Open Posterior Glenoid Reconstruction Using a Distal Tibial Allograft.

Background: Posterior instability is less common than anterior instability but can be seen in contact athletes and posttraumatically. Distal tibial allograft reconstruction for glenoid bone loss was first described by Provencher and colleagues in 2009 and an arthroscopic technique for posterior glenoid reconstruction using a distal tibial allograft was later described by Gupta et al in 2013. Indications: The primary indications for posterior distal tibial allograft include the failure of conservative management, recurrent instability after an arthroscopic stabilization, or glenoid bone loss > 20% to 25%. Technique Description: The patient is positioned in lateral decubitus, and examination under anesthesia is performed. Following arthroscopic evaluation, an incision is made medial to the posterolateral aspect of the acromion at the glenohumeral joint level. Electrocautery is carried to the deltoid, which is split in line with its fibers. A split between the infraspinatus and teres minor is performed. Vertical capsulotomy is performed, and deep retractors are placed. Attention is turned to the back table for graft preparation. The graft is measured, marked on the lateral aspect of the articular surface, and cut accordingly. Two 3.5-mm holes are drilled 1 cm apart, and the graft is thoroughly irrigated before being placed into the wound. A 2.5-mm drill is used in the 3.5-mm holes, and two 3.5-mm solid fully threaded screws are placed under power and tightened by hand. The wound is closed in the traditional fashion. Results: Graft nonunion and/or resorption are the primary concerns following posterior distal tibial allograft. Amar et al found no cases of nonunion or partial unions on 6-month computerized tomography (CT) scan, most patients having no or <50% resorption. Millet et al also found bony union by CT scan and improved patient-reported outcome measures. A case series by Gilat et al found 90% of patients reported restoration of stability. Discussion/Conclusion: Posterior distal tibial allograft is a successful surgical intervention for patients with recurrent posterior shoulder instability with glenoid bone loss.