of the foot and its alignment with the lower leg. CFO's are used to treat or prevent injury caused by excessive motion or a lack of motion in the foot and lower leg. Your prescription CFO device is tailored to your needs and activities. Your CFO is not just a piece of plastic. Chiropodists/podiatrists are trained to prescribe custom foot orthotics. The prescription CFO is based on the findings from the description your complaint, your medical history, a detailed biomechanical examination of your foot and lower extremity, a gait analysis of your walking pattern. All of this gathered information is used to formulate a prescription. Your prescription could include an addition such as an accommodation to relieve pressure that is causing callus on the bottom of your foot. Some additions can encourage joint motion or prevent joint motion. Ultimately, the prescription foot orthotic device must be tailored to your needs and activities. Unfortunately, you may not have a foot orthotic that is a custom made foot orthotic device.There are many kinds of in-shoe devices that are referred to as "Orthotics". You will see advertisements on TV infomercials, exhibits at consumer shows and retail stores for "Orthotics". Shoe inserts and arch supports are be increasingly referred to as " Orthotics". Foot orthotics are prescribed and/or dispensed by many varied health professionals including chiropodists/podiatrists, orthopedic surgeons, sports physicians, pedorthists, orthotists, chiropractors and physical therapists. The general public will have a difficult time telling the difference between a true CFO and an over the counter (OTC) type foot orthotic without asking the right questions. You must ask you foot orthotic provider if they are going to make your foot orthotic from a 3 dimensional cast of your foot.
The Prescription Foot Orthotic Laboratory Association(PFOLA) has developed technical standards to differentiate between various types of foot inserts(orthotics). The definitions are based on how the foot is evaluated and how the foot was casted.
The following are excerpts from PFOLA technical standards document on foot modeling and device definitions. These definitions are sent to extended health insurance providers to demonstrate they are reimbursing you for a true anatomical custom made foot orthotic which is made from a anatomical volumetric 3 dimensional model.
Foot Modeling Definitions
Anatomical Volumetric Foot Model (AVFM)
A digital or physical model that captures a person’s three dimensional(3D) plantar foot anatomy when the foot is non-weightbearing, semi-weightbearing, or fully-weightbearing.
A physical AVFM captures foot anatomy through direct contact to duplicate plantar foot anatomy. The most common examples are plaster of paris casts or foam impressions taken directly from the foot. Any material or method that uses direct capture of the entire plantar foot anatomy creates
an AVFM.A digital AVFM must use actual 3 dimensional (3D) data points taken directly from the foot to duplicate plantar foot anatomy. The most common examples include laser 3D scanners, stereo-digital 3D imaging systems, and pin array systems.
Extrapolated Volumetric Foot Model (EVFM).
A digital model that approximates a person’s 3D plantar foot anatomy through application of mathematical models that extrapolate pressure data, or extrapolate temperature data, or extrapolate light data to form the digital model when the foot is non-weightbearing, semi-weightbearing, or fully-weightbearing. The most common examples are pressure mapping systems, photographs and ink or carbon paper imprinting system. A physical 3D cast of your foot will not have been used to make the EVFM orthotic.
Device Definitions
Anatomical Custom Foot Orthotic (ACFO)
An in shoe device that is made directly from an Anatomical Volumetric Foot Model (AVFM). The AVFM is modified with the appropriate medial and/or lateral arch fill, lateral column expansion, heel expansion, and intrinsic forefoot and/or rearfoot corrections as defined by the prescribing chiropodist or podiatrist. The entire upper surface of the foot orthotic device matches the surface of the modified, or corrected, AVFM.
Extrapolation System Foot Orthotic (ESFO)
An in shoe device that is made directly from an Extrapolated Volumetric Foot Model (EVFM). The EVFM is modified with the appropriate medial and/or lateral arch fill, lateral column expansion, heel expansion, and intrinsic forefoot and/or rearfoot corrections as defined by the prescribing physician. The entire dorsal surface of said custom device matches the surface of the modified, or corrected, EVFM. The ESFO will not approximated the contours of your arch as well as a ACFO. If a close fit to your foot contours is required an ESFO may be contra-indicated.
Library System Foot Orthotic (LSFO)
An in shoe device that is made from a library of pre-manufactured shells, pre-manufactured corrected positive molds or pre-determined digital shape files (from which shells or molds are milled.) The foot orthotic shape is chosen by matching a library shape with either an AVFM or EVFM. Over the counter(OTC) foot orthotics are LSFO. Some of these LSFO will be used by chiropodists/ podiatrists when an ACFO is not indicated. OTC Powersteps ® orthotic supports are a good example of LSFO that might be dispensed in chiropody/podiatry office.
These industry definitions have helped to differentiate if a foot orthotic is truly a custom foot orthotic. The prospective foot orthotic patient has to be educated to ask the right question. Are you making my foot orthotic from a true representation of the surface contours of the bottom of my foot? Hopefully the answer is yes.
