Effect of functional bracing, quadriceps and hamstrings on anterior tibial translation in anterior cruciate ligament insufficiency: A preliminary study

Abstract

Abstract-Anterior tibial translation was measured in six patients with anterior cruciate ligament insufficiency. The tests were done in 15,45, and 90 degrees of knee flexion, partly with activated quadriceps or hamstrings, and partly with subjects wearing a 4-point functional DonJoy brace. The translation was evaluated with a computerized electrogoniometer (Acufex KSS). The anterior tibial translation was significantly reduced by use of the hamstrings in all three degrees of knee flexion. The effect of the 4-point brace was only significant in 15 and 45 degrees of flexion. The quadriceps did not reduce the anterior tibial translation.

The effect of thigh muscle activity on anterior knee laxity in the uninjured and anterior cruciate ligament-injured knee

“…In a sample of 15 ACL‐injured subjects, Iversen et al [19] showed that hamstrings muscle activity reduced anterior knee laxity by up to 31 % when measured using a stress radiography technique during Lachman testing at 15° of knee flexion. This study did not report to what extent subjects were asked to contract their hamstrings muscles and, as with other similar studies [2], muscle relaxation during the so‐called relaxed test was assumed rather than confirmed by measurement. Where the instruction for subjects is to maximally contract the hamstrings, it has been shown that anterior translation of the tibia is reduced by 88 % at 15° of knee flexion and by 94 % at 45° of flexion [2].…”

“…This study did not report to what extent subjects were asked to contract their hamstrings muscles and, as with other similar studies [2], muscle relaxation during the so‐called relaxed test was assumed rather than confirmed by measurement. Where the instruction for subjects is to maximally contract the hamstrings, it has been shown that anterior translation of the tibia is reduced by 88 % at 15° of knee flexion and by 94 % at 45° of flexion [2].…”

“…Inclusion criteria for the uninjured group required that they may be able to partake in the study testing procedures. The exclusion criteria for the uninjured group included (1) a previous ACL injury, (2) a history of neurological or muscular disease, (3) systemic rheumatological disease, (4) lower limb trauma or injury within the past 6 months that required medical attention and (5) posterior cruciate ligament injury. The inclusion criteria for the ACL-injured group were as follows: (1) diagnosed with one ACL-injured knee, (2) at least 6 weeks post-ACL injury or subsequent arthroscopic surgery for concurrent knee damage and (3) able to partake in the study testing procedures.…”

“…The factors that affect the reliability of knee laxity testing when measured using the KT arthrometers (Medmetric Corp., San Diego, USA) are predominantly examiner‐dependent [4, 7, 9, 15]. In contrast, hamstrings muscle activity, which has been consistently shown to affect the results of knee laxity testing [2, 19, 24], is highly dependent on the tested individual, with the ability of a tested individual to relax the thigh musculature influenced by the proficiency of the examiner [26]. As such, a number of studies have shown that thigh, and in particular, hamstrings muscle activity reduces anterior knee laxity in both weight‐bearing and nonweight‐bearing [2, 19, 24, 31] and reduces strain on the ACL [25], with a lesser effect at lower knee flexion angles [19, 25].…”

“…In contrast, hamstrings muscle activity, which has been consistently shown to affect the results of knee laxity testing [2, 19, 24], is highly dependent on the tested individual, with the ability of a tested individual to relax the thigh musculature influenced by the proficiency of the examiner [26]. As such, a number of studies have shown that thigh, and in particular, hamstrings muscle activity reduces anterior knee laxity in both weight‐bearing and nonweight‐bearing [2, 19, 24, 31] and reduces strain on the ACL [25], with a lesser effect at lower knee flexion angles [19, 25]. Furthermore, anterior knee laxity, as measured using the KT1000 arthrometer, is greater in the unconscious as compared to the conscious ACL‐injured individual [13, 17].…”