Trapeziometacarpal and Scaphotrapezial Arthroscopy Portals

Published on 11/04/2015 by admin

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Last modified 11/04/2015

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CHAPTER 2 Trapeziometacarpal and Scaphotrapezial Arthroscopy Portals

Trapeziometacarpal Joint Portals

Standard Portals

Menon initially presented his work on arthroscopy of the trapeziometacarpal joint as a meeting exhibit in 1994.1 He then published his experience with the arthroscopic management of trapeziometacarpal arthritis in 1996.2 He described two working portals: a volar portal just radial to the abductor pollicus longus tendon (APL) and a dorsal portal that is just ulnar to the APL along the line of the joint. Berger independently developed his technique for arthroscopic evaluation of the first carpometacarpal joint, which he first presented as an instructional course in 1995. He then published his clinical work in 1997. He named the volar radial portal the 1-R portal and the dorsal ulnar portal the 1-U.3 He defined the term dorsal as being in the plane of the thumb nail and volar in the plane of the distal pulp.

Radial and ulnar referred to the thumb when its nail is parallel to the fingernails, with the thumb supinated and radially abducted. He noted that the plane of the 1-R portal passes through the nonligamentous capsule just lateral to the anterior oblique ligament (AOL). This portal is preferred for viewing the dorsoradial ligament (DRL), the posterior oblique ligament (POL), and the ulnar collateral ligament (UCL). The plane of the 1-U portal, which is just posterior and ulnar to the extensor pollicus brevis (EPB), passes between the DRL and PRL. This portal provides views of the AOL and UCL. Both portals are along the radial border of the thumb, which makes it difficult to assess the lateral side of the joint.4 There is no true internervous plane because branches of the superficial radial nerve surround the field and are at risk for injury with improper technique. The radial artery courses immediately posterior and ulnar to the arthroscopic field.

Modified Radial Portal

Orrellana and Chow described a modified radial portal (RP) for improving the radial view of the TMJ.5 The RP is located just distal to the oblique ridge of the trapezium, following a line along the radial border of the flexor carpi radialis (FCR) tendon rather than the APL. In an anatomic study of six cadaver arms, the superficial radial nerve (SRN) was located a mean of 6.3 mm (range 4 to 8 mm) from the 1-U portal and 7.8 mm (range 4 to 12 mm) from the RP. The radial artery passed within 2.7 mm (range 2 to 3.5 mm) of the 1-U portal and 10 and 15 mm from the RP. To establish the RP, the scope is placed in the 1-U portal. The light source is pointed to the RP, which lies just radial to the AOL. A 22-gauge needle is inserted just distal to the ridge of the trapezium. The skin is incised, followed by blunt dissection through the capsule and insertion of the trocar and cannula, and then the arthroscope.