Functional Bracing for Anterior Cruciate Ligament Injuries: Current State and Future Direction

Introduction

Anterior cruciate ligament (ACL) tears are a common knee injury, with a reported estimate of 200,000 ACL injuries annually in the United States. Annual ACL reconstruction rates have been reported to be increasing in the United States, with recent estimates ranging from 60,000 to 175,000. Functional bracing often plays an important role in postoperative management of ACL reconstructions and in nonoperative management of ACL-deficient knees.

Early in the 20th century, functional ACL bracing sought to correct the forces imparted on the knee in an attempt to restore stability to ACL-deficient patients. Bracing evolved and soon became a common aspect of postoperative ACL reconstruction management. A survey conducted among American Orthopaedic Society for Sports Medicine members published in 2003 found that only 13% of physicians never braced patients following ACL reconstruction and only 3% of physicians never braced ACL-deficient patients. Accounting for the reported prevalence of ACL injuries and ACL reconstructions performed annually, an estimated 100,000 functional braces are prescribed each year in the United States.

The goal of functional ACL bracing is to reproduce the knee-stabilizing forces of the native ACL. Regardless of whether a patient requires a brace to stabilize an ACL-deficient knee or to unload an ACL graft following reconstruction, the goal is to reduce the risk of further injury such as meniscal tears or early onset osteoarthritis. Generally, functional ACL braces are used in four situations: nonoperative management of a chronic ACL-deficient knee, nonoperative management of a young patient with an ACL tear who will undergo surgery upon reaching skeletal maturity, preoperative management of an ACL tear prior to surgery, and postoperative management following ACL reconstruction.

While functional bracing is a common component of ACL management, biomechanical and clinical results remain inconclusive. Additionally, a variety of functional ACL braces currently exist ( Fig. 112.1 ), and they differ in cost, design, and recommended use. The purpose of this chapter is to summarize the current state of ACL functional bracing literature and offer direction for future functional ACL bracing research.