Biomechanical Assessment of Knee Expert Therapy

This involves a series of observations, tests, and measurements to assess the knee’s structure, function, and its relationship to the rest of the body.

Postural Assessment:

• Static Posture: Observing the patient’s alignment in standing, sitting, and lying positions. This includes looking at:
  • Knee alignment: Genu varum (bow-legged), genu valgum (knock-kneed), genu recurvatum (hyperextension).
  • Foot and ankle alignment: Pronation, supination, flat feet, high arches, which can influence knee mechanics.
  • Pelvic and hip position: Anterior/posterior pelvic tilt, hip rotation, leg length discrepancies, as these can affect forces transmitted to the knee.
  • Spinal alignment: Compensatory curves that might impact lower limb mechanics.
• Significance: Identifies habitual postures and static alignments that may contribute to chronic knee pain or dysfunctional movement patterns.

Range of Motion (ROM) Assessment:

• Active Range of Motion (AROM): The patient moves the knee through its available range without assistance (e.g., knee flexion and extension).
• Passive Range of Motion (PROM): The therapist moves the knee through its available range to assess joint play and end-feel (e.g., tissue stretch, bone-on-bone).
• Accessory Joint Mobility: Assessing small, involuntary movements within the joint (e.g., anterior/posterior glides of the tibia on the femur, rotations) that are crucial for normal large-range movements.
• Significance: Identifies limitations, stiffness, hypermobility, or pain within the joint capsule or surrounding soft tissues.

Muscle Strength and Endurance Testing:

• Manual Muscle Testing (MMT): Assessing the strength of individual knee muscles (quadriceps, hamstrings, gastrocnemius, tibialis anterior) on a scale (e.g., 0-5).
• Handheld Dynamometry: Provides more objective and quantitative measurements of muscle strength.
• Functional Strength Tests: Assessing strength in more dynamic, weight-bearing movements (e.g., single-leg squat, step-ups).
• Significance: Identifies muscle weakness, imbalances (e.g., quadriceps dominance, hamstring weakness, gluteal weakness), or inhibited muscle activation patterns that can lead to compensatory movements and increased stress on the knee. Key muscles assessed often include quadriceps, hamstrings, and hip abductors/extensors (gluteus medius/maximus).

Palpation: Systematic palpation of bony landmarks, ligaments, tendons, and muscles around the knee to identify tenderness, swelling, tissue texture abnormalities, or warmth.

Special Tests: Specific tests to assess the integrity of ligaments, menisci, and other structures. Examples include:

• Ligamentous Stability: Lachman test, Anterior Drawer test, Pivot Shift test (for ACL); Posterior Sag sign, Posterior Drawer test, Quadriceps Active test (for PCL); Valgus stress test (for MCL); Varus stress test (for LCL).
• Meniscal Integrity: McMurray’s test, Thessaly test, Apley’s compression and distraction test.
• Patellofemoral Joint: Patellar tracking, patellar apprehension test.
• Significance: Helps confirm or rule out specific structural damage.

Functional Movement Assessment: Observing the patient’s movement patterns during activities relevant to their daily life or sport. This provides insight into how the knee functions dynamically. Examples include:

• Squatting: Deep squat (evaluates bilateral, symmetrical mobility of hips, knees, ankles), assessing knee valgus, compensation.
• Lunging: In-line lunge (assesses hip, knee, and ankle mobility and stability, quadriceps flexibility, knee stability).
• Hopping/Jumping: Single-leg hop for distance, hop tests for return to sport (assesses power, stability, symmetry).
• Stair climbing/descending: Identifies pain, weakness, or compensatory patterns.
• Significance: Uncovers dynamic imbalances, poor motor control, compensatory movements, and pain during functional tasks.

Gait Analysis:

• Detailed observation and analysis of the patient’s walking or running pattern. This can be done visually or with advanced technology (e.g., video analysis, force plates, motion capture systems).
• Key aspects observed: Step length, stride length, cadence, joint angles (hip, knee, ankle) throughout the gait cycle, arm swing, trunk movement, and weight transfer.
• Significance: Identifies abnormalities in locomotion, such as gait deviations, compensatory movements, altered weight bearing, or excessive joint loading that contribute to knee pain or injury. For example, excessive pronation at the foot can lead to internal rotation of the tibia and increased stress on the patellofemoral joint.

Kinetic Chain Assessment (Regional Interdependence):

• Recognizing that the knee does not operate in isolation but is part of a “kinetic chain” involving the foot, ankle, hip, pelvis, and spine. Dysfunction in one area can impact the knee.
• Assessment involves: Evaluating the mobility, stability, and strength of joints both above (hip, pelvis, lumbar spine) and below (ankle, foot) the knee.
• Significance: Identifies “upstream” or “downstream” contributors to knee pain. For instance, weak glutes or tight hip flexors can alter hip mechanics, leading to increased stress on the knee. Similarly, poor ankle mobility can force compensatory movements at the knee.