Assistive Tecnology for People With Arthritis

Arthritis is defined as the inflammation or degeneration of joint structures, mainly cartilage. Patients suffering from this condition present symptoms such as pain, fatigue, stiffness and decreased muscle strength, causing a reduction in physical abilities to perform daily activities such as bathing, dressing, cooking, eating, cleaning, shopping, working and activities of daily living. daily. There are more than 100 types of arthritis, among the most common are rheumatoid arthritis, osteoarthritis, spondyloarthritis and psoriatic arthritis. According to the WHO, rheumatoid arthritis affects between 1 and 1.5% of the world population. A study published by Arthritis & Rheumatism estimates that by 2030, 67 million people will be affected by arthritis. The physical, personal, family, social and vocational consequences of arthritis are extensive, leaving people feeling unable to cope and excluded from society. The present work seeks to benefit the adult population with arthritis, since the investigations of the Medical Center of the VU University of Amsterdam (2017) report that the available technical aids do not fulfill their objective of facilitating the performance of activities of daily living that they require the manipulation of objects to cover basic needs such as eating and drinking, due to the limitations inherent in their control and design. 

Faced with this problem, it is proposed to design technical aids such as assistive technologies for eating and drinking for people with arthritis. For the technical aids for drinking, it is proposed to design a cap opener which can be adjusted to commercial bottle caps and by turning it will open to be able to drink the liquid. Two designs will be made, one pocket designed to open 600 ml bottles, whose caps measure 28 mm. While the other will be from home with other measures for other tapas, such as a jug.

As assistive technology for eating, it is intended to design the cutlery set that includes a spoon, knife and fork with a latex handle and a rough surface for a better grip, in addition, said stainless steel cutlery will have an angle of 90° in order to reduce joint movement in the action of taking food to the mouth, looking for a movement in the linear axes.

The prototype was designed in Catia. It has three different diameters of 31, 46 and 58 mm. with a groove to be able to generate that friction and to be able to open the bottle more easily, it also has a 40 mm can opener. and 60° opening. These diameters are stacked starting with the largest diameter on a 70mm base. The entire piece has a length of 185 mm. 150 mm are counted from the arm to hold and rotate.

The design of the prototype is made to achieve the function of opening commercial bottles of most beverages, the thread is 28 mm, coinciding with the diameter of the product, in addition to adding an opening to provide better grip and more opportunity to hold larger diameters having a successful result in both cases. 

The handle has a size of 17 cm which allows all people regardless of age or sex to use it without any problem

The AUTOCAD modeling of the AT knife was carried out by obtaining an image of a pre-existing AT knife and inserting it into the solidworks sketch, once having the image in the sketch, an array  of lines and splines are made in the contour of the knife to obtain its dimensions, Once this is fulfilled, the measurements are defined through dimensions with the average length of the man's right hand, which is 184.9 mm, and 185.6 of the left. By having the drawing in 2D with these measurements, an extrusion is applied to give it a 3D shape and we proceed to give it fillets and chamfers to obtain an ergonomic handle for the user, the edge of the knife goes through the same process until the length and dimensions are obtained.  Observations are made in different perspectives to corroborate the design and 3D print. The printed model is reviewed to corroborate the correct design and dimensions and, if necessary, the necessary adjustments are made.

For the spoon prototype the main goal was reducing the fine motor movements the user would have to make in order to move the liquid from the plate to their mouth. With that in mind the neck and the bowl of the spoon is bent at an angle. The most important measurements are as follow:

• Spoon neck angle: 45°
• Spoon neck (length): 3cm
• Spoon bowl (depth): 5cm
• Spoon bowl (thickness): 1cm
• Spoon handle (length): 12cm
• Spoon handle (width): 0.7cm
• Spoon handle (thickness): 0.5cm 

Other, less critical, measurements are shown explicitly in the plane and image above

The fork prototype followed the same conceptual line as the spoon, in other words, the neck is bent at an angle to maximize the comfort of the user and not make more movements than strictly necessary when eating. The most important measurements are as follow:

• Fork head angle: 45°
• Fork neck (length): 3cm
• Fork (thickness): 0.5cm
• Fork handle (length): 12cm
• Fork handle (width): 0.7cm

Other, less critical, measurements are shown explicitly in the plane and image above.