A study investigating the effects of 3D-printed insoles on patients with moderate adolescent idiopathic scoliosis (AIS) found that the insoles did not reduce the Cobb angle and angle of trunk rotation of patients but could improve postural stability.
Thirty-six volunteers with AIS and curves of 20-45 degrees were randomly divided into experimental and control groups. The control group received traditional rehabilitation with TLSOs and exercises, and the experimental group received the insole interventions in addition to traditional rehabilitation. The outcome measures were Cobb angle, angle of trunk rotation (ATR), postural stability, and quality of life (Scoliosis Research Society-22 questionnaire). Measurements were conducted at baseline examination, two months, and six months.
The insoles were fabricated to increase the stress points or cut off the load-free parts, including personalized increased arch support, adding wedge blocks with different heights to the heel for adjusting the heel in a neutral position, controlling the degree of forefoot inversion and eversion, and bilateral lower limb length compensation, etc.
After two and six months of treatment, the Cobb angle and ATR in both groups were significantly decreased as compared with the baseline, but no significant group difference in Cobb angle and ATR was found. There was a significant difference in the sagittal balance index at six months compared to the control group, and a significant difference in the coronal balance index was observed at six months compared to baseline in the experimental group. Quality of life did not change in either group.
The researchers noted that asymmetry of the spine due to scoliosis might result in an abnormal force on the pelvis, and that the asymmetric load and force on both sides of the body would lead to skeletal growth disorders, aggravating the condition. In addition, they wrote, AIS patients are associated with biomechanical abnormalities of the lower extremities, such as flat feet, high-arched feet, and leg length discrepancies, therefore adjusting the asymmetrical force on both sides of the body through insoles could balance the asymmetrical force and allow the spine to grow normally.
The open-access study, “The efficacy of 3D personalized insoles in moderate adolescent idiopathic scoliosis: a randomized controlled trial,” was published in BMC Musculoskeletal Disorders.