Single-bundle versus double-bundle ACL reconstructions in isolation and in conjunction with extra-articular iliotibial band tenodesis.

BACKGROUND: Intra-articular anterior cruciate ligament (ACL) reconstruction has been the primary treatment option for isolated ACL injuries for many years. An anatomic double-bundle reconstruction has been devised in an effort to improve rotational control. The role of the extra-articular iliotibial band tenodesis in ACL injuries has evolved from primary treatment, to an adjuvant secondary procedure, to being used more selectively in revision ACL reconstructions.

HYPOTHESES: 1) Single-bundle and doublebundle intra-articular ACL reconstructions will both restore pre-injury laxity measurements in an isolated ACL injury cadaver model. 2) The deep iliotibial band structures contribute to rotational control and in a dual ACL + ITB injury cadaver model, ACL reconstruction alone cannot restore rotational control.

STUDY DESIGN: Controlled Laboratory Design.

METHODS: 17 fresh frozen cadavers received intra-articular reconstructions, seven single-bundle and ten double-bundle; laxity was measured with the ACL intact/ITB intact, ACL reconstructed/ITB intact, after cutting the ITB, and after an ITB tenodesis procedure; laxity measurements of anterior tibial translation(ATT) and internal rotation(IR) were measured following applications of an anterior shear force, an internal torque and a coupled anterior shear force-internal torque at 30 and 90 degrees of flexion.

RESULTS: Single-bundle and double-bundle ACL reconstructions both restored IR to a native knee state under isolated internal torques and under coupled forces. Both reconstruction techniques also re-established anterior tibial translation to at least the pre-ACL injury level, with over-constraint in the double-bundle subgroup [5.00 (+2.11) to 3.50(+1.18), p-value 0.026] under coupled loads at 30 degrees of flexion. With the individual ACL reconstructions held constant, under coupled forces mean IR increased in the single-bundle subgroup [13.7(+1.1) to 17.6(+1.2), p-value 0.004] and the double-bundle subgroup [9.5(+1.0) to 12.4(+1.0), p-value 0.009] with the cutting of the ITB at 30 degrees. Under internal torque, mean IR increased in the single-bundle subgroup [14.0(+1.0) to 18.4(+1.6), p-value 0.016] with the cutting of the ITB at 30 degrees, while IR increased in the double-bundle subgroup [10.0(+1.3) to 13.4(+1.5), p-value 0.002] under the same internal torque at 90 degrees. With the ACL reconstruction held constant, ATT did not significantly change when the ITB was cut or when it was tenodesed under any specific loading condition.

CONCLUSION: Single-bundle and double-bundle intra-articular reconstructions were both able to restore internal rotation and anterior tibial translation to at least native knee laxity levels after an isolated laboratory ACL injury. When the ACL reconstructions were held constant, internal rotation statistically increased with the cutting of the ITB under multiple testing conditions in both the single-bundle and double-bundle subgroups.