An ACL injury is most likely to occur when children are taking part in sports involving twisting, pivoting and jumping, such as football, netball, tennis and rugby, which are all played regularly in UK schools. Skiing, due to the pressure on the knee whilst the ankle is kept in a fixed position, is also one of the sports with a higher than average occurrence of ACL tears.
It can also occur with certain movements, such as a child jumping and landing hard on their feet. If the quadriceps muscles aren’t strong enough, a movement can suddenly put too much pressure on the knee joint, causing the ACL, a rope-like band of tissue, to tear or rupture.
The increasing number of ACL injuries in children may be due to a number of factors: many children are heavier; they are competing at a higher level from a younger age and more are taking part in extreme sports such as skiing and snowboarding.
The increasing role of strength and conditioning in youth sport; all-year round pitch availability; improvements in footwear technology and increasingly accurate diagnosis also play a part.
A higher average pace of play is now common, increasing the need for the participants to change direction more frequently resulting in higher stresses through the stabilising structure of the knee more often.
Teenage girls are between two and ten times more likely than boys to tear an ACL, due to their body shape, limb alignment, neuromuscular control, and the presence of hormones which might loosen the ligament.