orthosis
Reading File
The query "orthosis" is broad. Let me clarify before diving in.
Asking for Preferences
What aspect of orthosis are you interested in?
Finding Sources
Finding Sources
Searching the Web
orthosis definition types classification overview
Reading File
Finding Sources
Reading File
I now have comprehensive coverage. Here is a structured overview:
Orthosis — Definition & Types Overview
Definition
An orthosis (pl. orthoses) is an externally applied device designed to modify the structural or functional characteristics of the neuromusculoskeletal system. The four core purposes are:
- Immobilization — restrict motion to protect injured/healing structures
- Mobilization — assist or enable movement (dynamic orthoses)
- Restriction — limit a specific range of motion
- Torque transmission / load redistribution — alter forces acting on a joint or segment
Orthoses are named by the body segments they span (e.g., AFO = ankle-foot orthosis).
Classification by Body Region
Lower Limb
| Abbreviation | Full Name | Key Uses |
|---|---|---|
| FO | Foot Orthosis | Align/support foot; three subtypes: rigid (limit motion), semirigid (support + shock absorption), soft (accommodate fixed deformities, neuropathic feet) |
| AFO | Ankle-Foot Orthosis | Most commonly prescribed lower-limb orthosis; footdrop, plantar spasticity, spinal cord injury; can be rigid or articulating; fabricated with metal bars or thermoplastic elastomer (TPE) |
| KAFO | Knee-Ankle-Foot Orthosis | Upper thigh to foot; unstable knee joint; mediolateral stability with flexion/extension control; various knee lock designs |
| HKAFO | Hip-Knee-Ankle-Foot Orthosis | Hip and pelvic stability; rarely used in adult paraplegics due to cumbersome nature; used in children with upper lumbar myelomeningocele (reciprocating gait orthosis) |
Upper Limb
| Abbreviation | Full Name | Key Uses |
|---|---|---|
| EO | Elbow Orthosis | Hinged (ligament instability), dynamic spring-loaded (flexion/extension contractures), elbow strap (lateral epicondylitis) |
| WHO | Wrist-Hand Orthosis | Post-injury/reconstructive care; static, static-progressive, or dynamic; wrist-driven devices for lower cervical quadriplegia (tenodesis-powered or motor-driven) |
Spine
| Region | Device | Details |
|---|---|---|
| Cervical | Soft collar → rigid collar → cervicothoracic orthosis (CTO) → halo vest | Range from basic motion reduction (C2–C5) to near-complete immobilization (halo vest); CTOs control C5–C7 and restrict flexion better than extension |
| Thoracolumbar | TLSO (thoracolumbosacral orthosis), corsets, rigid braces | Reduce back pain via three-point pressure mechanism and increased body cavity pressure; three-point orthoses use lever arm length to limit motion |
Fracture Braces
- Prefabricated fracture orthoses: used for simple foot/ankle fractures, ankle sprains, simple hand injuries
- Tibial/fibular fracture bracing: remains a valuable non-operative option
Pediatric Orthoses
- Pavlik harness — mainstay for developmental dislocation of the hip (DDH)
- Dynamic orthoses for Perthes disease containment
- Reciprocating gait orthoses (modified HKAFOs) for children with myelomeningocele
Material Types
| Material | Properties | Use Case |
|---|---|---|
| Rigid (metal, hard plastic) | Maximum control, least accommodation | Fracture immobilization, severe instability |
| Semirigid (semi-flexible plastics) | Balanced support and shock absorption | AFOs, functional ankle bracing |
| Soft (foam, leather, neoprene) | Best shock absorption, accommodating | Neuropathic/dysvascular feet, mild support |
Key Biomechanical Principles
- Three-point pressure system: two forces in one direction, one corrective force in the opposite; fundamental to spinal orthoses and many limb braces
- Ground reaction force (GRF) management: AFOs used post-hindfoot fusion to absorb and redirect GRF
- Trimline design in TPE AFOs: full/anterior, intermediate, or posterior trimlines determine degree of mediolateral control
- Tenodesis action: wrist-driven hand orthoses harness natural tenodesis to allow functional grasp in cervical SCI patients
— Miller's Review of Orthopaedics, 9th Edition, p. 887
This is a shared conversation. Sign in to Orris to start your own chat.