Winging of the scapula: the underlying biomechanics and an orthotic solution

Winging of the scapula occurring in muscular disorders (muscular dystrophy and spinal muscular atrophy) or nerve injury has been investigated, resulting in a thorough understanding and presentation of the underlying biomechanics causing this occurrence. This includes a biomechanical explanation of the characteristic prominence of the medial border of the scapula upon attempted elevation, together with the biomechanical reasons for the rotation of the scapula in a direction contrary to the normal scapulohumeral rhythm. Based on these findings, a non-invasive alternative to the surgical technique for scapular stabilization has been devised, using an inflatable orthosis, placed between the scapula and an external restraint (such as a spinal jacket). The device has been tested on one subject using a 3SPACE Isotrak electromagnetic source and sensor system, and gave encouraging results. Elevation increased by up to 35 degrees (37 per cent), and functional improvement in the use of the hand around the head and face has been achieved. The technique needs no aftercare or physiotherapy and is therefore both economical and functionally effective.

Patients with ankylosing spondylitis show individual patterns of variation in disease activity

Disease activity was monitored sequentially over 1 year in 22 patients with ankylosing spondylitis (AS) attending regularly the local NASS group. Assessments, using standard methods, were made at monthly intervals by the same observer. There was marked heterogeneity such that each patient's profile of disease activity was virtually unique. All patients experienced at least one exacerbation and most underwent exacerbations and remissions, reminiscent of the experience of many patients with rheumatoid arthritis. In most instances no reason for changes in disease activity could be discerned clinically. These observations raise the possibility that the natural history of disease in AS may be different for each individual patient, which, if true, would have important implications for the design of studies to test the efficacy of therapy and for approaches to investigating pathogenic mechanisms in patients with AS.

Observations on the causes of rheumatoid arthritis

Inflammatory, symmetrical peripheral polyarthritis is observed in a small proportion of patients following a variety of parasitic, viral and microbial infections. The development of such a post-infective arthritis disorder may depend on a sequence of events, which need not be confined to one extrinsic pathogenic organism.

An experimental mouse model of Yersinia-induced reactive arthritis

An experimental animal model of Yersinia-induced arthritis was successfully developed in mice using Yersinia enterocolitica WA. In order for the Yersinia to induce arthritis the strain had to be cured of plasmid. The arthritis-susceptible mouse strains were DBA/2 and BDF1. C57B1/6, Balb/c, CBA and DBA/1 were arthritis-resistant. Both the dose of bacteria and the route of administration were critical.

Studies with an enthesis index as a method of clinical assessment in ankylosing spondylitis

The histopathological characteristic of ankylosing spondylitis (AS) is the presence of chronic enthesitis. Our aim was to develop a clinical measurement of the severity of tenderness over entheses. The scoring system was based on the patients' response to palpation over entheses easily accessible to examination. The enthesis index (EI) correlated with pain (r = 0.67, p less than 0.01) and stiffness (r = 0.46, p less than 0.05) scores. A single, blind, crossover study was conducted to determine the sensitivity of the index to change in clinical state associated with non-steroidal antirheumatic drug therapy and to record the interobserver variability. The index showed significantly lower scores after one week's drug treatment (p less than 0.05). The EI is a convenient, non-invasive measure of disease severity in patients with AS. Potential applications include the assessment of enthesitis in other polyarthritides and a means of distinguishing clinically between severity of enthesitis and synovitis in different types of polyarthritis.