Résumé
The sever strain of the thumb's metacarpophalangeal joint interest specially the ulnar collateral ligament [UCL]. The authors reported their experience about managing the acute rupture of the UCL. Authors reported 26 cases of severe strain of the UCL of the thumb's metacarpophalangeal joint. There were 22 mans and 4 women. The mean age was 27 years [17-50 years]. The sports accident caused 77% of all injuries. The diagnosis was allowed by physical exam, standard and stress radiographies. There were 8 patients with avulsion fractures of the UCL [2 undisplaced], 7 with corporeal rupture and 11 with distal desinsetion of the UCL. Two patients [with undisplaced fracture avulsion] had an orthpaedic treatment and 24 were operated. With a mean follow-up of 3, 5 years 22 patients [85%] had a very good or good results, 2 patients [8%] had average result and 2 authors [8%] had poor result. The severe strain of UCL of the thumb's metacar-pophangeal joint may have a good result if diagnosed and treated correctly in the acute phases. Excepted undisplaced fracture avulsion, all these injuries must be treated surgically, immobilised in plaster for 4 weeks and reeducated adequately