RESUMEN
The authors give an account of their experience with early operation of acute instability of the knee at a surgical department of a type II hospital. The majority of patients with knee injuries is first examined and treated at these departments. The authors hold the view that the unfavourable percentage of wrongly diagnosed and operated patients with acute instability of the knee can be reduced when the following conditions are respected: 1. Make the clinical examination and X-ray pictures under local of preferably general anaesthesia. 2. Indicate operation on the basis of the simple Hasting's classification. 3. Revise during the operation accessible ligamentous structures of the knee, not only those the symptoms of which dominate during the clinical examination. 4. Operate acute instability of the knee within 24 hours, but not later than within three days.