Borsa_Module_Joint Injury

After completing this module, students will be able to:
1. Identify and describe joint structure and function.
2. Identify and describe joint injury.
3. Identify and describe impaired proprioception and neuromuscular control.
4. Identify and describe bone composition and fracture healing.

Articulation of Bones:
- Joints formed where two or more bones meet.
Connective Tissues Provide Support:
- Ligaments and cartilage provide stability, cushioning, and guide movement.
Synovium:
- Lining of joint producing synovial fluid for lubrication and nutrition.
Joint Cavity:
- Contains synovial fluid, ligaments, and cartilage.
Muscles & Tendons:
- Stabilize and facilitate movement.
Sensation (Proprioception):
- Sense of body position and movement.

Extent of Structural Damage:
- Involvement of capsule, ligaments, cartilage, and synovium.
Joint Function Impact:
- Potential instability (mechanical or functional).
Limitations Due to Injury:
- Effects of inflammation and degenerative changes on joint function.
Proprioception:
- Impaired sensory feedback affecting motion and position sense.

Mechanical Functions:
- Provide stability and restrain forces, guide movement, and protect joints.
Neural Functions:
- Offer sensory feedback to the CNS, aiding proprioception and controlled movement, affecting neuromuscular control.

Types of Restraints:
- Static (ligaments and connective tissues) vs. dynamic (muscles and tendons).
Muscle Contraction Types:
- Concentric, Eccentric, Isometric.
Instability Mechanisms:
- Injury to ligaments leading to inability to function:
  - Mechanical: Static loss but dynamic stabilization possible.
  - Functional: Loss of both types of stabilization leading to joint failure during stress.

Mechanical Instability:
- Decreased neuromuscular control and proprioception deficits.
- Ligament injuries (e.g., ACL) leading to repetitive trauma and functional instability.

Knee Structure:
- Includes connective tissues, joint cavity, articular capsule, lubricating synovial lining, articular cartilage, fibrocartilage (menisci), and bone (subchondral).

Involved Regions:
- Axial Skeleton: Spine (cervical, thoracic, lumbar regions).
- Appendicular Skeleton: Upper (shoulder, elbow, forearm/wrist, hand) and lower extremities (hip, knee, lower leg, ankle, foot).

Valgus Mechanisms:
1. Valgus load leading to medial opening.
2. Tibial displacement and axial rotation.
3. Lateral compartment impingement.
Terrible Triad:
- Injury involving ACL, MCL, and meniscus.

Structure:
- Semilunar wedges composed of fibrocartilage with radial & circumferential fibers.
Function:
- Load bearing, absorbing and distributing loads over articular surface, providing stability and proprioception.

Types of Forces Involved:
- Compression (femoral condyles on plateau), shear (anterior-posterior displacement), and tensile (stretch).

Zones of Tear Impact:
- Outer 30% is vascularized (red zone), inner area typically avascular.
Types of Tears:
- Radial, oblique, longitudinal, or avulsion from root/spine.

Also Known As:
- Post-traumatic osteoarthritis (PTOA).
Pathophysiology:
- Loss of fibro- and articular cartilage, resulting in narrowing of joint space, leading to early onset DJD.

Pathophysiology Overview:
- Trauma leading to ligament and cartilage damage along with abnormal biomechanical wear and tear.
Articular Cartilage Role:
- Acts as a shock absorber and reduces friction, with health depending on nutrient diffusion.

Pathophysiological Changes:
- Chondrocyte dysfunction, collagen breakdown, loss of proteoglycans, and increase in matrix metalloproteinases.
- Resulting changes: fissures, cartilage erosion, and synovial irritation/inflammation.

Resulting Structural Changes:
- Development of osteophytes (bone spurs), joint dysplasia, eburnation, and osteosclerosis.
- Associated muscle weakness and atrophy, particularly in the quadriceps, and impairment of proprioception and neuromuscular control.

Glucosamine Sulfate:
- A glycoprotein, aids in repairing damaged cartilage.
Chondroitin Sulfate:
- A glycoprotein acting as a binding molecule that obstructs cartilage-degrading enzymes.