Metal-Free Fixation for Free Bone-Block Reconstruction of Chronic Anteroinferior Shoulder Instability

Abstract

Background: Anterior shoulder instability is common and may cause a considerable effect on quality of life. For cases with glenoid bone loss, there is still a controversial discussion regarding the optimal treatment. Most of the recent methods are using metal implants to attach the needed graft to the glenoid with reported disadvantages such as metal impingement, damage to the humeral head, cartilage destruction, and premature arthritis. Indications: (1) Erosion-type defects with significant bone loss (>15%-20%); (2) chronic fragment-type defects if the size of the fragment is not large enough for an anatomical reconstruction; and (3) non-reconstructible, multifragmented acute fragment type of lesions. Technique Description: After placing the patient in a lateral decubitus position and fixing the arm in a traction devise, 3 arthroscopic entries are established: a posterior portal, an anterosuperior portal, and an anteroinferior portal. A harvested tricortical iliac crest bone graft is provided with 2 drilling holes which match the drilling holes through the glenoid. The tapes are then placed from the posterior to the anterior side of the glenoid, and then the graft is passed from the anterior to the posterior side, thus compressing the cancellous side of the bone block onto the glenoid defect. A following interconnection of the sutures creates a continuous loop. The end of the tapes was loaded into a pretied racking hitch knot system, which creates sliding knots between the 2 pair of tapes, whereon the knots can be reduced to the glenoid in a symmetrical fashion. Finally, the reconstruction of the anterosuperior labrum can be done, to cover the bone block with enough soft tissue. Results: First short-term results show radiographic consolidation after 3 months and an increased median glenoid estimated surface area at 12 months. The functional scores showed good outcomes, and there were no serious complications reported. Discussion/Conclusion: The presented arthroscopic reconstruction of the glenoid using a tricortical bone graft and high-strength fiber tapes provides a metal-free technique which results in a high primary stability of the construct and should therefore be considered when treating anterior shoulder instability with significant bone loss.