The Effect of Anterior Cruciate Ligament Trauma and Bracing on Knee Proprioception
abstract & commentary
Synopsis: The use of braces or sleeves for cruciate-deficient knees is of questionable value, at least with respect to proprioceptive input.
Source: Beynnon BD, et al. The effect of anterior cruciate ligament trauma and bracing on knee proprioception. Am J Sports Med 1999;27(2):150-155.
For several years, standard care for many clinicians regarding chronic cruciate-deficient knees has included the use of some type of neoprene sleeve and/or functional knee brace. The rationale for the use of these braces includes biomechanical and proprioceptive considerations. The main purposes of this study were to determine if wearing a neoprene sleeve or a functional knee brace makes a difference in proprioception and if a relationship exists between clinical measures of knee joint laxity (anterior-posterior knee laxity and pivot shift) and the individual’s ability to detect passive knee motion (proprioception). There were 20 subjects—13 males and seven females. The mean age was 40 years (range, 26-53) and the average time from anterior cruciate ligament (ACL) disruption to study was 5.5 years. Inclusion in the study required a 3-mm difference (injured to uninjured knee) as measured on a KT-1000. The primary measurements were passive knee motion and knee position as measured by their modification of an apparatus designed by Barrack et al.1 The reliability of this method has been reported in a previous study. Passive knee flexion was measured on three separate occasions (three testing conditions): 1) ACL deficient and contralateral knee; 2) ACL deficient knee with brace and contralateral knee (the Bledsoe ACL knee brace was used); and 3) ACL deficient knee with sleeve (the Bledsoe Sport Max Brace was used). Analysis here included paired students’ t-tests with Bonferroni correction done on the three. The KT-1000 measurement for anterior-posterior laxity was done at 133-N of anterior load. In addition, pivot shifts were measured clinically and graded from A to D, with A being normal stability and D representing gross instability.
Results indicated that there was a significant difference between the ACL deficient knee and the uninjured knee with respect to the threshold of detection of knee passive motion (proprioception), with the ACL deficient knee being "worse." This difference, while statistically significant, was only 0.28°. Neither bracing nor sleeve use significantly improved the individual’s ability to detect passive motion.
Comment by Clayton F. Holmes, EdD, PT, ATC
As Beynnon and colleagues point out in their discussion, several studies have indicated a proprioceptive benefit from braces and sleeves with a variety of diagnoses. However, no one has looked at anterior cruciate deficient knees. In fact, the findings of this study seem to confirm that the use of braces or sleeves for cruciate deficient knees is of questionable value, at least with respect to proprioceptive input. With regard to braces, there is still the question of a biomechanical benefit; however, the evidence of such a benefit in my mind is at best contradictory. It is important to note that Beynnon et al did not establish reliability of the KT-1000 measures, obviously a crucial measure in the study, other than to say that all measures were done by the same orthopaedic surgeon. This fact notwithstanding, this study should create questions regarding the cost-benefit ratio, particularly of expensive functional braces. Perhaps the neoprene sleeves could remain a part of postinjury knee care because they are inexpensive.
Reference
1. Barrack RL, et al. Proprioception in the anterior cruciate deficient knee. Am J Sports Med 1989;17:1-6.
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