Neurovascular relationships of the approaches for arthroscopic total trapeziectomy with ligamentous stabilization.

The aim of this study was to define the neurovascular relationships of the approaches used during arthroscopic total trapeziectomy with the Thompson "suspension-plasty." Fifteen fresh cadavers in which trapezio-metacarpal arthritis had been confirmed by preoperative radiographs were chosen. There were 12 women and 3 men (average age: 87 years), and small joint arthroscopy equipment was used. Two approaches for the trapezio-metacarpal joint were used: an ulnar approach situated at the ulnar border of the extensor pollicis brevis tendon and a radial approach placed at the middle of a line joining the tendons of the flexor carpi radialis and the abductor pollicis longus. A new transosseous approach at the base of the first metacarpal ("trans-M1" approach) is suggested and was used to do the ligamento-plasty. After the operation, a large skin flap was elevated in order to measure the distance between each surgical approach and the different neurovascular structures (radial artery, dividing branches of the superficial branch of the radial nerve and the end of the lateral cutaneous nerve of the forearm) and to verify the absence of neurovascular lesions. The different neurovascular structures at risk during this arthroscopic maneuver were the radial artery for the ulnar approach, the branches of the superficial branch of the radial nerve for all of the approaches and the ending of the lateral cutaneous nerve of the forearm for the radial and "trans-M1" approaches. The use of the approaches described allows arthroscopic trapeziectomy with the Thompson suspension-plasty without us having noted neurovascular lesion.