For a podiatrist, plaster casting is more than science - it is a form of an art that requires time and effort. Podiatrists spend many hours perfecting this technique. From molding the plaster strips around a patient’s foot to pressing up the fifth metatarsal for forefoot stability, to locating the lateral margin of the talus, and locking the midtarsal joint without pronating the medial column or supinating the lateral column.
Plaster casting has always been utilized in a podiatrist’s clinic. It creates a mold of a foot which is then used to manufacture bespoke functional orthoses. These orthoses have allowed podiatrists to treat patients with foot ailments such as plantar fasciitis, heel spurs, diabetes, arthritis and walking imbalances resulting from flat feet or high arches.
While many alternatives to plaster casting, such as laser 3D scanners, stereo-digital 3D imaging systems and pin array systems, have been used for many years, most podiatrists still prefer plaster casting over the other alternates.
3D scanning systems, on the other hand, are generally large, expensive equipment. While they are quick to generate a foot scan, they come with their own limitations. Most 3D scanners require patients to stand on the scanner that creates a weight bearing feet scan. A 1989 Northern Arizona University study showed that weight bearing scans resulted in an orthotic shape that has been shown to cause pain in the big toe joint and to increase tension on the plantar fascia. Failure in reducing forces lead to common foot problems such as bunions, big toe joint pain, heel pain, arch pain, and other conditions.
In recent years, portable 3D scanners, such as Structure Scanner, are being used for non-weight bearing foot imaging. GROM’s scanning app, for instance, allows podiatrists to scan a foot with a high precision within 20 seconds and fill in the prescription details on the app. The order is digitally received by the producer without the need for any physical shipment by the podiatrist, thereby, saving both time and money.
Generating precise scans within a short amount of time at a low cost is a distinct advantage that provides podiatrists the incentive to replace 3D scanning technology with traditional methods like plaster casting. As a result, an increased number of functional orthoses are now being produced using scans generated from 3D scanners.