By William Edward Sanders, MD

INTRODUCTION:

My “niche” in practice was chronic upper extremity pain and failed surgery. In our community, there was one surgeon who had complications from LRTI basilar joint arthroplasty. I re-operated on 6 of these patients where the CMC joint was adducted and contracted with minimal motion. Many variations of the LRTI have been described, usually with good results. However, in some patients there are complications. This is the procedure that I developed that does not require any of the structures commonly used for LRTI.

BASILAR JOINT ECRL CAPSULAR SHIFT ARTHROPLASTY:

1. I use a Wagner approach between the thenar muscles and the 1st metacarpal curving into the wrist flexion crease. In the distal portion of the incision there is usually a small branch of the superficial radial nerve that may need to be sacrificed and buried in muscle.

The Wagner incision follows the thenar eminence in a gentle curve towards its palmar aspect. I go directly along the volar side of the 1st metacarpal between the glabrous and non-glabrous skin. The radial artery and superficial radial nerve are retracted dorsally. The glabrous skin is not separated from the thenar muscles.

2. The thenar muscles are dissected directly off of the metacarpal and the basilar joint capsule as far mediately as the transverse carpal ligament insertion on the scaphoid and trapezium.

3. The basilar joint capsule is opened transversely at the scapho-trapezial level, and longitudinally between the trapezium and the flexor carpi radialis. The trapezium is excised preserving the capsule. The Radial Artery and Superficial Radial Nerve are protected dorsally and the Flexor Carpi Radialis tendon is easily dissected from the volar-ulnar groove of the trapezium. The radial side of the Trapazoid is excised (per J. W. Strickland).
4. The Extensor Carpi Radialis Longus inserts on the base of the 2nd metacarpal and on the thenar side. About 6 inches of this tendon is harvested through a small forearm incision, and left attached distally. The thumb is pronated and abducted by an assistant, and the tendon is passed through the joint capsule on it’s Dorsal side (deep to the radial artery). The tendon graft is successively sutured to the capsule holding the thumb in pronation and the base of 1st and 2nd together. The remaining tendon is then rolled into a large interposition graft, and sutured together (and to the remaining capsule) attaching it to both the metacarpal and the distal scaphoid.

5. A capsular shift is then performed, again pulling the thumb into pronation and palmer abduction. The proximal and ulnar corner of the capsular incision is shifted proximally and toward the ulnar side of the wrist. It is sutured to the volar strong soft tissue of the transverse carpal ligament. Usually the reconstruction is quite stable and does not require pinning. If necessary, I pin between the 1st and 2nd metacarpal.

(It was during this part of the procedure that I wondered what I was suturing to. Cadaver dissection revealed that this was the volar leaf of the transverse carpal ligament on the radial side of the wrist that lies volar to the Flexor Carpi Radialis. This eventually led to the discovery of the radial approach to carpal tunnel release.)

 

USE IN LAXITY OF THE BASILAR JOINT WITHOUT ARTHRITIS:

A variant of this procedure could also be utilized when there is ligament laxity (from injury or from genetic predisposition). A slip of the Extensor Carpi Radialis Longus or a tendon graft could be passed beneath the 1st metacarpal and 2nd metacarpal basilar ligament, looped back onto the ECRL and sutured. During this procedure, an assistant holds the thumb in pronation and abduction. The base of the thumb metacarpal is held tightly against the base of the 2nd metacarpal. Therefore the effects of joint laxity should be minimized. A capsular shift is performed and if the Abductor Pollicis Longus is a deforming force the tendon can be lengthened or a recession can be done at the muscle tendon junction. This would not prevent any future procedure from being done, and would allow preservation of the trapezium.

ACKNOWLEDGMENTS:

1. Drawings adapted from Grant’s Atlas of Anatomy, 5th edition, 1962.
2. Drawings adapted from Hollinshead’s Anatomy for Surgeons, 2nd edition, Volume 3, 1969.
3. Also from images available on the Internet that do not have citations.