Ortho Overview Part 1 (Steiner) Flashcards
What does orthopaedics literally mean?
Straight child
Orthopedics is the medical discipline devoted to which system?
Musculoskeletal
Functions of MSK system
Support, protection, movement
Function of bone
Provides support
Function of cartilage
Provides smooth surface for articulating bones
Function of intervertebral disks
Sustains and distributes load
Function of muscles
Contract to create movement
What do tendons connect?
Muscle to bone
What do ligaments connect?
2 bones
*Defines the motion of the joint
Is bone tissue dynamic or static?
Dynamic - osteoblasts make new bone and osteoclasts remove necrotic bone
2 types of bone
- Cortical (less porous, denser outer portion)
- Cancellous (more porous, trabecular, surrounded by cortical bone)
Strength and stiffness of bone is generally in which direction?
In the direction of load application
Which bones deal with longitudinal stresses best?
Long bones
Long bones deal with which stresses best?
Longitudinal stresses
How do fractures generally occur?
- Single momentary load exceeds the tolerance of that bone (usually from trauma)
- Repeated loading (stress)
When do stress fractures occur?
Repeated loading where rate of damage exceeds rate of repair
5 stages of fracture healing
- Impact
- Inflammation (hematoma formation)
- Soft callus formation
- Hard callus formation
- Remodeling
How does a hematoma progress at fracture site?
- Granulation tissue replaces hematoma
- Fibroblasts make collagen
- Osteoclasts remove necrotic bone
When does a fracture appear clinically healed?
When soft callus becomes hard callus
What procedure is performed when a fracture requires surgical intervention?
ORIF (open reduction and internal fixation)
ORIF vs. conservative tx of fractures
ORIF heal more quickly but are more at risk for infection, complications of anesthesia or surgery
Which type of hardware placed for fractures is better tolerated?
Deeper hardware
Are plates or rods better tolerated by pts?
Rods
What happens when a fracture fails to heal properly?
Non-union or malunion
Describe non-union of fracture
- When fragments fail to unite and heal
- If healing has not occurred w/in 6 months, it is called a “delayed union”
- Beyond 6 months it is considered a non-union
When can non-unions occur?
- Poor blood supply (elderly)
- Poor nutritional status
- Inadequate immobilization
- Soft tissue interposed b/w fragments
- Presence of infection or dead bone (sequestrum)
What is a sequestrum?
Piece of dead bone
Treatment of non-union
- Initially, stimulate normal osteogenic mechanisms
- Functional bracing combined w/wt bearing
- Use of implantable rods or compression plates
- Electrically w/bone stimulators
- Chemically w/autogenous bone transplants
How does bone respond to stress?
Becomes more dense
What is the most technologically advanced means of treating a non-union fracture?
Ilizarov method
-Application of an external fixator
Bony regeneration with the Ilizarov method occurs at what rate?
1 mm per day
Describe malunion of fracture
Healing has occurred but with an unacceptable degree of angulation, rotation, or shortening
Which type of fractures are more likely to be a/w nerve transections?
Open fractures
Which types of fractures are MC at risk of infection?
- Open
- Those treated surgically
What predisposes female athletes to osteopenia?
Amenorrhea
What may x-rays show with stress fractures?
Subtle cortical disruption or evidence of prior bone healing
What imaging is usually more helpful for stress fractures?
Bone scan
Treatment of stress fractures
- Rest
- Splints
- In some cases, casting
- Best thing is prevention
What can help amenorrheic women reduce the risk of osteopenia?
OCPs
Untreated stress fractures may evolve into:
Complete fracture
Definition and function of joints
- Articulation where 2 bones meet
- Allow movement of 1 bone on another
Types of joints
- Cartilaginous (minimal movement)
- Fibrous (immovable)
- Synovial (freely moveable)
Examples of cartilaginous joints
- Symphysis pubis
- Vertebral bodies
- AC joint
- Sternoclavicular joint
Examples of fibrous joints
Skull sutures
Examples of synovial joint
- Hip, shoulder (ball & socket)
- Fingers, elbow (hinge)
- Knee, TMJ (condylar)
Examples of ball & socket synovial joints
Hip, shoulder
Examples of hinge synovial joints
Fingers, elbow
Examples of condylar synovial joints
Knee, TMJ
Describe articular cartilage
- Avascular tissue composed of chondrocytes and an organic matrix
- Found at ends of bones (joint)
- One dimensional
Osteoarthritis occurs from:
Wearing down of articular cartilage and subsequent exposure of underlying bone
Why does articular cartilage have little capacity to repair itself?
Chondrocytes have a low rate of metabolism
How does the body attempt to repair articular cartilage?
- With new hyaline cartilage
- This results in fibrocartilage (not ideal for joint surfaces)
When is there NO capacity for repair to cartilage defects?
If they extend through entire thickness to the calcified plate at the bony junction
