospective gait data were analyzed from ambulatory children with CP undergoing bilateral soft-tissue lengthening (TDR-B), bilateral femoral derotational osteotomy with soft-tissue procedures (TDFR-B), or unilateral femoral derotational; osteotomy with soft-tissue procedures (TDFR-U). Linear modeling frameworks were used to examine associations between gait outcomes and predictors including time post-surgery, surgical group, normalized walking speed, age, and anthropometry, as well as within-group pre–post changes and between-group differences. Effect sizes were emphasized alongside statistical significance to characterize outcome sensitivity. Results demonstrated marked outcome-specific and SEMLS-context-dependent patterns of postoperative change. Global kinematic indices, spatiotemporal asymmetry measures, joint kinetic and energetic outcomes, and knee adduction moment (KAM)-based metrics captured distinct and sometimes dissociated aspects of postoperative adaptation and were not interchangeable. For example, improvements in global gait pathology were not consistently accompanied by parallel changes in joint kinetic or energetic measures, indicating dissociation between overall gait appearance and underlying mechanical demand. Temporal asymmetry differentiated hemiplegic and diplegic involvement patterns more consistently than spatial asymmetry, highlighting domain-specific sensitivity to clinical presentation. Developmental and speed-related associations varied by outcome and surgical protocol, indicating construct-specific behavior rather than uniform maturation effects. Modest reductions in frontal-plane knee loading metrics were observed following SEMLS with differential patterns across protocols and between peak and impulse-based measures. Furthermore, changes in KAM metrics did not consistently correspond to changes in sagittal-plane kinematics commonly referenced as influential for knee loading, underscoring the complementary information captured by these outcomes when considering implications for long-term joint health. Collectively, these findings support a validation-oriented interpretation of postoperative gait outcomes, emphasizing sensitivity to biomechanical constructs and clinical context rather than uniform responsiveness or direct inference of treatment efficacy. The observed heterogeneity underscores the need for structured, interdisciplinary, and condition-specific consensus approaches to outcome selection in SEMLS research. SEMLS should be viewed as an enabling intervention within a prolonged recovery process, with gait outcomes reflecting interactions among surgical correction, rehabilitation, neuromuscular adaptation, and individual patient characteristics. Future work should prioritize longitudinal designs, consensus-driven outcome frameworks, and integration of biomechanical measures with functional and patient-centered assessments to improve clinical interpretability.