ARTHROSCOPIC TENODESIS (BONE-TENDON-TENODESIS) A NEW SURGICAL TECHNIQUE FOR SCAPHOLUNATE INSTABILITY: CADAVER PRELIMINARY STUDY

Abstract

We present an anatomical study and the description of a new surgical technique for the arthroscopic treatment of scapholunate ligament injuries.

Materials and Methods: 5 specimens were used to perform the new arthroscopic technique and prove with confidence it’s reproducibility. After arthroscopic surgery, anatomic dissection had been performed to measure the distances to the critical wrist structures such as the posterior interosseous nerve, the radial artery and the distance of the portals to the extensor compartments.

Surgical Technique: Ligamentoplasty was performed with the flexor carpi radialis to reconstruct the dorsal scapholunate ligament.

First, a standard wrist arthroscopy was performed, and two bone tunnels were made. One across the scaphoid, through the 3/4 portal from its dorsal face to the tubercle, and another through the 4/5 portal to the lunate, perpendicular to its axis.

The plasty of the FCR was obtained by a volar approach, and it was passed through the tunnel of the scaphoid.

Subsequently, the plasty was passed from the 3/4 portal to 4/5, through a small 3-cm arthrotomy on this site.

Finally, we introduced the plasty in the lunate tunnel with a biotenodesis screw. At this manner the tenodesis Bone (insertion of FRC) - Tendon (FRC) - Tenodesis (FRC in lunate) was completed.

Results: Tenodesis were obtained in all 5 cases with no mayor damage to the structures described. The average of distance to IP nerve was 12 mm; to radial artery 17 mm and to superficial radial artery 9 mm. The average of distances from the portals to different extensor compartments are 3/4 portal to the second 2,8 mm, to the third 3,2 mm and to the forth 5,2 mm. 4/5 portal to the fourth 1,8 mm and to the fifth 7,2 mm. Radial midcarpal portal to the second 2mm and to the fourth 5,6 mm. Cubital midcarpal portal to the fourth 2,2 mm and to the fifth 7,4 mm

Discussion: This is a revolutionary wrist arthroscopic technique, because usual reconstruction techniques of the scapholunate damage are done openly.

With this arthroscopic technique three objectives are achieved. First, it reduces soft tissue damage, scar tissue and the section of secondary stabilizers of the wrist. Secondly, it ensures that, without doing and arthrotomy, the injured of IP nerve is avoided maintaining proprioception of the wrist and the properly function of the dynamic stabilizers. And finally the use of a stronger implant will shorten the time of immobilization.

Conclusion: We have developed a new surgical technique for arthroscopic reconstruction of the scapholunate ligament that will improve the outcomes of standard open techniques, as long as it will gain mobility and maintain the proprioception of the wrist.

However clinical trials in patients are needed to confirm with scientific rigor the new technique described.