This document provides an overview of lower limb prosthetics. It defines prosthetics as devices that replace missing limbs and discusses their aims of restoring function and mobility. It describes the common levels of lower limb amputation as transtibial and transfemoral. The key components of a lower limb prosthesis are then outlined as the socket, suspension system, knee joint, shank/pylon, and foot/terminal device. Issues related to prosthesis use like skin problems, pain, and ineffective suspension are also summarized.

1. Lower limb
Prosthesis
Adib Mursyidi Iskandar Mirza
Orthopedics

2. Outline
• Definition
• Aim of prosthesis
• Level of amputations of lower limbs
• Components of prosthesis
• General issues

3. Definition
• Prosthesis
• Device to replace part of the limb or missing limb
“substitute”
• Orthosis
• Externally applied mechanical devices
• Support weakened injured, paralyzed, diseased part
as supplementation
• Prosthetist
• Person skilled in prosthetics and its application

4. Aim of prosthesis
• To substitute for a lost part
• To restore lost function
• Comfortable ambulation
• Minimal/reduce of expenditure of energy
• Minimizing the shift of the center of gravity of the
body during gait

5. Level of amputation
• There are several
levels of lower limb
amputation
• Most common are
transtibial and
transfemoral

6. Component of
prosthesis of Lower
Limbs

7. Parts of prosthesis
1. Socket
2. Suspension system
3. Knee Joint
4. Shank/pylon
5. Foot/Terminal device

8. Suction&
Mechl close fitting

9. Socket
• Most important part
• Is the connection between the stump
and the prosthesis
• Protects the stump and transmits
forces
• Uncomfortable  rejected
• Contoured sockets fit closer to bone,
muscle, soft tissue
• Provide support and relief

10. Suspension systems
• For attaching socket
to body
• Types of suspension
• Sleeve, belt, straps,
or cuff
• Suction prosthesis
• Mechanical close
fitting or silicon sock
helps to maintain
airtight seal

11. Suspension systems materials
• Sleeve – made from
latex
• Cuff – used to hold
prosthesis in residual
limb
• Belt/straps – use a
waist belt with elastic
strap to suspend
prosthesis
• Suction method –
consist of silicon
sleeve with short pin
at the end  will fit
into residual limb and
locks into socket

12. Knee joint
1. Axis system
2. Friction
3. Stabilizer

13. Axis system
• Single axis
• Axis of prosthetic knee is same as that of weighty
bearing axis
• Flexion easier, but stance phase control difficult
• Polycentric
• Permits momentary axis of knee flexion to change
through the arc of motion  increase knee stability

14. Medium
friction
(hydraulic)
friction
Constant friction
Friction mechanism
• Changes knee swing by modifying the speed of knee motion
• Adjust knee swing accordingly
• Constant friction
• Applies uniform resistance throughout swing phase
• Variable friction-cadence control
• Greater friction is applied at early and late swing
• Medium friction
• Oil (hydraulic) friction
• Air (pneumatic)friction
• Allows best gait pattern  best for active patients, but expensive

15. Stabilizers
Manual locking
Stabilizer
Most unit do not have special device
to increase stability
Patient control knee actions through
hip motions by
• Manual locking : prevent knee
flexion
• Friction brake : resist knee flexion
during early stance

16. Shank/pylon

17. • Use to connect the socket to the ankle-foot assembly
• Allow axial rotation and absorb, store, and release
energy
Consist of two types
• Exoskeleton
• soft foam contoured to match other limb with hard
outer shell
• Endoskeleton
• internal metal frame with cosmetic soft covering

18. Ankle-Foot Assembly

19. Ankle Foot Assembly
• Designed to provide support during standing/walking
and shock absorption as well
• Consist of 3 categories
• Single axis foot
• Solid ankle cushioned heel (SACH) foot
• Dynamic response
• Articulating
• Non articulating

20. • Ankle hinge allow dorsiflexion and plantar flexion
• Disadvantages
• Poor durability
• Poor cosmesis
Single Axis Foot

21. Solid ankle cushion heel (SACH)
• Most widely
prescribed foot
• Due to simple, low
cost and durability
• Uses in patient with
low activity
• Disadvantages – may
overload the non
amputated foot

22. Dynamic response energy storing
foot
• General use for most
normal activities
• Consist of
• Articulating
• Non articulating

23. Articulating
• Allow motion at the level of human ankle
• Indications
• Patients walking on uneven surfaces
• Advantages
• 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

24. 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

25. Prescription of prosthesis
• Type of prosthesis required
• Level of amputation
• Material of socket
• Suspension mechanism
• Type of cosmesis required

26. 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

27. • 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
• Post operative scar

28. • Painful residual limb
• possible causes include bony prominences, poorly
fitting prostheses, neuroma formation, and insufficient
soft tissue coverage

29. • Ineffective suspension system
• Poor socket fit
• Stump volume changes
• Foot alignment abnormalities