Biomechanical effects of functional knee bracing. Practical implications.

Bracing of the anterior cruciate-deficient knee remains controversial. Close review of published data has revealed enough common observations about braces that strong suggestive information can be utilised for clinical purposes until more concrete data are provided. Brace function can vary with design. The primary differences noted are between the shell-type and strap-type braces. Shell braces tend to provide more stability to the knee than do the strap braces. Proper hinge placement, rather than type, affects pistoning and overall performance of the brace. Custom braces provide a better fit than off-the-shelf devices, but they can feel more restrictive, especially the shell braces. Static bench-testing data have shown that these braces provide little stability against anterior tibial translation at forces comparable to athletic play. Yet kinematic and force plate data suggest that they may produce some mechanical constraining effect to the entire lower extremity instead of just the knee joint. The literature still supports the philosophy that functional bracing should be considered as part of a comprehensive rehabilitation programme for an anterior cruciate-deficient athlete with significant functional deficits.