Hindlimb Growth after a Transphyseal Reconstruction of the Anterior Cruciate Ligament: A Study in Skeletally Immature Sheep with Wide-Open Physes

Abstract

Background:

There is a lot of controversy in the recent literature with regard to the optimal treatment of anterior cruciate ligament (ACL) injuries during growth. Iatrogenic growth disturbance due to physeal damage is a potential complication, forcing many orthopaedic surgeons to treat these injuries conservatively.

Hypothesis:

It is possible to perform a fully transphyseal ACL reconstruction in an ovine model with wide-open physes without creating growth disturbances.

Study Design:

Descriptive laboratory study.

Materials and Methods:

Four-month-old skeletally immature sheep underwent a transphyseal ACL reconstruction of the right knee. The surgical technique followed the criteria known to be essential to avoid growth disturbances in humans; the tibial tuberosity was spared to prevent a genu recurvatum, thermal damage to the growth plates was avoided, the physes were perforated with a small-diameter drill in the center of the growth plate, a soft tissue graft was used, graft fixation was achieved far away from the growth plates, the perforated growth plates were filled by the soft tissue graft, and the graft was moderately pretensioned before fixation. The left knee served as a control. A computer-assisted evaluation of long radiographs (frontal and sagittal plane) of the exarticulated hindlimbs was performed to exactly evaluate the limb alignment, joint orientation, and leg length. The animals were sacrificed in groups of 6 after 3, 6, 12, and 24 weeks.

Results:

No angular deformities or leg-length discrepancies occurred after this transphyseal ACL reconstruction procedure throughout the remaining growth.

Conclusion:

This large-animal study supports the clinical observation that it is possible to perform an ACL reconstruction without creating growth disturbances as long as a number of key principles are followed.

Clinical Relevance:

Previous animal studies argued against ACL reconstruction in skeletally immature patients. This large-animal study provides support for early operative treatment of ACL ruptures even in young patients with open physes.