Methods of preventing and treating knee injuries have changed with the rapid development and refinement of knee braces. Prophylactic knee braces are designed to protect uninjured knees from valgus stresses that could damage the medial collateral ligaments. However, no conclusive evidence supports their effectiveness, and they are not recommended for regular use. Functional knee braces are intended to stabilize knees during rotational and anteroposterior forces. They offer a useful adjunct to the treatment and rehabilitation of ligamentous knee injuries. Patellofemoral knee braces have been used to treat anterior knee disorders and offer moderate subjective improvement without significant disadvantages. Additional well-designed studies are needed to demonstrate objectively the benefits of all knee braces. Knee braces should be used in conjunction with a rehabilitation program that incorporates strength training, flexibility, activity modification and technique refinement.
Musculoskeletal injuries are commonplace in family practice patients, and many knee joint disorders are common among them. The knee is the largest joint in the body, and its exposed position makes it vulnerable to injury during athletic activities.1,2 While strength, flexibility and technique have historically been important components of knee injury management, the use of knee braces as preventive and therapeutic adjuncts has gained recent attention.3,4 The occurrence of knee injuries among high-profile athletes and the aggressive marketing of braces by manufacturers have also contributed to interest in the use of knee braces. As a result, patients may consult their family physicians for accurate, unbiased information about knee braces.
According to the American Academy of Orthopaedic Surgeons,5 knee braces fit into several categories: (1) prophylactic—braces intended to prevent or reduce the severity of knee injuries in contact sports; (2) functional—braces designed to provide stability for unstable knees; and (3) rehabilitative—braces designed to allow protected and controlled motion during the rehabilitation of injured knees. A fourth category includes patellofemoral braces, which are designed to improve patellar tracking and relieve anterior knee pain.
Knee braces may minimize knee injuries, but their true effectiveness remains debatable.1,2,6–9 The current situation is one of confusion among players, coaches, parents and physicians about when knee braces should be used, if at all. This article critically examines prophylactic, functional and patellofemoral knee braces and attempts to assist primary care physicians in selecting the appropriate brace for their active patients.
Prophylactic Knee Braces
After prophylactic knee braces were successfully tested in the National Football League, many athletes wanted access to similar products for use during contact activities. The prophylactic knee brace had been intended to protect the medial collateral ligament (MCL) during a valgus knee stress and to support the cruciate ligaments during a rotational stress.3 Their initial popularity has waned as increasing evidence has questioned their effectiveness, particularly considering the high cost of universal application.
BENEFITS AND LIMITATIONS
Shortly after the introduction of prophylactic braces, several national studies attempted to determine whether they reliably prevent knee injuries. In general, inadequate control groups, subjective biases, variable rules of football, alternative treatment modalities for MCL injuries and inconsistent methods of data collection have limited comparison among most studies of prophylactic knee braces.10–12 Some researchers have concluded that prophylactic knee braces significantly reduce MCL injuries,11–13while others have noted few beneficial effects with regular use.10
As with many types of athletic braces, reported subjective benefits often exceed objective findings. Brace wearers also have noted significant differences in joint position sense between braced and unbraced legs, but this noted difference has not been consistently confirmed.10