The reliability of a method for measuring the anterior cruciate ligament-hamstring reflex: an objective assessment of functional knee instability

Abstract

Anterior cruciate ligament (ACL) rupture leads to mechanical and functional knee instability. Functional instability is likely attributable to a sensorimotor deficit. In previous studies, a method has been introduced which allows this deficit to be objectively assessed using ACL-hamstring reflex measurements. There is evidence that subjectively stable and unstable patients with ACL rupture can be objectively distinguished by this method. This study on 34 men was conducted to investigate the reliability of this method on the basis of several factors (intra-individual reproducibility, side-to-side differences, inter-examiner reliability, audiovisual stimuli, fatigue, height, weight, physical fitness, and level of activity at work). The role of gender was assessed in 20 men and 20 women. None of the factors had a relevant influence on reflex responses. The tests were reproducible and reliable. The method described here can thus be used for further research and the clinical diagnosis of functional instability following ACL rupture.

Anatomy and Physiology of Knee Stability

“…As a result, it is the most frequently injured and has been the major focus of studies in recent decades, and its importance and fundamental role in knee stability has led to a substantial body of work investigating its anatomy [16,17], physiology [18,19], biomechanics [20][21][22], assessment [23][24][25][26][27], risks [28,29], and rehabilitation [30][31][32][33][34]. The ACL is supplied by branches of the genicular artery, which consists of two bundles, the anteromedial and posterolateral.…”

An Extensive Evaluation of Different Knee Stability Assessment Measures: A Systematic Review

“…It is used in operative theatres through a direct pull of the ACL to differentiate short and long latencies [75]. The reflex has been investigated intra-operatively by direct traction under arthroscopic visualization and in a research setting by instrumenting a laboratory-based rig [11]; thus, its clinical usefulness is doubtful. Three studies by Schoene et al [11], Friemert et al [26] and Melnyk et al [73] revealed that the ACL-hamstring reflex measurement could be elicited, specifically for injured ACLs.…”

“…The reflex has been investigated intra-operatively by direct traction under arthroscopic visualization and in a research setting by instrumenting a laboratory-based rig [11]; thus, its clinical usefulness is doubtful. Three studies by Schoene et al [11], Friemert et al [26] and Melnyk et al [73] revealed that the ACL-hamstring reflex measurement could be elicited, specifically for injured ACLs. Previous work by Friemert et al [26] has shown that a prolonged reflex was present in patients with a ruptured ACL.…”

“…On the other hand, Melnyk and Gollhofer [73] concluded that it was hamstring muscle fatigue during submaximal isometric exercises that was the reason behind the longer latencies of the hamstring stretch reflex and not the existing ACL injury. Despite the argument in the literature on its usefulness for detecting the aforementioned variables, the authors suggested that this technique has room for improvement in terms of its applicability in a clinical setting to guide rehabilitation protocols [3,11,74].…”

Hamstring stretch reflex: could it be a reproducible objective measure of functional knee stability?

“…Few studies have been conducted to better understand the applicability of an assessment of proprioception in the return to play decision (Beard et al 1993;Friemert et al 2005a;Schoene et al 2009;Tsuda et al 2001). Schoene et al (2009) noted that both the mechanical and functional (sensorimotor) components of the knee play a role in the subjective feeling of instability following ACL reconstruction. They defined functional instability as a feeling of instability due to muscular dysfunction, which is caused by impaired neuromuscular function.…”