Knee Joint Evaluation

• Notes on a knee joint evaluation

Knee Joint Evaluation: History

• Determine the duration of the injury or symptoms.
• Identify the mechanism of injury.
• Characterize the type of pain.
• Identify activities that increase or relieve pain.
• Inquire about any clicking, catching, snapping, popping, or grinding sensations.

Knee Joint Evaluation: Observation

• Scars should be noted.
• Assessment of the knee joint's alignment is important, including quadriceps angle.
• Genu varum (bowlegged), genu valgum (knock-kneed), and genu recurvatum (hyperextended knee) should also be noted.

Knee Joint Evaluation: Palpation of Anterior Structures

• Palpate the quadriceps and patellar tendons.
• Note the relationship of the patella to these structures.

Joint Line Structures

• The medial side possesses more surface area than the lateral.
• The posterior side of the patella has less surface area on the lateral side compared to the medial side.
• Ligaments, tendons, and other relevant structures should be palpated.

Medial Structures

• Medial Collateral Ligament (MCL) is located on the medial side of the knee.

Lateral Structures

• Lateral Collateral Ligament (LCL) is located on the lateral side of the knee.
• The Iliotibial Band runs from the ilium to the lateral side of the knee.
• Biceps femoris long head attaches posteriorly from the outside of the pubis, running diagonally down the back of the hamstring before connecting to the lateral side of the knee.

Posterior Structures

• Structures sit on top of the semimembranosus.
• The semitendinosus connects from the posterior side of the midpoint.
• The semimembranosus runs down the posterior part of the hamstring towards the medial side of the thigh, connecting to the medial side of the knee.
• Posterior to the quadriceps, the biceps femoris connects to the lateral side of the knee structure.

Quadriceps

• The quadriceps is composed of
  • Vastus Lateralis: Lateral side of the quad
  • Vastus Medialis: Medial side of the quad
  • Vastus Intermedius: Sits deep to rectus femoris
• From deepest to superficial, the order of the quadriceps muscles is vastus intermedius, vastus medialis, rectus femoris, and vastus lateralis.

Manual Muscle Testing (MMT)

• Semitendinosus/Semitendinosus: Flexion and medial rotation of the knee is tested with the patient prone. Flex the knee between 50° and 70°, medially rotating the thigh and leg. Stabilize the thigh and resist at the proximal ankle.
• Biceps Femoris: Flexion and lateral rotation of the knee is tested in a prone position. Flex the knee between 50° and 70°, laterally rotating the thigh and leg. Stabilize the thigh and resist at the proximal ankle.
• Quadriceps Femoris: Extension of the knee is tested with the patient sitting with knees over the side of the table. Apply resistance above the ankle in the direction of flexion.

MMT Grading Scale

• 5/5: Full ROM against gravity with full manual resistance (Normal).
• 4/5: Full ROM against gravity with moderate resistance (Good).
• 3/5: Full ROM against gravity, but unable to go through full ROM when resistance is applied (Fair).
• 2/5: Full ROM with gravity eliminated (Poor).
• 1/5: Evidence of muscle contraction but no joint movement (Trace).
• 0/5: No evidence of muscle contraction (Zero).

Knee Flexion Measurement

• Start Position: Prone with hip in neutral, foot off the table, bolster under the thigh.
• Stabilization: Stabilize the femur to prevent hip movement.
• Fulcrum: Lateral epicondyle of the femur.
• Stationary Arm: Parallel to the lateral midline of the femur, towards the greater trochanter.
• Moveable Arm: Parallel to the lateral midline of the fibula, towards the lateral malleolus.
• End position: Maximum knee flexion.
• Range: 120-145°.

Knee Extension Measurement

• Start Position: Prone with bolster under the thigh.
• Stabilization: Stabilize the femur to prevent hip movement.
• Fulcrum: Lateral epicondyle of the femur.
• Stationary Arm: Parallel to the lateral midline of the femur, towards the greater trochanter.
• Moveable Arm: Parallel to the lateral midline of the fibula, towards the lateral malleolus.
• End position: Maximum knee extension.
• Range: 0-15°.