Confirmation of the early prognostic value of bone scanning and pinhole imaging of the hip in Legg-Calvé-Perthes disease.

UNLABELLED

In about half of all patients with Legg-Calvé-Perthes disease (LCP), severe hip disorders that could be prevented by early surgery will develop. A prognostic test for this complication is also needed as part of routine care to help the surgeon manage LCD. The purpose of this study was to confirm the prognostic value of the bone scanning and pinhole imaging of the hip in LCP that Conway's group proposed in 1997 and to define accurate prognostic scintigraphic patterns.

METHODS

Fifty-eight patients with LCP were recruited at initial presentation and followed for 1 y. Each patient underwent bone scanning initially and after 5, 8, and 12 mo of disease. The severity of the disease was assessed by radiography (the Catterall classification), MRI, and arthrography. Retrospectively, initial scintigraphic findings were correlated with severity.

RESULTS

Among the 60 hips studied (2 patients had bilateral disease), severe hip disorders developed in 36. The positive predictive value of the scintigraphic classification proposed by Conway's group was 97% for the B pathway (absence of lateral column formation) and 85% for the A pathway (presence of lateral column formation). The hyperactivity of the metaphyseal growth plates was a sign of poor prognosis. The sensitivity was only 33%, but the positive predictive value was 92%. This prognostic information was obtained in as few as 5 mo after initial presentation.

CONCLUSION

This study confirms the high prognostic value of bone scanning in LCP as reported by Conway's group not only in terms of the accuracy of the classification but also in terms of the short time in which the prognostic information can be obtained. Thus, we propose that bone scanning be used as part of routine care for the management of LCP.