47. KNEE JOINT

Concise Notes – Knee Joint Assessment & Injury

• High injury susceptibility
  • Knee lies between two long lever arms: femur and tibia → greater stress during trauma.
  • Stability relies more on ligaments & muscles than bony structure (limited inherent bony stability).
• Importance of ligament testing
  • Ligaments are primary stabilizers → must always be examined.
  • Ligament tests are separated from “special tests” to prevent omission in evaluation.
• Complexity of assessment
  • Knee contains multiple interacting structures → careful, systematic examination required.
  • Examiner should allocate sufficient time to test all relevant tissues.
• Referred pain considerations
  • Pain may originate outside the knee:
    • Lumbar spine
    • Hip
    • Ankle
  • Always assess adjacent regions if symptoms are atypical.
• Key clinical example
  • Slipped capital femoral epiphysis (hip pathology) commonly presents as knee pain.
  • Referred pain may dominate clinical picture → risk of misdiagnosis if hip not examined.

Concise Notes – Tibiofemoral Joint

• General features
  • Largest joint in the body.
  • Modified hinge joint with 2° of freedom.
  • Extensive synovial membrane; communicates with multiple bursae & pouches.
• Synovium & cruciate ligaments
  • Synovial membrane encapsulates knee but cruciate ligaments are extrasynovial.
  • Cruciate = ligaments cross each other.
  • Cruciate ligaments run from tibial plateau → intercondylar femur.
• Articular surfaces & congruency
  • Tibia & femur surfaces are not fully congruent → allows differential movement.
  • Congruency increases in full extension → close-packed position.
  • Close-packed includes full lateral (external) rotation of tibia (Kaltenborn).
• Femoral condyle anatomy
  • Lateral femoral condyle projects more anteriorly than medial.
  • Helps prevent lateral patellar dislocation.
  • Particularly important in females:
    • Broader pelvis → increased femoral inward angle (Q-angle).
    • Condyles align parallel to ground.
• Joint positions & patterns
  • Resting position: ~ 25° flexion.
  • Capsular pattern: Flexion more limited than extension.