Effects of a tensioned tendon graft in a bone tunnel across the rabbit physis

Children who sustain anterior cruciate disruption often are denied the stan dard reconstructive procedures because of the concern that drilling across the physis of the tibia and femur and compression from a tensioned graft wi ll result in growth plate arrest. To test this concept and to assess whethe r a tendon placed in the tunnel would function in a manner similar to a fat graft after the resection of a physeal bar, tunnels were made across the p roximal tibial physis and distal femoral physis in a group of immature rabb its. Four tunnel diameters were used from 1.95 to 3.97 mm, in three rabbits at each diameter, with patellar tendon autografts being used as the recons truction of the anterior cruciate ligament in two of the animals. The knees were radiographed every 4 weeks, and the animals were euthanized 4 months after surgery. The surgically treated and control knees were salvaged, and each knee was examined grossly, radiographically, and histologically. Eight of the 11 animals had growth arrest of one or both physes. The larger the drill hole diameter the more marked was the deformity. The proximal tibial physis seemed to be the most vulnerable for growth arrest, occurring in eig ht of the knees. The insertion of a tendon did not seem to offer any protec tion to physeal arrest. Because of these findings, it is not recommended th at tunnels involving 1% or more of the area of the physis be placed across the tibial and femoral physis to reconstruct the anterior cruciate in very skeletally immature children.