Destruction of the epiphysis can occur due to an infection at the level of the epiphysis or an epiphyseal fracture in the distal part of the fibula. Growth in the distal fibular growth plate stops and works as a brake. However, the growth plate in the distal part of the tibia carries on growing on the medial side and this results in an ankle valgus deformity (Fig. 12.3). A valgus deformity can also be caused by a growth plate fracture as a result of damage to the lateral part of the distal tibial growth plate (Fig. 12.4).

A valgus deformity in the ankles can be part of achondroplasia.

This is a rare deformity. Four types can be classified (Fig. 12.5):

Dysplasia epiphysealis hemimelica is an osteochondral overgrowth of the epiphysis or articular cartilage. The condition is intra-articular and is limited to half of the extremity (hemimelia). The medial side of the tibia or talus is twice as often active than the lateral side. The valgus deformity occurs if the medial side is affected. (see also pp. 178, 179 and 183).

There is no more growth potential due to complete closure of the growth plate in the distal part of the fibula. One can try to correct the deformity by resecting part of the fibula shaft and carry out an epiphysiodesis of the medial malleolus (Fig. 12.3). One can also consider a supramalleolar varus osteotomy with a fibulotomy if the above mentioned techniques are insufficient (Fig. 12.6). Operative excision of the bony bridge can be considered after a growth plate fracture in the lateral part of the growth plate and the distal part of the tibia if less than a third of the total growth plate is involved. After this the growth plate generally functions normally and in many cases a spontaneous correction of the valgus deformity will occur because the growth plate tries to line up vertical to the weight bearing line (Hueter-Volkmann, law 1862). Temporary medial malleolus hemi-epiphysiodesis may possibly speed up this process (Fig. 12.4).

A temporary hemi-epiphysiodesis may be carried out by fixing the medial part of the growth plate in the distal part of the tibia with 1 screw, or 2 staples or a so-called eight-plate in the case of a minimal deformity (Fig. 12.7). The materials must be removed once the ankle is straight. These materials should not be left in position for more than 2 years because in that case a bony bridge will develop on the medial side of the growth plate in the distal part of the tibia which will result in a varus deformity. A supramalleolar valgus tibial osteotomy with a fibulotomy must be carried out in the case of more serious deformities (Fig. 12.6).

Plate fixation with an autologous cancellous bonegraft should be carried out in the case of complaints. At the same time correction of the valgus deformity must also be carried out. If the fibula pseudarthrosis is still present after the above mentioned treatments an artificial synostosis between distal part of the tibia and fibula will be carried out (Fig. 12.8). One can consider a correction of a possible valgus deformity with a temporary hemiepiphysiodesis of the medial malleolus using a screw or a superamalleolar varus osteotomy and fibulotomy once the child is grown up (for treatment of a tibia pseudarthrosis type IV congenital fibula pseudarthrosis, see p. 245).

A wedge excision at the level of the deformity to correct the deformity may be carried out. There is a high risk of recurrence.