Cerebral palsy (CP) is a neurological condition impacting gait and motor function in children. Gait deviations, often including toe-in walking and crouched gait, result from lower extremity muscle spasticity, leading to balance issues and falls. In CP, spasticity and muscle weakness cause ankle and foot dysfunction, resulting in foot deformities and gait disorders. Diplegic gait, characterized by slow speed and lower extremity muscle weakness and spasticity, is a common manifestation. Dynamic equinus, due to plantar flexor muscle spasticity, is a frequent deformity. Ankle-foot orthoses (AFOs), including rigid AFOs and dynamic AFOs like DAFO, are used to manage these issues. Rigid AFOs provide passive control, while DAFOs offer a more flexible approach, supporting the foot arches and subtalar joint while allowing limited movement. DAFOs aim to reduce abnormal muscle activity, improve biomechanical changes, and enhance proprioceptive feedback for improved posture and balance. Previous research has shown that AFOs positively impact gait kinematics and kinetics, improving stride length, speed, and range of motion while reducing energy expenditure. However, few studies have investigated the effects of DAFOs on plantar pressure distribution. This study aimed to evaluate the effects of DAFOs on plantar pressure distribution during gait in children with spastic CP to understand how it affects weight distribution and potentially improves gait patterns.

The literature extensively documents the impact of AFOs on gait in children with CP, reporting improvements in stride length, walking speed, ankle range of motion, and knee extension. Studies using various AFO types (rigid, hinged, dynamic) show positive effects on gait parameters, although the specific effects vary depending on the AFO design and the child's specific condition. Some research highlights the benefits of DAFOs in improving gross motor skills and reducing energy expenditure. However, the literature lacks detailed analysis of plantar pressure distribution under DAFO use in children with CP. Existing studies primarily focus on gait analysis, neglecting the crucial aspect of plantar pressure patterns. This gap highlights the need to explore the impact of DAFOs on foot loading and its potential correlation with improved gait efficiency.

This study involved eight children (aged 4–12 years) with spastic diplegic CP, classified as GMFCS levels I–II (Gross Motor Function Classification System) and with a maximum ankle spasticity score of 3 on the Modified Ashworth Scale. Participants had no surgical intervention in the past year or botulinum toxin injections in the past six months. DAFOs were custom-made by the same experienced prosthetist based on individual assessments of range of motion, muscle tone, and barefoot gait. Two children received DAFO4, and six received DAFO3. The same shoes were worn in both conditions (with and without DAFOs). Plantar pressure distribution was measured using eight WalkinSense sensors embedded in socks. Data were collected during dynamic walking under two conditions: with shoes only and with DAFO and shoes. Sensor placement included areas under the 1st metatarsal, 5th metatarsal, lateral midfoot, lateral heel, and medial heel. The order of trials was counterbalanced. Data analysis focused on the mid-stance phase. The Wilcoxon signed-ranks test was used to compare pressure values between conditions within each participant, due to the small sample size preventing homogeneity.

The study included eight children with mild cerebral palsy (mean age 9 ± 3.3 years; mean weight 31 ± 10.2 kg; mean height 126.5 ± 19.2 cm). All participants had a dominant right leg and had received physical therapy. The key finding was a significant difference in activation percentages for sensors 1 (under the 1st metatarsal) and 4 (under the lateral heel) between the DAFO and no-DAFO conditions. Sensor 1 activation percentage significantly decreased with DAFO use, while sensor 4 activation percentage significantly increased. This indicates a shift in weight distribution from the forefoot (specifically, the 1st metatarsal) to the lateral heel during the stance phase when wearing the DAFO. The pressure distribution without DAFO showed higher activation percentages for sensors 1, 2, and 3, indicating more weight bearing on the forefoot and medial-lateral longitudinal aspects of the foot. With DAFO, the weight transfer to the lateral part of the foot increased, with the maximum pressure point shifting two to three times. These findings suggest that DAFO usage alters plantar pressure distribution in children with CP.

The results demonstrate that DAFO use alters plantar pressure distribution in children with mild CP, specifically increasing pressure on the lateral heel during stance. This finding aligns with the DAFO's design, which aims to improve weight distribution and provide better support. The shift in pressure distribution might be beneficial in reducing pressure on the forefoot, potentially mitigating the effects of equinus gait and improving gait efficiency. The improvement in gait cycle and foot motion observed is consistent with findings from studies demonstrating positive effects of AFOs on gait parameters. The observed changes in plantar pressure distribution further validate the biomechanical influence of DAFOs on gait in children with CP. The results support the clinical application of plantar pressure measurement as a practical and useful tool for assessing gait abnormalities and rehabilitation outcomes in this population.

This study demonstrates that DAFOs influence plantar pressure distribution in children with mild CP, shifting weight bearing towards the lateral heel. This change in pressure distribution suggests a potential mechanism for the observed improvements in gait cycle and foot motion. The findings support the clinical use of DAFOs for managing gait abnormalities in children with CP. Future research should examine larger sample sizes, different types of DAFOs, and long-term effects to strengthen these findings. Comparative studies with other orthosis types would also provide valuable insights into optimal treatment strategies.

This study has several limitations. The small sample size limits the generalizability of the findings and reduces the statistical power of the analyses. The short-term nature of the study prevents conclusions about the long-term effects of DAFOs on functional activity. Furthermore, a comparison with other orthosis designs was not included, limiting the ability to determine the relative effectiveness of DAFO compared to other treatment options.