Short communicationACL reconstructed individuals do not demonstrate deficits in postural control as measured by single-leg balance
Introduction
Anterior cruciate ligament reconstruction (ACLR) is common among active individuals, reporting up to 130,000 per year [1]. For individuals who return to sport following ACLR, upwards of 30% experience a subsequent injury to the contralateral anterior cruciate ligament (ACL) or the reconstructed graft [2]. Of the individuals that sustain a subsequent ACL injury, up to 80% occur through a non-contact mechanism [3], proposing that proper neuromuscular movement patterns are not reestablished following the initial injury.
Many studies have addressed ACL injuries to be more than a mechanical injury, but also resulting in neurophysiological changes following both injury and reconstruction [4]. Proprioception, defined as the afferent information arising from internal peripheral areas that contribute to postural control [5], is targeted early in rehabilitation protocols to regain fundamental neuromuscular patterns throughout rehabilitation. Common exercises of postural control consist of single leg balance tasks, which have been used as clinical therapies and assessments to objectively measure patient improvement and as an indicator for return to sport [6].
Exploratory factor analyses completed on objective measures of return to sport testing in patients with ACLR identified single limb balance as providing unique information in muscle function, however it is unclear if these patients with ACLR have significantly diminished neuromuscular control compared to healthy individuals [7]. Traditional assessments are often administered with the knee in a straight, closed pack position. This position may not be accurately assessing the ability to detect joint deformation [8], though previous studies have established postural differences in ACLR populations [9]. Therefore, the purpose of this study was to assess single-leg postural control in healthy individuals and ACLR patients around the time point of return to sport progression.
Section snippets
Methods
This was a descriptive laboratory study with data collected in a controlled laboratory environment. Independent variables included the group (ACLR and healthy) and limb (involved and uninvolved) and the dependent variables included patient-reported outcomes and center of pressure average velocity during single-leg balance task.
Demographics
Descriptive values are reported in Table 1. There were no differences between groups for age, height, sex, or limb dominance. The ACLR group had a significantly greater mass than the healthy group. The ACLR group had significantly lower activity levels as quantified by the Tegner activity scale. The ACLR group also presented with significantly decreased subjective function on the IKDC and KOOS subscales compared to the healthy group (Table 1).
Balance
There were no significant main effects for group (F
Discussion
Individuals with ACLR did not demonstrate deficits in postural stability compared to healthy controls or the contralateral limb when assessed in a straight-knee position. COP average velocity, which has shown high relative reliability within this population [11], was also not correlated to subjective knee function in ACLR participants at the time of return to activity. At the time of return to sport, clinicians often perform a battery of muscular assessments to determine readiness of the
Declarations of interest
None.
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