The effect of placing a tensioned graft across open growth plates: A gross and histologic analysis

Background: Midsubstance tears of the anterior cruciate ligament in skeletally immature patients are increasingly common and are a challenging problem. The results of nonoperative treatment are no better in children than they are in adults. Physeal-sparing reconstructive procedures have yielded poor results. Reconstructive procedures that are utilized in adults violate the physis, potentially resulting in growth abnormalities. The objective of this study was to provide a model for reconstruction of the anterior cruciate ligament in skeletally immature patients by evaluating the effects of a tensioned connective-tissue graft placed across the canine physis. Methods: Twelve ten-week-old beagles underwent reconstruction of the anterior cruciate ligament consisting of placement of fascia lata autograft through drill-holes across the femoral and tibial physes, tensioning of the graft to 80 N, and fixing it with screws and washers. The contralateral limb served as a control. One dog was eliminated from the study secondary to a postoperative infection. Four months postoperatively, the dogs were killed and were inspected grossly, radiographically, and histologically for any evidence of growth disturbance. Results: Significant valgus deformity of the distal part of the femur (p < 0.001) and significant varus deformity of the proximal part of the tibia (p = 0.03) developed in the treated limbs. Neither radiographic nor histologic examination demonstrated any evidence of physeal bar formation. Conclusions: Significant growth disturbances occur with excessively tensioned transphyseal reconstruction of the anterior cruciate ligament in the canine model. These growth disturbances occur without radiographic or histologic evidence of physeal bar formation. Clinical Relevance: This study illustrates the risk to the physis associated with transphyseal reconstruction of the anterior cruciate ligament with the use of a tensioned connective-tissue graft in skeletally immature patients. We do not recommend transphyseal reconstruction of the anterior cruciate ligament in this patient population.