Femoral head vitality after femoral neck fracture. Comparison between pre- and peroperative tetracycline labeling.

Using fluorescence microscopy, a ratio between tetracycline labeling of the femoral head and of the greater trochanter was calculated for 370 femoral neck fractures. Sixty-three patients were given tetracycline on admission to hospital and 307 on the operating table after closed reduction. The following results were obtained: Visual grading of labeling correlated well to a distribution analysis based on a morphometric point-wave pattern. No significant difference concerning the degree of labeling between the pre- and peroperative groups was found. A redistribution into groups according to fracture displacement (Garden I-IV) did not alter this fact. In the total material, labeling was significantly better for undisplaced than for displaced fractures. No difference was found between different degrees of displacement. For patients less than 50 years of age, labeling values were significantly lower. Intact femoral head vascularization (ratio greater than or equal to 0.90) was found in less than three per cent of the total material.