Thirty-one cases of stage 1 or 2 osteonecrosis (ON) of the hip in 27 patients were studied with T1-weighted coronal magnetic resonance (MR) imaging. Three quantitative parameters were measured on the contiguous MR sections, corresponding to the 2-cm-wide median portion of the femoral head: the angle filled by ON (alpha), the percentage of weight-bearing femoral cortex involved with ON (WB), and the percentage of femoral head surface involved with ON. The clinical and radiologic courses were assessed after at least 2 years of follow-up (mean, 46 months). Core decompression was performed in 12 cases of ON. Values were strikingly lower in the group with good clinical or radiologic outcome versus poor outcome, with very little overlapping. WB was the more reliable parameter. Outcome of hips treated with versus without core decompression appeared closely related with these MR parameters and not with the treatment procedure. Thus, a quantitative approach to determination of extent and location of the lesion on the initial MR image appears accurate for use in the prediction of long-term outcome of ON. Effectiveness of core decompression should be reevaluated on this basis.

The pharmacokinetic profile of total and free methotrexate (MTX) and the effect of piroxicam on MTX pharmacokinetics was studied in 20 rheumatoid arthritis patients receiving a stable dosage of MTX (10 mg/week). Plasma protein binding ranged from 25 to 55%. To describe the variations with time of the unbound fractions a mathematical characterization relationship between the total and free MTX was used. Total and free MTX were correlated with the sigmoid maximum effect model. The slope factor (gamma) was proportional to the number of binding sites. The free fraction for a given patient can be evaluated from this relationship. Total clearance of MTX was not statistically different with piroxicam (8.0 l/h for total MTX, 13.7 l/h for free MTX) vs without piroxicam. Likewise, there were no significant difference in tmax, area under the plasma concentration vs time curve, distribution and elimination half-lives, mean resonance time, and volumes of distribution. Although the highest observed total MTX concentration was significantly lower with piroxicam, there were no significant pharmacokinetic interactions between low-dose MTX and piroxicam.

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The high prevalence of the association of contiguous intervertebral and intravertebral vacuum phenomenon could have implications in the pathogenesis of the intravertebral vacuum phenomenon. We hypothesize that the intravertebral vacuum phenomenon could simply be the result of migration of an intradiscal-gaseous collection through the fractured endplate of some osteoporotic collapses.

Seronegative spondylarthropathies are disorders with the same predisposing antigen, namely HLA B27, a class I molecule of the HLA system. The mechanisms of the different diseases are unknown, and there is no proof of immune system participation. We have investigated patients with spondylarthropathies in order to search for an immunological component in the pathophysiology of these disorders, by measuring the serum level of two inflammatory cytokines--IL1 beta and TNF alpha--by a radioimmunological assay and the serum level of two soluble T cell activation markers--soluble IL2 receptor and soluble CD8--by an enzyme-linked immunosorbent assay. The choice of soluble CD8 can be explained by the strong link between HLA B27 and spondylarthropathies. Our series compared 24 patients to 24 healthy matched controls. A similar IL1 beta serum level was observed in both groups, while in the patients there was a nonsignificant increase in the TNF alpha level, a significant decrease in the soluble IL2 receptor level and a significant increase in the soluble CD8 serum level. The normal or moderately increased serum IL1 beta and TNF alpha levels in the disease group do not exclude a local role for these cytokines in the synovium or other inflammatory areas. However, we found a higher soluble CD8 serum level in the patient group. Most of these patients were in clinical exacerbation of their disease. As the serum level of soluble CD8 is well correlated with T CD8 lymphocyte activation, our data suggest that this lymphocyte subset is stimulated and consequently probably involved in seronegative spondylarthropathies.