通用設計客製化三維列印鞋墊對於扁平足者平衡及行走功能之成效

The Effectiveness of Universally Designed Customized 3D Printed Insoles on The Balance and Walking Function of Flat-Footed Students

融合教育中強調要整合輔助科技的通用設計，對普通學生及特殊需求學生均極重要；扁平足會影響到日常功能行走表現，會造成足部疼痛，步態異常，也可能會影響平衡與協調能力，間接影響其他骨骼相關疾病；鞋墊可減少變形，預防下肢的疾病，但礙於特製鞋墊單價都過高，使扁平足個案卻步。應用3D列印適合小量客製化需求，能針對各種困難的情境做出相應的設計，將3D列印材質可塑性，與成本效益的可行性，結合生物力學原理，依照受試者行走習慣量身打造個別化鞋墊。本研究採準實驗設計，扁平足的人穿著長時間3D列印鞋墊為實驗組，對照組為穿3D列印鞋墊短時間的扁平足個案，探討12週日常生活對於兩組不同鞋墊之動作影響。課程開始前一週，實驗組與對照組皆進行動作評估，且實驗組會先採取足模來製作3D列印鞋墊；實驗期間兩組皆參與功能性動作介入；第九週則對實驗組與對照組進行動作訓練評估後測，以無母數考驗動作精練度。結果顯示3D列印技術適合個別化設計與發展鞋墊，在第二、三、四趾骨區域壓力達到統計上的顯著下降；扁平足個案使用3D列印鞋墊走路速度有提升且有顯著上的差異；穿著個別化定製鞋可幫助改變足底壓力異常分佈；部分扁平足受試者使用3D列印鞋墊，可提升其平衡能力。

 

Motivation, Problems and Rationales, Significances

Inclusive education emphasizes the integration of assistive technology and universal design. Gait is one of the keys to functional independence. The elasticity of the arch affects the cushioning of vibrations, the support and stability of the body’s upright position during walking and jumping; the height of the arch affects the posture or shape of the foot, because the medial longitudinal arch is responsible for absorbing most of the impact on the foot during daily activities. Flat foot is one of the diagnoses that can affect daily functional walking performance. This diagnosis may cause foot pain, abnormal gait, and may also affect balance and coordination, and indirectly affect other bone-related conditions. According to biomechanical principles, insoles can reduce deformation and prevent or treat diseases of the feet and lower limbs. Due to injury and disease, gait movement and posture may be affected, often resulting in reduced walking speed and step length. By analyzing biomechanical characteristics of gait, such as speed, cadence, step length, stance or swing time, it is possible to infer whether gait is impaired. Foot pain is an important issue because it can also negatively impact daily activities, health, and quality of life, and may increase the risk of falls. Insoles can be used as a temporary relief measure for patients with flat feet. Insoles can improve the arch of the foot and maintain individual balance, possibly reducing the local peak pressure of flat feet. However, the unit price of specially made insoles is too high, which discourages flat foot cases. 3D printing uses low-cost materials and shows that 3D printed insoles are more comfortable than traditional insoles. 3D printing is suitable for small-volume customization needs. It can produce finished products with complex shapes and structures, and can be designed and modified accordingly for various difficult situations.

Purpose and Specific Aims

This research is aimed to use the characteristics of three-dimension printing to be particularly suitable for small-volume customization needs and to make corresponding designs for various difficult situations. Therefore, the plasticity of three-dimension printing materials will be used to achieve cost-effectiveness. Personalized insoles are tailor-made according to the subject’s walking habits based on the field of study.

Materials & Methods

This study adopts a quasi-experimental research design. The steps for producing personalized 3D printed insoles in this study include: scanning and measuring the study participants’ foot models, designing personalized insoles using 3D printing painting software, transferring files to a 3D printer to print the insoles, Study participants tried on, adjusted, and beautified the finished insoles. The inclusion criteria of participants include the foot posture index-6 (FPI-6) posture assessment score reaches 6 points or above; Patients with flat feet must be over 18 years old; Cognitive function is normal and can cooperate with instructions; Only use insoles and no other mobility aids. And the exclusion criteria for participants include impaired cognitive function and inability to cooperate with instructions; Cases unable to walk; Pregnancy; Wearing corrective insoles within 6 months; Surgical treatment, lower limb injuries, and infectious complications within 6 months, rheumatoid arthritis, nervous, muscular, skeletal, and blood circulation system diseases.

People with flat feet wear three dimension printed insoles for a long time as the experimental group, while the control group consists of flat foot cases who wear three dimension printed insoles for a short time. The effect of twelve weeks of daily life on the two groups of different insoles is investigated. One week before the start of the course, both the experimental group and the control group conducted movement assessment on the front side, and the experimental group first took foot molds to make three dimension printed insoles. The high speed 0.5m hi-end-foot scan system with 500Hz produced by RS Scan Lab is used to measure the dynamic foot pressure distribution and pressure center coordinates, center of pressure-progression path, etc. During the experiment, both groups participated in functional movement intervention; in the ninth week, the experimental group The movement training evaluation such as one leg stand test as well as timed up and go, post-test of the experimental group and the control group was conducted, and the Kruskal-Wallis’s test was used to test the movement refinement of the experimental group and the control group.

Results & Discussion

Results of analysis of the pressure distribution diagram of the front and rear arches of the insole were included (1) An example of wearing the insole was for the longest time, analysis of the arch pressure distribution diagram before and after the insole; (2) The shortest wearing time of the insole was as an example, the effectiveness of walking speed in patients were with flat feet using 3D printed insoles; (3) The effectiveness of using 3D printed insoles were to balance flat feet; and (4) The Satisfaction with the comfort of 3D printed insoles and willingness were to use them in the future in flat foot cases, as well as comprehensive discussion were demonstrated in this section. Among the 12 questions regarding the satisfaction of flat feet with 3D printed insoles, they are size, weight, easy adjustment, safety and stability, durability, ease of use, comfort, use effect, service process, maintenance services, related professional services, and follow-up service.

Conclusion & Suggestions

The conclusions are as follows: This study investigated the suitability of three-dimension printing technology for personalized design and development of insoles, which achieved a statistically significant reduction in pressure in the second, third and fourth phalangeal areas; The walking speed of flat foot cases using three dimension printed insoles was improved and there was a significant difference. Wearing individually tailored shoes was the most common method that can help change the abnormal distribution of pressure on the bottom of the foot; The balance effect of flat-footed subjects was using three dimension printed insoles. The research results showed that three dimension printed insoles can improve their balance ability in some cases, but the overall average difference before and after did not reach a significant difference. The universally designed 3D printed customized insoles developed in this study can effectively improve the comfort of patients with flat feet. The findings of this study provide reasonable adjustment suggestions for students with flat feet to participate in courses and teaching in an inclusive education context. For example, in terms of physical adaptation, after finishing physical activities, they should stretch and relax the calf muscles; if they engage in running and jumping activities, they need to wear insoles in advance and use assistive devices for auxiliary support.