Prosthetics

A shoulder disarticulation prosthesis is a type of upper-limb prosthetic designed for individuals who have undergone an amputation through the shoulder joint, meaning the entire arm.

Common Indications

• Trauma (e.g., severe crush injury or avulsion)
• Malignancy (e.g., bone or soft tissue sarcoma)
• Infection (e.g., osteomyelitis)
• Congenital limb deficiency
• Failed reconstruction or vascular compromise

Types of Shoulder Disarticulation Prostheses

1. Passive (Cosmetic) Prosthesis
   • Lightweight, anatomically shaped for appearance only
   • No functional components; often used for symmetry or social comfort
2. Body-Powered Prosthesis
   • Operated using harnesses and cables, typically to control an elbow or terminal device
   • Durable and offers simple control, but limited motion at shoulder level
3. Externally Powered (Myoelectric) Prosthesis
   • Uses electrical signals from residual muscles or other input methods (e.g. switches) to control elbow, wrist, and hand
   • Offers greater function and natural motion; may include multi-articulating hands
   • Requires power source (battery), and routine calibration and charging
4. Hybrid Systems
   • Combine body-powered and myoelectric components (e.g., body-powered, elbow, myoelectric hand)
   • Used to balance weight, control, and functionality

An above-elbow prosthesis (also known as a transhumeral prosthesis) is designed for individuals who have undergone an amputation between the shoulder and elbow joints.

Common Indications

• Traumatic amputation
• Congenital limb deficiency
• Oncologic resection (e.g., sarcoma)
• Severe infection or failed limb salvage
• Vascular compromise

Types of Above-Elbow Prostheses

1. Passive (Cosmetic) Prosthesis
   • Lightweight, non-functional
   • Focuses on restoring appearance
   • Can be used for symmetry, clothing support, or light activities
2. Body-Powered Prosthesis
   • Operated using a harness and cable system
   • Movements of the shoulders or chest open/close the terminal device and flex the elbow
   • Durable, reliable, and lower cost, but requires physical effort and has a more limited range of motion
3. Myoelectric Prosthesis
   • Controlled via muscle signals (EMG) from the residual limb
   • Often includes powered elbow, wrist, and hand
   • Offers more natural movement and grip patterns but is heavier, more expensive, and requires charging and regular maintenance
4. Hybrid Prosthesis
   • Combines body-powered and myoelectric components
   • Example: myoelectric hand + body-powered elbow
   • Offers a balance of weight, control, and cost

A below-elbow prosthesis (also known as a trans-radial prosthesis) is designed for individuals with an amputation between the elbow and the wrist.

Common Indications

• Traumatic injury
• Congenital limb deficiency
• Tumor resection
• Infection or failed limb salvage (e.g., sepsis, necrosis)
• Vascular disease

Types of Below-Elbow Prostheses

1. Passive (Cosmetic) Prosthesis
   • Anatomically shaped, lightweight
   • Primarily for appearance and light bimanual activities
   • No active movement or grip
2. Body-Powered Prosthesis
   • Operated by harness and cable system attached to the opposite shoulder
   • Allows elbow flexion and voluntary opening/closing of a terminal device (hook or hand)
   • Durable, lightweight, and relatively low cost
3. Myoelectric Prosthesis
   • Uses electromyographic (EMG) signals from residual forearm muscles
   • Controls powered hand and sometimes wrist rotation
   • Offers more natural motion, multiple grip patterns, and improved function for fine tasks
   • Heavier, more expensive, and requires power and training
4. Hybrid Prosthesis
   • Combines myoelectric hand with a manual wrist
   • Balances functionality with weight and cost considerations
5. Activity-Specific Prostheses
   • Designed for specific tasks (e.g., sports, tools, instruments, biking, weightlifting)
   • Often used in addition to a primary prosthesis

A hand prosthesis is a device that replaces some or all of the function and appearance of a missing hand. It may be part of a partial hand, transmetacarpal or wrist disarticulation.

Common Indications

• Traumatic amputation (e.g., crush, laceration, avulsion)
• Congenital limb deficiency
• Tumor resection (oncologic amputation)
• Severe infection, sepsis, or necrosis
• Vascular conditions (e.g., Buerger’s disease, diabetes complications)

Types of Hand Prostheses

1. Passive (Cosmetic) Hands
   • Made of silicone or PVC with life-like skin tone and detailing
   • Non-functional or minimally functional
   • Lightweight, used for cosmetic appearance and symmetry
2. Body-Powered Hands
   • Operated via a cable and harness system controlled by the user’s shoulder or arm movement
   • Often attached to a body-powered below-elbow prosthesis
   • Durable and reliable, though less precise and aesthetic
3. Myoelectric Hands
   • Controlled by electrical signals (EMG) from residual limb muscles
   • May offer multiple grip patterns (e.g., tripod, lateral pinch, power grip)
   • Options include:
     • Single-speed hands
     • Multi-articulating hands
4. Activity-Specific Hands
   • Designed for targeted tasks (e.g., cycling, weightlifting, tools, instruments)
   • Often used interchangeably with primary prosthesis

A hip disarticulation prosthesis is a highly specialized lower-limb prosthetic device designed for individuals who have undergone an amputation through the hip joint, meaning the entire leg (femur, tibia, foot) is removed, but the pelvis is preserved.

Common Indications

• Malignancy (e.g., sarcoma of femur or pelvis)
• Severe trauma
• Life-threatening infection (e.g., necrotizing fasciitis)
• Congenital limb deficiency
• Failed limb salvage procedures or non-healing wounds

Components of a Hip Disarticulation Prosthesis

1. Pelvic Section (Socket/Bucket)
   • Custom-molded socket encasing part of the pelvis to anchor the prosthesis
   • Often includes a waist belt system to keep the device in place
2. Hip Joint
   • Mechanical or hydraulic component allowing flexion/extension and sometimes rotation
   • Can be single-axis or multi-axis, depending on user needs
3. Thigh Section
   • Connects the hip joint to the knee
4. Knee Joint
   • Can be manual-locking, hydraulic, power, or microprocessor-controlled for advanced mobility
5. Lower Leg and Foot
   • Often includes dynamic response foot for energy return
   • Foot selection varies based on activity level and terrain

An above-knee prosthesis (also known as transfemoral prosthesis) is designed for individuals who have undergone an amputation above the knee joint.

Common Indications

• Traumatic injury
• Peripheral vascular disease (e.g., diabetes-related complications)
• Infection (osteomyelitis, sepsis)
• Tumor (e.g., osteosarcoma)
• Congenital limb deficiency
• Failed limb salvage

Components/Types of Above-Knee Prosthesis

1. Socket
   • Custom-molded interface that fits over the residual limb
   • Can be ischial containment, subischial, or elevated vacuum-style
2. Suspension System
   • Keeps the prosthesis securely attached
   • Types include suction, pin-lock, lanyard, and vacuum-assisted systems
3. Knee Joint
   • Manual locking knee (stable, low-tech)
   • Hydraulic or pneumatic knee
   • Microprocessor-controlled knee
   • Power knee
4.  Feet
   • Chosen based on activity level (K1–K4 classification)
   • Common Styles include: 
     • SACH (solid ankle cushioned heel), 
     • dynamic response, 
     • multi-axial, 
     • or microprocessor feet

A below-knee prosthetic (also known as transtibial prosthesis) is used for individuals who have had an amputation through the tibia, preserving the knee joint.

Common Indications

• Peripheral vascular disease (most common in adults)
• Traumatic injury
• Infection (e.g., osteomyelitis, diabetic foot ulcers)
• Cancer or tumor resection
• Congenital limb differences
• Failed reconstruction or limb salvage

Components/types of Below-Knee Prosthesis

1. Socket
   • Custom-molded to fit the residual limb
   • Common styles include:
     • Patellar tendon-bearing (PTB)
     • Total surface bearing (TSB)
     • Elevated vacuum sockets (EVS)
2. Suspension System
   • Keeps the prosthesis attached
   • Common styles include:
     • Pin-lock liner
     • Suction suspension (with or without sleeve)
     • Vacuum-assisted suspension (e.g., Harmony, Unity systems)
3. Foot
   • Chosen based on activity level (K1–K4 classification)
   • Common Styles include:
     • SACH (solid ankle cushioned heel),
     • dynamic response,
     • multi-axial,
     • or microprocessor feet

A Syme’s prosthesis is designed for individuals who have had a Syme’s amputation (known as an ankle disarticulation)—removal of the foot at the ankle joint while preserving the heel pad for weight-bearing.

Common Indications

• Severe trauma to the foot
• Infections (e.g., diabetic foot with osteomyelitis)
• Tumors of the foot or lower ankle
• Congenital deformities
• Failed limb salvage below the ankle

Components/types of Syme’s Prosthesis

1. Socket
   • Encloses the bulbous end of the residual limb
   • Often includes a door, window, or removable panel to allow donning
   • May use pelite liners or gel liners for cushioning
2. Suspension
   • Often relies on anatomical suspension (over malleoli or bulbous end)
   • May be assisted with strap suspension or sleeve suspension depending on fit and activity level
3. Prosthetic Feet
   • Are low-profile to accommodate clearance between socket and ground

A partial foot prosthesis can be custom designed based on the level of amputation to protect the remaining foot.

Common Indications

• Severe trauma to the foot
• Tumor removal
• Vascular insufficiency
• Infection or gangrene
• Congenital abnormalities

Components/types of Foot Prosthesis

• Custom Molded Foot Orthosis with Insert/Toefiller
  • Designed to protect the foot and alignment
  • Offloads pressure points and provides soft-tissue support
• AFO-Style or Clamshell Prosthesis
  • Often extends above the ankle to:
    • Prevent equinus deformity (by maintaining dorsiflexion)
    • Restore push-off function