Insoles are inserts that fit within a shoe. Most are designed to provide additional support for the feet of the wearer. This can be as simple as a flat cushion or contain complex geometry providing different supporting structures in different areas. Some are made from dense foam, while others are made from more rigid materials to hold their shape. Still others have sections with air pockets to redistribute the pressure. Standard insoles are available at retail stores and vary in price based on the complexity.
In addition, custom insoles can be produced to match foot geometry exactly. These are called a foot orthoses or orthotics. They are produced by an orthotist, a type of healthcare professional who specializes in the design and manufacturing of these type of devices. Some orthoses are used to redistribute foot pressure to treat foot problems. Others are lifted on one side to correct for improper foot angle. These not only impact the distribution of forces within the foot, but also the load distribution within the knee and the spine. Thus, they are used to treat a variety of different problems affecting the lower portion of the musculoskeletal system.
