Weightbearing Casting or Scanning for Best Results

Custom orthotics, those that are uniquely designed for each individual foot, are made in one of two ways:

1. Weightbering - where the measurements are taken with the patient standing up.

2. Subtalar Neutral (non-weightbearing) - where the measurements are taken from the patient sitting or lying down, without any weight on the foot.

All Foot Levelers custom-made Spinal Pelvic Stabilizers are designed from weightbering casting or electronic scanning, because the weightbering method has been shown to be the most reliable, accurate, and effective process for providing patients with optimal Stabilizer fit and support.

Effects of Weightbering Posture on Chiropractic Care

Weightbering stance is a key consideration in the diagnosis of musculoskeletal dysfunction and development of sound therapeutic protocols. It creates functional demands on the bones and tissues of the musculoskeletal system. The professional concerned with restoring structural integrity, relieving symptoms and pain, or improving musculoskeletal function and should always be concerned with and focused on a patients upright posture. Pathologies in structure and function are most apparent when the body is in the position of function.

Stance further affects musculoskeletal integrity because it creates a closed kinetic chain among the body's four main components: feet, pelvis, torso, and cervical region. Forces are transmitted in such a way that misalignments in one region can instigate problems elsewhere. Gravitational forces and heel-strike shock from normal gait are two examples of ordinary forces which affect the kinetic chain daily.

To demonstrate this effect, sit with one leg extended and rotate the foot from side to side. You will feel motion within the lower extremity, but little visible movement occurs above the ankle. Next, stand and roll the same foot from medial to lateral. Pronounced motion can be seen and felt along the entire leg and into the pelvic region.

A third consideration of weightbering stance is that it creates a load or stress that precipitates soft tissue deformation. Over time, unchecked stress due to imbalance or structural abnormalities can create plastic deformation (permanent stretch) and laxity in connective tissue. An example is "fallen arches", the loss of support in pedal tissues due to the repeated stress of normal pronation.

Independent clinical measurements emphasize the effects of weightbering stance on the human form. A study of scoliosis patients involved comparison of standing and recumbent X-rays. Weightbering increased the degree of lumbar curves and changed postural and iomechanical vertebral patterns. Another group of subjects free from relevant biomechanical abnormalities also manifested weightbering influences. Calcaneal eversion or subtalar pronation was significantly greater in stance than during passive calcaneal eversion maneuvers.

Why Weightbering Works

Monte H. Greenwalt, DC, DABCO, explains the success of and rationale for using the weightbering design procedure as follows:

"In explaining the casting procedure o your patients, it may be helpful to compare the method to repairing a flat tire. Note that a mechanic doesn't put a car on the hydraulic lift to determine which tire is flat; it is apparent only in the position of function. Likewise, fallen arches or dropped metatarsals would not be evident if the foot were cast in a non-weightbearing position."

When the feet are flat on the ground, the body represents a closed kinetic chain. From a foam cast showing the foot in full contact (or via electronic transmission from Foot Levelers' Associate digital casting system), a skilled Foot Levelers technician can determine the amount of hyperpronation, plastic deformation of arches, abnormal weightbering, and foot misalignment. A weightbering analysis records functional deformation, and Stabilizers made from that analysis provide proper fit and accurately represent arch placement when the patient is standing.

In his landmark text, Essentials of Skeletal Radiology, Terry Yochum, DC, DACBR, Fellow, ACCR, says: "To prescribe the most effective orthotic support, use of a weight-bearing casting method to obtain quantifiable information on the extent of pedal imbalance is recommended ... This method also results in a more accurate fit, since the true length and width of the foot during the closed-chain stance are thoroughly assessed. And John Danchik, DC, FICC, CCSP, has written that a "professional examination including weightbering casting of both fet will provide real-life, position-of-function information for use in constructing a corrective orthotic device.

Why Subtalar Neutral Doesn't Work

In the 1970's Root revolutionized the way podiatrists, physical therapists, and orthopedists managed foot and ankle problems. His two systems of analysis for fabricating rigid orthotics included non-weightbearing goniometric measurement and palpation of the ankle to find an ideal neutral position. However, a 2002 literature search conducted by Kevin Ball, PhD and Margaret Afheldt, PT, questioned the rationale for neutral casting and the resulting rigid orthotics. Although Root's methods for evaluating subtalar neutral and non-weightbearing casting are well referenced, Ball and Afheldt clearly demonstrated that Root's original paradigm, and all subsequent variations based upon this paradigm, are flawed as follows:

1. Non-weightbearing subtalar neutral approach is not reliable. Elveru et al found that fourteen experienced clinicians could not establish a consistent level of inter-examiner ability.

2. Root's definition of subtalar neutral does not accurately represent the position o the foot and ankle during dynamic weightbering. Two different studies have shown that while measuring the stance phase of gait in normal individuals, the subtalar joint rarely reaches the subtalar-neutral position.

3. The subtalar-neutral position is not functionally significant during normal gait patterns. McPoil and Pierrynowski found that the standing foot posture at rest, not Root's subtalar neutral, best represents the actual position of the rear foot during the gait cycle.

Donald Baxter, MD, the past president of the American Orthopedic foot and Ankle society, has expressed his belief that "the 'neutral' or 'corrected' subtalar position is ill defined-and not physisologically reproducible. Furthermore, the subtalar joint ranges through nearly 40 degrees of motion during running and we can't determine which of these 40 degrees is the 'correct' position for each athlete. And Dana J. Lawrence, DC, editor of the Journal of Manipulative and Physiological Therapeutics (JMPT), says that "Assessing joint play is based in part on the assumption of a neutral position for the subtalar joint, yet no clear understanding of that neutral position exists."

Conclusion

the weightbering position-of-function method of Stabilizer design (with either the casting kit or Associate system,) produces an orthotic which is superior to those made by the non-weightbearing system. Weightbering assessment takes into account the role that gravitational and stress forces play upon the entire body; the subtalar neutral system doesn't. Effective chiropractic care for the whole-body needs to start at the postural foundation in a weightbering stance