Bowlegs and knock-knees are among the most common misalignments of the leg axis and affect both children and adults. In bowlegs, also known as genu valgum, the legs turn inward, while in knock-knees, or genu varum, the leg axis shifts outward. This misalignment can place uneven stress on the knee joint and, over time, lead to osteoarthritis or knee pain. In childhood, bowlegs or knock-knees often occur physiologically as part of normal development.
However, causes of leg alignment abnormalities can also include vitamin D deficiency, rickets, obesity, or a bone metabolism disorder. Treatment depends on the severity of the misalignment, the patient’s age, and any associated symptoms. Orthotically customized insoles, physical therapy, or surgery to correct the leg alignment can reduce stress on the knee joint and prevent further damage.
What exactly do the terms “bowlegs” and “knock-knees” mean?
Bowlegs and knock-knees (ICD code for both conditions: Q74.15) are types of knee misalignment. Bowlegs are also known as genu valgum or valgus alignment. In X-legs, the angle between the lower leg and the body’s midline is greater than 185°. This phenomenon is also referred to as angulation.
In people with bowlegs (genu varum), on the other hand, the legs splay widely apart at the knees. This means that the knees do not touch even when the legs are closed.
How do these deformities develop?
Both bowlegs and knock-knees are rarely congenital. These misalignments usually develop during childhood, often as a result of vitamin D deficiency (rickets) in infancy. The body produces the vitamin D necessary for healthy bone growth on its own. A deficiency can result from a congenital disorder or from insufficient exposure to sunlight.
Without enough vitamin D, the bones do not harden sufficiently. They cannot support the growing weight of the affected individual, leading to the development of bowlegs or knock-knees over the years.
These misalignments first become noticeable between the ages of one and five.
In addition, bowlegs and knock-knees can result from a flat foot or fallen arch. In this case, the feet are positioned at an angle relative to the knees. The misalignment of the feet thus leads, in the long term, to additional misalignment of the knee joints.
In adults, bowlegs and knock-knees occur almost exclusively as a result of an accident. Another cause is sitting in a specific position for many years. A typical example is a jockey, who develops clearly visible bowlegs from frequently sitting on a horse.
Other, though rather rare, causes of knee joint misalignment include:
- Bone metabolism disorders (hypophosphatemia)
- Tumors
- Hormonal disorders
- Inflammation
- Obesity
What are the symptoms of bowlegs and knock-knees?
Bowlegs and knock-knees are generally considered primarily to be cosmetic flaws. However, those affected also suffer from joint pain. The pain can worsen in cold, wet weather or during a change in weather.
In addition, there are postural problems that negatively affect other joints (such as the hip joint). The uneven stress on the joint structures causes disproportionate wear and tear on the cartilage, bones, and menisci. This increases the risk of knee osteoarthritis (known as gonarthrosis) or meniscus damage. In children, growth is also often impaired.
How are bowlegs and knock-knees diagnosed?
Bowlegs and knock-knees are not always visible at first glance. Especially when the misalignment is not yet severe, the gait is often completely normal. This is one more reason to have children examined regularly by a doctor so that action can be taken early on. The doctor can take various measurements and confirm the diagnosis with an X-ray.
How are bowlegs and knock-knees treated?
It’s advisable to watch for any misalignments in children from an early age. Be sure to take your child for regular checkups with the pediatrician.
Initially, the misalignments are usually just monitored, as spontaneous correction is certainly possible. In many cases,
- shoe inserts,
- night splints, or
- physical therapy
.
If these measures are not sufficient, surgery may be considered—but only toward the end of the growth phase.
Correcting these misalignments is important to prevent long-term damage to the joints, which can lead to lifelong knee pain. Without treatment, the joints will be subjected to incorrect stress over the long term. This increases the risk of developing severe osteoarthritis at an early age—as early as age 30.
Taking Active Steps Against Bowlegs and Knock-Knees: Exercise and Orthotics
Leg alignment exercises (specialized physical therapy exercises) can help prevent the misalignment from worsening. They also help reduce pain and other symptoms.
The exercises must be supervised by an experienced physical therapist. However, patients are usually also given instructions for exercises they can do at home.
Typical leg alignment exercises include, for example, special squats. These exercises focus particularly on the position of the legs and help strengthen the thigh muscles.
Standing on one leg is also a simple way to
- strength,
- coordination, and
- balance
. You can vary the one-legged stand—for example, by using a soft mat. It’s best to perform these self-assessment exercises in front of a mirror. Another option for treating bowlegs and knock-knees is orthotics. These are used in particular for adults whose misalignment was not corrected early on.
An orthosis cannot eliminate the misalignment. However, it can significantly reduce pain by providing effective support and simultaneously strengthening the leg. Without an orthosis, on the other hand, there is a risk that the misalignment will continue to worsen.
Therefore, the rule is: Have misalignments treated early! The earlier bowlegs and knock-knees are treated, the better the chances of leading a life that is largely free of pain and discomfort. Parents should therefore have their children examined regularly. In adults, orthotics can significantly reduce the negative effects of knee misalignment.
FAQ
What are bowlegs and knock-knees?
Bowlegs and knock-knees are misalignments of the legs or the leg axis. With bowlegs, the knees point inward, while with knock-knees, the legs curve outward. This misalignment of the legs alters the load on the knee joint and can cause joint wear and tear over time.
What causes leg axis misalignments?
Causes of leg alignment abnormalities often include congenital abnormalities, vitamin D deficiency, rickets, or a disorder of bone metabolism. Being overweight, bone fractures, or misalignments of the growth plate can also cause leg alignment abnormalities. In childhood and adolescence, mild bowlegs usually occur for physiological reasons.
When do bowlegs or knock-knees cause symptoms?
Symptoms usually arise when the load on the knee joint is consistently unevenly distributed. Affected individuals often complain of knee pain, misalignment, or difficulty walking. The inner or outer sides of the knee joint, in particular, may develop areas of stress due to the misalignment.
How are bowlegs and knock-knees treated?
Treatment for leg alignment abnormalities depends on the cause and severity. Orthopedic surgeons and orthopedic specialists often use orthotic inserts, physical therapy, or conservative measures. In cases of severe alignment abnormalities, surgery involving an osteotomy or alignment correction may be necessary to restore a straight leg axis.
How are bowlegs and knock-knees diagnosed?
The diagnosis is made through a clinical examination, gait analysis, and X-rays of the leg axes. During this process, the orthopedic surgeon assesses the position of the legs, the bone structure, and any possible axial deviations. Leg alignment abnormalities are also examined radiologically in infants, toddlers, adults, and children to detect secondary damage and osteoarthritis at an early stage.
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