Lateral Side Augmentation

Over the past decade, operative procedures for the treatment ligament instabilities have improved substantially. However it is important to understand that an injury to either the ACL or PCL is often associated with a complex injury mechanism rather than an isolated force. As a result the other soft tissue restraints within the knee may be injured. With this in mind, it is important to realize that both acute and chronic “simple ligament tears” may involve a more complex injury than earlier considered.

Specifically, the lateral structures may be compromised in chronic and acute ligament disruption, resulting in severe rotary instability. In such instances, the secondary restrains may be so damaged and the rotary instability so severe that an isolated ligament reconstruction using any graft source may fail. This is especially true in those patients where prior lateral reconstructions may have affected the lateral structures. If severe antero-lateral rotary instability is diagnosed, we have found that an extra-articular anterolateral reconstruction (ALR) should be performed in conjunction with the primary ligament reconstruction. Antero-lateral instability is most commonly associated with ACL disruption.

Additionally, in cases of PCL disruption the postero-lateral structures of the knee may be damages. In these cases where postero-lateral instability is identified a postero-lateral reconstruction (PLR) is performed in conjunction with a primary PCL reconstruction. There are cases, often following knee dislocation where both the PCl and ACL is torn, when both an antero-lateral and postero-lateral reconstruction is needed. We feel that the failure to recognize such instabilities (antero-lateral; postero-lateral; combined) and to perform the appropriate extra-articular reconstruction is an under-recognized cause of ligament reconstruction failure.

The Physical Exam

Physical Exam

A compromise of the lateral structures is suspected in those patients who have had a prior lateral side procedure, a knee dislocation, or a prior ACL reconstruction procedure that has failed. It is also highly suspected following a PCL tear.

The internal and external rotation (Fig 1) dial tests can be used to assist in the diagnoses of severe lateral rotary instability . The point is that the greater the degree of lateral rotary instability and the more evidence supporting a compromise of the lateral supporting structure, the more likely it is that an “isolated” intra-articular ligament reconstruction will fail.

Therefore, the greater the evidence of severe instability and the greater the evidence of compromise of the lateral structures, the more likely it is that the surgeon should add a lateral stabilizing procedure to the intra-articular procedure.