Lower limb symmetry index (LLSI) pre- and post-reconstruction of the ACL: a controlled study

Abstract

Background: The anterior cruciate ligament (ACL) lesion causes a deficit in joint stability and mobility, trophism and muscular strength, generating asymmetries between the lower limbs. Objective: To verify the effect of a physiotherapeutic protocol on the Lower Limb Symmetry Index (LLSI) and the correlation between strength and EMGs, pre and post reconstruction of the ACL. Methods: Twenty subjects (10 ACLrg + 10 CONTg) were evaluated regarding isometric force and electrical activity of knee extensors, knee flexors and hip abductors. Results: A significant increase (P<0.01) in knee extension and flexion strength and hip abduction strength were observed both for the affected limb and non-affected limb. Regarding the LLSI, a significant increase was observed for knee extension and hip abduction movements in the pre- and post-treatment comparison, and between ACLrg X CONTg (P<0.01) for the knee extension movement in the pre-reconstruction phase of the ACL. A very strong correlation (r=0.945; P<0.01) was also observed between the LLSI strength X EMGs during knee extension, pre- and post-reconstruction surgery. Conclusions: Six months after reconstruction of the ACL, there was an increase in strength and EMG activity of the knee flexor, knee extensor and hip abductor muscles, leveling the LLSI between ACLrg and the CONTg, however, with a significant correlation between the two variables (strength X EMGs) for only one of the three movements (knee extension).

The Reliability of Common Functional Performance Tests within an Experimental Test Battery for the Lower Extremities

“…However, other parameters affect the reliability analysis and were therefore included in this study: the coefficient of variation (CV) for the extent of variability, defined as the ratio of the SD to the mean (CV = SD/Mean × 100); the standard error of measurement (SEM) for the effect of measurement error, defined as the SD of an individual's repeated measurements (SEM = SD × √ 1 − ICC); the smallest real difference (SRD), defined as a measure of sensitivity to change (SRD = 1.96 × √ 2 × SEM) [42,43]. To assess the magnitude of the reliability analysis, the threshold values were considered as follows: poor (<0.5), moderate (0.50-0.75), good (0.75-0.90), and excellent (>0.90) for the ICC [44]; unacceptable (<0.5), poor (0.5-0.6), questionable (0.6-0.7), acceptable (0.7-0.8), good (0.8-0.9), and excellent (>0.90) for the Cronbach's α [45]; not acceptable (>30), acceptable (20)(21)(22)(23)(24)(25)(26)(27)(28)(29)(30), good (10)(11)(12)(13)(14)(15)(16)(17)(18)(19)(20) and very good (<10) for the CV [46]; perfectly reliable (equal to 0) and completely unreliable (equal to the SD) for the SEM [46]; acceptable (<30%) for the SRD [47]. Finally, for the analysis of variance of the dependent variables, repeated measures ANOVA (p < 0.05) was used separately to compare differences in mean scores between the two testing sessions (T1 and T2).…”

“…It can provide valuable baseline data for pre-injury screenings or for rehabilitation progression purposes. In order to allow side-to-side performance comparisons, functional tests can be performed unilaterally (on one leg) and the LSI can be detected [ 15 , 16 , 17 , 18 , 19 ]. The LSI is an indicator that quantifies the symmetry of the limbs in percentage and can be calculated in multiple ways: uninjured/injured, non-dominant/dominant, or less-performant/more-performant limbs [ 20 , 21 ].…”

Wingate-based shuttle run test and limb symmetry index (back to activity algorithm) as the basis for a function-based rehabilitation of a young soccer player with torn ligament injury of the left ankle due to inversion trauma

“…The quantitative tests are assessed based on a Limb Symmetry Index (LSI), which expresses differences between the affected and the unaffected side in percent. 7 If the patient passes the qualitative test (LSI, if quantitative data are available) and the quantitative LSI value of over 85% (90%) is achieved, the level is passed. 4,8 The patient can now start with the next level, if he/she strives for the goal of a higher level of stress.…”

“…4,8 The patient can now start with the next level, if he/she strives for the goal of a higher level of stress. 9 This depends on the sport being played (Table 3) 7 or desired activity of daily living.…”