Rugby football is associated with a number of biomechanical stresses which are frequently associated with knee injury. Consequently, there has been a significant interest within the game regarding the techniques of knee surgery and accelerated rehabilitation and the prophylactic use of external knee support. Knee bracing and strapping techniques are widely practised by rugby players but their results vary and there are mixed opinions over their usefulness. This article discusses the current trends in external knee support, draws on the experiences of other professional football codes and extrapolates these to the rugby union setting. Widespread opinion confirms that improper or incomplete rehabilitation is linked to re-injury. There is also a general acceptance that external support for the knee in sport should never be used to mask an injury. There is no evidence that the prophylactic taping of the knee joint provides any significant external stabilisation for more than the first few minutes of play. This lack of lasting stabilisation is due to the vigorous physical activity associated with rugby which results in a rapid loss of the custom fit of the external support to the profile of the joint. The taping the patella to reduce the pain associated with poor patellar alignment is considered to be effective; however, the correction of other biomechanical influences is also important. Adhesive tape, when applied correctly, will reposition the patella but this technique is limited by factors such as sweating and movement. A number of knee braces are currently available and these are classified according to their prophylactic, rehabilitative or functional design. In this article, their use in rugby applies to external support as an aid to rehabilitation rather than injury prevention.