Does my child need a different ACL surgery than an adult?

The reason children are treated differently is anatomical. Near each end of the femur and tibia is a growth plate — a layer of cartilage where the bone lengthens. In a skeletally immature athlete these plates are still open and still working. A conventional adult ACL reconstruction drills bone tunnels that pass directly through them, and the concern has always been that this could disturb growth, producing a limb length difference or an angular deformity as the child finishes growing.

Several techniques exist to address this. Some avoid the growth plate entirely by keeping the tunnels inside the epiphysis, the segment of bone beyond the plate. Others cross it in a limited or controlled way. A hybrid transepiphyseal technique keeps the femoral tunnel within the epiphysis while managing the tibial side differently, and it can be combined with a quadriceps tendon graft taken from the patient rather than tissue from a donor.

The clearest published outcome data on that particular combination comes from a case series of skeletally immature athletes with a mean age of 12.6 years, ranging from 9.4 to 16.0. Fifty patients were eligible and 40 responded, a response rate of 80%, and they were followed for a mean of 5.7 years. Thirty-seven of the 40 — 92.5% — returned to unrestricted sport, at an average of 10.6 months after surgery. Thirty-five, or 87.5%, returned to the level of competition they had played before the injury.

Further surgery was uncommon but not absent. Two patients, 5.0%, needed revision ACL reconstruction. Two more had subsequent meniscal surgery and one had hardware removed. Three patients, 7.5%, went on to tear the ACL in the opposite knee — a reminder that returning to sport carries risk on both sides, not only the operated one.

The important limitation is the study design. This is a Level IV case series with no comparison group, so it cannot tell you that this technique produces better results than another one. Outcomes were collected by survey rather than in-person examination, and 10 of the 50 eligible patients did not respond. It is a description of how one group of children did. It is not a head-to-head trial, and no such trial currently settles this question.

The first question is not chronological age but skeletal age. A 13-year-old can be nearly finished growing or have years of growth remaining, and those are different operations. Surgeons estimate remaining growth using a bone age radiograph, the stage of pubertal development, height and growth history, and parental height. How much growth is left is what determines whether growth-plate-sparing technique is needed at all.

The second question is what else is injured. A repairable meniscus tear changes the calculus, because a meniscus that can be saved is generally better saved sooner. Cartilage damage does the same. In a knee that keeps giving way, each episode of instability carries a risk of adding a meniscal or cartilage injury that is harder to fix than the ACL was.

That is the core of the timing argument. Delaying reconstruction until a child finishes growing avoids the growth plate question entirely, but it means spending months or years with an unstable knee, and the accumulating risk to the meniscus and cartilage is real. Most surgeons now weigh that risk against the growth risk rather than treating delay as automatically safer.

Graft choice follows from the same considerations — what tissue is available, the size of the child, and the surgeon’s own experience with a given technique. Surgeon familiarity is a legitimate factor here rather than an evasion. These are technically demanding operations, and the person doing them regularly is usually the person who should be doing yours.

If you are a parent, the version of this decision you are likely to be offered is not "surgery or no surgery" but "which technique, and when." Both parts are legitimate questions, and both have reasonable answers that depend on your child specifically.

It is fair to ask how much growth your child has left and how that was estimated, because the answer drives everything else. It is also fair to ask what the surgeon’s own experience is with the technique being proposed — not as a challenge, but because it genuinely matters for operations performed less often than adult reconstructions.

The return-to-sport numbers above are encouraging, and they are also averages from a group of 40 children, most of whom were boys, followed by survey. Your child is not an average. The figure worth holding onto is not 92.5% but the shape of the finding: most children in this series returned to sport, a small number needed further surgery, and a meaningful number injured the other knee. All three of those are part of the honest picture.