Orthotic Fabrication: Principles and Practice

Figure 1-1. This orthosis immobilizes the wrist but allows for full finger and thumb movement.

Orthotic Designs

The overall purpose of a given orthosis will determine its design. In general, orthoses used in occupational therapy or physical therapy practice can be grouped into two categories: orthoses that immobilize body structures, and orthoses that mobilize a joint, muscle, or soft tissue. Immobilization orthoses, also known as static orthoses, have no moveable parts and are used to immobilize a body part, prevent movement, encourage rest of injured structures, and provide support (Figure 1-1). Mobilization orthoses typically have additional adjustable parts called outriggers, such as turnbuckles, hinges, or others, and are designed to apply low load stress to contracted, stiff tissues to improve joint and tissue movement or to facilitate UE function by substituting for weak or paralyzed muscles (Figures 1-2 through 1-4). These are further categorized by the specific type: static, serial static, dynamic, and static progressive (Table 1-1).

Figure 1-2. This serial static proximal interphalangeal extension orthosis positions the proximal interphalangeal joint in maximum extension and is remolded on a regular basis as joint motion improves. (Reprinted with permission from Orfit Industries.)

Figure 1-3. Muscles innervated by the radial nerve may become paralyzed or weak following injury to the radial nerve. This dynamic metacarpophalangeal extension mobilization orthosis helps to support these muscles and facilitates grasp and release hand function.

Figure 1-4. This static progressive composite digit flexion mobilization orthosis applies mobilization force to the metacarpophalangeal, proximal interphalangeal, and distal interphalangeal joints to improve digit flexion.

Orthotic Intervention Terminology

The practitioner must consider descriptive terminology that is used to help accurately describe an orthosis provided to a client. This helps to clarify the orthosis being requested by the referral source, optimize understanding of the purpose and intent of the orthosis, assist with billing and reimbursement, and ensure accurate and complete documentation. The descriptive terms contained in Boxes 1-2 and 1-3 are commonly used by hand surgeons and practitioners and are based on the anatomical location and body segment included in the orthosis. The authors use this terminology consistently throughout this textbook to describe the type of orthoses.

Reimbursement and Documentation

In addition to the descriptive terms associated with orthotic provision, it is imperative for the practitioner to be aware of other factors that influence billing and reimbursement for orthoses provided to clients, specifically terms used to code and bill for the type of orthosis provided. In the United States, these include HCPCS codes and L-codes (see description following), as well as knowledge of the insurance contracts associated with the practice setting where service is provided (which L-codes are covered and at what rate). In addition, accurate and complete documentation of orthotic intervention(s) provided is essential to optimize reimbursement for services.

HCPCS CODES AND L-CODES

An HCPCS code, part of the Level II Health Care Common Procedural Coding System, is a five-character alphanumeric code. The first character is a letter that describes the type of service billed, and the other four numeric characters describe the specific type of service provided (Box 1-4). L-codes are part of the HCPCS and are used to report and bill for fabrication and fitting of specific orthoses for the UE. Introduced by the U.S. Centers for Medicare & Medicaid Services, and revised in 2006 in conjunction with the American Society of Hand Therapists, these codes accurately describe common UE orthoses provided by occupational therapists and physical therapists. These codes collectively represent the evaluation, cost of materials, fabrication time, fitting, and adjustments required when making and fitting an orthosis for a client. Many private insurance carriers also follow these guidelines, but not all codes are accepted by all payers, including Medicare. When billing for an orthosis, the practitioner must select the most appropriate L-code and anatomical heading that accurately describes the orthosis provided: S = shoulder, E = elbow, W = wrist, H = hand, F = finger, O = orthosis. Refer to Box 1-4 for L-codes and anatomical headings for common UE immobilization orthoses and anatomical headings.

Table 1-1

CATEGORIES OF ORTHOSES

IMMOBILIZATION ORTHOSES	MOBILIZATION ORTHOSES
Static: An orthosis without an outrigger or moveable components (see Figure 1-1).	Serial Static: Orthosis that holds a body part in its end range position to regain passive joint motion. It is periodically remolded to accommodate changes in joint position. This serial static orthosis is designed to improve PIP joint extension range of motion (see Figure 1-2).
	Dynamic: Orthosis that incorporates outriggers with variable tension such as springs, coils, or elastic components to assist in function or place force on stiff joints or soft tissue. This dynamic orthosis is designed to support the wrist and MCP joints in a functional position to improve hand function following injury to the radial nerve and paralysis of the wrist and digit extensor muscles (extensor carpi radialis longus, extensor carpi radialis brevis, extensor carpi ulnaris, and extensor digitorum; see Figure 1-3).
	Static Progressive: Orthosis that incorporates an outrigger with constant tension designed to progressively reposition a stiff joint in its maximum tolerable end range position. This static progressive orthosis is designed to apply a low load, constant force to the digit to improve flexion of the MCP, PIP, and DIP joints (see Figure 1-4).
Abbreviations: DIP, distal interphalangeal; MCP, metacarpophalangeal; PIP, proximal interphalangeal.

Box 1-2. Anatomical Location Terminology

Volar, anterior, or palmar	The front part of the body segment in anatomical position
Dorsal or posterior	The back part of the body segment in anatomical position
Radial	The same side as the thumb and radius
Ulnar	The same side as the fifth digit and ulna
Circumferential	Covers both the front and back of the body segment
Arm	The area between the shoulder and elbow
Forearm	The area between the elbow and wrist
Wrist	The area that includes the carpal bones, distal radius, and ulna
Hand	The area from the wrist to the fingertips
Fingers or digits	The area from the metacarpophalangeal joints to the tips of the fingers
Digits I to V	I = thumb, II = index finger, III = long or middle finger, IV = ring finger, V = small finger

Box 1-3. Orthoses Descriptors

Digit based	Orthosis includes one or more joints distal to the metacarpophalangeal joints (Figure 1-5).
Hand based	Orthosis includes one or more joints distal to the wrist (Figure 1-6).
Forearm based	Orthosis includes one or more joints distal to the elbow (Figure 1-7).
Arm based	Orthosis includes one or more joints distal to the shoulder (Figure 1-8).
Thumb based	Orthosis includes one or more joints of the thumb; may or may not include the wrist (Figure 1-9).
Dorsal based	Orthosis is located on the dorsal or posterior aspect of the body segment (Figure 1-10).
Volar based	Orthosis is located on the volar or anterior aspect of the body segment (Figure 1-11).
Ulnar gutter	Orthosis is on the ulnar aspect of the body segment (same side as ulna; Figure 1-12).
Radial gutter	Orthosis is on the radial aspect of the body segment (same side as radius; Figure 1-13).