Knocked Knees (Genu Valgum): Appearance, Associated Deviations, and When to Seek Help

What do knocked knees look like?

Knocked knees, medically known as genu valgum, present as an inward angulation of the knees, causing them to touch or appear to touch when the ankles are separated, creating an "X" shape with the legs. This common lower limb alignment variation is characterized by specific visual cues identifiable in static posture and during movement.

Understanding Genu Valgum: The Medical Term

Genu valgum, or knocked knees, is an anatomical deviation where the femur (thigh bone) and tibia (shin bone) meet at an exaggerated outward angle at the knee joint. This results in the knees being closer to the midline of the body than the hips and ankles when standing. While a slight degree of valgus is normal, particularly in children, an excessive or persistent presentation can indicate a structural or functional issue that warrants attention.

The Visual Presentation of Knocked Knees

Observing an individual with genu valgum reveals distinct visual characteristics:

• Standing Posture:
  • When standing with feet together, the knees visibly touch or overlap, while the ankles remain separated, often by a significant gap.
  • Conversely, if the individual attempts to stand with their ankles together, the knees will significantly overlap or press against each other, preventing the lower legs from aligning straight.
• Kneecap (Patella) Orientation:
  • The patellae may appear to point inward or medially (towards each other), rather than straight ahead. This is often due to internal rotation of the femur.
• Leg Alignment:
  • From a frontal view, the thighs (femurs) angle inward from the hips to the knees, and the shins (tibias) then angle outward from the knees to the ankles, forming the characteristic "X" shape.
• Foot and Ankle Compensation:
  • To compensate for the inward knee angle, the feet often display excessive pronation (flattening of the arch) and eversion (rolling outward of the ankle). This is a common compensatory mechanism to allow the foot to make full contact with the ground.

Common Accompanying Postural Deviations

Genu valgum is rarely an isolated issue; it often coexists with or contributes to other postural and movement dysfunctions throughout the kinetic chain:

• Internal Femoral Rotation: The thigh bones may rotate excessively inward at the hip joint.
• Pelvic Tilting: An anterior pelvic tilt (forward rotation of the pelvis) or posterior pelvic tilt (backward rotation) may be present, influencing hip and knee alignment.
• Hyperpronation of the Feet: As mentioned, flattened arches and excessive inward rolling of the ankles are very common compensatory patterns.
• Compensatory Tibial External Rotation: While the femur rotates internally, the tibia may sometimes externally rotate relative to the femur to help the foot point forward, leading to increased torsional stress on the knee.
• Altered Gluteal Muscle Activity: Weakness or inhibition of the gluteus medius and maximus can contribute to inward knee collapse.

Distinguishing Knocked Knees from Normal Alignment

In a healthy, neutral lower limb alignment, when standing with feet together, the knees should lightly touch or have a minimal gap, and the ankles should also touch or be very close. The center of the kneecap should align with the second toe. In contrast, knocked knees show a clear and often significant separation between the ankles when the knees are together.

To self-assess:

1. Stand with your feet together, ensuring your inner ankles are touching.
2. Observe the space between your knees. If there is a noticeable gap (more than an inch or two, depending on body type) or if your knees overlap significantly, you likely have genu valgum.

Why Understanding the Appearance Matters

Recognizing the visual cues of knocked knees is crucial for several reasons:

• Movement Impairment: Genu valgum can alter the biomechanics of walking, running, and squatting, potentially leading to inefficient movement patterns.
• Increased Injury Risk: The altered alignment places increased stress on various knee structures, including the medial collateral ligament (MCL), patellofemoral joint, and can increase the risk of anterior cruciate ligament (ACL) injuries and patellofemoral pain syndrome.
• Targeted Exercise Prescription: For fitness professionals, identifying genu valgum allows for more precise exercise programming, focusing on strengthening hip abductors and external rotators, improving ankle stability, and correcting movement patterns to mitigate associated risks.
• Early Intervention: Early recognition, especially in children, can lead to timely interventions that may prevent long-term complications.

When to Seek Professional Advice

While some degree of valgus alignment is common and often asymptomatic, it is advisable to consult a healthcare professional (such as a physical therapist, orthopedist, or kinesiologist) if:

• The knocked-knee appearance is asymmetric (one knee is more affected than the other).
• It is accompanied by persistent pain in the knees, hips, or ankles.
• It interferes with daily activities, exercise, or sports performance.
• There is a rapid onset or progression of the condition.

Understanding the visual presentation of knocked knees is the first step in addressing its potential implications for musculoskeletal health and functional movement.