Low-Profile Hybrid Fixation for Pediatric ACL Reconstruction

With injuries occurring in children as young as 5 years old, Anterior Cruciate Ligament (ACL) tears seem to be occurring more frequently. For female soccer players between 14 to 18 years old, the ACL injury rate is 14.08 for every 100, 000 athletic exposures. Male football players of the same age have an ACL injury rate of 13.78 per 100, 000 athletic exposures. After analyzing the insurance data for 6 million pediatric and adolescent athletes, a previous study found that knee injuries accounted for 22% of all claims. Of these, 37% of female and 24% of male knee injury claims were for ACL tears.

Experts and evidence from previous studies suggest that young patients with complete ACL tears should undergo surgical treatment. Skeletally immature patients who undergo nonsurgical treatment are at higher risk of secondary meniscus tears, episodes of instability, and difficulty returning to the same level of athletic performance. Experts even recommend reconstructive surgery for young athletes with partial tears greater than 50%.

In order to optimize surgical techniques for ACL reconstruction in pediatric and adolescent patients, R. Justin Mistovich, M.D. and Theodore J. Ganley, M.D. from the Children’s Hospital of Philadelphia introduced a low-profile hybrid fixation technique in the May 2014 issue of Orthopedics. This technique utilizes hybrid fixation techniques for tibial fixation of soft tissue grafts in conjunction with knotless anchors. Although the low-profile technique’s original creators were Coleman et al, Mistovich and Ganley modified the technique for use on younger patients and described it in their article, “Pediatric Anterior Cruciate Ligament Reconstruction Using Low-Profile Hybrid Tibial Fixation.”

Ganley and Mistovich use the modified hybrid fixation technique on patients who are approaching physical maturity but still have an open proximal tibial physis, usually 13 or 14 year olds. The authors prefer using a hamstring tendon autograft, although other soft tissue autografts and allografts can be used with the technique. The tibial interference screw is carefully measured so that it does not cross the open physis. These screws are typically 23mm shorter than adult fixation length. Once the doctor fixes the graft in place and anchors it in the two anchor sites, the resulting construct provides low-profile supplemental fixation for the tibial interference screw and still respects the physis.

Although hybrid techniques are biomechanically superior to a single interference screw for fixation of soft tissue ACL grafts, hybrid fixation methods have the added disadvantage of hardware that may require another surgery for removal. The low-profile technique lessens the prominent hardware and Mistovich and Ganley’s modification to this technique benefits younger patients by keeping the physis free from any potential disturbances from the crossing interference screw.