Upper Limb Orthotic Devices

Chapter 14 Upper Limb Orthotic Devices



This chapter provides a guide for prescribing and the basic principles for using upper limb orthotic devices, commonly known as splints or braces. The word orthosis (derived from the Greek orthos, meaning to correct or make straight) encompasses the full spectrum of devices currently fabricated by therapists and orthotists.16 As defined by the International Standards Organization of the International Society for Prosthetics and Orthotics, an orthosis is any externally applied device used to modify structural and functional characteristics of the neuromuscular skeletal system.30 Orthosis—or alternatively, orthotic device—is the preferred term.21 The terms splint and brace are less preferred because they imply mere immobilization and do not suggest either improved function or restoration of mobility. However, these terms remain common, and in this chapter we use the terms orthotic device and splint interchangeably.




Classification


We use many different terms to describe upper limb orthotic devices. We call them by the joint they cover, the function they provide (e.g., immobilization), or the condition they treat. Some are named by their appearance (e.g., banjo or sugar tong), and still others bear the name of the person who designed them (e.g., Kleinert).28


Most splints are known by their common names (Table 14-1)—names that have evolved over time. But such names are not fully informative, are not systematic, and are not even universally accepted. This lack of a universally accepted terminology often presents a communication barrier between the physician and other health professionals. Consequently, more systematic naming systems have been developed that classify orthotic devices according to anatomic region or to purpose and function. Table 14-1 compares the common names of several orthotic devices with those in three other naming systems.



The simplest naming system is that developed by the International Organization for Standards. It reports the anatomic region the orthotic device encompasses. A wrist-hand orthosis, for example, is called a WHO.32 This system, however, fails to define the purpose or function of the orthosis.


In 1991 the American Society of Hand Therapists (ASHT) published the ASHT Splint Classification System.1 This system provides standard nomenclature for splints based on function. It classifies splints by characteristics (e.g., articular or nonarticular) and location of the body part covered. A humeral fracture brace, for example, is identified as a nonarticular splint—humerus. It also identifies the direction of the force applied, and whether the splint is for mobilization, immobilization, or restriction. In this system a long arm splint (Figure 14-1) is characterized as a 45-degree elbow flexion immobilization. The problem with the system is that one splint design can provide many different functions.10




Biomechanical and Anatomic Considerations


Health care personnel involved in the fabrication and application of orthotic devices need a good understanding of biomechanics and anatomy as well as the physiologic response to tissue healing. They also need technical and creative skills that allow them to design and fabricate orthotic devices that can win the patient’s acceptance and satisfy the treatment goals. In the United States upper limb splinting is performed by occupational therapists, certified hand therapists, orthotists, and some physical therapists. Physicians ordering these devices need to understand the technical factors involved in fabrication and fitting. Some of these are listed here.



The MCP (some experts refer to this as the MP) joint is the key for finger function. When MCP joints are hyperextended, the IP joints flex because of the tension of the flexors and the delicate balance between the finger extensors and flexors. Extension stability of the wrist is important for optimal function of the hand. The wrist should also be placed in slight extension to maintain flexor tendon length and to improve hand function (Figure 14-2). This position will place the MCP collateral ligaments on maximum stretch, preserve the anatomic arches of the hand and thus oppose the development of a “claw hand” deformity. This position is also referred to as the ”safe” or “intrinsic plus.”10 This position fosters the weaker intrinsic motions of the MCP flexion and IP extension that are difficult to obtain.


When increasing joint range of motion with splinting, the angle of pull needs to be perpendicular to the bony axis that is being mobilized.6 Otherwise the forces on the skin and underlying structures can be sufficient to cause injury through excessive pressure on the skin and deforming stresses on the underlying healing structures.

The improvement in range of motion is directly proportional to the length of time a joint is held at its end range.18 This is referred to as the TERT principle and is used with static progressive splinting. The load should be low and the application long for effective tissue deformation. the clinically safe degree of force covers a very narrow range.



Design Categories


Orthotic devices can be classified by the support (or forces provided) to improve motion or function. The categories of splint design are listed below.34














Diagnostic Categories and Splint Examples


There are many common clinical conditions for which orthotic intervention is appropriate. This section gives a brief overview of the features of specific diagnoses, followed by the type of splints commonly indicated for each diagnosis. This is not an all-inclusive list, and the reader is referred to comprehensive overviews of upper limb orthotic devices in splinting texts and other references.



Musculoskeletal Conditions



Tendonitis, Tenosynovitis, and Enthesopathy


Tendonitis (inflammation of the tendon), tenosynovitis (inflammation of the tendon sheaths), and enthesopathy (inflammation at a muscle or tendon origin or insertion) can all result from excessive repetitive movement or external stressors. The upper limb tendons most commonly involved are the wrist extensors or the abductor pollicis longus and extensor pollicis brevis muscles of the thumb, commonly called de Quervain’s stenosing tenosynovitis. The goal of splints for these conditions is to immobilize the affected structures in order to facilitate healing and decrease inflammation. The thumb spica splint, forearm-based, immobilizes the wrist, the carpometacarpal (CMC) joint, and the MCP joint of the thumb. The IP joint of the thumb does not need fixation because the affected tendons do not move this joint (Figure 14-14).



Lateral epicondylitis is a more common enthesopathy of the upper limb.34 It can be treated by a tennis elbow orthosis (Figure 14-15). This is a forearm band that changes the lever arm against which the wrist extensors pull. In essence, it puts the origin of the extensor muscles at rest and decreases the microtrauma from overuse. This orthotic device is placed approximately two fingerbreadths distal to the lateral epicondyle, and is a firm strap against which the extensors press against when contracting. A similar brace is used for medial epicondylitis (also known as golfer’s elbow). (See Chapter 38.)


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Jul 12, 2016 | Posted by in PHYSICAL MEDICINE & REHABILITATION | Comments Off on Upper Limb Orthotic Devices

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