Bracing for patellar instability.
 Knee pain secondary to problems with patellar tracking is common.
 The initial treatment for these problems is conservative.
 Patellar orthotics have been used extensively to treat a variety of extensor mechanism problems.
 Millions of health care dollars are spent annually on the use of these braces.
 There are many different patellar orthotics on the market today.
 The use and design of most of these devices are unclear and often lack a solid biomechanical foundation.
 The practical mechanical function of these braces is to reduce the lateral displacement of abnormal patellofemoral tracking.
 Orthotics that are designed and tested using practical biomechanical principles for applying a medially directed force to the patella seem to have a role in treating patients with knee pain secondary to patellar malalignment and instability.
 Well-defined and controlled clinical studies of the use of patellar braces are lacking.
