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Y Asakura,
T Atsumi, Y Hiranuma, K Yamano, T Kajiwara, Y Takemura,
S Tamaoki, E Kato, M Watanabe
Department of Orthopedic Surgery, Fujigaoka Hospital, Showa University School of Medicine, Yokohama, Japan.
Purpose:
We investigated the necrotic area and its shrinkage on stage 1 femoral
head necrosis with band pattern low intensity on MRI.
Methods & Patients: 11 femoral heads (6 patients) with a history of steroid treatment were subjected. In heads, band pattern was detected by MRI. The mean age was 40 years.
The location of the lesion shown by band pattern low intensity was determined by Japanese investigation committee as follows. Type A lesion occupies the medial one-third or less, Type B occupies the medial two-thirds or less, Type C-1 occupies more than the medial two-thirds and Type C-2 extends laterally to the acetabular edge at the neutral position. Types were observed initial and final MRIs. . The mean follow up was 4 years and 3 months. For the repair patterns, the direction were observed in the anterior and posterior slices of MRIs.
Results: Initial MRIs showed types were Types A, B, C-1, and C-2 in 3, 3, 3, and 2 femoral heads, respectively. At the final observation, no band pattern was noted on the weight-bearing surface in 3 Type-A femoral heads. The femoral head surface was repaired, and the lesion was present only in the non-weight-bearing region. In all of 3 Type-B femoral heads and 5 Type-C1 and -C-2 femoral heads, the lesion shrank to Type A. The articular surface was covered with normal intensity area from the posterior direction in all femoral heads
Conclusion: We thought the repair occurred during the disease process of stage 1 necrosis.