ACL Injuries in Children

Patient information for parents and carers — Dr Christopher Spelman, Orthopaedic Surgeon

Overview

Anterior cruciate ligament (ACL) injuries were once thought to be rare in children, but they are becoming increasingly common as more children play intensive, organised sport from a young age. The ACL is a key stabilising ligament in the centre of the knee. In children, ACL injuries pose a particular challenge because the knee still contains open growth plates (physes), which must be respected during any surgery to avoid disturbing growth.

How they occur and symptoms

As in adults, ACL injuries in children usually happen during pivoting, landing or a sudden change of direction, often with a “pop”, rapid swelling and a sense that the knee has given way. A child with a significant knee injury and swelling should be assessed, as ACL tears in this age group are frequently accompanied by injuries to the meniscus or cartilage.

Treatment considerations

Historically these injuries were treated without surgery because of concern about damaging the growth plates. However, leaving the knee unstable exposes the meniscus and cartilage to further damage with each episode of giving way. Current practice therefore favours surgical reconstruction in most active children, using techniques specifically designed to protect the growth plates – so-called physeal-sparing and physeal-respecting reconstructions. The choice of technique depends on the child’s age and remaining growth. Careful, structured rehabilitation and appropriate return-to-sport testing are essential.

Outcomes and what the evidence shows

Contemporary evidence supports surgical reconstruction over non-operative treatment for most skeletally immature children with an ACL tear, showing favourable patient-reported outcomes and high rates of return to sport, while growth-plate-friendly techniques keep the risk of growth disturbance low.

Graft re-tear rates in children and adolescents are low in absolute terms but are higher than in most adult populations, reflecting their young age and high activity levels. Emerging evidence suggests that adding a lateral extra-articular procedure and applying strict return-to-sport criteria may further reduce re-tear rates.

Dr Spelman will perform a Lateral Extra-Articular Tenodesis (LEAT) in almost all patients under 25.

There are several variations in surgical technique that are available for paediatric patients that will minimse the risk of damage to growth plates, and Dr Spelman can explain these to you in detail as required by your specific case.

Complications

Reconstruction in a growing child carries the general risks of ACL surgery plus some specific to skeletal immaturity:

Graft re-tear – more common than in adults, particularly in young athletes returning early to pivoting sport; a further injury to the opposite knee is also a recognised risk.

Growth disturbance – the main concern unique to children. Injury to a growth plate during surgery can rarely cause the leg to grow crooked (angular deformity) or to end up longer or shorter; growth-plate-protecting techniques are used specifically to minimise this.

Associated meniscal or cartilage damage – a delay in stabilising the knee, or repeated instability, can lead to meniscal tears that affect the long-term health of the joint.

Stiffness – loss of movement after surgery, usually responsive to physiotherapy.

The general risks of knee surgery – infection and blood clots – which are uncommon.

Summary

ACL injuries in children are increasingly common and are best managed with growth-plate-protecting reconstruction in most active children, as an unstable knee risks further damage. Outcomes are good, though re-tear rates are a little higher than in adults and growth disturbance is a small but specific risk. Decisions are individualised to the child’s age, maturity and activity, with structured rehabilitation central to a safe return to sport.

Please see the summary of ACL reconstruction for more detailed surgical information