The prognostic value and significance of serial bone scintigraphy in Legg-Calvé-Perthes disease.

We reviewed 44 consecutive patients treated for Legg-Calvé-Perthes disease who underwent serial technetium 99m diphosphonate bone scintigraphy. The average follow-up was 4.4 years. The bone-scintigraphy classification characterizes the A pathway by early lateral column formation not seen in the B pathway. Pathway A had 20 hips. The average age at presentation was 6.1 years. At last follow-up, this group had an average Mose classification of 1.2 and Catterall score of 2.4, without any patient having "head-at-risk" signs or requiring operative treatment. Pathway B had 20 hips. The average age at presentation was 5.8 years. At last follow-up, this group had an average Mose classification of 5.2, a Catterall score of 3.5, and 18 patients had head-at-risk signs, with 11 requiring operative treatment. Our bone-scintigraphy classification preceded the radiographic head-at-risk signs by an average of 3 months, allowing earlier treatment and correlated with subsequent femoral head involvement.