Overview of Prosthetics

Question 1

UE Prosthetics

Answer 1

Can be body or externally powered or combo
External power = myoelectric devices, movement generate by mm cxn
Body = includes terminal device such as wrist/elbow that is powered by a cable system

Terminal devices

• Ex. passive hand or fist to a myoelectric hand
• May need multiple terminal devices to accommodate needs of child and based on activities child participates in

Types of prosthetic is selected based on: age/size, parent/child desires of function and goals, and appropriate terminal device

Harnessed system used to suspend prosthesis or to control terminal device

• can be used by above and below elbow amputations
• Figure 8 and chest strap are 2 options for harness systems- both securely anchor the prosthesis without limiting shoulder movement
• Self suspending socket- young children

Question 2

LE prosthetics

Answer 2

often fitted to accommodate for some growth

SACH Foot- popular pediatric prosthetic foot
- Lil foot = variation of SACH foot with more flexible plastic that allows for better response with kneeling or pulling to stand
Can also be fitted with dynamic response or energy storing feet – study found that dynamic helped to improved children’s endurance, dynamic preferred cosmetically

Shank

• Exoskeletal- increased durability
• Endoskeletal- looks more like a leg, skin like covering

Knees Toddlers

• single axis constant friction knee- set to function at a certain walking speed, not very stable, buckles, prosthesis lags behind bc shank cannot swing as quickly
• – Toddler getting fitted- knee is placed anterior to the knee center to increase stability
• Polycentric knee with a four bar linkage mechanism- mimics anatomy of knee joint to increase stability
• – axis of motion is posterior during stance to provide added stability and anterior during swing to shorten shank and assist with clearance

Knees Teenagers- more variety available
- hydraulic and pneumatic- variable friction units that allow variable walking/running speeds, have swing control mechanism that sets drag of shank through swing and a stance control that allows knee flexion without collapse of the leg– good for those involved in activities, drawback is increased weight/cost/intricate adjustments

Sockets

• narrowed medial lateral socket with ischial containment for transfemoral amp- allows for equal distribution of weight, allows less lateral mvmt of femur = increased stability in stance
• Adolescents with BKA or transtibial amp- can be fitted with standard patellar tension bearing prosthetic or total surface bearing design
• –young children may need supracondylar design that offers increased suspension
• SYME prosthesis = most common LE socket design in peds**
• suction socket- appropriate for older child who is not rapidly growing or if undergoing weight fluctuations d/t chemo

Suspension

• silesian below or total elastic suspension– younger AKA or PFFD, preschoolers
• Neoprene sleeves/silicone liners with a locking mechanism are often used

Rotationplasty- socket is BKA with a thigh cuff attachment and external hinges for knee hoint, use silesian or TES belt for suspension if needed

Encourage participation in age appropriate activities

Protheses- must be replaced every 12-18 months in growing children
- those involved in sports may want additional components