Post-traumatic instability of the trapeziometacarpal joint of the thumb. Diagnosis and the results of reconstruction of the beak ligament.

In 28 patients with a solitary diagnosis of instability of the trapeziometacarpal joint because of a rupture of the anterior oblique ligament, reconstruction was carried out using a slip of the tendon of flexor carpi radialis. We were able to review 26 patients. The results after a follow-up of four years seven months showed that most (87%) had significant relief from pain and symptoms. Seventeen were graded as good to excellent. The mean grip strength recovered to 86% of the contralateral side. Most patients (81%) felt that they had subjective improvement and would have undergone the operation again. A lesser functional result was seen in those who developed a flexion deformity because of overtightening of the reconstruction. Increased awareness of this lesion can lead to an early and clear diagnosis so that the patient may be advised adequately. We describe a specific, diagnostic, clinical test which we have used consistently and successfully.