During infancy, the presence of genu varum in both legs is physiological. The hip joints are often in pronounced exorotation and the lower legs in endotorsion. By the age of 18 months, the legs are almost straight. During the second and third year of life, they switch to genu valgum (‘knock-knees’). During this process, the hip joints are frequently in pronounced endorotation due to more pronounced anteversion and the lower legs are in exotorsion. Knock-knees can be aggravated by fat upper legs and flat feet. By seven years of age, the valgus position will have been corrected in the majority of children. Genu varum is pathological if it occurs unilaterally. If after the age of one year, no spontaneous recovery occurs or if after 18 months, genu varum occurs again.
Genu valgum is pathological if it occurs unilaterally, and if after the age of seven years genu valgum persists. Be aware of excessive body weight.
The Measurement Of Genu Valgum And Genu Varum
Genu Valgum
Physiological genu valgum and pes planovalgus (with a valgus position of the calcaneus) in a toddler [Figures 147, 148].
Figure 147
Figure 148
Procedure
- The child lies with extended legs in supine position on the examination table.
- Take hold of the feet and from this position, turn the legs so that the patellae point straight forward and the knees are pushed against each other.
- Measure the distance between the two medial malleoli (intermalleolar distance) with a measuring tape [Figure 149].
- A distance greater than 10 cm, in children aged over 7 years, is abnormal.
- Try to bring the medial malleoli towards each other [Figure 150]. If this cannot be achieved, there is a large chance that the genu valgum will not correct spontaneously.
Figure 149
Figure 150
Genu Varum
Procedure
- The child lies with extended legs in supine position on the examination table.
- Take hold of the feet and from this position, turn the legs so that the patellae point straight forward and the ankles are pushed against each other.
- Measure the distance between the two medial femoral condyles (intercondylar distance) with a measuring tape.
- A distance greater than 10 cm, in children aged 18 months or older, is abnormal.
A better measurement for an abnormal varus or valgus position is the tibiofemoral angle, which can only be measured properly using radiographic techniques.