Lipochondral degeneration of capsular tissue in osteoarthritic hips

Histopathology of the A1 pulley in adult trigger fingers

The histopathology of the central parts of 40 A1 pulleys from adult patients with primary trigger fingers was studied using light and transmission electron microscopes and the findings were compared with those in a control series of 10 normal A1 pulleys. The evaluation of the normal A1 pulley revealed a bi-laminar structure. The deepest layer was composed of dense normal connective tissue. The outermost layer was formed by loose connective tissue. In trigger digits, it was possible to identify a tri-laminar structure. The deepest layer was composed of irregular connective tissue, formed by small collagen fibres and abundant extracellular matrix. A considerable amount of chondroid-metaplasia was present in this layer. The middle layer contained dense, normal connective tissue with some fibrocytes. The outermost layer was formed of loose connective tissue. In conclusion, there was an additional layer in the A1 pulley in pathological cases which was not present in normal pulleys.

[Unusual "lipid cysts" in the acetabular labrum of patients with hip joint osteoarthrosis]

Diagnostic pathological examination of surgical specimens from patients with hip joint osteoarthrosis occasionally exhibits as yet undescribed pseudocysts consisting of folded granular membranes in necrotic or chondroid tissues. When stained with Sudan red, the content of these cysts indicates the presence of lipid substances. The presence of S100 protein-positive cells with intracytoplasmic fat vacuoles as well as such cells in the walls indicate that they develop from fat inclusions occurring in the chondroid cells of the labrum. Two different wall structures were detected by electron microscopy. The first type exhibited small walls of a granular material similar to the endoplasmic reticulum that surrounds intracytoplasmic fat globules. The second type consisted of broad layers of very tiny granules indicating a more advanced stage of the development of these cysts. The reason for the occurrence of these "chondrocytogenic lipid cysts" remains unknown-it may be assumed that they are due to mechanical labrum destruction that occurs in osteoarthrosis.

The anatomical basis for disease localisation in seronegative spondyloarthropathy at entheses and related sites

The 2 major categories of idiopathic inflammatory arthritis are rheumatoid arthritis and the seronegative spondyloarthropathies. Whilst the synovium is the primary site of joint disease in the former, the primary site in the latter is less well defined. However, it has recently been proposed that enthesitis-associated changes in the spondyloarthropathies are primary and that all other joint manifestations are secondary. Nevertheless, some of the sites of disease localisation have not been adequately explained in terms of enthesitis. This article summarises current knowledge of the structure, function, blood supply, innervation, molecular composition and histopathology of the classic enthesis (i.e. the bony attachment of a tendon or ligament) and introduces the concept of 'functional' and articular 'fibrocartilaginous' entheses. The former are regions where tendons or ligaments wrap-around bony pulleys, but are not attached to them, and the latter are synovial joints that are lined by fibrocartilage rather than hyaline cartilage. We describe how these 3 types of entheses relate to other, and how all are prone to pathological changes in spondyloarthropathy. We propose that the inflammatory responses characteristic of spondyloarthropathies are triggered at these seemingly diverse sites, in genetically susceptible individuals, by a combination of anatomical factors which lead to higher levels of tissue microtrauma, and the deposition of microbes.