[Traumatic luxation of the extensor apparatus of the dorsum of the metacarpophalangeal joint of the little finger. Six cases].

Dislocation of the extensor tendon over the MP joint as a result of trauma is a rare and unrecognized injury as our six patients were only operated subsequently. The diagnosis is simple: flexion is possible, while extension is not. The patient is able to hold the extension despie resistance if the dislocation is reduced by artificial extension. X-rays eliminate any possible fracture. Six cases have revealed two different assumptions: either the two tendons (extensor digitorum communis and extensor digiti quinti proprius) are simultaneously dislocated together on the ulnar side, or they are dislocated on either sides of the joint. In the first assumption, the injury occurred ulnar-wise tearing the sagittal band. This case concerns the three older patients. The dislocation was reduced and stabilized by the Michon surgery method. The second assumption concerns the three youngest patients who suffered from a direct axial shock. This separation was reduced by suture of the two tendons on the dorsal base of the joint. The postoperative care was ensured in all cases by a splint attached to the palm, keeping the MP joint in extension and enabling immediate web-fingered reeducation. This therapeutic technique has given satisfactory results as over an average period of six years no recurrence of stiffness has been observed.