Development of SSPO Temporary Mechanical Ankle Joint (SSPO-TMAJ 1) for Ankle Foot Orthotic Prescription

Abstract

A successful orthotic prescription has two important factors that influence fitting, the accuracy of the patient’s assessment and the ability of the device to fulfill the impairments of patient. From orthotic clinical experience, clinicians are often faced with some difficulties during prescription because of the large variety of pathologies. An orthosis which does not meet precise patient needs will ultimately affect the initial fitting as the orthosis might be inappropriate with the patient’s condition. Currently, there are not that many tools or equipment to assist in making the precise and suitable prescription for each individual patient. Instead, the prescription is dependent upon the skill or experience of the clinician. Therefore, the purpose of this study was to develop a mechanical ankle joint called the SSPO temporary mechanical ankle joint or SSPO-TMAJ 1 which could adjust in three planes (sagittal, coronal and transverse) in order to be fit initially during assessment and orthotic prescription. This device could assist orthotists in during assessment and prescription by properly positioning the foot and ankle alignment in each plane following the patient conditions. There were 3 phases of the study; design and stress-strain distribution testing with the SolidWorks program; simulation task with participants; clinical trial with an able-bodied participant. The results of mechanical property testing with simulation software evidenced that all parts of joint were strong enough during force application. SSPO-TMAJ 1 was firstly fabricated by 3D printing with plastic ABS and secondly machined and milled with Aluminum. There were 16 participants involved in this phase of the study which scored the adjustability level and satisfaction level for adjustment and appearance. As a result, a satisfactory score was given to adjustability level and satisfaction level for adjustment. However, a score of 2.6/4 marks was observed in satisfaction level for appearance due to bulkiness, un-cosmetic, and non-labeled number of angles on the joint surface. These were issues which need to be to reconsidered for further studies. During sitting, standing, and walking, SSPO-TMAJ 1 is able to adjust, fix, or allow a desirable angle, range of movement and position.