[Description of a novel arthroscopic surgical technique for radio-ulnar instability in a cadaveric model]. / Descripción de una nueva técnica artroscópica para la inestabilidad radiocubital distal en modelos de cadáveres humanos.

INTRODUCTION: The distal radioulnar joint is subjected to two resultant loads. Axial load caused by grip and the transversal load due to the possibility of lifting weight against gravity. Therefore, instability of this joint leaves as a consequence a great functional incapacity. For this reason, numerous techniques have been described for its treatment such as Dr. Scheker's technique, a reconstruction technique based on a logical, anatomical, biological, mechanical, and functional solution. METHODS: We performed a descriptive study based in seven cadaveric models and fourteen wrists using a normal minimally invasive arthroscopic technique. The first step of the technique consisted in reproducing instability of the joint by means of a direct lesion of the dorsal fascicle of the triangular fibrocartilage complex. After this procedure, the reconstruction of the distal dorsal radioulnar ligament was carried out with a graft of palmaris longus tendon passed through the drilled tunnels in the distal methaphysis of the radio and ulna. Tunnels were performed under arthroscopic direct vision. The graft was inserted through the tunnels and then, fixed with a 2 mm. Endo-button system and a biodegradable screw of 5 mm. We measured range of motion before and after the surgery. The anterior-posterior translation test was applied on the models to measure instability of distal dorsal radioulnar joint, before, and after the surgical procedure. We performed descriptive statistics with SPPS 10.0 software. RESULTS: The technique was performed in fourteen wrists, with a mean surgical time of 104 minutes (80-164 min). The mean range of motion in flexion was 90.1 degrees before surgery and 90 degrees after surgery. Mean range of motion in extension was 86 degrees before and 88 degrees after the procedure. This finding was significant statistically with a value of p 0.008; the rest of measurements did not reach statistic significance. Stability was achieved in 12 models and 2 had a doubtful anterior-posterior translation test. DISCUSSION: The post-surgery extension was modified by the position and traction of the extremity in the cadaveric models. Two wrists remain unstable, by a technical defect while tensioning the graft at moment of fixation. CONCLUSION: Arthroscopic reconstruction for the distal dorsal radioulnar instability with a tendon graft is a technically reproducible technique. We recovered stability of the joint, and conserved range of motion in a cadaveric study.

[Arthroscopy of the trapeziometacarpal joint: anatomical study on cadavers]. / Artroscopía de la articulación trapeciometacarpiana: estudio anatómico en cadáver.

INTRODUCTION: Osteoarthritis of the trapeziometacarpal joint is one of the most common degenerative diseases of the hand for which a variety of surgical procedures have been developed. Arthroscopic techniques offer good results, although they have not been standardized. OBJECTIVE: To identify the main anatomical structures in relation to arthroscopy portals from the trapeziometacarpal joint and to determine their security area. MATERIAL AND METHODS: We conducted a transversal and descriptive study in which the anatomy was analyzed in seven cadaveric specimens. Fourteen thumbs were dissected after the arthroscopic portals were made. In all of the specimens the distance between the radial artery, the articular line and the arthroscopy portals was measured. RESULTS: The radial artery was found dorsal to the Extensor Pollicis Longus (EPL), 4-5 mm proximal to the dorsal arthroscopic portal, 4-8 mm to the articular line and 8-11 mm to the Extensor Pollicis Brevis (EPB). In two cases sensitive branches of the radial nerve were found through the dorsal portal. CONCLUSION: The anatomical evaluation defined a secure area for the dorsal portal between the EPL and the EPB. The proximal radial zone to the EPL must be avoided so that the dorsal branch of the radial nerve is not damaged.