Instrumented Assessment of Gait in Pediatric Cancer Survivors: Identifying Functional Impairments After Oncological Treatment—A Pilot Study

<b>Background/Objectives</b>: Pediatric cancer survivors frequently experience neuromuscular sequelae related to chemotherapy-induced neurotoxicity. Agents such as vincristine, methotrexate, and platinum compounds can lead to persistent gait alterations and sensorimotor deficits that impair mobility and quality of life. This study aimed to objectively assess gait in pediatric cancer survivors after the completion of oncological pharmacological treatment to identify specific spatiotemporal, kinematic, and kinetic alterations and characterize neuromechanical patterns associated with neurotoxic exposure. <b>Methods</b>: A cross-sectional observational study was conducted including pediatric cancer survivors (6-18 years) who had completed chemotherapy and age- and sex-matched healthy controls. Gait was analyzed using a Vicon^®3D motion capture system, with reflective markers placed on standardized anatomical landmarks. Spatiotemporal, kinematic, and kinetic variables were compared between groups using parametric tests and statistical parametric mapping (SPM) with Holm-Bonferroni correction (α = 0.05). <b>Results</b>: Pediatric cancer survivors showed slower gait velocity (Mean Difference (MD) = 0.17, <i>p</i> = 0.018, Confidence Interval CI95% = 0.04; 0.4), shorter step (MD = 0.1, <i>p</i> = 0.015, CI95% = 0.01; 0.19) and stride length (MD = 0.17, <i>p</i> = 0.018, CI95% = 0.03; 0.31), as well as reduced single support time (MD = 0.1, <i>p</i> = 0.043, CI95% = 0.01; 0.19), along with significant alterations in pelvic, hip, knee, and ankle kinematics compared with controls. Increased pelvic elevation (MD = 0.92, <i>p</i> = 0.018, CI95% = 0.25; 1.58), reduced hip extension during stance (MD = -2.99, <i>p</i> = 0.039, CI95% = -5.19; -0.74), knee hyperextension in mid-stance (MD = -3.84, <i>p</i> < 0.001, CI95% = -6.18; -0.72), and limited ankle dorsiflexion (MAS MD = -4.04, <i>p</i> < 0.001, CI95% = -6.79; -0.86, LAS MD = -3.16, <i>p</i> < 0.001) and plantarflexor moments in terminal stance (MAS MD = -149.65, <i>p</i> = 0.018, CI95% = -259.35; -48.25, LAS MD = -191.81, <i>p</i> = 0.008, CI95% = -323.81; -57.31) were observed. Ground reaction force peaks during loading response (MAS MD = -16.86, <i>p</i> < 0.001, CI95% = -26.12; -0.72 LAS MD = -11.74, <i>p</i> = 0.001, CI95% = -19.68; -3.94) and foot-off (MAS MD = 10.38, <i>p</i> = 0.015, CI95% = 0.41; 20.53, LAS MD = 11.88, <i>p</i> = 0.01, CI95% = 3.15; 22.38) were also reduced. <b>Conclusions</b>: Children who have completed chemotherapy present measurable gait deviations reflecting persistent neuromechanical impairment, likely linked to chemotherapy-induced neurotoxicity and deconditioning. Instrumented gait analysis allows early detection of these alterations and may support the design of targeted rehabilitation strategies to optimize functional recovery and long-term quality of life in pediatric cancer survivors.