Types of knock knees: what to know

Knock knees can be described by whether they are flexible or fixed, equal or unequal, and associated with symptoms or an underlying condition. These distinctions help a clinician decide whether observation, rehabilitation, imaging, or specialist care is appropriate.

A flexible or dynamic pattern changes with posture, walking, or muscle control. A fixed pattern remains when the person changes position and may reflect the shape or orientation of the bones. The alignment can also be symmetrical, affecting both legs in a similar way, or asymmetrical, with a clear difference between sides.

Clinicians may also consider whether the pattern is part of growth, followed an injury, or occurs alongside a bone, joint, or muscle condition. Symptoms provide another useful category: some people have no pain, while others experience kneecap discomfort, fatigue, stiffness, or difficulty with activity. A label does not replace an examination.

Look for changes over time rather than comparing the legs with photographs online. Note pain, swelling, walking changes, falls, and activities that are becoming harder. A healthcare professional may assess the hips, knees, ankles, feet, gait, and growth history; imaging may be used when the pattern is fixed, uneven, or symptomatic.

Care is matched to the pattern. Rehabilitation may improve strength and movement control in a flexible pattern, while observation can be suitable when there are no concerning features. [Paediatric Physiotherapy](/treatments/physiotherapy-and-rehabilitation/paediatric-physiotherapy/) may help younger patients. A specialist may discuss [Osteotomy](/treatments/reconstructive-orthopedic-surgery/osteotomy/) for selected fixed skeletal problems.

Arrange a review for persistent pain, swelling, stiffness, limping, repeated falls, worsening alignment, or a noticeable difference between sides. Prompt advice is needed after a significant injury or when weight-bearing becomes difficult. An asymptomatic appearance may be monitored, but changes during growth should still be discussed if they concern you.

Ask which pattern best describes the alignment, whether it is flexible or fixed, and whether both legs are developing similarly. Discuss what to monitor, whether exercises could help, whether imaging is needed, and what would lead to an orthopaedic referral.