For knock knees and bow legs (ICD code for both conditions: Q74.15) are knee deformities.
Knock knees are also known as genu valgum or valgus position. With knock knees, the angle of the lower leg to the centre of the body is more than 185°. This phenomenon is also known as angular deflection.
In people with bow legs (genu varum), on the other hand, the legs gape wide apart at the level of the knees. The knees do not touch each other even when the legs are closed.
Comparison of knock knees and bow legs with a normal, healthy leg position © Double Brain / Fotolia
Both knock knees and bow legs are rarely congenital. The deformities usually occur in childhood, often as a result of vitamin D deficiency (rickets) in infancy. The body itself produces the necessary vitamin D, which is required for healthy bone growth. A deficiency occurs, for example, due to a congenital disorder or as a result of too little sunlight.
Without enough vitamin D, the bones do not become hard enough. They cannot support the growing weight of the affected person, so that over the years, knock knees or bow legs develop.
The malpositions are first noticed between the first and fifth year of life.
In addition, knock knees and bow legs can be the result of bent or flat feet. In this case the feet take an oblique position to the knees. The malposition of the feet therefore causes an additional malposition of the knee joints in the long term.
In adults, knock knees and bow legs occur almost exclusively after an accident. Another cause is sitting in a certain position for many years. A typical example is the jockey who develops clearly visible bow legs due to the frequent sitting on the horse.
Other, but rather rare, causes of malalignment of the knee joints are:
- Bone metabolism disorders (hypophosphatia)
- Hormone disorders
- Being overweight.
Knock-knees and bow-legs are generally regarded as a cosmetic blemish. However, those affected also suffer from pain in the joints. The pain can increase in wet and cold weather or when the weather changes.
In addition, there are postural problems that have a negative impact on other joints (such as the hip joint). The uneven loading of the joint structures rubs the cartilage, bone and menisci disproportionately. This increases the risk of knee joint arthrosis (the so-called gonarthrosis) or meniscus damage.
In children, growth is also often impaired.
Knock knees and bow legs are not always obvious at first sight. Especially when the deformity is not yet very pronounced, the gait is often completely inconspicuous. All the more reason to have children regularly examined by a doctor so that action can be taken at an early stage.
The doctor can take various measurements and make the diagnosis with the help of an X-ray.
It is advisable to look out for any malpositions already in children. Take your child to the paediatrician for regular check-ups.
At first, the malpositions are usually only observed, because spontaneous regressions are quite possible. In many cases
- Shoe insoles,
- Night splints or
If these measures are not sufficient, surgery can be considered – but only towards the end of the growth phase.
Correcting the deformities is important to avoid long-term damage to the joints, which can be associated with lifelong knee pain. Without therapy, this leads to permanently incorrect joint loading. This increases the risk of developing cancer at an early age – from the age of 30 onwards. Year of life – severe arthroses can develop.
Leg axis training (special gymnastic exercises) can help prevent the deformity from getting worse. They also serve to reduce pain and other impairments.
The performance must be supervised by an experienced physiotherapist. However, the patient is usually also given instructions for gymnastic exercises that they can do at home.
Typical exercises for leg axis training are, for example, special squats. More attention is paid to the position of the legs and they help strengthen the thigh muscles in particular.
The single-leg stand is also a simple way of improving
- Coordination and
You can vary the one-leg stand – for example, by using a soft pad. It is best to do the self-control exercises in front of a mirror.
Another way to treat knock knees and bow legs is with orthoses. These are used in particular for adults who have failed to correct the malposition at an early stage.
An orthosis cannot eliminate the malposition. However, it can significantly reduce pain by effectively supporting and strengthening the leg at the same time. Without an orthosis, on the other hand, there is a risk that the malposition will get worse and worse.
Therefore: Have malpositions treated at an early stage! The sooner knock knees and bow legs are treated, the better the chances of a largely pain-free and symptom-free life.
Parents should therefore have their children examined regularly.
In adults, orthoses can significantly reduce the negative effects of knee malalignment.