In Tampere Central Hospital, Finland, 30 thumb replantations or revascularisations were carried out between March 1977 and March 1980. 22 were complete amputations and 8 were incomplete severances. Half of this material was due to avulsion injury and the other half consisted of local crush or sharp cut injuries. Ten cases in each group were considered equal and functional comparison was possible. Some technical points in replanting avulsed thumbs are presented. In particular the reconstruction of the flexor pollicis longus tendon and muscle is described. The avulsed flexor tendon was rerouted and refixed to its own torn muscle remnants in 11 of 12 cases with totally avulsed tendon. The results show that by abundant use of free veingrafts (in 80% of cases) the survival rate with avulsion injury can be almost as high as with local crush or more sharp injuries. Three thumbs were lost--two in the avulsion group--giving an overall primary survival of 90%, avulsion 87%, local crush 93%. Functional results show after 9 to 36 months follow-up time (mean 21 months +/- 8) that sensory recovery is superior after local crush compared with replantations after avulsion injury. Otherwise the differences are small and a useful end result can be obtained in most avulsion cases. 80% of the patients returned to their original work within the first six months (four months mean). Avulsion injury of the thumb, which is rather common among people working with fast rotating axles, seems to be an important indication for replantation surgery although more painstaking work is needed to obtain a favourable end result.