Ultrasound measures of the lumbar multifidus: effect of task and transducer position on reliability.

OBJECTIVE: To (1) assess the intra- and inter-rater reliability of different ultrasound (US) measures of the lumbar multifidus muscle in subjects with and without chronic low back pain and (2) test 3 different ways to enhance reliability, that is, by testing different tasks, using a template, and averaging trials within or between days. DESIGN: Cross-sectional repeated-measures design. SETTING: Laboratory setting. PATIENTS: Fifteen subjects with chronic low back pain and 15 control subjects. METHODS: Subjects (n = 30) performed contralateral arm lifting and contralateral leg lifting while in the prone position. Two 7-second videos of the lumbar multifidus (from rest to contraction) were collected with and without a template (transparency) to reposition the transducer on the skin. One of the two raters repeated the testing 7 to 14 days later to assess intrarater reliability in addition to inter-rater reliability. Reliability was assessed with the generalizability theory as a framework. MAIN OUTCOME MEASUREMENTS: US imaging measures of the lumbar multifidus thickness were obtained in patients at rest and during standardized contractions (hereafter called primary measures) at 2 vertebral levels and on both sides. These primary measures were used to calculate different, potentially useful US parameters (hereafter called derived measures). RESULTS: Intrarater reliability was better than inter-rater reliability, and primary measures were more reliable than derived measures. The tasks investigated showed comparable reliability results, and the use of the transducer position template was not effective to increase reliability. Averaging the measures of 3 images increased reliability substantially. CONCLUSIONS: Optimal reliability requires the use of a single rater and the averaging of at least 3 images per visit. In these conditions, primary measures reach acceptable levels of reliability, which was more difficult to achieve for most derived measures. Arm or leg lifting tasks showed similar reliability, and thus the arm-lifting task is recommended for comparisons with previous studies. The use of a transducer position template is not recommended.

Reliability of ultrasound measures of the transversus abdominis: effect of task and transducer position.

OBJECTIVE: To assess the reliability of ultrasound (US) measures of the transversus abdominis (TrA) muscle in a sample of subjects with and without specific chronic low back pain and to test whether reliability is enhanced by using different abdominal muscle activation tasks, with use of a foam cube for US transducer stabilization or by averaging 3 measures on the same image. DESIGN: Cross-sectional repeated-measures design. SETTING: Laboratory setting. PATIENTS: Fifteen subjects with chronic low back pain and 15 control subjects. METHODS: Subjects (n = 30) performed 3 tasks in the supine position: (1) contralateral straight leg raise (SLR), (2) bilateral hook-lying leg raising (HLR), and (3) abdominal drawing-in maneuver (ADIM) (control subjects only). Two 7-second videos of the right and left abdominal wall (from rest to contraction) were collected, with and without use of the foam cube. One of the 2 raters repeated the testing 7 to 14 days later to assess intrarater reliability. MAIN OUTCOME MEASUREMENTS: US imaging of abdominal muscles thickness. RESULTS: The TrA muscle was recruited preferentially in the ADIM task compared with the automatic tasks (SLR and HLR). The reliability was comparable among the 3 tasks, with intrarater reliability results being better than interrater reliability results. The use of the foam cube or averaging measures on the same image was generally not effective to increase reliability. CONCLUSIONS: Although they are not as preferential in TrA recruitment as the ADIM, the SLR and HLR tasks showed comparable reliability results. The foam cube used to control transducer orientation and pressure and averaging measures on the same image had limited effect on reliability.

Age-related differences in center of pressure measures during one-leg stance are time dependent.

The aim of this study was to evaluate the changes in center of pressure (COP) movement in four time intervals (5, 10, 15 and 30 s) during a one-leg stance test performed by young and elderly adults. Twelve young adults (mean 20 years) and 12 elderly subjects (mean 68 years) participated in this study. The subjects performed three 30 s trials of an eyes open one-leg stance test on a force platform, in which the COP parameter was computed at four points in time from same original COP signal. Significant differences were found between the young and elderly adults (P < .007) only at the 10, 15 and 30 s intervals. For both groups, COP changes were significantly different between the 5 s time interval and other intervals (10, 15 and 30 s). In conclusion, these results pointed out that age-related difference in COP changes were time dependent. This suggests that the use of longer durations increases the possibility of distinguishing more subtle differences in postural strategy among different groups of subjects.

Evaluation of reconstructive surgery using artificial ligaments in 71 acute knee dislocations.

This retrospective study assessed the results of 71 patients with knee dislocations who underwent acute combined repair and reconstruction using Ligament Advancement Reinforcement System (LARS) artificial ligaments between June 1996 and May 2008 with a follow-up between two and eight years. The outcome measures used were the Lysholm score, the International Knee Documentation Committee form (IKDC 2000), the Tegner activity level score, the Meyers ratings, Telos stress radiography, range of motion and clinical knee stability testing. When comparing high- versus low-energy dislocations and knee dislocation (KD) II/III versus KD IV injuries, a better Lysholm score for the knee dislocation (KD) II/III group was found compared with the KD IV group. The subjective and objective findings from our study are satisfactory and comparable with the results of other studies of knee dislocations. Our findings suggest that with a mean follow-up of 54 months, acute combined repair and reconstruction with LARS ligaments is a valid alternative for treating knee dislocations.

Back muscle strength and fatigue in healthy and chronic low back pain subjects: a comparative study of 3 assessment protocols.

OBJECTIVE: To compare the sensitivity of 3 different back test protocols in measuring differences in strength and fatigue between subjects with and without chronic low back pain (CLBP). DESIGN: Descriptive study using a repeated-measures design. SETTING: A research laboratory within a rehabilitation center. PARTICIPANTS: Eighteen healthy subjects and 13 subjects with CLBP were assessed in a single session to compare the 3 protocols. The protocols were an upright position test (UPP), a semicrouched lifting test (LIF), and the Sorensen fatigue test. INTERVENTIONS: Not applicable. MAIN OUTCOME MEASURES: Moments of force and surface electromyography were recorded bilaterally from 4 homologous back muscles while the subjects performed static trunk extension efforts for each protocol. Fatigue was quantified by the slopes of the linear regression of electromyography time-series. RESULTS: The back muscle fatigue and strength scores did not differ significantly for the 2 subject groups for any of the 3 protocols. The electromyography fatigue indices revealed that the Sorensen fatigue test and UPP produced more fatigue in the back muscles than the LIF. CONCLUSIONS: It was impossible to specify which protocol is more sensitive to low back status because no between-group difference was observed for any of the 3 tests.