Orthotic Fitting: Patient Assessment, Measurement, and Device Selection
Start with the prescription and the patient, not the product
Orthotic fitting begins with verifying the prescription (device type, side, joints, straps, and any physician-specified modifications) and then assessing the patient. A candidate must understand dermatologic status (intact skin, scars, grafts, sensation), vascular status (pulses, temperature, capillary refill, edema), neurologic status (protective sensation, proprioception, spasticity, tone), joint range of motion and contractures, limb alignment and deformity, and functional goals (ambulation distance, transfers, sitting tolerance).
Measurement discipline
Measure bilaterally and record landmarks consistently: limb circumference at defined levels, malleolar and knee widths, calf and thigh contours, and foot length and width. For footwear, measure in a weight-bearing position when possible, at the end of the day, and account for the longest toe. Note that a circumferential measurement taken over an edematous limb will change; document the time of day and position.
Selection logic and common traps
Questions often describe a patient with insensate feet and diabetes; the trap is selecting a thin off-the-shelf insert instead of a total-contact, pressure-redistributing device with accommodative layers. Another trap is fitting a rigid AFO to a patient with fixed equinus, or ignoring knee instability when choosing a floor-reaction design. Always match device mechanics to the impairment: tone reduction and contracture management differ from simple dorsiflexion assistance.
Worked rule of thumb
If a patient has a fixed plantarflexion contracture, do not force the ankle to neutral in a rigid device; instead, consider a heel wedge, serial casting referral, or a hinged design with adjustable stop, and document the rationale. Rule of thumb: assess, measure, then select - never select before assessing.
Documentation
Record findings, measurements, device chosen, modifications, wearing schedule, and patient education. Reassessment intervals matter for growing children and for patients with fluctuating edema.