Trapezio-metacarpal arthrodesis: procedure and results.

Abstract

The high prevalence of trapezio-metacarpal joint (TMJ) osteoarthritis leads to develop techniques to improve surgical outcomes when conservative treatment has failed. We have evaluated 18 patients with Eaton III TMJ osteoarthritis, who underwent an arthrodesis. Using a dorsal-radial curved shaped skin incision the TMJ was exposed through the space between the abductor pollicis longus and the extensor pollicis brevis muscles. The articular capsule was divided and the TMJ was opened. Neat curettage was then performed in both joint surfaces by removing all the articular cartilage until some cancellous bone hints appeared underneath. The joint was then fixed in the optimal position by a 1.6mm Kirschner wire and a 1.1mm guide wire. A cannulated drill for the guide wire was used and matched to a cannulated lag screw. Then, a cylinder-shaped cancellous bone autograft harvested from the distal radius by a percutaneous approach was applied in the hole by drilling backwards in order to spread the bone about onto the hole walls. The joint was then definitively fixed by the cannulated lag screw. The K wires were removed by that time. DASH score changed from an average of 68 in the preoperative assessment to 39.4 at the end of the evolution time. The evolution of pain has decreased from 9.2 points preoperatively to 3.9 points in the postoperative using the visual analogue scale. In terms of mobility, it has decreased from 4 points preoperatively to 3.9 postoperatively, 14 patients got opposition of the thumb to the fifth finger, two of them to the head of the fifth metacarpal bone, one patient to the fourth finger, and one to the third. This slight decrease of mobility had no effect on performing activities of daily life, as expressed by the patients. The grip strength increased from 17 to 21.7kg and the thumb opposition from 7.8 to 11.2kg. All patients, except one, would have the operation again after knowing the final results. This patient said that results did not meet previous expectations. On the radiographic evaluation, consolidation has been achieved in 17 patients. When thumb carpo-metacarpal arthrodesis is indicated, the procedure provides a reliable and lasting treatment with satisfactory results. The development of new implants and the possibility of introducing autologous graft percutaneously as is described using this technique leads to improve the results.