Pathology of femoral heads in patients with rheumatoid disease.

In a study of 107 femoral heads removed surgically from 91 patients with generalized rheumatoid arthritis (RA), 96 showed rheumatoid stigmata; in 24 of these, fractures were a dominant feature. Of the 11 heads without rheumatoid stigmata, 5 had changes indistinguishable from osteoarthritis (OA), 5 had intracapital fractures and 1 had massive necrosis. The nature of eburnation was analyzed. Attention was drawn to fractures involving all the pillars supporting the subchondral plate and named "the dome shear fracture." The high incidence of fractures (29 of 107) was attributed to steroid therapy. The controls used were femoral heads from 400 patients with OA, 10 with ankylosing spondylitis and 10 treated with steroids for reasons other than RA. In most instances, a clear distinction could be made between RA and OA in the femoral head.

Osteochondritis dissecans 1887-1987. A centennial look at König's memorable phrase.

In 1887, König claimed that loose bodies in the knee joints of young persons had three causes: (1) very severe trauma; (2) lesser trauma causing contusion and necrosis; and (3) minimal trauma acting on an underlying lesion-for which he suggested the name osteochondritis dissecans. His thesis has stood the test of time. We still confuse the second and third categories but osteochondritis dissecans has been identified as an ossification defect.

Unexpected sites of wear in the femoral head.

In a study of 637 femoral heads removed surgically because of osteoarthritis, the wear was predominantly on the posterior half in 13.2% and was more than two-thirds posterior in 7.5%. Wear was more than two-thirds anterior in 37.8%. In 36 heads from patients with rheumatoid arthritis, the wear was predominant posterior in 27.8%. No anatomical reason was found for these marked asymmetries, which, from their position, could not possibly be the result of simple weight bearing. The finding underlines the importance of muscular action in the causation of wear.

Hypothesis--a diagram of the form and origin of loose bodies in osteochondritis dissecans.

As an aid to explaining the relationship between the form and origin of loose bodies in osteochondritis dissecans (OD), diagrams are presented and discussed.

Histologic changes in rheumatoid disease of the metacarpal and metatarsal heads as seen in surgical material.

A histologic study of surgically removed rheumatoid metatarsal and metacarpal heads showed that, at this late stage of the disease, the changes in residual cartilage are mainly reparative. An outstanding one is the formation of a new surface under dead cartilage, analogous to the replacement of a snake's skin. Dead cartilage has to be eroded in toto. When live cartilage is exposed to vascular tissue, the chondrocytes take part in the involutionary process. Chondrocytes also appear to initiate the process described as pannus. Deformities are often produced by flask-shaped defects showing severe marginal osteitis. Active erosion of the surface by synovial adhesions has probably been overemphasized in the literature.

Hypertrophy and laminar calcification of cartilage in loose bodies as probable evidence of an ossification abnormality.

Of 83 loose bodies containing hyaline cartilage, 54 were composed of cartilage alone, and 29 of cartilage and bone. In both groups, hypertrophy of the cartilage was common but 53 per cent of the chondral bodies contained in laminar calcification close to the tidemark. The evidence suggested that this feature ante-dated separation of the loose body, and may have indicated a metabolic insufficiency because of the increased thickness of the cartilage. The most likely explanation for the hypertrophy was that it was secondary to a local retardation of ossification in the periphery of the epiphysis.

Ganglion migrans of the proximal tibiofibular joint causing lesions in the subcutaneous tissue, muscle, bone, or peroneal nerve: report of three cases and review of the literature.

Three cases illustrate the variety of ways a ganglion may arise from the tibiofibular joint. In one case, the diagnosis was initially obscure because the swelling occurred under the muscles of the lateral compartment of the lower leg; the lesion was also intraosseous and extended into a tendon. In the second case, the ganglion had invaded the peroneal nerve, and in the third, the ganglion was a palpable subcutaneous tumor.

The pathogenesis and significance of menisceal cysts.

From a total of 1571 surgically excised menisci, 112 (7.1 per cent) were found by gross and microscopic examination to contain one or more cysts. All of these cysts were associated with tears, either primarily horizontal or with a horizontal component. Tracks were often demonstrable leading from the tear to the cysts, and in some cases of osteoarthritis, detritus of bone could be found in their periphery. It is concluded that the cysts are fuelled by synovial fluid. The relationship of cysts to "myxoid" change of the meniscus is discussed.

Intra-articular loose bodies regarded as organ cultures in vivo.

A study of the changes which occur in the intra-articular loose bodies which contain hyaline cartilage, showed the chondrocytes to be very versatile. To effect the transformation of a fractured portion of the articular surface from an angular to a rounded body, peripheral chondrocytes lyse the surrounding glycans and revert to fibroblasts before proliferating and forming fibrocartilage. The central chondrocytes show a wide variety of changes which may mask the original structure of the hyaline cartilage. Remodelling can occur by the formation of osteoclasts. Analogies are drawn between the behaviour of chondrocytes in culture and in some pathologic processes.