Effectiveness of physiological flexion swaddling and oromotor interventions in improving preterm infants' oral feeding ability in the NICU: a randomized controlled trial.

OBJECTIVE: This study aimed to prove the effectiveness of physiological flexion swaddling and oromotor interventions in terms of the duration needed to achieve the oral feeding ability of preterm infants in the NICU. METHODS: A randomized clinical trial in five Neonatal intensive care units (NICU) was performed involving 70 preterm infants born at 28-34 weeks gestational age. Participants were allocated to 1) the experimental group (n = 39) received physiological flexion swaddling and oromotor interventions, and 2) the control group (n = 31) received conventional swaddling and oromotor interventions. Mann-Whitney U analysis was used to determine the effectiveness of each group according to the duration needed to achieve oral feeding ability, while Kaplan-Meier survival analysis was applied to compare the duration of both groups. RESULTS: The experimental group had a significantly shorter duration in achieving oral feeding ability [4 (1-15) vs. 7 (2-22) days; p = 0.02]. The Kaplan-Meier survival curve analysis showed that infants in the experimental group achieved full oral feeding ability earlier than those in the control group (15 vs. 22 days). CONCLUSIONS: Physiological flexion swaddling and oromotor interventions have been proven to be effective in shortening the number of days needed to achieve the oral feeding ability of preterm infants in the NICU.

Reliability and construct validity of the Craniocervical Flexion Test in patients with migraine.

BACKGROUND: Migraine may be accompanied by several cervical musculoskeletal dysfunctions, for example an altered performance on the Craniocervical Flexion Test (CCFT). However, CCFT measurement properties are still unclear in patients with migraine. OBJECTIVES: To determine intra- and inter-examiner reliability, construct validity, standard measurement error (SEM), and minimal detectable change (MDC) of the CCFT in patients with migraine. METHODS: Women diagnosed with migraine were considered eligible for this study. Participants were assessed by two examiners for the inter-examiner reliability, and with 7-10 days interval for the intra-examiner reliability. Construct validity was assessed considering headache and neck pain frequency and intensity, and self-reported questionnaires, including the Headache Impact Test - 6 items (HIT-6), the 12-item Allodynia Symptom Checklist/Brazil (ASC-12), and the Neck Disability Index (NDI). In addition, participants performed cervical endurance and maximal voluntary isometric contraction of the cervical flexors. RESULTS: A total of 103 women with migraine were recruited. The intra-examiner reliability was rated as good (ICC= 0.81, 95% CI: 0.73, 0.87), while the inter-examiner reliability was rated as moderate (ICC= 0.55, 95% CI: 0.40, 0.67). The intra and inter-examiner SEM were 1.31 and 1.36 mmHg respectively, and MDC were 3.63 and 3.77 mmHg. The HIT-6 and the cervical endurance flexion test were associated with the CCFT in a multiple linear regression model (p = 0.004, R = 0.35). CONCLUSION: The CCFT presents adequate intra- and inter-examiner reliability. Better performance on the CCFT test was associated with better HIT-6 scores and greater cervical endurance time, which was not influenced by the presence of neck pain.

Biomechanical Effects of Angiotensin 1-7 in Diabetes Rats Femur / Efectos Biomecánicos de la Angiotensina 1-7 en el Fémur de Ratas Diabéticas

SUMMARY: It is known that diabetes mellitus has late complications, including microvascular and macrovascular diseases. Diabetes can affect bones through biochemical markers of bone structure, density, and turnover. This study aimed to biomechanically investigate the bone-protective effects of angiotensin 1-7 (Ang 1-7), one of the active peptides in the renin-angiotensin system, in rats with diabetes. Thirty male Wistar albino rats, three months old and weighing 250-300 g, were divided into four groups: diabetes, Ang 1- 7, diabetes plus Ang 1-7, and control. One month later, diabetes developed in rats; the rats were sacrificed, and their right femur was removed. Three-point bending biomechanical tests were performed on the femurs. The diabetic group had significantly higher bone fragility than the other groups (Pr >.05). Bone fragility was lower, and bone flexibility was higher in the Ang 1-7 groups (Pr>F value 0.05). As a result of our study, the effect of Ang 1-7 on the bones of rats with diabetes was investigated biomechanically. Ang 1-7 has a protective impact on the bones of rats with diabetes.

Se sabe que la diabetes mellitus tiene complicaciones tardías, incluyendo enfermedades microvasculares y macrovasculares. La diabetes puede afectar los huesos a través de los marcadores bioquímicos de la estructura, la densidad y el recambio óseo. Este estudio tuvo como objetivo investigar biomecánicamente los efectos protectores en los huesos de la angiotensina 1-7 (Ang 1-7), uno de los péptidos activos en el sistema renina-angiotensina, en ratas con diabetes. Treinta ratas albinas Wistar macho, de tres meses de edad y con un peso de 250-300 g, se dividieron en cuatro grupos: diabetes, Ang 1-7, diabetes más Ang 1-7 y control. Un mes después, se desarrolló diabetes en ratas; se sacrificaron los animales y se extrajo su fémur derecho. Se realizaron pruebas biomecánicas de flexión de tres puntos en los fémures. El grupo diabéticos tenía una fragilidad ósea significativamente mayor que los otros grupos (Pr > 0,05). La fragilidad ósea fue menor y la flexibilidad ósea fue mayor en los grupos Ang 1-7 (valor Pr>F 0,05). Como resultado de nuestro estudio, se determinó biomecánicamente el efecto de Ang 1-7 en los huesos de ratas con diabetes. Se concluye que Ang 1-7 tiene un impacto protector en los huesos de ratas diabéticas.

Strength Assessment After Reverse Shoulder Arthroplasty.

Objective: The main objective was to evaluate the anterior flexion force (AFF) and the lateral abduction force (LAF) of patients who underwent reverse shoulder arthroplasty (RSA) and to compare the measured force with that in a similar-age control group. The secondary objective was to identify prognostic factors for muscle strength recovery. Methods: Forty-two shoulders that underwent primary RSA between September 2009 and April 2020 met the inclusion criteria and were called the arthroplasty group (AG). The control group (CG) consisted of 36 patients. The mean AFF and the mean LAF were evaluated with a digital isokinetic traction dynamometer. Results: The average AFF found in the AG was 15 N, while in the CG, the average AFF was 21 N (P < .001). The average LAF in the AG was 14 N (standard deviation [SD] 8 N), while in the CG the average LAF was of 19 N (SD 6 N) (P = .002). All prognostic factors studied in the AG showed no statistical significance: dominance (AFF 0.697/LAF 0.883), previous rotator cuff repair surgery (AFF 0.786/LAF 0.821), Hamada radiological classification (AFF 0.343/LAF 0.857), magnetic resonance imaging (MRI) pre-operative evaluation of the quality of the teres minor (AFF 0.131/LAF 0.229), suture of the subscapularis at the end of the arthroplasty procedure (AFF 0.961/LAF 0.325) and postoperative complications (AFF 0.600/LAF 0.960). Conclusion: The mean AFF was 15 N, and the mean LAF was 14 N. The comparison of AFF and LAF with a CG showed a 25% reduction in muscle strength. It was not possible to demonstrate prognostic factors for muscle strength recovery after RSA.

Influence of an armrest support on handgrip strength in different arm and shoulder flexion angles in overhead postures.

A study was undertaken in which the handgrip strength in three arm positions above the shoulder was measured to compare handgrip strength when arm support is used and when it is not used. Grip forces were generated in pairs of flexion angles, corresponding to shoulder and elbow at 90°-90°, 135°-45° and 160°-20°. Thirty-two participants completed the present study; 23 men and nine women with a median age of 23.1 (SD ±3.6) years. A manual handgrip dynamometer (0-90 kg) and an adjustable angle arm support (AAAS) were used during the data collection. Two-way analysis of variance (ANOVA) for repeated measurements indicates a significant effect of the AAAS factor on the handgrip strength, as well as on the AAAS × angle interaction. However, there is no significant effect of the angle factor on the AAAS × angle interaction.

The effect of curing modes and times of Third-Generation led LCU on the mechanical properties of nanocomposites / Efecto del modo y tiempo de fotocurado de la lámpara LCU Led de tercera generación en las propiedades mecánicas de los nanocompuestos

Abstract This study evaluates the effect of curing modes and times on the mechanical properties of nanocomposites. Two nanocomposite resins were investigated: suprananohybrid (Estelite Posterior Quick; EP) and nanohybrid (Solare X; SX). They were polymerized with a light-emitting diode light-curing units (LED LCU, Valo) as follows: standard mode for 20s (ST20), high power mode for 12s (HP12), high power mode for 20s (HP20), extra power mode for 6s (XP6), and extra power mode for 20s (XP20). For Vickers microhardness (HV), disc-shaped specimens were fabricated (n=10). For the three-point bending test, bar-shaped specimens were fabricated (n=10). Flexural strength and resilience modulus were calculated. The fractured surfaces and specimen surfaces of composites were observed using scanning electron microscopy. The data were analyzed with repeated measures ANOVA, two-way variance, and Bonferroni tests (p<0.05). On the top and bottom surfaces of the EP nanocomposite resin, ST20 and HP12 revealed statistically higher HV than with XP6. Moreover, HP20 and XP20 had statistically higher HV than HP12 and XP6. For the SX nanocomposite resin, HP20 had statistically higher HV than HP12. For EP and SX, there were no significant differences in flexural strength and resilience modulus regarding the curing modes and times. Furthermore, SX demonstrated lower mechanical properties than EP. Scanning electron microscopy indicated that both nanocomposites had similar surface appearances. However, with all curing modes and times, SX exhibited layered fractures and more crack formations than EP. Different curing modes and times could influence the microhardness of nanocomposites.

Resumen Este estudio evalúa el efecto del modo y tiempo de fotocurado sobre las propiedades mecánicas de los nanocompuestos. Se investigaron dos resinas nanocompuestas: supra-nanohíbrida (Estelite Posterior Quick; EP) y nanohíbrida (Solare X; SX). Se polimerizaron con unidades de fotopolimerización de diodos emisores de luz (LED LCU, Valo) de la siguiente manera: modo estándar durante 20s (ST20), modo de alta potencia durante 12s (HP12), modo de alta potencia durante 20s (HP20) , modo extra power durante 6s (XP6) y modo extra power durante 20s (XP20). Para la microdureza Vickers (HV), se fabricaron especímenes en forma de disco (n=10). Para el ensayo de flexión de tres puntos, se fabricaron probetas en forma de barra (n=10). Se calcularon la resistencia a la flexión y el módulo de resistencia. Las superficies fracturadas se observaron mediante microscopía electrónica de barrido. Los datos se analizaron con ANOVA varianza de dos vías y pruebas de Bonferroni (p<0,05). En las superficies superior e inferior de la resina nanocompuesta EP, ST20 y HP12 revelaron un HV estadísticamente mayor que con XP6. Además, HP20 y XP20 tenían un HV estadísticamente más alto que HP12 y XP6. Para la resina nanocompuesta SX, HP20 tenía un HV estadísticamente más alto que HP12. Para EP y SX, no hubo diferencias significativas en la resistencia a la flexión y el módulo de resistencia con respecto al modo y tiempo de fotocurado. Además, SX demostró propiedades mecánicas inferiores que EP. La microscopía electrónica de barrido indicó que ambos nanocompuestos son similares en la superficie. Sin embargo, SX exhibió fracturas en capas y más formaciones de grietas que EP. Diferentes modos y tiempos de fotocurado podrían influir en la microdureza de los nanocompuestos.

Effect of low back pain on clinical-functional factors and its associated potential risk of chronicity in adolescent dancers of classical ballet: cross-sectional study.

BACKGROUND: Low back pain (LBP) is a common symptom in classical ballet dancers, which can limit their daily activities and dance training routines. The purpose of the study was to verify the association and comparison of clinical-functional outcomes (spine flexibility and foot posture) between different levels of intensity low back pain in adolescents of classical ballet and the potential risk of chronicity using the STarT back tool. METHODS: Cross-sectional study. PARTICIPANTS: 78 adolescent girls who practice classical ballet were evaluated and divided into groups according to level of low back pain: mild (n = 21), moderate (n = 17), and high (n = 20), and a control group (n = 20). MAIN OUTCOME MEASURES: Pain, flexibility of the spine (thoracic and lumbosacral), risk of chronicity for low back pain, and foot posture were assessed using the visual analogue scale, clinical tests, STarT back screening tool (SBST) questionnaire, and foot posture index (FPI), respectively. RESULTS: Dancers with high-intensity low back pain showed a potential risk of chronicity by the SBST. The spine pain intensity was not different considering thoracic and lumbosacral flexibility in the sagittal plane, but was different with greater supine FPI when compared to control dancers. Mild low back pain was associated with greater supine FPI. The SBST score was associated with higher exposure time-frequency and time of dancing. CONCLUSION: Adolescents of classical ballet with high-intensity low back pain showed a potential risk of chronicity by the SBST. The level of intensity low back pain did not influence the clinical-functional aspects of spine flexibility in the sagittal plane, but the level of intensity moderate pain promoted changes in foot posture (more supinated). The potential risk of chronicity using the SBST was also associated with higher exposure time-frequency and time of dancing, in adolescents of classical ballet.

Use of ultrasound and targeted physiotherapy to manage nerve sutures placed under joint flexion: a case series.

BACKGROUND: Joint flexion to diminish the gap and avoid nerve grafts fell into disuse for decades, but recently attention for using this technique was regained. We report a case series of nerve suture under joint flexion, ultrasound monitoring, and physiotherapy. Our main objective was to determine how effective this multimodality treatment is. METHODS: A retrospective review of 8 patients treated with direct repair with joint flexion was done. Depending on the affected nerve, either the knee or the elbow was flexed intraoperatively to determine if direct suturing was possible. After surgery, the limb was held immobilized. Through serial ultrasounds and a physiotherapy program, the limb was fully extended. If a nerve repair rupture was observed, the patient was re-operated and grafts were used. RESULTS: Of the eight nerve sutures analyzed, four sustained a nerve rupture revealed by US at an early stage, while four did not show any sign of dehiscence. In the patients in whom the nerve suture was preserved, an early and very good response was observed. Ultrasound was 100% accurate at identifying nerve suture preservation. Early detection of nerve failure permitted early re-do surgery using grafts without flexion, ultimately determining good final results. CONCLUSIONS: We observed a high rate of dehiscence in our group of patients treated with direct repair and joint flexion. We believe this was due to an incorrect use of the immobilization device, excessive movement, or a broken device. In opposition to this, we observed that applying direct nerve sutures and joint flexion offers unusually good and fast results. If this technique is employed, it is mandatory to closely monitor suture status with US, together with physiotherapy providing progressive, US-guided extension of the flexed joint. If nerve rupture occurs, the close monitoring dictated by this protocol should ensure the timely application of a successful graft repair.

Inter-Rater Reliability of Clinical Testing for Laxity After Knee Arthroplasty.

BACKGROUND: The clinical examination for laxity has been considered a mainstay in evaluation of the painful knee arthroplasty, especially for the diagnosis of instability. More than 10 mm of anterior-posterior (AP) translation in flexion has been described as important in the diagnosis of flexion instability. The inter-observer reliability of varus/valgus and AP laxity testing has not been tested. METHODS: Ten subjects with prior to total knee arthroplasty (TKA) were examined by 4 fellowship-trained orthopedic knee arthroplasty surgeons. Each surgeon evaluated each subject in random order and was blinded to the results of the other surgeons. Each surgeon performed an anterior drawer test at 30 and 90 degrees of flexion and graded the instability as 0-5 mm, 5-10 mm or >10 mm. Varus-valgus testing was also graded. Motion capture was used during the examination to determine the joint position and estimate joint reaction force during the examination. RESULTS: Inter-rater reliability (IRR) was poor at 30 and 90 degrees for both the subjective rater score and the measured AP laxity in flexion (k = 018-0.22). Varus-valgus testing similarly had poor reliability. Force applied by the rater also had poor IRR. CONCLUSION: Clinical testing of knee laxity after TKA has poor reliability between surgeons using motion analysis. It is unclear if this is from differences in examiner technique or from differences in pain or quadriceps function of the subjects. Instability after TKA should not be diagnosed strictly by clinical testing and should involve a complete clinical assessment of the patient.

The innervation of the biceps brachii and brachialis muscles in specimens with a high incidence of an accessory biceps head.

We describe the patterns of motor branches to the elbow flexors in 106 fresh-frozen cadaveric upper extremities from 53 donors of the Latin American mestizo race. We identified a 20% incidence of an accessory biceps head. The innervation patterns to this accessory head were specifically described and added to the Yang classification as Type IV for the biceps and Type III for the brachialis. The patterns arising from the musculocutaneous nerve to the biceps brachii were of Type I in 69%, Type II in 9%, Type III in 7% and Type IV in 11%, and to the brachialis of Type I in 77%, Type II in 11% and Type III in 9%. In 4%, the branches did not originate from the musculocutaneous nerve. We hypothesize that the branch to the accessory biceps head might be considered as a donor for nerve transfer in selected brachial plexus injuries.

Assessment of the Kinematic Adaptations in Parkinson's Disease Using the Gait Profile Score: Influences of Trunk Posture, a Pilot Study.

INTRODUCTION: Postural abnormalities are common in patients with Parkinson's disease (PD) and lead to gait abnormalities. Relationships between changes in the trunk posture of PD patients and gait profile score (GPS) and gait spatiotemporal parameters are poorly investigated. The aim of the current study was to investigate the relationships between trunk posture, GPS, and gait spatiotemporal parameters, in patients with PD. MATERIALS AND METHODS: Twenty-three people with PD and nineteen age-matched healthy people participated in this study. A 3D gait kinematical analysis was applied to all participants using the Plug-In Gait Full BodyTM tool. Trunk and limb kinematics patterns and gait spatio-temporal parameters of patients with PD and the control group were compared. Additionally, correlations between trunk kinematics patterns, gait spatio-temporal parameters, and GPS of the PD group were tested. RESULTS: Cadence, opposite foot off, step time, single support, double support, foot off, gait speed, trunk kinematics, and GPS showed significant differences between the two groups (p ≤ 0.05). Posture of the trunk during gait was not related to the spatio-temporal parameters and gait profile score in the PD group. The trunk flexor pattern influenced GPS domains, mainly of the ankle and the knee. DISCUSSION AND CONCLUSIONS: Flexed posture of the trunk in patients with PD seems to influence both ankle and knee movement patterns during the gait. The GPS analysis provided direct and simplified kinematic information for the PD group. These results may have implications for understanding the importance of considering the positioning of the trunk during gait.

Effects of dry needling of the obliquus capitis inferior on sensorimotor control and cervical mobility in people with neck pain: A double-blind, randomized sham-controlled trial.

BACKGROUND: Impairments of sensorimotor control relating to head and eye movement control and postural stability are often present in people with neck pain. The upper cervical spine and particularly the obliquus capitis inferior (OCI) play an important proprioceptive role; and its impairment may alter cervical sensorimotor control. Dry needling (DN) is a valid technique to target the OCI. OBJECTIVES: To investigate if a single DN session of the OCI muscle improves head and eye movement control-related outcomes, postural stability, and cervical mobility in people with neck pain. METHODS: Forty people with neck pain were randomly assigned to receive a single session of DN or sham needling of the OCI. Cervical joint position error (JPE), cervical movement sense, standing balance and oculomotor control were examined at baseline, immediately post-intervention, and at one-week follow-up. Active cervical rotation range of motion and the flexion rotation test were used to examine the global and upper cervical rotation mobility, respectively. RESULTS: Linear mixed-models revealed that the DN group showed a decrease of JPE immediately post-intervention compared to the sham group (mean difference [MD]= -0.93°; 95% confidence interval [CI]: -1.85, -0.02) which was maintained at one-week follow-up (MD= -1.64°; 95%CI: -2.85, -0.43). No effects on standing balance or cervical movement sense were observed in both groups. Upper cervical mobility showed an increase immediately after DN compared to the sham group (MD= 5.14°; 95%CI: 0.77, 9.75) which remained stable at one-week follow-up (MD= 6.98°; 95%CI: 1.31, 12.40). Both group showed an immediate increase in global cervical mobility (MD= -0.14°; 95%CI: -5.29, 4.89). CONCLUSION: The results from the current study suggest that a single session of DN of the OCI reduces JPE deficits and increases upper cervical mobility in patients with neck pain. Future trials should examine if the addition of this technique to sensorimotor control training add further benefits in the management of neck pain.

Construct validity and reliability of tests for sacroiliac dysfunction: standing flexion test (STFT) and sitting flexion test (SIFT).

CONTEXT: Sacroiliac dysfunction is characterized by a hypomobility of the range of motion of the joint, followed by a positional change regarding the relationship between the sacrum and the iliac. In general, the clinical tests that evaluate the sacroiliac joint (SIJ) and its dysfunctions lack validity and reliability values. OBJECTIVES: This article aims to evaluate the construct validity and intra- and inter-rater reliability of the standing flexion test (STFT) and sitting flexion test (SIFT). METHODS: In this prospective study, the sample consisted of 30 individuals of both sexes, and the evaluation team was composed of five researchers. The evaluations took place on two different days: first day, inter-rater reliability and construct validity; and second day, intra-rater reliability. The reference standard for the construct validity was 3-dimensional measurements obtained utilizing the BTS SMART-DX system. For statistical analysis, the percentage (%) agreement and the kappa statistic (K) were utilized. RESULTS: The construct validity was determined for STFT (70% agreement; K=0.49; p<0.01) and SIFT (56.7% agreement; K=0.29; p<0.05). The intra-rater reliability was determined for STFT (66.3% agreement; K=0.43; p<0.01) and SIFT (56.7% agreement; K=0.38; p<0.01). The inter-rater reliability was determined for STFT (10% agreement; K=-0.02; p=0.825) and SIFT (13.3% agreement; K=0.01; p=0.836). CONCLUSIONS: The STFT confirmed the construct validity and was reliable when applied by the same rater to healthy people, even if the rater had no experience. It was not possible to achieve minimum scores using the SIFT either for construct validity or reliability. We suggest that further studies be conducted to investigate the measurement properties of palpatory clinical tests for SIJ mobility, especially in symptomatic patients.

Surface wave elastography is a reliable method to correlate muscle elasticity, torque, and electromyography activity level.

The shear elastic modulus is one of the most important parameters to characterize the mechanical behavior of soft tissues. In biomechanics, ultrasound elastography is the gold standard for measuring and mapping it locally in skeletal muscle in vivo. However, their applications are limited to the laboratory or clinic. Thus, low-frequency elastography methods have recently emerged as a novel alternative to ultrasound elastography. Avoiding the use of high frequencies, these methods allow obtaining a mean value of bulk shear elasticity. However, they are frequently susceptible to diffraction, guided waves, and near field effects, which introduces biases in the estimates. The goal of this work is to test the performance of the non-ultrasound surface wave elastography (NU-SWE), which is portable and is based on new algorithms designed to correct the incidence of such effects. Thus, we show its first application to muscle biomechanics. We performed two experiments to assess the relationships of muscle shear elasticity versus joint torque (experiment 1) and the electromyographic activity level (experiment 2). Our results were comparable regarding previous works using the reference ultrasonic methods. Thus, the NU-SWE showed its potentiality to get wide the biomechanical applications of elastography in many areas of health and sports sciences.

Nerve Graft Length and Recovery of Elbow Flexion Muscle Strength in Patients With Traumatic Brachial Plexus Injuries: Case Series.

BACKGROUND: Traumatic brachial plexus injuries cause long-term maiming of patients. The major target function to restore in complex brachial plexus injury is elbow flexion. OBJECTIVE: To retrospectively analyze the correlation between the length of the nerve graft and the strength of target muscle recovery in extraplexual and intraplexual nerve transfers. METHODS: A total of 51 patients with complete or near-complete brachial plexus injuries were treated with a combination of nerve reconstruction strategies. The phrenic nerve (PN) was used as axon donor in 40 patients and the spinal accessory nerve was used in 11 patients. The recipient nerves were the anterior division of the upper trunk (AD), the musculocutaneous nerve (MC), or the biceps branches of the MC (BBs). An index comparing the strength of elbow flexion between the affected and the healthy arms was correlated with the choice of target nerve recipient and the length of nerve grafts, among other parameters. The mean follow-up was 4 yr. RESULTS: Neither the choice of MC or BB as a recipient nor the length of the nerve graft showed a strong correlation with the strength of elbow flexion. The choice of very proximal recipient nerve (AD) led to axonal misrouting in 25% of the patients in whom no graft was employed. CONCLUSION: The length of the nerve graft is not a negative factor for obtaining good muscle recovery for elbow flexion when using PN or spinal accessory nerve as axon donors in traumatic brachial plexus injuries.

Do technical components of microanastomoses influence the functional outcome of free gracilis muscle transfer for elbow flexion in traumatic brachial plexus injury?

INTRODUCTION: The traumatic lesions of the brachial plexus in adults are devastating injuries causing continuous severe functional impairment for both work and daily living activities. The restoration of elbow flexion is one of the most important movements for patient recovery to previous activities. Free gracilis muscle transfer has good outcomes for cases with late presentation or as a rescue surgery to regain elbow flexion, however, bad results are present in all cohorts with insufficient recovery of muscle strength for elbow flexion. A number of hypotheses can be postulate to explain the fair results observed in some cases of free gracilis muscle transfer for elbow flexion. Most studies in the current literature compare the choice of the donor nerve used in neurotization and nerve grafts. The aim of this study is to evaluate if technical components of microvascular anastomosis could influence the functional outcome of free functional muscle transfer for elbow flexion in adult patients with traumatic brachial plexus injury. MATERIAL AND METHODS: Included all adult patients with traumatic brachial plexus injury submitted to free functional gracilis muscle transfer for elbow flexion. The complications and functional results according to British Medical Research Council (BMRC) score were recorded. RESULTS: We assessed 26 patients with mean age of 32.8 years. The most common donor nerve for gracilis muscle was the accessory nerve in 18 patients. Eighteen patients presented with good result (M3/M4). The mean ischemia time was higher for patients with bad results (132 minutes) comparing with patients with good results (122 minutes). Patients with only one venous anastomosis had 41% of poor functional outcome compared with 22% of cases with two venous anastomoses. No statistically significant difference in the ischemia time of the cases with good or poor functional outcome was observed (p=0.657), as for the number of venous anastomoses (p=0.418). CONCLUSION: Our study observes that patients with only one venous anastomoses for drainage of free gracilis and those with longer intraoperative ischemia time had higher incidence of poor functional outcome of free gracilis muscle transfer for elbow flexion, but not statistically significant. LEVEL OF PROOF: II; prospective cross-sectional study.

Effect of fatigue load on internal mechanical properties of the intervertebral disc / Efecto de la carga de fatiga en las propiedades mecánicas internas del disco intervertebral

SUMMARY: Lumbar disc herniation is considered to be the main pathological factor for the common clinical disease of low back pain. Biomechanical factor is an important cause of lumbar disc herniation, so it is urgent to analyze the stress/strain behavior of intervertebral disc under different loading condition. Slow repetitive loading is considered to be an important factor of spine and disc injuries, and the effect of fatigue load on internal displacement in the intervertebral disc was investigated by applying the optimized digital image correlation technique in this study. The first finding was that fatigue load had a significant effect on the displacement distribution in the intervertebral disc under compression. Superficial AF exhibited the largest axial displacements before fatigue load, while it exhibited the smallest axial displacements after fatigue load. Inner AF exhibited slightly smaller radial displacements than outer AF before fatigue load, while it exhibited significantly greater radial displacements than outer AF displacements after fatigue load. The second finding was that fatigue load had a certain effect on the internal displacement distribution in the flexed intervertebral disc under compression. Middle AF exhibited the smallest axial displacements before fatigue load, while deep AF exhibited the smallest axial displacements after fatigue load. The radial displacement distribution did not change before and after fatigue load, as the radial displacement in outer AF was the smallest, while the radial displacement in inner AF was the largest. The third finding was that with the increase in fatigue time and amplitude, the Young's modulus of the intervertebral disc increased significantly. This study can provide the basis for clinical intervertebral disc disease prevention and treatment? and is important for mechanical function evaluation of artificial intervertebral disc as well.

RESUMEN: La hernia de disco lumbar se considera el principal factor patológico para la enfermedad clínica común del dolor lumbar. El factor biomecánico es una causa importante de hernia de disco lumbar, por lo que es urgente analizar el comportamiento de esfuerzo / tensión del disco intervertebral bajo diferentes condiciones de carga. La carga repetitiva lenta se considera un factor importante de lesiones de columna y disco, y en este estudio el efecto de la carga de fatiga sobre el desplazamiento interno en el disco intervertebral se investigó mediante la aplicación de la técnica de correlación de imagen digital optimizada. El primer hallazgo fue que la carga de fatiga tuvo un efecto significativo en la distribución del desplazamiento en el disco intervertebral bajo compresión. El AF superficial exhibió los desplazamientos axiales más grandes antes de la carga de fatiga, mientras que exhibió los desplazamientos axiales más pequeños después de la carga de fatiga. El AF interno exhibió desplazamientos radiales ligeramente más pequeños que el AF externo antes de la carga de fatiga, mientras que exhibió desplazamientos radiales significativamente mayores que los desplazamientos AF externos después de la carga de fatiga. El segundo hallazgo fue que la carga de fatiga tenía un cierto efecto sobre la distribución del desplazamiento interno en el disco intervertebral flexionado bajo compresión. El AF medio exhibió los desplazamientos axiales más pequeños antes de la carga de fatiga, mientras que el AF profundo exhibió los desplazamientos axiales más pequeños después de la carga de fatiga. La distribución del desplazamiento radial no cambió antes ni después de la carga de fatiga, ya que el desplazamiento radial en la FA externa fue el más pequeño, mientras que el desplazamiento radial en la FA interna fue el más grande. El tercer hallazgo fue que con el aumento del tiempo de fatiga y la amplitud, el módulo de Young del disco intervertebral aumentó significativamente. Este estudio puede proporcionar la base para la prevención y el tratamiento clínico de la enfermedad del disco intervertebral, y también es importante para la evaluación de la función mecánica del disco intervertebral artificial.

Comparison Between Supraclavicular Versus Video-Assisted Intrathoracic Phrenic Nerve Section for Transfer in Patients With Traumatic Brachial Plexus Injuries: Case Series.

BACKGROUND: The phrenic nerve has been extensively reported to be a very powerful source of transferable axons in brachial plexus injuries. The most used technique used is supraclavicular sectioning of this nerve. More recently, video-assisted thoracoscopic techniques have been reported as a good alternative, since harvesting a longer phrenic nerve avoids the need of an interposed graft. OBJECTIVE: To compare grafting vs phrenic nerve transfer via thoracoscopy with respect to mean elbow strength at final follow-up. METHODS: A retrospective analysis was conducted among patients who underwent phrenic nerve transfer for elbow flexion at 2 centers from 2008 to 2017. All data analysis was performed in order to determine statistical significance among the analyzed variables. RESULTS: A total of 32 patients underwent supraclavicular phrenic nerve transfer, while 28 underwent phrenic nerve transfer via video-assisted thoracoscopy. Demographic characteristics were similar in both groups. A statistically significant difference in elbow flexion strength recovery was observed, favoring the supraclavicular phrenic nerve section group against the intrathoracic group (P = .036). A moderate though nonsignificant difference was observed favoring the same group in mean elbow flexion strength. Also, statistical differences included patient age (P = .01) and earlier time from trauma to surgery (P = .069). CONCLUSION: Comparing supraclavicular sectioning of the nerve vs video-assisted, intrathoracic nerve sectioning to restore elbow flexion showed that the former yielded statistically better results than the latter, in terms of the percentage of patients who achieve at least level 3 MRC strength at final follow-up. Furthermore, larger scale prospective studies assessing the long-term effects of phrenic nerve transfers remain necessary.

Improvements in Isokinetic Quadriceps and Hamstring Strength Testing After Focused Therapy in Patients With Flexion Instability.

BACKGROUND: There is a paucity of literature to guide non-operative treatment for patients with problems after total knee arthroplasty (TKA). We sought to quantify how quadriceps and hamstring strength could improve with focused physical therapy (PT) and whether improving leg strength may prevent revision surgery for patients with flexion instability (FI) after TKA. METHODS: This retrospective study included patients diagnosed with FI by one of the 4 fellowship-trained arthroplasty surgeons at a single academic institution. Patients with FI were referred for strength measurements and a focused PT program. In total, 166 patients completed isokinetic testing to quantify their relative quadriceps and hamstring power, torque, and work measures compared to their contralateral leg. Fifty-five (33.5%) patients subsequently completed post-PT isokinetic testing. Statistical analysis was conducted to evaluate strength deficits in the knee with FI. RESULTS: Patients with FI were found to be 20.5%-38.4% weaker in all strength domains compared to the contralateral leg (P < .001). Patients who completed PT and pre-isokinetic and post-isokinetic testing demonstrated statistically significant gains in all extension metrics by a net range of 24.7%-34.2% (P = .011-.029) and their flexion strength metrics improved by 32.5%-40.2% (P = .002-.005). About 81.9% of patients in this subgroup did not undergo revision TKA. Those subjects who went on to revision did not statistically improve in any strength domain (P = .063-.121). CONCLUSION: Patients with FI after TKA have significantly weaker quadriceps and hamstrings in the operative compared to contralateral leg. Patients who did not undergo revision knee arthroplasty and completed a formal PT program improved quadriceps and hamstring strength by 30%. LEVEL OF EVIDENCE: IV (Case series).