Presentation on theme: "Below Knee prosthesis Department of Orthotics and Prosthetics prosthesis Mahmood Bahramizadeh."— Presentation transcript:
Below Knee prosthesis Department of Orthotics and Prosthetics prosthesis Mahmood Bahramizadeh
History The earliest recorded use of a limb prosthesis is that of a persian soldier, Hegesistratus. (Herodotus). The oldest known artificial limb in existence was a cooper and wood leg. 300B.C.
Partial foot amputation Vascular disorders and trauma are the major causes of lower limb amputation. Prediction of healing is the most important part of level selection. As a general rule, all length possible should be saved.
Types of prosthesis 1. Postoperative pros. 2. Initial pros. 3. Preparatory pros. 4. Definitive pros. 5. Special use pros.
Postoperative pros Provided within 24 hours of amputation. Most commonly prescribed for the younger, healthier individual. Acronyms: IPSF: immediate postsurgical fitting. IPOP: immediate postoperative prosthesis.
Initial pros. Provided as soon as the sutures are removed. Due to the usual rapid atrophy of the residual limb, is generally directly molded on the residual limb by using plaster of paris or fiberglass bandage. Acronyms: EPSF: early postsurgical fitting.
Initial pros. 1 to 4 weeks after amputation. Until the suture line is stable and the skin can tolerate the stresses.
Preparatory pros. Used in cases to assess ambulatory or rehabilitation potential and help clarify details of the prosthetic prescription. Used a few days following suture removal. Lacks the protective and cosmetic. It used until stump matures. Used to optimize alignment. Used 3 to 6 months following the date of amputation.
Preparatory pros. Amputees may wearing ten plies of prosthetic socks to compensate for atrophy.
Definitive pros. Residual limb has stabilized to insure that the fit of the new prosthesis will last as long as possible. The average life span for a definitive prosthesis is from 3-5 years.
Special use pros. A certain number of patients will require for such activities as swimming, skiing.
Great toe amputation does not affect standing or walking at a slow or moderate pace. Amputation of the second toe result in severe hallux valgus.
Prosthesis Sponge rubber or foam is usually inserted into the tip of the shoe. A long steel spring shank can be used in the sole of the shoe to assist push off and prevent deformity of the shoe.
Amputation of all toes Clawing of toes. Severe hallux valgus Painful metatarsophalangeal dislocation.
Prosthesis An insole is used for supporting the metatarsal to relieve weight from the metatarsal heads. A cavus support for the high arch. A cork or foam toe block is attached distally as a filler.
Prosthesis A rocker sole may be necessary to replace the action of rocking forward on the foot. The sole can be stiffened with a long steel spring.
Prosthesis The break is an ordinary shoe is at the metatarsophalangeal joints. The vamp of the shoe may irritate the top of the stump, resulting in sores. Adding the steel spring between inner and outer sole.
Prosthesis Adding a rocker bottom. Without support in the front of the bottom the patient will display a limp as walking speed increases.
Lisfrance. (M.T complete). In the growing child where it is desirable not to interfere with the distal tibial epiphysis and yet to allow end bearing. In individual who do heavy labor or farm work.
Lisfrance. (M.T complete). Problems: 1. A fixed equinus deformity may result from a loss of the distal attachment of the dorsiflexors.
Prosthesis Shoe filler: weight bearing will be on the plantar heel skin. If only a shoe filler is used the toe break is located more proximal than in the normal foot.
Prosthesis Rigid plate : if an equinus deformity that can be passively corrected is present, for prosthetic stabilization is necessary. Attached to shank piece that goes above the calf.
Prosthesis Steel spring with heel cup: Extends out to the toe and posteriorly to form the heel cup.
Through the talonavicular and calcaneocuboid joints. Is recommended for neuropathic lesions.
Chopart Problems: equinovarus
Prosthesis Boot with toe filler: nothing to improve the gait over walking barefooted. Rub the end of the stump, causing pressure and ulceration.
Prosthesis Boot with semirigid metal sole and toe filler: From mid-stance until toe-off a long steel spring shank assists push-off by resisting the forces acting to dorsiflex the forefoot.
Prosthesis A.F.O: A posterior leaf spring AFO. Resistance to plantar flexion at heel strike. Allowing a slow descent of the foot. Resist dorsiflexion and assist push-off from mid-stance to toe-off.
Prosthesis Chopart prosthesis: is almost identical to the syme prosthesis in fabrication. Unlike the syme amputation, there is no distance between the end of the residual limb and floor with the chopart.
Pirogoff amputation Calcaneal fragment- tibia arthrodesis End-bearing stump. Advantages: 1. End-bearing 2. Walk with less limp 3. The heel flap does not wobble as it may do on the syme limb.
Prosthesis Shoe filler. PUSH OFF IS LOST Thick shoe sole with soft padding PUSH OFF IS LOST PLS AFO
Syme Ankle disarticulation. The advantages of the Syme over below knee amputation: 1. Decreased risk of serious hemorrage 2. Decreased mortality 3. A more comfortable limb 4. A more useful limb for W.Bearing. 5. Function is enhanced by limb length.
Syme Bilateral syme amputee walk with a better gait and can stand longer than bilateral below knee. Phantom Pain is rare after a syme amputation.
Prosthesis The syme amputation has had only limited popularity until recently, at least in part because of the difficulty of providing a suitable prosthesis. Syme pros. Should have durability especially in the ankle region.
Historic syme pros.
Front lacing leather socket. Strong steel frame forms medial and lateral uprights that reinforce the leather. The tightness of the the thigh-lacer provides a means of adjusting the relative distribution of weight bearing between the proximal and distal aspects of the limb.
Historic syme pros. A single-axis joint. Uncosmetic Heavy Used in countries where plastic laminates are unavailable.
Canadian syme pros. A posterior door that extends to the brim of the socket allows insertion of the limb and then is bulked into place into place for closure.
Veterans administration syme pros.
Medial window. Enhances the mechanical strength of the prosthesis over the canadian syme. Some weight bearing occurs along the proximal trim lines. Casting at 10 degrees flex.
Veterans administration syme pros. Suspension: 1. Circumference proximal to the bulbous end. 2. Auxiliary suspension: femoral condyle strap.
Elastic liner syme prosthesis
Closed, Expandable socket. Miami syme prosthesis Window less prosthesis.
Elastic liner syme prosthesis Cosmetic Stronger than canadian and VAPS. Foam is compressed as the limb is pushed into the prosthesis.
Socket foot junction The weakest point in the prosthesis Shearing force at push off
Ankle/ Foot Mechanisms Single axis Multiple axis
Single Axis Dorsiflex. (5 to 7) and plantarflex. (15) No mediolateral or transvers rotary motion. May become noisy. Heavier than SACH Less cosmetic than the SACH
Single axis 1. Wooden foot (historic) Flexible sole Toe break should be far enough forward and back : for stability and smooth transition from stance to swing phase.
Single axis Durable Easily repaired Little shock absorption Socks catch Toe break is in one plane.
Variation of the wooden foot
Multiple axis (functional) ankle Articulated assemble Cable: flexible cable between the foot and shank. Movement occurs in any direction. Otto bock universally movable Greissinger Non Articulated assemble Solid ankle cushion heel Post operative flat heeled foot Litefoot Veterans administration/ kingsley Beachcomber foot Stationary attachment flexible endoskeletal (SAFE)
Articulated assembles Mediolateral and torsional forces are reduced (absorption). Accommodates well to uneven ground. Less cosmetic than single and SACH
Articulated assembles Otto bock Greissinger foot: Can be used for above knee and below knee. More cosmetic and lighter in weight than cable.
Non articulated SACH: Shock absorption and motion provided by the material and structure.
Non articulated Heel wedge compresses at heel strike The shape and length of the wooden keel provide the smooth rocker motion and support. Foam rubber sole and nylon belting resistance to toe extension. External keel provide more stability than internal keel.
SACH The arch should provide at least 0.3 cm (1/8 in) clearance between the foot and shoe. The lower third of the SACH foot heel should fit snugly into the heel counter.
Variations of the SACH Syme foot: 2.5 cm (1in). The keel is larger and wider for stability and durability. The stud bolt is reversed to prevent any potential irritation.
Variations of the SACH Hi-heel SACH foot;
Variations of the SACH Sculptured toe SACH foot: In various heel height and firmnesses
Non articulated Post operative flat heeled foot; For immediate prosthesis Good lateral stability The weight 20 percent less than the regular molded foot. Resistance to the toe break is less than standard SACH. Used for swimming and water skiing. Used with flat heeled shoes such as tennis shoes.
Non articulated Lite foot: Lighter and softer than the regular SACH For early ambulation and for a definitive porsthesis.
Non articulated Veterans administration/kingsley Beachcomber foot: Waterproof Can locks at 120 degrees for swimming.
Stationary attachment flexible endoskeletal (SAFE): Like windlass effect At heel off the bands tithens to create a semirigid toe lever. Flexible keel is used to adapt in irregular surfaces. Long plantar ligament band span the arch to stabilize that when wearer stand.
Non articulated The anterior surface of the Bolt Block is cut at 50 degrees and the inferior surface is rounded to provide a subtalar- like surface. It has no mechanical joint.
Axial rotation device This device is used to absorb the torque and shearing force and provide the wearer to be safe of skin abrasion and allows the socket to rotate independently of the foot position.
Advantages of B.K as opposed to A.K Mortality is lower. Much better prospect of prosthetic rehabilitation. Phantom limb is lower.
Prosthesis Historic below knee: Consists of a leather thigh corset + side bars+ open ended socket. Weight bearing is carried on the residual limb and through the suspension mechanism.
Historic below knee (advan.) The thigh corset supports some of the weight bearing. Prevent hyperextension at the knee. Provides lateral-medial stability. The socket is cooler than the total contact PTB because of lack of total contact pressure.
Historic below knee (disadvanta.) Edema Bulky and heavily Uncosmetic Atrophy Relative motion causing irritation. Ischemia The hinge breaks frequently. No normal gait.
Slip socket Design to minimize relative motion between the socket and skin. The socket is either elastically suspended from the sidebars or is attached to shank by a compression spring. The socket can rotate and piston up and down.
Slip socket Is used for only for those people with short or tender limb.
Slip socket Advantages: The amputee with the slin graft can ambulate early. It preserves the knee joint.
Slip socket Disadvantages: Uncosmetic. Bulky and heavy Produce atrophy. Tear of clothing. Walk more like an A.K amputees.
P.T.B Was developed at the university of california (1959). More intimate fit and more efficient than historic.
P.T.B Advantages: Total contact design. 1. Improve circulation 2. Prevent edema 3. To distribute the W.B. 4. Better proprioception.
P.T.B Lighter than the historic. More freedom of movement than the thigh corset. More cosmetic gait. Gait looks ssentially normal except for the lack of push off.
P.T.B More cosmetic. Easier to don and remove. Require less time for fabrication.
P.T.B DisAdvantages: Require more critical fit Excessive perspiration There is a tendency for the amputee to hyperextend the knee. Frequent readjustments may be necessary.
Shank Connect the ankle/foot assembly with the socket in a specific alignment.
Weight bearing areas
Modification of the positive
Posterior brim The posterior brim is generally 0.6 to 1.3 cm (1/2 to ¼ in) higher than the patellar shelf tendon shelf. For very short limbs the posterior brim may be so high that flexion is limited to 60 degrees.
Anterior brim The anterior brim comes to the midpatellar level.
Medial and lateral brim M-L brims come to about the level of the proximal edge of the patella. The proximal aspect of the medial and lateral walls support the femoral condyles and are usually 6.5 cm (2.5in) above the medial tibial plateau in height.
Non-weight bearing areas
Hard socket The hard socket may or may not have a distal pad. Advantages: 1. Less problem with perspiration. 2. Easy to clean 3. Less bulk at knee 4. Fabrication time is less 5. More intimate fit than with an insert. Disadvantages: 1. More difficult to fit 2. Less adjustability
Soft insert socket Soft inserts are used between the hard socket and the limb. Advantages: 1. Less difficult to fit 2. Possible added comfort 3. Can make donning easier
Soft insert socket Disadvantages: 1. Hot 2. Poor hygiene 3. More weight 4. Some sacrifice of stability.
Ultralight below knee A completely crustacean PTB Exoskeletal type can be much lighter in weight while providing the same strength. The outer structure is farther from the axis and thus has a longer lever arm.
Ultralight below knee Socket: P.P Is vacuume-formed. Foot: A sole and heel cushion like that used with any SACH can be used for it Waterproof: the presence of buoyancy causes a problem during swimming
Ultralight below knee Advantages: 1. Require less energy to walk. 2. Less pistoning 3. Can be worn in and around water
Ultralight below knee DisAdvantages: 1. Not durable 2. Defficult to modify
Bent- knee prosthesis Is used in cases of irreducible knee flexion contractures. A plaster negative is made of entire limb from well up on the lower third of the femur with the knee joint in maximum extension.
Bent- knee prosthesis External knee joint Weight is borne through the remaining portion of the tibia, patellar tendon, thigh cuff. Durable cheap
Bent- knee prosthesis Is required because of poor skin condition, limited weight bearing capability, or limited knee function.
Cuff suspension Suspends the prosthesis during swing phase. Checks against knee hyperextension.
Cuff suspension Atrophy does not occur. Does not create relative motion. Not bulky. More cosmetic.
Cuff suspension Does not give M-L stability. Uncosmetic when sitting Positioning of studs is critical.
Forks, jack, or inverted Y strap to a waist belt Is used for disvascular amputee. When hip is extended and the knee is flexed during walking, the fork is under tension and acts to extend the knee and bring the shank forward.
Forks, jack, or inverted Y strap to a waist belt Good auxiliary suspension. Uneven suspension through swing phase.
Suspension prosthesis (PTS) Sc/sp. Pts: prosthese- tibiale- supracondylienne. Better M_L stability. The patellar shelf is less pronounced in the PTS than in the PTB.
Suspension prosthesis (PTS) Sc/sp. For short stump: <7.5cm. Knee instability due to lig. And muscle dysfunction.
Suspension prosthesis (PTS) Sc/sp. Less restrictive. Easier to don. Prevents genu recurvatum. More cosmetic.
Suspension prosthesis (PTS) Sc/sp. The prosthesis tend to slip down when the knee is flexed 90. Patellar enclosure may inhibite extreme knee flex. Is not suitable for long stump. Difficult for obese limb.
Supracondylar wedge suspension
Detachable medial brim
Molded rubber sleeve suspension Rolled or pulled up to cover 5 to 10 cm (2 to 4 in) of the thigh above the stump.