We examined the ability of a soft tissue graft to inhibit the formation of a bony bridge within tunnels drilled across open femoral and tibial growth plates in a canine model. A fascia lata autograft was placed in tunnels drilled across the distal femoral and proximal tibial physes in four skeletally immature dogs. Four additional dogs had a similar procedure performed, but the drill holes were left empty. The growth plates were evaluated at either 2 weeks or 4 months postoperatively using high-resolution radiography and routine histologic study. A bony bridge spanned the growth plate in all nongrafted animals as early as 2 weeks postoperatively. However, the fascia lata autograft prevented bone formation within the tunnels of all grafted animals, which maintained normal growth plate anatomy throughout the length of the study. The results of this study demonstrate that a soft tissue graft of fascia lata placed in drill holes across open growth plates will prevent the formation of a bony bridge. These findings provide basic science support to those clinical studies that report no apparent alteration in growth plate function after the use of intraarticular techniques to reconstruct the anterior cruciate ligament in children and adolescents.