PURPOSE: To determine the metaphyseal changes occurring in Legg-Calve-Perthes(LCP) disease using MRI. MATERIALS AND METHODS: Between 1992 to 1999, 80 LCP patients (87 hips) underwent MR imaging and plain radiography. All MR images were reviewed, bone marrow signal intensity, the size and location of the metaphyseal cyst and its epiphyseal necrosis grade determined. RESULTS: Metaphyses were abnormal in 43hips (49%), while bone marrow edema was present in 28 (32%) and a metaphyseal cyst in 30 (34%). Metaphyseal cysts were classified as either 'true' (n=9) or 'false' (n=21) according to the enhancement pattern. The maximum diameters of true and false cysts were 1.1+/-0.3 cm and 1.1+/-0.4 cm, respectively. Their most commom location was the anterior column; a true cyst occurred there in 7cases (78%), and false cyst in 16 (76%). Using the Waldenstrom classification, seven of the nine hips wih a true cyst (78%), were found to be at the avascular stage and 15 of the 21 with a false cyst (71%) were at the fragmentation stage. Seven of these nine (78%) and 19 of these 21 (90%) were Catterall grade IV. CONCLUSION: According to the findings of MR imaging, the metaphyseal changes occurring in LCP disease were bone marrow edema and metaphyseal cyst. This latter was visualized mainly in the anterior column and severely affected hip, and was classified as 'true' or 'false'.
Bone Marrow ; Classification ; Edema ; Hip ; Humans ; Legg-Calve-Perthes Disease* ; Magnetic Resonance Imaging ; Necrosis ; Radiography

BACKGROUND: Within the lateral pillar classification of the Legg-Calve-Perthes (LCP) disease, hips seem quite variable in the pattern of fragmentation as seen in radiographs. The purpose of this study was to determine: if it is possible to reliably subdivide the lateral pillar groups into femoral head fragmentation patterns, and if such a subdivision of the lateral pillar groupings is clinically useful in managing LCP disease. METHODS: Two hundred and ninety-three anteroposterior radiographs taken at the maximal fragmentation stage (189 lateral pillar B, 57 B/C border, and 47 C hips; mean bone/chronologic age at the time of first visit, 6.2/7.9 years) and at skeletal maturity (mean age, 16.6 years) were analyzed. We distinguished 3 fragmentation patterns in each pillar group based on the region of major involvement. We tested the inter- and intraobserver reliability of our classification system and analyzed the relationships between the fragmentation patterns and the Stulberg outcomes as well as other factors such as surgical treatment and age. RESULTS: Inter- and intraobserver consistency in fragmentation pattern assignments was found to be substantial to excellent. A statistically significant trend (p = 0.001) in the proportion of Stulberg III or IV outcomes in comparison with Stulberg I and II was only found for the different fragmentation patterns in our lateral pillar B patients: fragmentation patterns having mainly lateral-central necrosis led to poor outcomes. No significant association was found between fragmentation patterns and Stulberg outcomes in pillar groups B/C border and C. CONCLUSIONS: Our results are consistent with the lateral pillar classification itself. Therefore, fragmentation patterns in each lateral pillar classification did not provide clinical usefulness in the management of LCP disease.
Adolescent ; Child ; Femur Head/*radiography ; Femur Head Necrosis/classification/radiography ; Humans ; Legg-Calve-Perthes Disease/*classification/radiography ; Observer Variation ; Prognosis ; Retrospective Studies ; Young Adult