Valgus Angulation

The ACL resists anterior tibial translation and rotational loads. With a ruptured ACL, the anterior translation of the tibia relative to the femur can be four times greater than in normal knees. It also restrains internal rotation significantly and plays a minor role in controlling the external rotation and varus-valgus angulation. Moreover, the ACL prevents medio-lateral translation of the tibia. In an ACL-defident knee, this poor translation can lead to tears in the medial meniscus and hypertrophy of the tibial spine and notch, and it increases contact loading of the medial compartment of the knee. ... 

The arrangement of the muscular compartments is such that the anteromedial face of the tibia is subcutaneous and therefore also more likely to sustain open or compound fractures than other long bones. Because the major muscle bulk in the lower leg is lateral and posterior to the skeletal structures, there is also a tendency for diaphyseal midshaft fractures of both bones to develop valgus angulation (Fig. 9.8). 

Radiographs will often confirm the fracture pattern and the degree of displacement, and often these injuries will reduce when the deforming force is removed, with 10° of angulation in the line of the joint being acceptable but there can be no obvious varus or valgus angulation. 

A varus or valgus angulation is caused by adduction or abduction forces, respectively. Occasionally, in boys nearing skeletal maturity, the tibia may show a flexion type injury. This occurs when taking off or landing from a jump. 

Radiographs show a torus or greenstick fracture of the proximal tibial metaphysis. The fracture line may be poorly visible or even incomplete, running from the medial (tension) side. Occasionally, there may be valgus angulation and the fibula may also be fractured. 

Treatment is to place the child in a non-weight bearing long-leg cast for 4-6 weeks. Any valgus angulation must be noted and corrected. This often in-... 

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