Measurement properties of movement smoothness metrics for upper limb reaching movements in people with moderate to severe subacute stroke.

BACKGROUND: Movement smoothness is a potential kinematic biomarker of upper extremity (UE) movement quality and recovery after stroke; however, the measurement properties of available smoothness metrics have been poorly assessed in this group. We aimed to measure the reliability, responsiveness and construct validity of several smoothness metrics. METHODS: This ancillary study of the REM-AVC trial included 31 participants with hemiparesis in the subacute phase of stroke (median time since stroke: 38 days). Assessments performed at inclusion (Day 0, D0) and at the end of a rehabilitation program (Day 30, D30) included the UE Fugl Meyer Assessment (UE-FMA), the Action Research Arm Test (ARAT), and 3D motion analysis of the UE during three reach-to-point movements at a self-selected speed to a target located in front at shoulder height and at 90% of arm length. Four smoothness metrics were computed: a frequency domain smoothness metric, spectral arc length metric (SPARC); and three temporal domain smoothness metrics (TDSM): log dimensionless jerk (LDLJ); number of submovements (nSUB); and normalized average rectified jerk (NARJ). RESULTS: At D30, large clinical and kinematic improvements were observed. Only SPARC and LDLJ had an excellent reliability (intra-class correlation > 0.9) and a low measurement error (coefficient of variation < 10%). SPARC was responsive to changes in movement straightness (rSpearman=0.64) and to a lesser extent to changes in movement duration (rSpearman=0.51) while TDSM were very responsive to changes in movement duration (rSpearman>0.8) and not to changes in movement straightness (non-significant correlations). Most construct validity hypotheses tested were verified except for TDSM with low correlations with clinical metrics at D0 (rSpearman<0.5), ensuing low predictive validity with clinical metrics at D30 (non-significant correlations). CONCLUSIONS: Responsiveness and construct validity of TDSM were hindered by movement duration and/or noise-sensitivity. Based on the present results and concordant literature, we recommend using SPARC rather than TDSM in reaching movements of uncontrolled duration in individuals with spastic paresis after stroke. TRIAL REGISTRATION: NCT01383512, https://clinicaltrials.gov/ , June 27, 2011.

What causes increased passive stiffness of plantarflexor muscle-tendon unit in children with spastic cerebral palsy?

PURPOSE: The term 'stiffness' is commonly used in the literature to refer to various components of 'hyperresistance' by which spastic muscles oppose to their passive lengthening, especially in children with cerebral palsy (CP). Originally, stiffness consists of mechanical resistance to passive movement in the absence of any muscle activation. Increased muscle stiffness in CP therefore refers to alterations to the mechanical properties of the tissue. It is closely linked to muscle shortening, yet the two phenomena are not equivalent. Both increased stiffness and shortening are present early in childhood in the plantarflexor muscles of children with spastic CP. METHODS: This narrative review provides a comprehensive overview of the literature on passive stiffness of the plantarflexor muscles measured at the joint, muscles, fascicles, and fiber level in children with CP. Articles were searched through the Pub'Med database using the keywords "cerebral palsy" AND "stiffness". RESULT: The ambiguous use of the term 'stiffness' has been supported by discrepancies in available results, influenced by heterogeneity in materials, methodologies and characteristics of the participants among studies. Increased stiffness at the joint and muscle belly level may be explained by altered structural properties at the microscopic level. CONCLUSION: This thorough investigation of the literature suggests that the pathophysiology and the time course of the development of stiffness and contracture remain to be elucidated. A consideration of both morphological and mechanical measurements in children with CP is important when describing the alterations in their plantarflexors.

Passive stiffness of monoarticular lower leg muscles is influenced by knee joint angle.

PURPOSE: While several studies demonstrated the occurrence of intermuscular mechanical interactions, the physiological significance of these interactions remains a matter of debate. The purpose of this study was to quantify the localized changes in the shear modulus of the gastrocnemius lateralis (GL), monoarticular dorsi- and plantar-flexor muscles induced by a change in knee angle. METHOD: Participants underwent slow passive ankle rotations at the following two knee positions: knee flexed at 90° and knee fully extended. Ultrasound shear wave elastography was used to assess the muscle shear modulus of the GL, soleus [both proximally (SOL-proximal) and distally (SOL distal)], peroneus longus (PERL), and tibialis anterior (TA). This was performed during two experimental sessions (experiment I: n = 11; experiment II: n = 10). The shear modulus of each muscle was compared between the two knee positions. RESULTS: The shear modulus was significantly higher when the knee was fully extended than when the knee was flexed (P < 0.001) for the GL (averaged increase on the whole range of motion: + 5.8 ± 1.3 kPa), SOL distal (+ 4.5 ± 1.5 kPa), PERL (+ 1.1 ± 0.7 kPa), and TA (+ 1.6 ± 1.0 kPa). In contrast, a lower SOL-proximal shear modulus (P < 0.001, - 5.9 ± 1.0 kPa) was observed. CONCLUSION: As the muscle shear modulus is linearly related to passive muscle force, these results provide evidence of a non-negligible intermuscular mechanical interaction between the human lower leg muscles during passive ankle rotations. The role of these interactions in the production of coordinated movements requires further investigation.

Stiffness mapping of lower leg muscles during passive dorsiflexion.

It is challenging to differentiate the mechanical properties of synergist muscles in vivo. Shear wave elastography can be used to quantify the shear modulus (i.e. an index of stiffness) of a specific muscle. This study assessed the passive behavior of lower leg muscles during passive dorsiflexion performed with the knee fully extended (experiment 1, n = 22) or with the knee flexed at 90° (experiment 2, n = 20). The shear modulus measurements were repeated twice during experiment 1 to assess the inter-day reliability. During both experiments, the shear modulus of the following plantar flexors was randomly measured: gastrocnemii medialis (GM) and lateralis (GL), soleus (SOL), peroneus longus (PL), and the deep muscles flexor digitorum longus (FDL), flexor hallucis longus (FHL), tibialis posterior (TP). Two antagonist muscles tibialis anterior (TA), and extensor digitorum longus (EDL) were also recorded. Measurements were performed in different proximo-distal regions for GM, GL and SOL. Inter-day reliability was adequate for all muscles (coefficient of variation < 15%), except for TP. In experiment 1, GM exhibited the highest shear modulus at 80% of the maximal range of motion (128.5 ± 27.3 kPa) and was followed by GL (67.1 ± 24.1 kPa). In experiment 2, SOL exhibited the highest shear modulus (55.1 ± 18.0 kPa). The highest values of shear modulus were found for the distal locations of both the GM (80% of participants in experiment 1) and the SOL (100% of participants in experiment 2). For both experiments, deep muscles and PL exhibited low levels of stiffness during the stretch in young asymptomatic adults, which was unknown until now. These results provide a deeper understanding of passive mechanical properties and the distribution of stiffness between and within the plantar flexor muscles during stretching between them and thus could be relevant to study the effects of aging, disease progression, and rehabilitation on stiffness.

Benefits of repetitive transcranial magnetic stimulation (rTMS) for spastic subjects: clinical, functional, and biomechanical parameters for lower limb and walking in five hemiparetic patients.

Introduction. Spasticity is a disabling symptom resulting from reorganization of spinal reflexes no longer inhibited by supraspinal control. Several studies have demonstrated interest in repetitive transcranial magnetic stimulation in spastic patients. We conducted a prospective, randomized, double-blind crossover study on five spastic hemiparetic patients to determine whether this type of stimulation of the premotor cortex can provide a clinical benefit. Material and Methods. Two stimulation frequencies (1 Hz and 10 Hz) were tested versus placebo. Patients were assessed clinically, by quantitative analysis of walking and measurement of neuromechanical parameters (H and T reflexes, musculoarticular stiffness of the ankle). Results. No change was observed after placebo and 10 Hz protocols. Clinical parameters were not significantly modified after 1 Hz stimulation, apart from a tendency towards improved recruitment of antagonist muscles on the Fügl-Meyer scale. Only cadence and recurvatum were significantly modified on quantitative analysis of walking. Neuromechanical parameters were modified with significant decreases in H max⁡ /M max⁡ and T/M max⁡ ratios and stiffness indices 9 days or 31 days after initiation of TMS. Conclusion. This preliminary study supports the efficacy of low-frequency TMS to reduce reflex excitability and stiffness of ankle plantar flexors, while clinical signs of spasticity were not significantly modified.

Motor performance, motor impairments, and quality of life after eccentric resistance training in neurological populations: A systematic review and meta-analyses.

BACKGROUND: Many overlapping factors impair motor performance and quality of life in neurological patients. Eccentric resistance training (ET) has potential benefits for improving motor performance and treating motor impairments better than some traditional rehabilitation approaches. OBJECTIVE: To estimate the effect of ET in neurological settings. METHODS: Seven databases were reviewed up to May 2022 according to PRSIMA guidelines to find randomized clinical trials involving adults with a neurological condition, who underwent ET as set by the American College of Sports Medicine. Motor performance (main outcome) was assessed as strength, power and capacities during activity. Secondary outcomes (impairments) were muscle structure, flexibility, muscle activity, tone, tremor, balance and fatigue. Tertiary outcomes were risk of fall, and self-reports of quality of life. RESULTS: Ten trials were included, assessed using Risk of Bias 2.0 tool, and used to compute meta-analyses. Effective effects in favour of ET were found for strength and power, but not for capacities during activity. Mixed results were found for secondary and tertiary outcomes. CONCLUSION: ET may be a promising intervention to better improve strength/power in neurological patients. More studies are needed to improve the quality of evidence underlying changes responsible for these results.

Prolapse repair for aortic regurgitation in tricuspid aortic valves.

OBJECTIVE: Cusp prolapse is an important cause of aortic regurgitation (AR) in tricuspid aortic valves (TAVs) and can be caused by myxomatous degeneration or cusp fenestration. Long-term data for prolapse repair in TAVs are scarce. We analyzed the results of aortic valve repair in patients with TAV morphology and AR caused by prolapse and compared the results for cusp fenestration and myxomatous degeneration. METHODS: Between October 2000 and December 2020, 237 patients (221 male; 15-83 years) underwent TAV repair for cusp prolapse. Prolapse was associated with fenestrations in 94 (group I) and myxomatous degeneration in 143 patients (group II). Fenestrations were closed using a pericardial patch (n = 75) or suture (n = 19). In myxomatous degeneration, prolapse was corrected by free margin plication (n = 132) or triangular resection (n = 11). Follow-up was 97% complete (cumulatively 1531, mean 6.5, median 5.8 years). Cardiac comorbidities were present in 111 patients (46.8%), and more frequent in group II (P = .003). RESULTS: Ten-year survival was better in group I (I: 84.5%; II: 72.4%; P = .037), and patients without cardiac comorbidities (89.2% vs 67.0%; P = .002). Ten-year freedom from reoperation (P = .778), moderate or greater AR (P = .070), and valve-related complications (P = .977) were similar in both groups. AR at discharge was the only significant predictor for reoperation (P = .042). The type of annuloplasty did not affect repair durability. CONCLUSIONS: Repair of cusp prolapse in TAVs with preserved root dimensions can be performed with acceptable durability, even in the presence of fenestrations.

Hyperbaric oxygen in children with cerebral palsy: A systematic review of effectiveness and safety.

PURPOSE: To report current evidence regarding the effectiveness of hyperbaric oxygen therapy (HBOT) on the impairments presented by children with cerebral palsy (CP), and its safety. MATERIALS AND METHODS: PUBMED, The Cochrane Library, Google Scholar, and the Undersea and Hyperbaric Medical Society database were searched by two reviewers. Methodological quality was graded independently by 2 reviewers using the Physiotherapy Evidence Database assessment scale for randomized controlled trials (RCTs) and the modified Downs and Black (m-DB) evaluation tool for non RCTs. A meta-analysis was performed where applicable for RCTs. RESULTS: Five RCTs were identified. Four had a high level of evidence. Seven other studies were observational studies of low quality. All RCTs used 100% O2, 1.5 to 1.75 ATA, as the treatment intervention. Pressurized air was the control intervention in 3 RCTs, and physical therapy in 2. In all but one RCTs, similar improvements were observed regarding motor and/or cognitive functions, in the HBOT and control groups. Adverse events were mostly of mild severity, the most common being middle ear barotrauma (up to 50% of children). CONCLUSION: There is high-level evidence that HBOT is ineffective in improving motor and cognitive functions, in children with CP. There is moderate-level evidence that HBOT is associated with a higher rate of adverse events than pressurized air in children.

Social Media in Health Studies: A Systematic Review of Comparative Learning Methods.

Learning modifications particularly increased due to the SARS-CoV-2 pandemic, which made it necessary to offer distance health education for many months. Social media allows students to have interactive activities such as discussing specific subjects or sharing data with each other, and also to have interactions with their teachers and tutors. So, we aimed to compare the effects of the use of social media on knowledge, skills and perceptions in health students compared to other methods. We performed a systematic review on PubMed, ScienceDirect and Embase about comparative learning methods using social media. The search followed PRISMA guidelines, and the quality assessment of the studies was performed using the Medical Education Research Quality instrument (MERSQI). Eight studies were analyzed including 1014 participants. Mean age ranged from 19.9 to 23.4 years, and 70% were females. About 54.4% of the participants were medical students and 20.9% were dental students. The mean MERSQI was 11.7 ± 2.6. Various subjects were included-anatomy, cultural competences, sterile surgical techniques, radiology, arthrocentesis, medical pathologies and cariology. As far as knowledge evaluation was concerned, we found that the use of social media may have had a positive effect from a short-term point of view but results concerning skills were less consistent across studies. Students usually had a positive perception of the use of social media as a complementary method but not as a complete alternative so it is not excluded that this effect might result from an increase in working time. The impact on patient care should also be assessed in future studies.

Use of Electroneuromyography in the Diagnosis of Neurogenic Thoracic Outlet Syndrome: A Systematic Review and Meta-Analysis.

Neurogenic thoracic outlet syndrome (NTOS) is a disabling condition. Its diagnosis remains challenging and is mainly guided by examination. Yet, electrophysiological evaluations are the gold standard for diagnosis of entrapment syndromes. We aimed to assess the interest of electrophysiological evaluation to diagnose NTOS. A systematic literature research was performed using PubMed, ScienceDirect, Embase, Cochrane and Google Scholar databases to collect studies reporting results of electrophysiological assessment of patients with NTOS. Then, a meta-analysis was conducted. Nine studies were eligible and concerned two hundred and thirteen patients. Results were heterogenous among studies and the quality of evidence was very low to moderate. Data could not evaluate sensitivity or specificity of electrophysiological evaluations for NTOS. The meta-analysis found significantly decreased amplitudes of medial antebrachial cutaneous nerve SNAP (sensory nerve action potential), ulnar SNAP, median CMAP (compound motor action potential) and ulnar CMAP. Needle examination found abnormalities for the abductor pollicis brevis, first dorsal interosseous and adductor digiti minimi. Unlike most upper-limb entrapment syndromes, nerve conduction assessment only provided clues in favour of NTOS. Decreased amplitude for ulnar SNAP, medial antebrachial cutaneous SNAP, median CMAP and ulnar CMAP should be assessed, as well as needle examination. Larger studies are needed to evaluate the sensitivity and specificity of electrophysiology in NTOS diagnosis.

Gait Alteration Due to Haemophilic Arthropathies in Patients with Moderate Haemophilia.

Some patients with moderate haemophilia (PWMH) report joint damage potentially responsible for gait disorders. Three-dimensional gait analysis (3DGA) is a relevant tool for the identification of complex musculoskeletal impairment. We performed an evaluation with 3DGA of 24 PWMH aged 44.3 ± 16.1 according to their joint status [Haemophilia Joint Health Score (HJHS) < 10 or HJHS ≥ 10] and assessed the correlation with the radiological and clinical parameters. Sixteen had HJHS < 10 (group 1) and eight had HJHS ≥ 10 (group 2). They were compared to 30 healthy subjects of a normative dataset. Both knee and ankle gait variable scores were increased in group 2 compared to the controls (p = 0.02 and p = 0.04, respectively). The PWMH of group 2 had a significant increase in their stance phase, double support duration, and stride width compared to the controls and group 1 (p < 0.01). Very low correlations were found for the ankle gait variable score with the ankle Pettersson sub-score (r2 = 0.250; p = 0.004) and ankle HJHS sub-score (r2 = 0.150; p = 0.04). For the knee, very low correlation was also found between the knee gait variable score and its HJHS sub-score (r2 = 0.290; p < 0.0001). Patients with moderate haemophilia presented a gait alteration in the case of poor lower limb joint status.

3-D lower extremity bone morphology in ambulant children with cerebral palsy and its relation to gait.

Changes in lower-extremity bone morphology are potential mid- to long-term secondary consequences of cerebral palsy (CP), affecting activity. Little is known about the 3-D morphology of lower-extremity bones in children with CP and the association with gait deviations. The main aim of this study was to describe and compare 3-D lower-extremity bone morphology in ambulant children with unilateral or bilateral CP. Secondary aims were to determine whether certain bone parameters were related to the unilateral or bilateral CP and to quantify the association between bone parameters and gait deviations. Among 105 ambulant children with CP (aged 3 to 17 years), 48 had bilateral CP (Bilat-CP) and 57 had unilateral CP (Unilat-CP); the unaffected limb of children with Unilat-CP was used as control limbs. Fifteen bone parameters were calculated by EOS® biplanar radiography, and the Gait Deviation Index (GDI) was calculated by 3-D gait analysis. Data were compared by descriptive and comparative statistical analysis (Anova, principal component analysis [PCA] and focused-PCA). Mean (SD) neck shaft angle was significantly greater for Unilat-CP than control limbs (134.9° [5.9] vs. 131.3° [5]). Mean mechanical tibial angle was significantly smaller (85.8° [6.7] vs. 89° [4.6]) and mean femoral torsion was significantly greater (29.4° [1.6] vs. 19.1° [11.8]) for Bilat-CP than control limbs. On PCA of the main determinants of 3-D bone morphology, bone shape was more complex with Bilat-CP, with changes in all 3 dimensions of space, than Unilat-CP and control limbs. Few bone parameters were correlated with the GDI in any limbs. In ambulant children with CP, femoral and tibial growth are not affected by the condition. The unilateral or bilateral nature of CP must be considered during treatment to prevent bone deformities and bone morphology affecting gait quality.

A practical guide to optimizing the benefits of post-stroke spasticity interventions with botulinum toxin A: An international group consensus.

This consensus paper is derived from a meeting of an international group of 19 neurological rehabilitation specialists with a combined experience of more than 250 years (range 4-25 years; mean 14.1 years) in treating post-stroke spasticity with botulinum toxin A. The group undertook critical assessments of some recurring practical challenges, not yet addressed in guidelines, through an exten-sive literature search. They then discussed the results in the light of their individual clinical experience and developed consensus statements to present to the wider community who treat such patients. The analysis provides a comprehensive overview of treatment with botulinum toxin A, including the use of adjunctive therapies, within a multidisciplinary context, and is aimed at practicing clinicians who treat patients with post-stroke spasticity and require further practical guidance on the use of botulinum toxin A. This paper does not replicate information published elsewhere, but instead aims to provide practical advice to help optimize the use of botulinum toxin A and maximize clinical outcomes. The recommendations for each topic are summarized in a series of statements. Where published high-quality evidence exists, the recommendations reflect this. However, where evidence is not yet conclusive, the group members issued statements and, in some cas-es, made recommendations based on their clinical experience.

Effect of chronic stretching interventions on the mechanical properties of muscles in patients with stroke: A systematic review.

BACKGROUND: Muscle contractures are common after stroke and their treatment usually involves stretching. However, recent meta-analyses concluded that stretching does not increase passive joint amplitudes in patients with stroke. The effectiveness of treatment is usually evaluated by measuring range of motion alone; however, assessing the effects of stretching on the structural and mechanical properties of muscle by evaluating the torque-angle relationship can help in understanding the effects of stretching. Although several studies have evaluated this, the effects remain unclear. OBJECTIVE: A systematic review of the literature on the effectiveness of stretching procedures for which the outcomes included a measurement of torque associated with range of motion or muscle structure (e.g., fascicle length) in stroke survivors. METHODS: PubMed, ScienceDirect and PEDro databases were searched by 2 independent reviewers for relevant studies on the effects of chronic stretching interventions (>4 weeks) that evaluated joint angle and passive torque or muscle structure or stiffness. The quality of the studies was assessed with the PEDro scale. RESULTS: Eight randomized clinical trials (total of 290 participants) met the inclusion criteria, with highly variable sample characteristics (at risk/existing contractures), program objectives (prevent/treat contractures) and duration (from 4 to 52 weeks) and volume of stretching (1 to 586 hr). All studies were classified as high quality (>6/10 PEDro score). Six studies focused on the upper limb. Many programs were less than 12 weeks (n=7 studies) and did not change mechanical/structural properties. The longest intervention (52 weeks) increased muscle fascicle length and thickness (plantar flexors). CONCLUSION: Long interventions involving high stretching volumes and/or loads may have effects on muscle/joint mechanical properties, for preventing/treating contractures after stroke injury, but need to be further explored before firm conclusions are drawn.

Recursive Decomposition of Electromyographic Signals With a Varying Number of Active Sources: Bayesian Modeling and Filtering.

OBJECTIVE: This paper describes a sequential decomposition algorithm for single-channel intramuscular electromyography (iEMG) generated by a varying number of active motor neurons. METHODS: As in previous work, we establish a hidden Markov model of iEMG, in which each motor neuron spike train is modeled as a renewal process with inter-spike intervals following a discrete Weibull law and motor unit action potentials are modeled as impulse responses of linear time-invariant systems with known prior. We then expand this model by introducing an activation vector associated with the state vector of the hidden Markov model. This activation vector represents recruitment/derecruitment of motor units and is estimated together with the state vector using Bayesian filtering. Non-stationarity of the model parameters is addressed by means of a sliding window approach, thus making the algorithm adaptive to variations in contraction force and motor unit action potential waveforms. RESULTS: The algorithm was validated using simulated and experimental iEMG signals with varying number of active motor units. The experimental signals were acquired from the tibialis anterior and abductor digiti minimi muscles by fine wire and needle electrodes. The decomposition accuracy in both simulated and experimental signals exceeded 90%. CONCLUSION: The recruitment/derecruitment was successfully tracked by the algorithm. Because of its parallel structure, this algorithm can be efficiently accelerated, which lays the basis for its real-time applications in human-machine interfaces. SIGNIFICANCE: The proposed method substantially broadens the domains of applicability of the algorithm.

Chronic effects of muscle and nerve-directed stretching on tissue mechanics.

Tissue-directed stretching interventions can preferentially load muscular or nonmuscular structures such as peripheral nerves. How these tissues adapt mechanically to long-term stretching is poorly understood. This randomized, single-blind, controlled study used ultrasonography and dynamometry to compare the effects of 12-wk nerve-directed and muscle-directed stretching programs versus control on maximal ankle dorsiflexion range of motion (ROM) and passive torque, shear wave velocity (SWV; an index of stiffness), and architecture of triceps surae and sciatic nerve. Sixty healthy adults were randomized to receive nerve-directed stretching, muscle-directed stretching, or no intervention (control). The muscle-directed protocol was designed to primarily stretch the plantar flexor muscle group, whereas the nerve-directed intervention targeted the sciatic nerve tract. Compared with the control group [mean; 95% confidence interval (CI)], muscle-directed intervention showed increased ROM (+7.3°; 95% CI: 4.1-10.5), decreased SWV of triceps surae (varied from -0.8 to -2.3 m/s across muscles), decreased passive torque (-6.8 N·m; 95% CI: -11.9 to -1.7), and greater gastrocnemius medialis fascicle length (+0.4 cm; 95% CI: 0.1-0.8). Muscle-directed intervention did not affect the SWV and size of sciatic nerve. Participants in the nerve-directed group showed a significant increase in ROM (+9.9°; 95% CI: 6.2-13.6) and a significant decrease in sciatic nerve SWV (> -1.8 m/s across nerve regions) compared with the control group. Nerve-directed intervention had no effect on the main outcomes at muscle and joint levels. These findings provide new insights into the long-term mechanical effects of stretching interventions and have relevance to clinical conditions where change in mechanical properties has occurred.NEW & NOTEWORTHY This study demonstrates that the mechanical properties of plantar flexor muscles and sciatic nerve can adapt mechanically to long-term stretching programs. Although interventions targeting muscular or nonmuscular structures are both effective at increasing maximal range of motion, the changes in tissue mechanical properties (stiffness) are specific to the structure being preferentially stretched by each program. We provide the first in vivo evidence that stiffness of peripheral nerves adapts to long-term loading stimuli using appropriate nerve-directed stretching.

COVID-19 pandemic. What should Physical and Rehabilitation Medicine specialists do? A clinician's perspective.

COVID-19 pandemic is rapidly spreading all over the world, creating the risk for a healthcare collapse. While acute care and intensive care units are the main pillars of the early response to the disease, rehabilitative medicine should play an important part in allowing COVID-19 survivors to reduce disability and optimize the function of acute hospital setting. The aim of this study was to share the experience and the international perspective of different rehabilitation centers, treating COVID-19 survivors. A group of Physical Medicine and Rehabilitation specialists from eleven different countries in Europe and North America have shared their clinical experience in dealing with COVID-19 survivors and how they have managed the re-organization of rehabilitation services. In our experience the most important sequelae of severe and critical forms of COVID-19 are: 1) respiratory; 2) cognitive, central and peripheral nervous system; 3) deconditioning; 4) critical illness related myopathy and neuropathy; 5) dysphagia; 6) joint stiffness and pain; 7) psychiatric. We analyze all these consequences and propose some practical treatment options, based on current evidence and clinical experience, as well as several suggestions for management of rehabilitation services and patients with suspected or confirmed infection by SARS-CoV-2. COVID-19 survivors have some specific rehabilitation needs. Experience from other centers may help colleagues in organizing their services and providing better care to their patients.

Influence of low muscle activation levels on the ankle torque and muscle shear modulus during plantar flexor stretching.

During stretching studies, surface electromyography (sEMG) is used to ensure the passive state of the muscle, for the characterization of passive muscle mechanical properties. Different thresholds (1%, 2% or 5% of maximal) are indifferently used to set "passive state". This study aimed to investigate the effects of a slight activity on the joint and muscle mechanical properties during stretching. The joint torque and muscle shear modulus of the triceps surae muscles were measured in fifteen healthy volunteers during ankle dorsiflexions: (i) in a "fully relaxed" state, (ii) during active conditions where participants were asked to produce an sEMG amplitude of 1%, 2% or 5% of their maximal sEMG amplitude of the triceps surae. The 1% condition was the only that did not result in significant differences in joint torque or shear modulus compared to the relaxed condition. In the 2% condition, increases in joint torque were found at 80% of the maximal angle in dorsiflexion, and in the shear modulus of gastrocnemius medialis and gastrocnemius lateralis at the maximal angle in dorsiflexion. During the 5% condition, joint torque and the shear modulus of gastrocnemius medialis were higher than during relaxed condition at angles larger than 40% of maximal angle in dorsiflexion. The results provide new insights on the thresholds that should be considered for the design of stretching studies. A threshold of 1% seems much more appropriate than a 2% or 5% threshold in healthy participants. Further studies are required to define similar thresholds for patients.

Surgical management of lower limb fractures in patients with spinal cord injury less associated with complications than non-operative management: A retrospective series of cases.

OBJECTIVES: To evaluate the difference in terms of overall complications between surgical and non-surgical management of lower limb fractures in patients with chronic spinal cord injury (SCI). DESIGN: A 13-year retrospective study including patients with chronic spinal cord lesion admitted for sublesional lower limb fractures. SETTING: University hospital SCI reference departments (Rehabilitation department and orthopedic department). PARTICIPANTS: Forty patients with SCI were included, 24 men and 16 women. Fifty-six distinct fracture occurrences were responsible for a total of 59 lower limb fractures. We compared the number of overall complications between surgical and non-surgical management of fractures. RESULTS: Non-surgical management was realized for 19 fractures and surgery for 40. Characteristics of operated and non-operated patients at the time of each fracture occurrence did not differ concerning age (P = 0.430), sex (P = 0.890), lesion levels (P = 0.410) and AIS classification (P = 0.790). Data analysis highlighted 20 complications directly due to the fracture site for 16 distinct fractures. Seven medical complications were found in 5 distinct fracture events. Only 10 (25.0%) of 40 surgical managements had at least one medical or post-surgical complication, whereas 12 (63.2%) of 19 non-operative managements had at least one complication. Therefore, the overall rate of complications was significantly higher after non-surgical treatment (P = 0.044). CONCLUSION: Lower extremity fractures due to osteoporosis in patients with SCI are responsible for local and general complications. When possible, surgery may be the best management to propose because of fewer overall complications.