THE JOURNAL OF BONE AND JOINT SURGERY surface involved by necrosis in antero-posterior and lateral radiographs of the head, and adding the two angles (Fig. 1). The extent was considered large when the sum was 200 degrees or more and small when 160 degrees or less. The figures so obtained were: large, 47 per cent: medium, 38 per cent; and small, 15 per cent.

This study shows that when the posterior injury is a fracture of the iliac wing or a mixed fracture with SI propagation, a long-term satisfactory functional result can be obtained without an exact reduction even in cases of vertical instability. Simple methods are usually sufficient, and it seems unnecessary to propose more aggressive treatment. It is important, however, to recognize that SI fracture-dislocations (17 percent in this series) seem to be quite different from pure SI disruptions in terms of persistent pain. Moreover, it appears that exact reduction of pure SI lesions is critical for good functional results, something that is difficult to obtain with conservative procedures. Sacral fractures represent a special problem for the surgeon because of the frequency of fair results in which neurologic lesions whose pathophysiology is poorly known seem to be responsible.

Objective. To retrospectively assess, with a sufficiently long followup (mean 11.6 years; median 9 years), the long-term outcome of chronic recurrent multifocal osteitis (CRMO), a multifocal, inflammatory bone disease.Methods. Patients included were 8 children/ adolescents and 7 adults with no family history of rheumatic disease who had been diagnosed as having CRMO between 1979 and 1995. Ten patients had undergone at least 1 bone biopsy of the lesions, with histologic examination and multiple cultures. In 1996, in addition to an in-depth interview, 12 patients underwent an extensive physical examination, laboratory evaluation, HLA-A, B, C, and DR typing, bone radiography and scintigraphy, and computed tomography scan of the sternoclavicular and sacroiliac joints.Results. Remission was observed in 3 patients. The other 12 patients developed various associations of vertebral (n ‫؍‬ 10), sacroiliac (n ‫؍‬ 6), anterior thoracic (n ‫؍‬ 7), peripheral articular (n ‫؍‬ 2), enthesopathic (n ‫؍‬ 4), or dermatologic (palmoplantar pustulosis in 3 cases and psoriasis in 2) involvements. Spine involvement was the most common and occurred the earliest (median time to appearance after the onset of osteitis 5.63 years). Clinical sacroiliitis was always unilateral. No patients carried the HLA-B27 haplotype. CRMO responded well to nonsteroidal antiinflammatory drugs. Twelve patients met the European Spondylarthropathy Study Group criteria for spondylarthopathy.