Limited Support for Trunk and Hip Deficits as Risk Factors for Athletic Knee Injuries: A Systematic Review With Meta-analysis and Best-Evidence Synthesis.

OBJECTIVE: To determine whether neuromuscular deficits in trunk and hip-related function are risk factors for athletic knee injuries. DESIGN: Etiology systematic review with meta-analysis. LITERATURE SEARCH: Six online databases (MEDLINE, Web of Science, Embase, CINAHL, Scopus, and SPORTDiscus) were searched up to April 2019. STUDY SELECTION CRITERIA: Studies assessing trunk and hip neuromuscular function as risk factors for knee injuries in healthy athletic populations were included. DATA SYNTHESIS: Outcomes were synthesized quantitatively using meta-analysis of odds ratios, and qualitatively using best-evidence synthesis. RESULTS: Twenty-one studies met the inclusion criteria. There was very low-certainty evidence that greater hip external rotation strength protected against knee injuries (odds ratio = 0.78; 95% confidence interval: 0.70, 0.87; P<.05). There was limited evidence that deficits in trunk proprioception and neuromuscular control, and the combination of excessive knee valgus and ipsilateral trunk angle when landing unilaterally from a jump, may be risk factors for knee injuries. CONCLUSION: Most variables of trunk and hip function were not risk factors for injuries. Further research is required to confirm whether hip external rotation strength, trunk proprioception and neuromuscular control, and the combination of knee valgus angle and ipsilateral trunk control are risk factors for future knee injuries. J Orthop Sports Phys Ther 2020;50(9):476-489. Epub 1 Aug 2020. doi:10.2519/jospt.2020.9705.

Reliability and Validity of Frontal Plane Kinematics of the Trunk and Lower Extremity Measured With 2-Dimensional Cameras During Athletic Tasks: A Systematic Review With Meta-analysis.

BACKGROUND: Two-dimensional (2-D) analysis is commonly used to quantify frontal plane kinematics of the trunk and lower extremity. However, there are conflicting results regarding the reliability and validity of these measurements. OBJECTIVE: To synthesize the current literature to determine whether 2-D analysis is a reliable and valid method of measuring frontal plane kinematics of the trunk and lower extremity during squatting, landing, and cutting tasks. METHODS: For this systematic review with meta-analysis, MEDLINE, CINAHL, Embase, Scopus, and SPORTDiscus databases were searched from inception until March 2017. The authors included 16 studies that evaluated the reliability and/or validity of 2-D measurements of frontal plane trunk and/or lower extremity kinematics when compared to 3-D measurements during any of the following tasks: squatting, landing, or cutting. RESULTS: Intrarater reliability (intraday and interday) and interrater reliability of the 2-D video measurements varied from moderate to excellent. In terms of validity, there was poor agreement between the 2-D and 3-D methods, with no correlation between 2-D knee frontal plane projection angle and 3-D knee frontal plane angles (r = 0.127, P = .094) for the single-leg squat, but a moderate to good relationship (r = 0.619, P<.001) for the landing task. CONCLUSION: Two-dimensional video analysis of frontal plane trunk and lower extremity kinematics is reliable, but this appears to be dependent on the task and the type of reliability evaluated. The current evidence does not support the use of 2-D video analysis for measuring trunk and lower extremity frontal plane kinematics when accurate measures are required. LEVEL OF EVIDENCE: Diagnosis, level 3. J Orthop Sports Phys Ther 2018;48(10):812-822. Epub 12 Jun 2018. doi:10.2519/jospt.2018.8006.

Diagnostic accuracy of the electromyography parameters associated with anterior knee pain in the diagnosis of patellofemoral pain syndrome.

OBJECTIVE: To assess the diagnostic accuracy of the surface electromyography (sEMG) parameters associated with referred anterior knee pain in diagnosing patellofemoral pain syndrome (PFPS). DESIGN: Sensitivity and specificity analysis. SETTING: Physical rehabilitation center and laboratory of biomechanics and motor control. PARTICIPANTS: Pain-free subjects (n=29) and participants with PFPS (n=22) selected by convenience. INTERVENTIONS: Not applicable. MAIN OUTCOME MEASURE: The diagnostic accuracy was calculated for sEMG parameters' reliability, precision, and ability to differentiate participants with and without PFPS. The selected sEMG parameter associated with anterior knee pain was considered as an index test and was compared with the reference standard for the diagnosis of PFPS. Intraclass correlation coefficient, SEM, independent t tests, sensitivity, specificity, negative and positive likelihood ratios, and negative and positive predictive values were used for the statistical analysis. RESULTS: The medium-frequency band (B2) parameter was reliable (intraclass correlation coefficient=.80-.90), precise (SEM=2.71-3.87 normalized unit), and able to differentiate participants with and without PFPS (P<.05). The association of B2 with anterior knee pain showed positive diagnostic accuracy values (specificity, .87; sensitivity, .70; negative likelihood ratio, .33; positive likelihood ratio, 5.63; negative predictive value, .72; and positive predictive value, .86). CONCLUSIONS: The results provide evidence to support the use of EMG signals (B2-frequency band of 45-96 Hz) of the vastus lateralis and vastus medialis muscles with referred anterior knee pain in the diagnosis of PFPS.

Neuromuscular electrical stimulation for stroke rehabilitation: is spinal plasticity a possible mechanism associated with diminished spasticity?

Although the specific pathophysiological mechanisms underlying the development of spasticity are not fully understood, a large amount of evidence suggests that abnormalities in spinal pathways regulating the stretch reflex may contribute to the hypertonia and hyperreflexia that characterize spasticity. It is quite interesting that neuromuscular electrical stimulation (NMES) has been reported as an efficient treatment for reducing spasticity after stroke while other reports have shown that it promotes neuroplasticity in healthy subjects. The hypothesis addressed in this paper is that plastic effects within some spinal cord pathways may be a possible mechanism associated with the NMES-induced improvements in spasticity. If the hypothesis is proven corrected, the association between plasticity within specific spinal pathways and NMES-induced improvements in spasticity may be used to guide the choice of stimulation parameters to be used in NMES-based stroke rehabilitation protocols.

Comparison of different analysis techniques for the determination of muscle onset in individuals with patellofemoral pain syndrome.

To understand patellofemoral pain syndrome (PFPS), recent studies have focused on assessing the onset in the vastus medialis and vastus lateralis to determine whether there is a delay between these muscles' activation. However, the results of these studies are not in agreement, as some research shows that there is a delay in the VMO, while others do not show delay. It has been suggested that this discrepancies may be due to differences in the signal processing and analysis. For this reason, this study aimed to compare the three techniques used for onset determination - automatic detection, visual inspection and cross-correlation - and to verify whether these methods are able to detect PFPS. The surface electromyography evaluation procedure was conducted in 22 pain-free control individuals and 11 with PFPS diagnoses, during a stair climbing. The standard error of measurement (SEM) showed that cross-correlation presents the lower variation (2.56/3.27, control/PFPS) in relation to visual (3.77/10.19, control/PFPS) and automatic detection (43.23/51.98, control/PFPS, respectively). But when using the cross-correlation technique, we were not able to distinguish the groups (-6.56/-9.74ms, control/PFPS, p=0.15). Therefore, use of muscle onset may not be the best way to distinguish individuals with PFPS.