Self-rated walking disability and dynamic ankle joint stiffness in children and adolescents with Juvenile Idiopathic Arthritis receiving intraarticular corticosteroid joint injections of the foot

Background: Children and adolescents with Juvenile Idiopathic Arthritis (JIA) exhibit deviations in ankle dynamic joint stiffness (DJS, or moment-angle relationship) compared to healthy peers, but the relationship between ankle DJS and self-reported walking impairments has not been studied. This secondary analysis aimed to investigate the relationship between ankle DJS and self-reported walking disability in juveniles with JIA, and to determine whether intraarticular corticosteroid foot injections (IACI) were associated with long term changes in ankle DJS. Research questions: Is ankle DJS altered in children with JIA reporting walking difficulties compared to children with JIA reporting no walking difficulties? Are IACIs associated with persistent alterations in ankle DJS? Methods: Gait dynamics (DJS), foot pain, and foot-related disability were assessed in 33 children with JIA before intraarticular corticoid foot injection (IACI), and three months after IACI. Using self-reported walking capacity scores, children were classified as either having no walking difficulties (ND) or having walking difficulties (WD). Inferential statistics were used to compare demographics, pain, impairment scores, and ankle DJS between the groups. Results: Before treatment, in the WD group, ankle DJS was significantly decreased both in the early rising phase (ERP = 0.03+0.02 vs. 0.05+0.02 Nm(kg*deg)− 1) and late rising phase (LRP = 0.11+0.06 vs. 0.24+0.22 Nm(kg*deg)-1) compared to the ND group. At three months, the ERP was still significantly decreased in the WD group (ERP = 0.03+0.01 vs. 0.05+0.03 Nm(kg*deg)-1). Significance: Among children and adolescents with JIA who reported walking difficulties prior to IACIs, alterations in DJS in early stance phase (decreased ERP) remained three months after IACI suggesting persistent gait adaptations, possibly related to pain. Pre-treatment gait analysis may aid in identifying children who will not have long term benefit from IACIs in terms of improved gait, and therefore, may be informed and have the choice to be spared the risk of side effects associated with this treatment

European consensus on the concepts and measurement of the pathophysiological neuromuscular responses to passive muscle stretch

Background and purpose To support clinical decision-making in central neurological disorders, a physical examination is used to assess responses to passive muscle stretch. However, what exactly is being assessed is expressed and interpreted in different ways. A clear diagnostic framework is lacking. Therefore, the aim was to arrive at unambiguous terminology about the concepts and measurement around pathophysiological neuromuscular response to passive muscle stretch. Methods During two consensus meetings, 37 experts from 12 European countries filled online questionnaires based on a Delphi approach, followed by plenary discussion after rounds. Consensus was reached for agreement ≥75%. Results The term hyper-resistance should be used to describe the phenomenon of impaired neuromuscular response during passive stretch, instead of for example ‘spasticity’ or ‘hypertonia’. From there, it is essential to distinguish non-neural (tissue-related) from neural (central nervous system related) contributions to hyper-resistance. Tissue contributions are elasticity, viscosity and muscle shortening. Neural contributions are velocity dependent stretch hyperreflexia and non-velocity dependent involuntary background activation. The term ‘spasticity’ should only be used next to stretch hyperreflexia, and ‘stiffness’ next to passive tissue contributions. When joint angle, moment and electromyography are recorded, components of hyper-resistance within the framework can be quantitatively assessed. Conclusions A conceptual framework of pathophysiological responses to passive muscle stretch is defined. This framework can be used in clinical assessment of hyper-resistance and will improve communication between clinicians. Components within the framework are defined by objective parameters from instrumented assessment. These parameters need experimental validation in order to develop treatment algorithms based on the aetiology of the clinical phenomena