The companies that manufacture knee braces tout their products as effective in the prevention, treatment and rehabilitation of knee injuries. The scientists who test such braces have less glowing opinions. Clinical evaluations of the effectiveness of knee braces often deliver mixed or conflicting results.
Knee braces are made in different materials and sizes. Designs vary from simple elastic sleeves to complex metal braces with moving parts. Knee braces are designed with four main purposes in mind.
Prophylactic Knee Braces
Prophylactic braces are designed to prevent injury and are used by athletes who participate in sports where the knee is vulnerable. The sudden stops and turns necessary in sports such as basketball, football, tennis and soccer can cause painful tears in the ligaments of the knee.
The use of prophylactic knee braces is looked upon with skepticism by the American Association of Orthopaedic Surgeons (AAOS), who has stated that "there is no credible long-term scientifically conducted study that supports using knee braces on otherwise healthy players."
The Henry Ford Hospital in Detroit, Michigan, and the University of Iowa Hospitals have found that prophylactic braces can protect knee ligaments from trauma that forces them to angle or twist laterally from their normal alignment. However, this additional protection comes at a cost -- prophylactic leg braces appear to decrease performance level, and increase leg cramping and fatigue.
Functional Knee Braces
Functional braces are designed to provide support to knees that are vulnerable due to prior injury, while still allowing the performance of normal functions. They can be custom made or store bought. The AAOS has found functional knee braces to be helpful only in low-load conditions -- meaning, conditions where low amounts of compressive and rotation force are exerted on the knee joint.
The sports medicine department of the Karolinska Institutet in Stockholm, Sweden, has concluded that functional bracing contributes a subjective sensation of stability to patients with an anterior cruciate ligament (ACL) tear. But this outcome is merely psychological -- no actual physical benefit arises from functional bracing in that situation.
Rehabilitative Knee Braces
Rehabilitative braces prevent movement that could detract from the healing process of a knee that has been injured or has recently undergone surgery.
The AAOS has found that rehabilitative knee braces, in conjunction with supervised rehabilitation and management of an injury, have a positive effect on the rehabilitation process.
Unloader/Offloader Knee Braces
Unloader/offloader braces are made for use by osteoarthritis patients whose arthritis is affecting their knees.
Two types of offloader knee brace were evaluated by the Faculty of Health at the University of Central Lancashire. Valgus braces, which shift the body weight to the lateral part of the knee, were compared with simple hinged braces in the treatment of patients who experienced osteoarthritis of the medial knee compartment. The valgus brace delivered improvements in "pain, function, and loading and propulsive forces," while the hinged brace only improved the loading force to which the knee was subjected.
