[Prognostic factors for avascular necrosis following talar fractures].

Aim: We performed an investigation of factors for avascular necroses after talus fracture and on the reliability of the Hawkins Sign.

Method: From 1984 until 1997 a total of 98 patients with 99 talus fractures were surgically treated. Of these, 79 patients with 80 fractures were examined clinically and radiologically. The average postoperative interval was 6 years and 2 months.

Results: With respect to the 65 central fractures, the rate of necrosis amounted to 14 %, that of collum fractures to 17 %. Necroses arose solely in dislocated central fractures of the talus, type III and IV according to Marti/Weber fracture classification. The rate of necrosis rose with the degree of dislocation of the fractures. In 24 patients the Hawkins Sign could be retrospectively investigated. It proved to be a relatively reliable sign for vitality since only 1 out of 12 patients with positive or partial positive Hawkins Sign developed avascular necrosis. Neither a short interval between accident and operation, the age at the time of the accident, nor the ipsilateral fracture of the medial malleolus showed a necrosis preventive influence. In 5 out of 9 talus necroses the patients were very or mostly satisfied with the result of their treatment.

Conclusion: The Hawkins Sign proved to be a relatively reliable sign for vitality of the talus after fracture. Risk for avascular necrosis increases according to the degree of fracture dislocation.