A Cadaveric Analysis of the Arthroscopic Fixation of Anterior and Posterior SLAP Lesions Through a Novel Lateral Transmuscular Portal

Abstract

To compare the most commonly used portals with a novel, lateral transmuscular portal for the treatment of anterior and posterior SLAP lesions. Six paired cadaveric shoulders underwent arthroscopy to assess 3 different instrumentation portals: the anterior-superior lateral (AL) portal, the Neviaser (N) portal, and the Rothman-lateral (RL) transmuscular portal. After each portal was established, 5-mm cannulas were inserted followed by guidewire-assisted placement of implant fixation instruments. Each shoulder was then dissected to assess the relation of the instruments to the surrounding anatomic structures. When the AL portal was used, instrumentation consistently passed through the rotator interval. When the N and RL portals were used, instrumentation penetrated the rotator cuff muscle belly at a mean distance of 25.75 and 7.67 mm, respectively, from the tendon. The mean angles of entry into the glenoid rim with respect to the glenoid articular surface were 32 degrees, 38 degrees, and -6 degrees for the AL, RL, and N portals, respectively. There was no violation of subchondral bone; however, 2 specimens showed weakened articular surfaces with use of the N portal. The RL portal was the only portal that allowed placement of instrumentation into all 3 zones of the superior glenoid rim (anterior superior, direct superior, and posterior superior) without violation of the subchondral bone and at the recommended 30 degrees to 45 degrees angle of entry. The RL portal provides a safe and efficient method of arthroscopic fixation and knot tying of anterior and posterior SLAP lesions by use of a single instrumentation portal. This novel, lateral transmuscular portal allows optimal angles of implant placement in all areas of the superior glenoid and provides a direct, simplified approach for arthroscopic knot tying.