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CURRENT CONCEPTS

ACL Tears in Athletes with Open Physes
Some patients developed MRI documented focal physeal

disruption without a perceived clinical growth disturbance.
Traditional surgical techniques for adult ACL reconstruction Moreover comparing the physes of the surgically
include the creation of transphyseal tunnels followed by graft
reconstructed knee and the contralateral knee 6 months
tensioning and fixation. In the skeletally immature patient, postoperatively, MR imaging showed narrowing of the
conventional tunnel placement and graft tensioning risks
iatrogenic growth disturbance caused by physeal violation. growth plates in the reconstructed knee in comparison with
that in the contralateral knee. Radiographic analyses showed
Multiple animal and human clinical series have documented corticalization around the drill holes in all cases. Although ACL
such growth disturbances. More recent animal studies
reconstruction caused narrowing or the early closure of the
have investigated the effect of small tunnels and soft-tissue open physes in adolescents, the patients did not experience
grafts on physeal bar formation and subsequent growth
limb-length discrepancies and angular deformities. All
arrest. They confirmed that the presence of soft-tissue the authors concluded that, although transphyseal
grafts in the transphyseal tunnels prevented physeal bar
reconstruction of the ACL may not be a benign procedure
formation. Furthermore they also found that transphyseal in younger children with substantial growth potential, it is
tunnels that occupy <5% of the physeal cross-sectional
possible to safely perform this procedure in adolescents with
area do not appear to cause growth disturbance. However, limited growth remaining.
when >7% to 9% of the cross-sectional area of the physis
is violated, growth disturbance is possible even in the Independently from the surgical technique adopted to

presence of a soft-tissue graft. Clinical reports of growth reconstruct the ACL, an unanimous agreement has been
disturbance are rare. Kocher et al. surveyed members of the found concerning the graft choice. In case of a prepubescent
patient, a tendon with bone plugs (e.g., bone-patellar
Herodicus Society and ACL Study Group regarding growth
disturbance after skeletally immature ACL reconstruction tendon bone graft) may induce local growth arrest if placed
across the physis, so a soft tissue graft must be used. In
and noted 15 cases of growth disturbance out of more
than 500 ACL reconstructions. They concluded that case of pubescent patients with closing physes the graft
selection follows the same indications as the adult patients
associated risk factors for growth disturbance included
fixation hardware across the physis, large tunnels (≥12 mm), and the surgeon preference. Conversely, there has been
lateral extra-articular tenodesis, dissection in proximity to considerable controversy regarding the use of autograft

the perichondrial ring of LaCroix, and suturing near the tibial versus allograft tissue. In a recent study, the Multicenter
tubercle. More recent clinical studies have examined the Orthopaedic Outcomes Network patient database was
analyzed to evaluate graft choice and the risks associated
use of MRI to characterize physeal injury after transphyseal
ACL reconstruction in skeletally immature patients. Using a with failure and graft rupture. Patients between ages 10 and
19 years were found to have the highest percentage of graft
custom three-dimensional modeling following transphyseal
ACL reconstruction, it has been found that, with 8-mm failures regardless of graft type. Moreover, the odds of graft
rupture were four times higher with allograft reconstruction
tunnels, less than 3% of the cross-sectional area of the
physis is violated. Moreover, using a custom computerized than with autograft reconstruction.

model of the physis, it has been documented that tunnel Modern surgical techniques can be classified as physeal
diameter is potentially more offensive to the physis than sparing, partial transphyseal and complete transphyseal. A
drill angle. Also the effect of an anatomic positioning of the
variety of physeal-sparing techniques has been described.
femoral tunnel with the use of single – or double-bundle In one technique, the hamstring tendons were kept intact at
techniques has been investigated. The anatomic placement
their distal attachment, passed through a transepiphyseal
of the femoral tunnel is drilled at a more oblique angle that, tibial tunnel, looped over a staple at the femoral ACL origin,
if performed in a skeletally immature patient, places the brought back through the tibial tunnel, and sutured onto

lateral physis at an increased risk of injury. Using a computer- themselves. In a second technique an autograft hamstring
aided three-dimensional model to incorporate the drilling tendon was passed through the distal femoral epiphysis

of an anatomic double-bundle ACL femoral tunnel with a and fixed using a suspension fixation device over the lateral
variety of drill-hole diameters it has been found that the femoral condyle.

average physeal volume removed, as a percentage of the
total physeal volume, was between 3.7% and 6.5%. Based
on these data, anatomic double-bundle drill-hole placement

during ACL reconstruction seems to produce a zone of
physeal injury that appears to increase the risk of abnormal

growth in the distal femoral physis postoperatively. Several
other studies with MRI investigated the postoperative effects

a transphyseal ACL reconstruction on the growth plate in
young athletes. It was confirmed that the average bone

tunnel–to–growth plate cross-sectional area ratio was less
than 3%.

22 ISAKOS NEWSLETTER 2014: Volume II
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