Understanding Arthritic Knee: Anatomy, Causes, and Treatments

Anatomy of the Knee

• Right Knee Identification:
  • Patella (kneecap) indicates the front (anterior aspect) of the knee.
  • Femur (thigh bone) and bones of the lower leg: tibia and fibula.
  • Fibula reminder: "LA" in fibula helps remember it as the lateral bone.

Key Ligaments in the Knee

• Medial Collateral Ligament (MCL):
  • Broad and flat, commonly injured.
  • Attaches to the medial meniscus; damage can affect both.
• Lateral Collateral Ligament (LCL):
  • Found on the lateral side.
• Posterior Cruciate Ligament (PCL):
  • Prevents the lower leg from sliding backward.
  • Forms a cross with the ACL.
• Anterior Cruciate Ligament (ACL):
  • Prevents the lower leg from sliding forward.
  • Commonly torn in sports injuries.

Ligament Functions

• MCL: Prevents lower leg abduction (outward movement).
• LCL: Prevents lower leg adduction (inward movement).
• ACL: Prevents hyperextension.
• PCL: Prevents posterior sliding.

Degenerative Changes in Osteoarthritic Knee

• Articular Cartilage:
  • Rough, not smooth or uniform -> indication of osteoarthritis.
  • Healthy cartilage is glossy, smooth, and uniform.
• Meniscus:
  • Fibrocartilage pads for shock absorption and knee tracking.
  • Severe arthritis can lead to almost complete erosion.

Causes of Osteoarthritis

1. Age: Joint tissues more susceptible.
2. Joint Injuries: Can lead to cartilage degeneration.
3. Obesity: Adds mechanical stress and pro-inflammatory states.
4. Genetics: Family history increases risk.
5. Anatomical Factors: Misalignments (e.g., bowleggedness).
6. Sex: Women may be more prone.

Pathophysiology of Osteoarthritis

• Cartilage Damage:
  • Lack of blood supply (avascular) -> slow healing.
  • Chondrocytes in the extracellular matrix maintain cartilage.
  • Damage can cause proteoglycans to attract more water, leading to breakdown.
  • Subchondral bone thickens, furthering cartilage degeneration.
• Inflammation: Synovial inflammation leads to joint swelling and instability.
• Osteophytes: Bone spurs adding to pain and instability.

Prevention and Treatment Strategies

Lifestyle Modifications

• Exercise:
  • Strengthens quadriceps and hamstrings to support the knee.
  • Maintains joint mobility and function.
  • Dispelling myths: Exercise doesn't worsen osteoarthritis; can reduce pain similar to NSAIDs.
• Weight Management:
  • Reduces mechanical stress and pro-inflammatory states.
  • 10% body weight loss can drastically reduce pain.
• Supplements:
  • Mixed efficacy for curcumin, glucosamine, and chondroitin.

Medication and Injections

• Topical NSAIDs: Lower risk of side effects compared to oral NSAIDs.
• Oral NSAIDs: Needed for moderate to severe cases.
• Intraarticular Injections:
  • Hyaluronic Acid: Potential knee lubrication, mixed results.
  • Corticosteroids: Short-term pain relief, long-term risks.

Surgical Options

• Arthroscopic Surgery: Clean-up cartilage.
• Knee Replacement: For severe cases.
• Positive outcomes but individualized decisions.

Learning Note

• Interactive Learning: Importance of hands-on learning in anatomy labs.
• Engaging Learning Platforms: Mention of Brilliant.org for interactive lessons in various subjects.

Summary

Understanding knee osteoarthritis involves identifying degenerated cartilages, ligaments, and the overall knee structure. Preventative measures through lifestyle modifications are key, and a variety of medical and surgical treatments are available depending on the severity of the condition.