Module 2- Joints and Total Joint Replacement Flashcards
How many types of joints are there?
3
What are the 3 types of joints?
- Fixed
- Cartilaginous
- Synovial
Fixed joints
Immovable or fixed joints hold our skull together
Cartilaginous joints
Slightly movable joints (cartilaginous) are the joints in the vertebral column
Synovial joints
Freely movable joints (synovial) comprise 90% of our joints
What makes up a synovial joint?
What can go wrong with joints?
Tendons/ligament injury
- Making movement of the joint painful and difficult
Antagonistic muscle damage due to too overloading
- Making movement of the joint painful and difficult
Dislocation
- The bones move out of position, causing pain and preventing joint movement
Cartilage damage
- Movement becomes painful or impossible and the joint becomes inflamed
Diagram showing what can go wrong with joints
Another example of something going wrong with joints- osteoarthritis
- Osteoarthritis is a degenerative joint disease and is the most common chronic condition of the joints.
- It is characterized by degeneration of articular cartilage leading to increased friction between bones.
- Traumatic cartilage damage presents similarly to osteoarthritis
Arthritis- the damage in degeneration
- In arthritis, articular cartilage degenerates faster than its regeneration and as a result the cartilage cannot cope and often fragments.
- As a result, there is loss of joint movement and pain.
Factors leading to arthritis include aging, sport, injury, obesity and genes.
Graph sowing increase in prevalence of arthritis with age
With the aging US population, the prevalence of doctor-diagnosed arthritis is expected to increase in the coming decades
Cost of arthritis
Total costs associated with arthritis are over 82 billion USD per year, including hospital + drug costs, nursing home costs, and lost productivity and work
How can we treat arthritis?
- Pain is initially treated with over the counter pain medication and anti-inflammatories.
- As arthritis progresses, more invasive techniques are used to manage pain. But these treatments aren’t curative and only prolong surgery.
Treatment 1 for arthritis- Corticosteroid Injections
- Corticosteroid injections, which resemble cortisol (stress hormone), are used to treat inflammation.
- They are advantageous because they help with pain relief, but can be dangerous since they can loosen soft tissues (cartilage + tendons), leading to further damage.
Treatment option 2 for arthritis- Hyaluronic Acid Injections
- Hyaluronic acid injections are one of the major components of synovial fluid (the other is lubricin), responsible for viscous and elastic components.
- There are no serious side effects to this treatment option, however effectiveness has not been well established.
Treatment option 3 for arthritis- coolief
- Coolief is an advanced procedure that uses cooled radiofrequency energy to safely target the sensory nerves causing pain.
- This is called an ablation (meaning to destroy) procedure — and was FDA approved in 2017.
Partial and complete joint replacement
Depending on the damage, a joint can be partially or completely replaced
Characteristics of prosthetic joints
Characteristics of prosthetic joints include:
●Strength
○ Mechanical stress
○ Fatigue strength
●Flexibility
●Biocompatibility
●Resistance to wear
●Resistance to corrosion
Wear rate and coefficient of friction of joint prosthesis materials
Typical metals include titanium. Typically non-ferromagnetic. Safe for MRI
Cemented versus Cementless Fixation in joint prosthetics
Cemented:
* Elderly (>65) * Low demand
* Better early fixation
* late loosening
Cementless:
* Younger
* More active
* Protected weight-bearing first 6 weeks
* Better long-term fixation
What are the two largest weight bearing joints in the body?
- Hip (ball joint)
- Knee (hinge joint)
Anatomy of the knee
There are three bones (femur, tibia, and patella), ligaments, and articular cartilage
Diagram of knee prosthetics
Femoral and tibial implant metal alloy, patellar implant and joint liner polyethylene
Bone cuts and implantation for knee prosthetic
Anatomy of the hip
There are two bones (the femur and pelvis), ligaments, and articular cartilage
The Mechanisms of Hip Prosthetics
There are four components, the Femoral stem and neck, the Femoral head, the Polyethylene liner, and the Acetabular shell
How is a hip replacement implanted?
Hip resurfacing
An option for younger patients — Hip Resurfacing
Total joint replacement- early failure
- Early TJR Failure (<10%)
Total joint replacement- late failure
Late TJR Failure (symptoms > 5 years post-op)
