[Dynamic magnetic resonance tomography (MRI): a follow-up study after femur core decompression and instillation of recombinant human bone morphogenetic protein-2 (rhBMP-2) in avascular femur head necrosis].

Object: The aim of the study was to test the use of dynamic magnetic resonance imaging study with Gd-DTPA-application and the dynamic changes of signal intensity at patients with avascular femoral head necrosis after having installed rhBMP-2 and/or decompressed the core.

Material and methods: Six patients with avascular necrosis of the femoral head ARCO-stage I- or II-lesions were treated surgically by femoral head core decompression. Three of these patients were additionally treated with rhBMP-2-instillation. The progression or regression could be confirmed by T1- and T2-weighted spinecho-sequences (zero, four, ten, sixteen weeks and 24 months follow up).

Results: Corresponding ARCO-classification with partly more sensitive measurement of vitality signs in comparison to the optical x-ray classification. The objective, quantitative measurement of signal intensity post contrast medium reduces the influence of experience and level of education. The dynamic sequences results are reproducible.

Conclusion: The dynamic magnetic resonance imaging study after Gd-DTPA-application and the dynamic changes of signal intensity after Gd-DTPA enhancement in the necrotic areas of the femoral head were the important subject of our study and it seems, that these sequencies and the ascertainment of signal intensity changes will be an efficient method for judgement of vitality, vascularisation and perfusion after therapeutical intervention. Combination of femoral head core decompression and rhBMP-2-instillation for the purpose of osseous regeneration seems to stabilize the affection.