The Use of Knee Braces

by Denver T. Stanfield, MD


Orthopaedists are the medical specialists most often called upon to diagnose and treat injuries to the knee joint. Through the American Academy of Orthopaedic Surgeons, orthopaedists have undertaken the continuing review of the effectiveness of knee braces in the prevention and treatment of knee injuries. The Academy's goal has been to provide physicians and others in the medical community with an informed assessment of the state of the art of knee bracing and to provide guidance to physicians and others in the use of knee braces.

The Academy's Knee Braces Seminar Report classified existing knee braces into three groups:

- prophylactic knee braces which are designed to prevent or reduce the severity of knee injuries

- rehabilitative knee braces which are designed to allow protective motion of injured knees or knees that have been treated operatively

- functional knee braces which are designed to provide stability for the unstable knee

Based on the examination by individual physicians, faculty at continuing medical education programs and by relevant Academy committees, the Academy has adopted the following statement.

AAOS believes that the routine use of prophylactic knee braces currently available has not been proven effective in reducing the number or severity of knee injuries. In some circumstances, such braces may even have the potential to be a contributing factor to injury.

Because knee injuries are common in many sports, particularly contact sports such as football, there is a widespread concern about their impact on players and teams. Non-contact stresses in many other sports also can produce significant knee injuries. Tears of the ligaments and menisci and damage to the articular cartilage of the knee may result in lost playing time and may lead to permanent disability. Most players, coaches, athletic trainers and physicians would welcome a device such as a brace that would reduce the incidence and/or the severity of injuries to the knee. Current prophylactic knee braces are intended to, and may mistakenly be believed, to meet these goals.

Scientific studies undertaken to demonstrate the effectiveness of prophylactic knee braces in reducing the frequency and severity of knee injuries have failed to show consistent findings regarding the braces that are currently available. Moreover, few studies in this field have included objective data collected over a significant period of time. injuries to the medial collateral ligament have been the most studied, and no consistent reduction in these injuries attributable to the use of a particular brace has been demonstrated. No reduction in injuries to the anterior cruciate ligament or the menisci have been demonstrated. In some studies there has been evidence that the use of a prophylactic knee brace on a "normal" knee in an athletic situation actually increased the severity of certain injuries.

AAOS believes that to require players to use knee braces "just in case they might help," is not supported by the studies that have examined the effectiveness of such braces.

The intent of this statement is not to argue that prophylactic knee braces do not work and never will. Instead it is to state that medical science has not demonstrated that, as currently constructed and used, they are effective today. There is no credible, long-term, scientifically conducted study that supports using knee braces on otherwise healthy players. The Academy is concerned that significant amounts of money are being expended in schools in the United States for equipment that is, at best, only hoped to be effective in reducing the frequency or severity of knee injuries.

In regard to other categories of braces, AAOS believes that rehabilitative knee braces and functional knee braces can be effective in many treatment programs, and that this efficacy has been demonstrated by /long-term scientifically conducted studies.

Types of braces other than prophylactic knee braces have different structural designs and have been developed to help treat specific problems stemming from injury or disease. Rehabilitative knee braces have been designed to provide a compromise between protection and motion. That is, they allow the knee to move, but within specific limits, which has been shown to be beneficial to the injured knee. Rehabilitative knee braces generally are more effective in protecting against excessive flexion and extension than in protecting against anterior and posterior motion.

Functional knee braces aid in the control of unstable knees. Studies have shown that some of the currently available braces are very effective in controlling abnormal motions under low load conditions but not under high loading conditions that occur during many athletic activities. Most studies designed to test whether functional knee braces protect against the knee "giving way" have demonstrated some beneficial effect of the brace. However, the patient and the physician must guard against a false sense of security evoked by the use of such a brace; bio-mechanical studies show that functional knee braces do not restore normal knee stability under high forces related to certain activities. However, when it is properly fitted, used in conjunction with a knee rehabilitation program, and the patient modifies his or her activities appropriately, a functional knee brace can provide an important adjunct in the treatment of knee instability.