Cervical spine

Cervical orthoses are fitted for the purpose of supporting the cervical muscles; limiting rotation, flexion, and extension; or immobilization of the cervical spine. A soft cervical collar can be fitted for lesser injuries such as sprains and strains. The soft collar is a prefabricated orthosis made of foam with a cotton cover and has a hook and loop closure in the back (Fig. 26-8). They are available in different heights and lengths. A cervicothoracic orthosis is a semirigid, two-piece brace that can be fitted for whiplash, degenerative joint disease, arthritis, and presurgical or postsurgical repairs. These collars are adjustable in height, circumference, and rigidity, but, as with all bracing, the therapist must always check pressure points to make sure that there is no skin breakdown.

Lumbosacral spine

When supporting the spine, there are numerous custom and off-the-shelf products available. The severity of the injury, pain, or disease determines the amount of support that should be fitting to each individual. The more that an individual wears the support, the more dependant he or she becomes upon the support because the abdominal muscles are now not required to work as when unsupported. With this concept in mind, the least amount of support necessary is always the best option.

Trunk support encompasses abdominal binders, rigid panel supports, hyperextension braces, and custom fabricated scoliosis orthoses. Each orthosis will require certain specific circumferential measurements, length measurements, width measurements, and for custom bracing, casting of the torso. When making a custom spinal orthosis, material selection becomes very important. Selecting the necessary amount of rigidity with the least amount of weight is crucial.

The most flexible and therefore the least rigid lumbosacral orthosis (LSO) is the abdominal binder. This orthosis is a stretchy surgical elastic binder that is available in varying widths and lengths to provide optimal fit to a wide range of sizes. The LSO provides support and compression to the abdominal muscles, which in turn support the lower back. The abdominal binder is most often fitted for low back pain.

Pregnancy supports are abdominal binders and are available for use during pregnancy. They provide relief to the lumbar spine as well as support and assistance with unloading the abdomen while compressing the hip complex.

There are numerous styles of rigid back panel LSOs. Depending upon where the injury or disease is in the lumbar region, there are two choices for which orthosis style to fit. If the region lies between L1 and L5, there are supports that fit and support this narrow region. This type of orthosis limits motion in the sagittal plane. This support is created by intracavity pressure to reduce the intervertebral load on the discs. The Aspen QuickDraw RAP is an example of a prefabricated orthosis that falls into this category. This LSO is easy to don and doff, which contributes to the compliance of the patient in wearing the support. It is fabricated of a material that is made to be worn next to the skin. This decreases the occurrence of migration. The fabric is lightweight and breathable, which makes cleaning easier and prolongs the life of the orthosis and increases the patient’s hygiene. The back panel has a pocket in which to insert the customizable rigid panel, and a hot or cold pack can be placed in the pocket for therapeutic benefit. This LSO uses effective compression and leverage to give strong support and immediate pain relief.³

An LSO can be transformed into a thoracolumbosacral orthosis (TLSO) by adding shoulder straps, chest panel, and the torso straps. With the additional strapping and pads, the region of support now includes the posterior side from the sacrococcygeal junction to just inferior to the scapular spine. The anterior section of the TLSO extends from the symphysis pubis to the sternal notch, restricting motion in the transverse and sagittal planes and therefore restricting gross trunk movement (Fig. 26-9). TLSOs also provide intracavity pressure to the lumbar and lower thoracic region. Typically, using the least software and hardware necessary makes it easier to don and doff the orthosis. Therefore a higher level of compliance by the wearer is required when adding more componentry (or pieces) to the orthosis.²

Hyperextension TLSOs are worn on the anterior side of the body. They operate and function by using a three-point pressure system to maintain full extension and allow for healing of stress fractures. Two pads are used on the anterior portion of the trunk: a sternal pad that sits below the sternal notch and a pubis pad that sits just superior to the symphysis pubis. A third pad is on the posterior side attached to the strap, and it applies pressure in the center of the spine. This orthosis is typically indicated for stress fractures due to osteoporosis, and therefore it is commonly used by elderly women. Since the design of the TLSO is to hold the wearer in good posture, compliance is often an issue with wearing this support, because good posture often decreases with age.

In order to provide complete spinal support throughout the cervical to lumbar vertebrae, a cervicalthoracolumbosacral orthosis (CTLSO) should be fitted. A CTLSO has a mandibular piece on which the chin rests (Fig. 26-10). A forehead strap is also incorporated to assist in controlling the rotation on the head. This type of orthosis is very rigid and therefore immobilizing. These devices are usually fitted for degenerative diseases, fractures, or after spinal surgeries.

Hip orthoses

The realm of splinting for the hip joint encompasses immobilization during injury, presurgical and postsurgical intervention, and limited ROM control to meet rehabilitation protocols. When splinting for hip dislocations, subluxations, or postsurgical hip replacement, a hip spica abduction orthosis is often selected (Fig. 26-11). The hip orthosis provides hip stability and proper hip alignment, limits unwanted motion, and reduces stress on the hip. The hip orthosis is prefabricated and offers hip joint options to provide the best orthosis to meet individual rehabilitation protocols. Hip joints will have settings for flexion, extension, abduction, and adduction. The pelvic section and the thigh cuff section can be ordered individually for optimum fit. The interface is soft and can be removed for cleaning. Depending upon the need, there can be either one or two hip joint hinges and thigh cuffs attached to the pelvic section, making the orthosis adaptable for one or two leg spica supports.¹²

Certain neuromuscular disorders, especially cerebral palsy, are associated with pronounced instability and poor balance due to spastic hip adduction. This hip adduction creates a very narrow base of support when sitting and standing, causing crouched posture, genu valgum, foot pronation, and poor gait. One hip orthosis on the market today that may be helpful for these conditions is called the S.W.A.S.H. (Standing, Walking And Sitting Hip Orthosis) by Allard (Rockaway, NJ) (Fig. 26-12). This orthosis is designed for children with neuromuscular diagnoses, such as spastic hemiplegia, quadriplegia, low trunk tone, or cerebral palsy, or who have a risk of hip displacement. This orthosis should not be fit to patients with chronic hip dislocation or fixed hip flexion contracture greater than 20°. The S.W.A.S.H. is designed to reduce hip adduction, promote hip abduction, and allow for better control in gait and sitting. This product has been shown to reduce hip adduction and tone, improve hip alignment and ambulation, and create greater independence for patients over time. Maximum success can be achieved with ongoing therapy while wearing this device. S.W.A.S.H. also allows for greater interaction during play and rehabilitation since it frees the patient’s hands.¹

Knee orthoses

Knee orthoses range from a neoprene sleeve to a structured combined instability orthosis that has a rigid frame and is hinged at the knee joint. A knee sleeve can be selected when the knee instability is not significant. Reasons to select a knee sleeve may be that heat is desired to relieve pain in an arthritic joint, or to provide proprioceptive cues. Diagnoses such as knee pain or mild osteoarthritis (OA) can be qualified for the fitting of the knee sleeve.

Patella tracking knee orthoses are usually fit for someone with patellofemoral syndrome, patella tracking problems, or patella dislocations. The main symptom for these diagnoses is knee pain in front of the knee exacerbated during squatting or climbing steps. Patella tracking orthoses are usually a neoprene fabric with an additional strap that presses against the patella to promote normal tracking during ambulation and prevent further dislocations or injury. Increasing quadriceps strength is also beneficial.

A hinged knee orthoses may be indicated when more significant knee pain or some mild instabilities are involved. A knee sprain or strain or possible meniscal tear is indicated for the fitting of a hinged knee brace. By adding the hinges to the knee orthosis, medial and lateral stability is gained; therefore the hinged splint provides more stability. Hinged knee orthosis may be neoprene with hinges, a single upright hinge with strapping for placement and support, or a more structured combined instability brace (Fig. 26-13). Combined instability orthoses are used for anterior cruciate ligament (ACL) tears, posterior cruciate ligament (PCL) tears, medial collateral ligament (MCL) tears, or meniscal tears. These orthoses are also fit for prophylactic needs for athletes to prevent ligament injuries or instabilities. Combined instability knee orthoses can be either prefabricated or custom-made depending upon the size and deformity of the knee. These braces provide protection against hyperextension and medial and lateral shifting.

For the diagnosis of OA with medial or lateral compartment failure involved, there are OA knee braces to be fitted. This particular style of knee orthosis is designed to assist with realigning the skeleton to unload the compressed side of the knee joint. By decreasing the load on the compressed compartment, pain will be decreased and the degeneration will be slowed in the joint. By providing proper support and correction to the compromised joint, the likelihood of increasing the patient’s quality of life and mobility is the main goal to maintain a healthy lifestyle. These knee braces are available in prefabricated or custom sizes. Custom knee orthoses require casting and measuring.

Postoperative knee orthoses use a knee hinge with adjustable ROM settings that can be changed as the rehabilitation protocols are met and changed. The knee brace can be set to hold a certain position or allow only desired ROM as prescribed by the physician, or reassessed by the PT or the physical therapist assistant (PTA). This type of knee orthosis is generally not meant for long term use and the patient will either graduate out of a knee orthosis altogether or move into a knee orthosis that is less bulky, is more durable, and has a more specific design depending on the diagnosis.

Ankle orthoses

When providing an orthosis for an ankle sprain, there are two common choices available. The stirrup splint will allow free dorsiflexion and plantar flexion to occur while providing limitations to inversion and eversion to prevent the sprain from recurring. This splint is often used for patients who chronically sprain their ankles. The other variety is the ankle gauntlet. This splint provides more immobilization in all planes of motion and is also easily worn inside a tennis shoe. Therefore, depending upon the diagnosis, physician’s prescription, and the patient’s history, assessments will be made as to which orthosis to provide.

Boot walkers or cam walkers are appropriate selections when treating fractures or severe sprains or for immobilizing the foot or ankle after surgery. These orthoses are removable for bathing and sleeping. The sole of the boot walker incorporates a rocker bottom to assimilate a more natural gait. The length of time worn is dependent upon the patient’s required healing time.

Foot orthoses

Custom foot orthoses are another means of obtaining proper foot position and protecting areas of great pressure in the foot. The transverse arch and the medial and lateral longitudinal arches can then be supported. By creating pocketed areas of relief for the plantar surface of the foot, we can slow down degenerative processes and correct skeletal alignment of the foot. Prominent bony landmarks in the anatomy of the foot, such as the metatarsal heads, navicular, talus, and cuneiform bones, can be supported or relieved depending upon the condition of the foot. Diagnoses such as diabetes, plantar fasciitis, heel spurs, pronation, ulcerations, and collapsed arches all benefit from the use of custom made arch supports to correct the position of the foot and assist with a better gait pattern. There are numerous materials available to use to meet the needs of each individual patient, including but not limited to carbon fiber, cork, pelite, Plastazote, and elastomer gel offering a wide range of firmness from rigidity to softness. Individual needs can be met by combining two or more materials to obtain forgiveness and cushion in portions of the foot requiring soft support and firm support to align the foot in the best position possible.

Combination orthoses

Ankle-foot orthoses

Diagnoses such as CVA, multiple sclerosis (MS), spinal cord injury (SCI), and various neuropathies can cause a condition known as foot drop. This condition causes the patient to lose the ability to fire the peroneal nerve, thus losing the ability to contract the anterior tibialis muscle. The patient is essentially unable to pick the toe up by dorsiflexing the ankle complex. When this happens the frequency of dragging the toe during the gait cycle increases and can cause the patient to fall. AFOs can help this condition by holding the ankle foot complex at 90°. The AFO will allow dorsiflexion as the patient rolls over the foot during the stance phase of the gait cycle.

All AFOs limit inversion and eversion and place the foot in subtalar neutral position if obtainable. A pelite liner can also be molded into the AFO as a soft interface, creating a more comfortable, padded support for the patient. The diabetic patient population especially needs custom AFOs to decrease the potential for developing sores or ulcers that may not heal because of rubbing or areas of high pressure. When a custom AFO is fabricated, areas of relief are built into the orthosis. These areas accommodate heavy callused areas, ulcerations, and provide support and relief for collapsed arches that cannot be corrected. Plastic AFOs are in complete contact with the patient’s foot and calf and are fitted inside a shoe, causing the shoe to be an integral part of the orthosis. Shoe wear is limited to mostly lace or hook and loop attachments because this feature of the shoes seats the heel of the AFO into the shoe. Slip-on shoes do not work as well because they allow the heel to slip in and out of the shoe too easily.

There are several types of AFO, including leaf spring, solid ankle, free ankle, and dorsi-assist (Fig. 26-14). These orthoses fall into two categories, static or dynamic, with both types consisting of either prefabricated or custom fabricated devices. AFOs can be classified either as static orthoses (prohibiting motion at the ankle) or dynamic orthoses (permitting ankle motion, primarily in the sagittal plane). The solid ankle AFO, the anterior floor reaction brace, and the patellar tendon-bearing (PTB) AFO are examples of static AFOs. Those in the dynamic group include posterior leaf spring and hinged-ankle (articulating) AFO designs.⁹ Dynamic AFOs are contraindicated in patients with severe edema, nonhealing diabetic ulcers, and severe foot deformity.

The most simple and cost-effective AFO is the leaf spring. The leaf spring AFO fits under the plantar surface of the foot and into the shoe. It extends up the posterior portion of the calf and has a single strap just distal to the fibula head. It is lightweight, streamlined, and effective, especially if no other instabilities or weaknesses are present. The leaf spring is available in a wide variety of sizes of foot length, foot width, and height of the upright portion.

The solid ankle AFO provides the highest level of support and immobilization. The dorsi-assist ankle joint allows and assists dorsiflexion, while plantar flexion can be limited to stopping at 90° or free plantar flexion. A free ankle AFO allows free plantar and dorsi flexion.

Prefabricated Versus Custom Ankle-Foot Orthoses

If a prefabricated AFO does not fit properly under the foot or have proper contouring around the malleoli, a custom AFO can be made. Fabricating a custom AFO will provide a more intimate fit and thus creates an orthosis that the patient can wear for longer periods of time, which increases compliance and quality of life. The custom AFO will incorporate areas of relief for bony prominences such as malleoli; dropped or collapsed bones of the foot, such as the navicular or talus; and dropped, callused, or ulcerated metatarsal heads. When fabricating a custom AFO, the design of the orthosis is dependent upon patient requirements as well as the practitioner’s expertise in componentry selection. If minimal support is required, the trim lines can be very narrow, therefore allowing more movement and flexibility and it is less limiting. If the trim lines are wide and encompassing of the malleoli, then the AFO is more rigid and immobilizing, thus providing increased levels of ankle stability and immobilization.

Plastic Versus Metal Ankle-Foot Orthoses

The plastic AFO is total contact and this feature is not an option for certain patient populations. For patients who suffer from edema in their lower extremities, the metal AFO is a good choice because it does not touch the patient except for the one strap that is just distal to the fibula head. This allows for edema accumulation during the day without rubbing along all of the trim lines that the plastic AFO has. Another reason to select a metal AFO is that it enables incorporation of a custom arch support into the shoe. There would not be enough depth in a shoe for a plastic AFO and a custom arch support. A metal AFO, more commonly known as a short leg brace, consists of metal uprights contoured specifically to each patient and attached to the shoe using a metal stirrup that is riveted into the sole of the shoe. The options of solid ankle, limited motion, or dorsi-assist apply to metal bracing as well as plastic. Metal AFOs are heavier and less cosmetic, but when the patient is not a candidate for a plastic total contact AFO, then a metal brace must be fabricated. Metal ortheses are most commonly fit for diagnoses of post-polio syndrome, CVAs, spinal cord injuries, cerebral palsy, and multiple sclerosis patients. Making the proper selection for metal type used for the uprights in a lower extremity brace is crucial for optimal patient outcome. For instance, if the patient is of small stature, experiencing weakness, or fairly inactive, choosing aluminum uprights for the patient’s bracing allows the practitioner to provide a material with required strength and adequate support for ambulation without fabricating a brace that would be too heavy for the patient to use. The consideration of patient ability is a crucial factor in choosing fabrication materials. Providing a patient with an orthosis that is too heavy for use will lead to nonuse of the orthosis and noncompliance of the patient, therefore increasing the likelihood of injury and further progression of the deformity. The shoe attached to the orthosis is considered to be a part of the orthosis. Shoe selection is limited to walking shoes and other closed heel and toe shoes. Please refer to the previous section on shoe wear for more information about shoes.

Specialized Ankle-Foot Orthoses

Certain conditions may not respond to commonly used types of AFOs and may require the use of specialized ortheses. The ToeOFF, an orthosis to aid gait manufactured by Allard USA (Rockaway, NJ), and the Charcot restraint orthotic walker (CROW) are two types of specialized custom AFOs.

The CROW is one form of a custom fabricated boot using a clam shell two-piece design and a rocker bottom sole. The function of the CROW is to provide a custom, intimate fit to eliminate friction, shear forces, and motion inside the boot to promote the healing process for nonhealing decubitus ulcers or fractures of the foot, or Charcot deformities. Since it is removable, the boot helps to promote proper hygiene. Often patients who are fitted with a CROW are also receiving wound care treatment. The CROW has an anterior/posterior bivalve construction and is fabricated using a mold of the patient’s lower leg. The closure for the CROW uses a butterfly chafe design with hook and loop for ease of don and doff.

Knee-ankle-foot orthoses

When instability, deformity or both are present in the knee as well as the foot and ankle, a KAFO can be fabricated. The KAFO will extend from just distal of the femur head and extend to the foot. Oftentimes fitting both a knee orthosis and an AFO is tried but is not always successful or optimal for patient outcomes. Because of the difficulty in trying to fit a patient with the two components of a knee orthosis and an AFO, the fit is compromised where the two orthoses meet or overlap. Frequently, there will be rubbing and pinching at this junction. The knee orthosis would have to extend down past the proximal edge of the AFO causing the purchase of the knee orthosis to be sacrificed.

Types of Knee-Ankle-Foot Orthoses

For the KAFO, there are options for different types of knee joints in order to accommodate varied levels of instabilities (Fig. 26-15). Locked knee joints hold the patient in full extension to prevent knee buckling during ambulation. The patient must use hip hiking or circumduction to progress the limb forward during ambulation, thus providing supported and secure ambulation. The use of drop locks enables the patient to release the locked position and allow knee flexion for sitting. The drop locks can be unlocked by simply grasping with the hands and pulling up until the joint is cleared, or by the use of a trigger release mechanism attached to the upper, lateral portion of the KAFO. If quadriceps strength is adequate, a free knee joint can be used to allow full ROM and a more natural gait for ambulation. This type KAFO will not lock during heel strike, and therefore will not protect against knee buckling. For patients with a disease such as OA or deformity, this type of orthosis provides adequate support for ambulation due to the patient having adequate quadriceps strength while still providing medial and lateral support.

In the last few years the benefits of technology have become substantial in the realm of KAFOs. New knee joint designs that allow a locked knee at heel strike and/or full knee extension and a free knee swing during the swing phase of the gait cycle are becoming more widely prescribed and fitted. The mechanism for locking and unlocking the knee unit is determined by the manufacturer, and therefore each design will have a slightly different patient population selection.

The Free Walk KAFO by Otto Bock (Minneapolis, Minn.) helps achieve a more natural gait by locking during the stance phase and unlocking during the swing phase. The automatic lock is initiated by knee extension moment, and is only released to swing freely when a knee extension moment and dorsiflexion occur simultaneously in terminal stance. The KAFO joint requires the simultaneous extension moment and 10° of dorsiflexion to release the lock, making it safe for descents and ascents. The Free Walk has an open frame design that uses only one upright instead of two (Fig. 26-16, A). The upright is on the lateral side of the leg. The locking mechanism control cable is contained in the tubular stainless steel sidebar. The Free Walk is a custom fabricated orthosis, but the patient must be able to obtain a knee extension moment and dorsiflexion of ankle and foot to operate this device.⁷

Fillauer Company (Chattanooga, Tenn.) has designed a dynamic KAFO called the Swing Phase Lock (SPL). The SPL KAFO utilizes a simple internal pendulum mechanism to lock and unlock the knee depending upon the angle of the joint in the sagittal plane (Fig. 26-16, B). During the gait cycle, the knee joint will lock just before heel strike for support during stance and unlock the knee at heel off in preparation for swing phase. The SPL KAFO has three modes of operation controlled by a proximal remote push-button switch: automatic lock and unlock, manual unlock, and manual lock. These three modes allow the patient to select automatic lock for walking, unlock for sitting, or lock for standing. Candidate selections for this KAFO are patients with post-polio syndrome, spinal involvement, CVA, peripheral paresis or paralysis, nerve inflammations, neurological failures, myopathies, and MS or similar diseases. Contraindications are knee flexion contractures greater than 10°, central paralysis, hip flexion contractures, hip musculature involvement, poor balance/coordination, and knee hyperextension greater than 10°.⁷

Both of these KAFOs eliminate the need for circumduction or hip hiking as seen in the traditional KAFOs.

Hip-knee-ankle-foot orthoses

The HKAFO is a hip-knee-ankle-foot orthosis that supports all of the joints that it crosses. There are different styles, materials, and componentry to choose from to design every orthosis specifically to each individual’s needs (Fig. 26-17). Some styles of HKAFO can be heavy and cumbersome simply because of the bulk of the orthosis and the number of anatomical joints that it crosses, creating a steep learning curve for the patient as well as the PT and PTA. Practicing the donning and doffing process, focusing rehabilitation sessions on upper body strength, ROM, and developing a successful gait pattern are a few of the hurdles that face the patient, PT, PTA, and family members and caregivers. In addition to the physical demands, the emotional stressors should also be addressed by setting clear, concise, attainable goals and ensuring that each individual has the patience needed to fulfill the physical therapy sessions and protocols. Indications are spina bifida, traumatic paraplegia, muscular dystrophy, and osteogenesis imperfecta. The patient must have plantigrade feet, knees should not have flexion contractures greater than 5° to 10°, hips should be free of contractures and flexible (not rigid or spastic), upper extremity strength should be good, the patient should be well motivated and have a supportive family, and goals and expectations should be realistic.

Contraindications are severe contractures, spasticity or other involuntary movements, obesity, and poor upper extremity strength. The reciprocating gait orthosis (RGO) provides excellent walking function and hands-free standing, and the use of the orthosis helps to stretch the hip flexors to prevent contractures. With every step, as one leg flexes, the other leg must extend and thus stretch the hip flexors. The age one can be fitted with the isocentric RGO is as young as 17 months, giving them a better chance for walking and standing and therefore enjoying earlier the physiologic, skeletal, and psychological benefits of being upright. In order to ambulate, the patient must be able to use forearm crutches to provide upper body support. A tripod gait is often used when covering a greater distance is required, such as when outdoors. When using the isocentric RGO inside one’s house or indoors, the patient can use a normal ambulation pattern with their crutches. The RGO is a custom-made device in which measurements and a cast of the torso and hip portion of the patient is required. There are two styles available. One is an open design in which the wearer will don the device by slipping into the open posterior side. It fits over all clothing including shoes. The second will fit more intimately to the patient and the ankle-foot portion will fit into a shoe.⁶

Locking pins

Many prostheses, whether upper or lower extremity, are suspended by the use of a liner with a locking pin. The pin is located on the distal end of the liner and slips into a locking mechanism that is housed within the distal end of the socket (Fig. 26-18). A liner is a means of interface that lies between the skin and the socket. Liners are made of silicone, polypropylene, elastomer gels, or urethane blends. The liners act as a cushion for shock absorbency, prevent abrasions, and protect against shearing forces and skin breakdown of the residual limb. This type of suspension provides a secure attachment, and because of the visual and audible cues made as the pin engages into the lock, this type of suspension provides a factor of emotional security that the prosthesis is donned correctly. There is a release button to press that will disengage the lock and allow the prosthesis to be removed.

The Alpha Liner, for example, is composed of a unique, mineral oil–based, thermoplastic, elastomer gel with durable fabric covering that makes the liner last longer. The mineral oil within the liner seeps into the skin, creating a skin friendly environment. This gel liner also conforms to the shape of the residual limb providing a custom fit. The Alpha Liner is available in prefabricated and custom-made variations for pediatric, transfemoral, transtibial, and upper extremity amputees. Liners are also available without the distal umbrella for pin attachment and provide an interface between the socket and the limb.¹¹

Suction/vacuum suspension

Suction is also a viable and desirable way to suspend a prosthesis. Suction creates an airtight socket through the use of an expulsion valve. At the distal end of the prosthesis there is a valve that the wearer pulls a thin sock through, which pulls the residual limb completely into the socket, and then the valve cap is placed back into the opening to create a closed environment (Fig. 26-19). The top cap of the valve uses an expulsion valve that the amputee can press to release air that may get trapped inside the socket to regain optimal fit.

The use of a vacuum system within the socket provides multiple benefits to the amputee. Fluid fluctuation throughout the course of the day is better managed, less pistoning occurs, and circulation is enhanced, thus contributing to a healthier residual limb. One of the main problems that amputees experience on a daily basis is the control of volume change within the socket during the length of the day. The more active the amputee, the more volume loss the individual will experience throughout the day. Traditionally the way to control volume changes inside the socket is to add prosthetic socks as the residual limb volume decreases. If the amputee does not use sock management effectively, then chaffing and pistoning become a problem and cause skin breakdown.

Patella straps

A patella strap can be added to a transtibial prosthesis to provide suspension above the femoral condyles while still allowing full flexion and extension. This strap can be made out of leather or other strapping materials and secured with buckles or hook and loop closures.

Supracondylar suspension is obtained by the design of the socket. By creating a snug, intimate fit just superior to the femoral or humeral condyles, this design creates a suspension that is easy to use, maintains appropriate fit, and allows for full ROM.

Harnesses

For upper extremity prostheses, the use of a harness for suspension is widely used. The harness not only suspends the prosthesis, but also acts as a mechanism for control of the terminal device (TD) or hand for opening and closing the hand for grip (Fig. 26-20). The hand can be one of several types of hooks or a hand that has more cosmesis and looks like a real hand. By elevating or depressing the shoulder or scapular manipulations, the cables that connect to the hand are tightened, and this tension on the cable opens the hand. The harness will also operate the elbow unit for the transhumeral amputee. There are separate cables, controls, and body movements necessary to lock and unlock the elbow joint.

There are many designs for harnesses. The style desired is the most simple that will provide the amputee with the ability to control the TD. Harnessing uses the body’s movements and transmits them to the cable portion of the harness and causes movement of the TD. The movements necessary for TD control are glenohumeral forward flexion, biscapular abduction, shoulder depression and elevation and chest expansion. Depending upon the level of amputation and the amputee’s strength and ROM, the correct harness can be chosen. Different motions can be used to control the TD or the elbow joint. Each movement must be mastered to efficiently use the prosthesis.¹⁶

There are advantages and disadvantages to using a harness. These can be found in Box 26-1.

Locking Knee

A locking knee is inherently the most stable and safe knee. This knee will have a manual switch or button that will unlock the knee and allow flexion for sitting. During ambulation the knee will remain locked throughout the gait cycle. This feature allows the amputee to ambulate and roll over the knee without fear of buckling, and thus decreasing the percentage of falls. Since the knee does not bend during swing phase, hip hiking or circumduction may be used to propel the prosthesis.

Weight Activated Knee

A weight activated or stance control knee unit will provide some limited locked knee moments and also allow free swing during the swing phase of the gait. In order to lock the knee for a safe stance phase, the knee must reach full extension at heel strike. Most weight activated knees have a built-in angle of flexion of approximately 15° before breaking and releasing the knee for swing phase. As the amputee rolls over the foot and the knee begins to break, the knee will release the locked, safe position and flex, then swing forward freely. This swing phase of the knee units is adjustable and can be set to meet each individual’s cadence requirements. The use of hydraulics or pneumatics controls the rate of swing by increasing or decreasing the viscosity or pressure of fluids or air within the knee component.

Microprocessor Knee

Current technology has added some very important control features that have not been offered until the past few years. The use of computerized componentry to control swing and stance phase has provided transfemoral amputees with a new type of freedom. The C-Leg, Rheo Knee, Plié MPC Knee, and Smart Adaptive are all examples of microprocessor (MPC) knee components (Fig. 26-23). Each knee works on a slightly different mechanism of gait, but this freedom of cadence change without the fear of falling and less use of mental focus required by traditional knee units provides huge gains for the transfemoral amputees.¹³