This study assessed the role of diagnostic arthroscopy following a wrist injury in patients with normal standard radiographs, an unclear clinical diagnosis and persistent severe pain at 4 to 12 weeks. Forty-three patients were included after conservative management had failed to improve their wrist pain so that a stability test could be performed satisfactorily and underwent arthroscopy within 12 weeks. Arthroscopy revealed recent pathology in 41 wrists, of which 17 had significant ligament lesions that might have benefited from acute repair. We conclude that patients with marked persistent post-traumatic symptoms despite conservative management are likely to have sustained ligament injuries despite normal radiographs. We therefore recommend that under these circumstances an arthroscopy is carried out within 4 weeks if the patient and surgeon wish to acutely repair significant ligament injuries.