[Subtalar dislocations. Apropos of 35 cases].

PURPOSE OF THE STUDY: The subtalar dislocation is a rare injury. The authors appreciate the difference of frequency between medial and lateral displacement, the factors likely to increase a classical favorable prognosis and the therapeutic attitude to suggest.

MATERIAL AND

METHODS

35 observations were included of which two bilateral, 26 had a medial displacement, 9 a lateral displacement. Treatment was conservative in 21 cases and surgical in 14 cases. The results were analysed using Gay and Evrard's clinical scoring system at which we added radiological results.

RESULTS

The average follow-up was 7 years and 7 months. The global results are 11 excellent, 13 good, 9 fair, 2 poor.

DISCUSSION: The high frequency of medial displacement is explained by the fact that the subtalar joint is only really unstable in inversion. The lateral displacement is rare. The prognosis is good in pure dislocation. It is only good enough every time a fragmentary talar fracture is associated as a factor of stiffness. The 11 arthrosis cases are secondary to a dislocation associated with a talar dislocation, a scaphoid dislocation or a vascular injury. In the series, there is no syndrome of tarsal sinus, and no post traumatic instability. Talar necrosis are rare: 3 cases in this series. They occur following large dislocations at the limit of enucleation. The reduction is urgent. The treatment is more often conservative. It must be surgical in case of associated injury requiring a surgical procedure or in front of widely open dislocation.

CONCLUSION

Subtalar dislocation is a rare injury. In the majority of cases, the displacement is medial. The prognosis is good in pure cases. It's only good enough every time a fragmentary talar fracture is associated as a factor of joint stiffness.