During 1994-2003, we treated 20 patients with post-traumatic radial-sided wrist pain and dynamic radiocarpal instability. After arthroscopy confirmed no disruption of the radioscaphocapitate ligament and an increased laxity of the ligament, we passed a strip of the radioscaphocapitate ligament through the long radio-lunate ligament. The rationale of this procedure was to increase tension of the two ligaments and to close the space of Poirier. Eighteen patients were assessed after 1-3.7 years (mean 2.5 years). Four patients were symptom-free and 11 patients were markedly improved. Fourteen patients were followed for 11-15 years; four patients were symptom-free and eight patients were markedly improved. Two reported unchanged symptoms and none was worse in the follow-up. Based on our findings, we suggest a cause of post-traumatic radial-sided wrist pain is laxity of the radiocarpal joint. We conclude that our surgical procedure increases tension in the radioscaphocapitate and long radio-lunate ligaments and decreases wrist pain at rest and during activity. Level of Evidence: IV