Words Matter: Is it Really “Custom Molded”?

Content provided by The O&P EDGE
Current Issue - Free Subscription - Free eNewsletter - Advertise

Importance of Knowledge

Fabricating custom feet orthoses properly takes time, experience, and a commitment to quality. Many professionals such as podiatrists, pedorthists, physical therapists, chiropractors, athletic trainers, and massage therapists advertise custom feet orthoses. In many cases, the professionals dispensing the products believe that they are receiving a "custom-molded" product from the orthotics lab. Most dispensing practitioners do not fabricate nor do they have any fabrication experience. Consequently, many are unaware of the cost-cutting measures that are implemented. Increasing demands for lower prices have forced many labs to cut corners in regards to quality and standards of excellence. If lower prices become the primary concern instead of positive results, the future of our industry could be in peril.

Methods Matter

The casting method or material selection does not determine whether a foot orthosis is functional or not. The functional posting method applies the apex of the intrinsic post precisely at the talonavicular joint for a varus post and at the calcaneocuboid joint for a valgus post. This midtarsal posting method allows for a more efficient midtarsal joint lock and induces plantarflexion of the first metatarsal, allowing for normal first metatarsal phalangeal dorsiflexion.

The commonly used Root posting method places the apex of the intrinsic post at the neck or mid portion of the first metatarsal shaft. This method can cause the first metatarsal to be lifted dorsally which can "jam" the first metatarsal phalangeal joint and cause a functional hallux limitus, but may work well for an uncompensated forefoot varus deformity. Advanced intrinsic posting methods—such as Blake Inverted, and polysectional techniques such as dual-axis and triaxial—could be more efficient. As professionals, we must know the terminology and what each method can or cannot accomplish.

Words Have Meaning

A product that is referred to as "custom molded" should in fact be "custom molded." However, many of the large national labs are using library systems. Library systems use computerized scanners that digitize the patient's casts or impression boxes and then compile the scans into a massive database according to that patient's foot type. When an order is placed, a computer program matches the scan of the patient's casts and finds an existing model in the lab's library of pre-made orthoses that closely matches the patient's feet. This product is dispensed to the patient as a "custom-molded" orthosis. This is a common method used by orthotic labs to cut production times.

Other labs cut production times by using mirror imaging. Mirror imaging is a way to match the left and right orthoses so they are identical. The patient's casts or impressions are scanned and then edited via a CAD program, and the data for one foot is flipped or "mirrored" to create the image of the other foot; therefore, there are no questions or concerns from the patient about the left and right orthoses being different. But no two feet are alike, and the custom-molded product should reflect this. Mirror imaging could be viewed as bait and switch. Where are the ethics? Isn't having a product that is custom molded to each foot the goal?

Under Pressure

Cast-foot scanners, CAD/CAM software, and computer numerical control (CNC) machining technologies are implemented at P.T.I. Orthotic Lab, Boulder, Colorado, and have proven to be extremely accurate. However, some technologies are not so "foot friendly." Some labs implement systems that capture scans of the feet as the patient walks across or stands on a computerized two-dimensional (2D) data pressure mat. The foot is a three-dimensional (3D) object with an X, Y, and Z axis. Pressure-mapping systems can only capture 2D (X and Y axes) data and therefore cannot create a 3D object. These 2D systems analyze data, and then a library system matches a pre-made device to the foot. Many practitioners knowingly dispense these products as "custom-molded" orthoses. Would a prosthetist be taken seriously if he or she pressed the residual limb of a transtibial amputee onto a 2D pressure mat and from that data, commanded a computer program to generate a 3D model to fabricate a custom prosthesis?

Ask your foot orthotic lab the following questions to determine if you are receiving custom-molded feet orthoses:

  • What posting methods do you use?
  • Are any of your orthotics made from library systems?
  • How big is your library system?
  • Do you use mirror-imaging technology?

You just might be surprised at the answers you get.

Aaron Anderson, CPed, BOCPD, is president of P.T.I. Orthotic Laboratory, a central fabrication and patient care facility located in Boulder, Colorado. He also is a member of the Pedorthic Footcare Association (PFA).

Bookmark and Share