Articular Erosions

US can detect a variety of minus lesions ranging from small para-articular erosions caused by chronic synovitis to large post-traumatic defects. One of the most common bone defects is the Hill-Sachs lesion, a compressive fracture of the humeral head that follows anterior shoulder dislocation (see Chapter 6). The lesion derives from the traumatic action of the sharp anterior glenoid border against the posterolateral aspect of the dislocated humeral head. US has proved to be an efficient modality to detect a Hill-Sachs lesion and assess... 

Rheumatoid arthritis (RA) is a multisystem disorder in which immunological abnormalities characteristically result in symmetrical joint inflammation, articular erosions and extra-articular complications. It is the most common and disabling autoimmune arthritis, and genetic susceptibility is well defined. The production of increased amounts of IgG and the presence of rheumatoid factor (immunoglobulins directed against the Fc portion of IgG) are two characteristic features associated with RA [36]. 

The early stages of bone pathology in rheumatoid disease manifest as periarticular osteoporosis and juxta-articular bone erosion. Osteoclast overactivity is the predominant influence in such bone erosion and NO has a direct inhibitory efiect on osteoclastic bone resorption (MacIntyre et al., 1991). Endothelial cells, present in abundance and in close proximity to the osteoclast may therefore play a role in down-regulating osteoclast activity through the production of NO. Since the osteoclast is of macrophage lineage, it is likely to be... 

Corticosteroids have been used in 60-70% of rheumatoid arthritis patients. Their effects are prompt and dramatic, and they are capable of slowing the appearance of new bone erosions. Corticosteroids may be administered for certain serious extra-articular manifestations of... 

Corticosteroids have been used in 60-70% of rheumatoid arthritis patients. Their effects are prompt and dramatic, and they are capable of slowing the appearance of new bone erosions. Corticosteroids may be administered for certain serious extra-articular manifestations such as pericarditis or eye involvement or during periods of exacerbation. When prednisone is required for long-term therapy, the dosage should not exceed 7.5 mg daily, and gradual reduction of the dose should be encouraged. Alternate-day corticosteroid therapy is usually unsuccessful in rheumatoid arthritis. 

Contraindications Fluoroquinolones should be avoided in pregnancy, in nursing mothers and in children under 18 years of age, since articular cartilage erosion (arthropathy) occurs in immature experimental animals. 

The biosynthesis and turnover of HA were shown to decrease with age. This decrease is of major importance for the age related increase of several tissue and organ modifications as for instance in osteoarthritis, because of lack of protection against frictional erosion of articular cartilage and also retinal detachment due to the degradation of HA in the joints and the vitreous body in the eye. Wrinkling of the aging skin is also one of its consequences. The precise cellular nature of this age-dependent decline of HA biosynthesis remains to be more deeply investigated. 

Plain radiographs can be normal or show intra-articular effusion, an ill-defined para-articular soft-tissue mass and, in longstanding disease, juxta-articular bone erosions and subchondral cysts caused by pressure and hypertrophied synovium. CT shows hemosiderin and fat deposits, and is able to detect bone erosions that are not manifest on radiographs. 

Fig. 10.71. Caput ulnae syndrome in rheumatoid arthritis. Schematic drawing of a transverse view through the distal radioulnar joint outlines the rupture of the triangular fibrocartilage (arrowheads) and marginal erosions at the distal radio-ulnar joint level due to intra-articular pannus (asterisks). As a result, the ulna subluxes dorsally (gray arrow). Pannus (star) inside the extensor carpi ulnaris tendon (open arrow) sheath leads to cortical erosions, tear of the retinaculum and tendon thinning and splitting. St, styloid of the ulna Rad, radius...

In rheumatoid arthritis, chronic synovitis leads to hypertrophy and hyperplasia of the synovium (pannus), progressive thinning of the articular cartilage and exposure of the subchondral bone. In early disease, when the cartilage still retains a certain thickness, the pannus typically causes marginal bone erosions, located at the periphery of the joint. 

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