Introduction The goal of prosthetics are to restore limb function to as close to original function Requires a multidisciplinary team approach for coorindation of efforts to achieve the best outcome Prosthetics upper limb limb salvage is ideal in the upper arm given lack of sensation with prosthetic residual limb length is important for suspending prosthetic socket lower limb goals for prosthetic are comfort, easy to get on and off, light, durable, cosmetic, and functional Gait Antalgic gait describes any gait abnormality resulting from pain shortened stance phase on the affected limb Gait pattern of ambulation with an assistive device 3-point both the crutch and the injured limb move forward together with weight-bearing on the crutches followed by all of the weight on the uninjured limb 4-point first one crutch is advanced, then the opposite leg, then the second crutch, then the second leg, and so on swing-to that in which the crutches are advanced and the legs are swung to the same point swing-through that in which the crutches are advanced and then the legs are swung past them Crutch walking requires more energy than walking with a prosthesis muscles that need strengthening in preparation for crutch walking latissimus dorsi triceps and biceps quads hip extensors hip abductors Wheelchair propulsion 9% increase in energy expenditure compared to ambulation in normal subjects Ambulation assistive devices cane shifts center of gravity towards affected side when cane is used on contralateral side axillary crutch 2 axillary crutches are required for proper gait if lower extremity is non weight-bearing or toe-touch weight-bearing Upper Extremity Prostheses Timing of prosthetic fitting as soon as possible, even before complete wound healing has completed better outcomes if fitted within 30 days Midlength transradial amputation Myoelectric prostheses best candidate is a patient with a midlength transradial amputation transmits electrical activity to surface electrodes on residual limb muscles advantages better cosmesis allows more proximal coverage disadvantages heavier and more expensive prosthesis requires more maintenance Body-powered prostheses indications best for heavy labor with less maintenance needed techniques activate terminal device with shoulder flexion and abduction center the harness ring just off the midline of C7 towards the non-amputated side advantages moderate cost and weight most durable prosthesis higher sensory feedback disadvantages poorer cosmesis requires more gross upper limb movement for proper function Elbow disarticulation or above elbow amputation requires a prosthesis to recreate functional motion of two joints (elbow and wrist) this creates heavy and less efficient as the only solution best function with least weight is achieved by combining the various options of myoelectric, body-powered, and body-driven switch components Proximal transhumeral and shoulder disarticulation amputation an amputation this proximal has lost the ability to create a lever arm with mechanical advantage best option is a universal shoulder joint that is positioned in space with the contralateral arm this can be combined with lightweight hybrid prosthetic components Components Terminal device passive terminal device more cosmetic but less functional than active terminal devices active terminal device more functional, but less cosmetic than passive terminal devices either hooks and prosthetic hands with cables or myoelectric devices grips precision grip (pincer-type) tripod grip (palmar grip, 3-jaw chuck pinch) lateral pinch (key pinch) hook power grip spherical grip prehension devices handlike device thumb, index, and long finger components may be covered with a glove for better cosmesis good choice for office worker non-hand prehension device hook or two-finger pincer with parallel surfaces may attach task-specific tools with quick release mechanism good for physical labor myoelectric devices can only be used in an environment clean from dirt, dust, water, grease, or solvents mechanisms voluntary opening device is closed at rest and opens with contraction of proximal muscles more common than voluntary closing voluntary closing device is open at rest and residual forearm flexors grip the desired object heavier and less durable than voluntary opening wrist units quick disconnect wrist allows easy swapping of devices with specialized function locking wrist unit prevents rotation during grasping and lifting wrist flexion unit used in bilateral upper extremity amputees placed on longer residual limb to allow midline activities (shaving, buttoning) elbow units rigid elbow hinge indications short trans-radial amputation with inability to pronate or supinate with maintenance of elbow flexion flexible elbow hinge indications wrist disarticulation or long transradial amputation with sufficient pronation, supination, and elbow flexion and extension shoulder units due to increased energy expenditure and weight of prosthesis many choose to use a purely cosmetic prosthesis indications forequarter or shoulder level amputation Lower Limb Prosthesis Foot prosthesis Single axis foot ankle hinge allows dorsiflexion and plantar flexion disadvantages poor durability and cosmesis SACH (solid ankle cushioned heel) foot indications general use in patients with low activity levels use is being phased out disadvantages overloads the nonamputated foot Dynamic response (energy-storing) foot indications general use for most normal activities patients who regularly ambulate over uneven surfaces likely benefit from multi-axial articulated prostheses articulating and non-articulating dynamic-response foot prostheses are available articulating allows inversion, eversion, and rotation of the foot indications patients walking on uneven surfaces advantages allows inversion, eversion, and foot rotation absorbs loads and decreases shear forces flexible keels acts as a spring to decrease contralateral loading, allow dorsiflexion, and provide a spring-like push-off posterior projection from keel gives a smooth transition from heel-strike sagittal split allows for inversion and eversion non-articulating have short or long keels shorter keels are not as responsive and are indicated for moderate-activity patients longer keels are indicated for high-demand patients different feet for running and lower-demand activities available Shanks provide structural support between components endoskeleton (soft exterior) or exoskeleton model (hard exterior) can provide a lever arm for propulsion following transmetatarsal amputation Knee prosethesis Indications transfemoral and knee disarticulation amputations patient functional status is an important consideration Six types of prostheses for AKA or through knee polycentric (four-bar linkage) knee indications transfemoral amputation knee disarticulations bilateral amputations techniques variable knee center of rotation controlled flexion ability to walk at a moderately fast pace supports increased weight compared to constant friction knee stance-phase control (weight-activated) knee indications older patients with proximal amputations patients walking on uneven terrain techniques acts like a constant-friction knee in swing phase weightbearing through the prosthesis locks up through the high-friction housing fluid-control (hydraulic and pneumatic) knee indications active patients willing to sacrifice a heavier prosthesis for more utility and variability techniques allows for variable cadence via a piston mechanism prevents excess flexion extends earlier in the gait cycle constant friction (single axis) knee indications general use patients walking on uneven terrain most common pediatric prosthesis not recommended for older or weaker patients technique hinge that uses a screw or rubber pad to apply friction to the knee to decrease knee swing only allows a single speed of walking relies on alignment for stance phase stability variable-friction (cadence control) technique multiple friction pads increase knee flexion resistance as the knee extends variable walking speeds are allowed not very durable manual locking knee technique constant friction knee hinge with an extension lock extension lock can be unlocked to allow knee to act like a constant-friction knee Socket the connection between the stump and the prosthesis computer screening technology can decrease time to socket fabrication preparatory socket may need to be adjusted several times as edema resolves patellar tendon-bearing prosthesis is most common for BKA transfemoral or quadrilateral sockets make it hard to keep the femur in adduction transfemoral allow 10 degrees of adduction and 5 degrees of flexion Suspension systems attaches prosthesis to residual limb using belts, wedges, straps, and suction suction suspension standard suction form-fitting rigid or semi-rigid socket which fits onto residual limb silicon suction silicon-based sock fits over the stump and is then inserted into the socket silicon provides an airtight seal between prosthesis and amputated stump Pylon simple tube or shell that attaches the socket to the terminal device newer styles allow axial rotation and absorb, store, and release energy exoskeleton soft foam contoured to match other limb with hard outer shell endoskeleton internal metal frame with cosmetic soft covering Osseointegration direct attachment of a prosthesis to the skeleton may improve biomechanical advantage of prosthesis and rehabiliation Terminal device Most commonly a foot, but may take other forms Prosthetic Complications General issues choke syndrome caused by obstructed venous outflow due to a socket that is too snug acute phase red, indurated skin with orange-peel appearance chronic phase hemosiderin deposits and venous stasis ulcers skin problems contact dermatitis most commonly caused by liner, socks, and suspension mechanism treatment remove the offending item with symptomatic treatment cysts and excess sweating signs of excess shear forces and improperly fitted components scar massage and lubricate the scar for a well-healed incision painful residual limb possible causes include heterotopic ossification, bony prominences, poorly fitting prostheses, neuroma formation, and insufficient soft tissue coverage Transtibial prostheses swing-phase pistoning ineffective suspension system stance-phase pistoning poor socket fit stump volume changes (stump sock may need to be changed) foot alignment abnormalities inset foot (medialized) varus strain, circumduction and pain outset foot (lateralized) valgus strain, broad-based gait and pain anterior foot placement stable increased knee extension with patellar pain posterior foot placement unstable increased knee flexion drop-off or knee buckling can be improved by moving the foot more anterior dorsiflexed foot increased patellar pressure plantar-flexed foot drop-off and increased patellar pressure pain or redness related to pressure prosthetic foot abnormalities heel is too soft leads to excessive knee extension heel is too hard leads to excessive knee flexion and lateral rotation of toes