[Reorientation osteotomy of the trapezial saddle]

Abstract

At its early stage, the thumb TM osteo-arthritis is occasionally painful during some activities and there are mainly radiological signs, only visible on specific views and with maximum amplitudes. They are the first metacarpal base imperfect reintegration in the trapezium saddle in ante-position and an increased slope angle of 140 degrees. So, the "slippery saddle" of the trapezium induces a metacarpal base subluxation. The goal of the proposed technique is to correct the orientation of the trapezial saddle. The slope angle must return to its normal value of about 125 degrees, thanks to an opening wedge osteotomy into the trapezium, completed with a bony wedge insertion. Proposed for the first time in 1983, and used only once by Dr. Heim, this technique was "rediscovered" recently and used on five patients in ten years. It is easy to do, the only complication being two post-operative radial nerve sensitive branch neuromas. In six cases on seven, the pain disappeared, even if the osteo-arthritis was evolving for the two former cases. The functional recovery was total and the patients were satisfied in most of the cases. In spite of this short series, this technique is worth being used for the early stage of thumb osteo-arthritis, eventually combined with others techniques like tenotomy of the Abductor pollicis longus accessories or different types of ligamentoplasties. It is, in any case, more logical than the first metacarpal osteotomy.