Posterior Glenoid Augmentation With Extra-articular Iliac Crest Autograft for Recurrent Posterior Shoulder Instability

Abstract

Several techniques have been described for bone block augmentation as a treatment for posterior shoulder instability, including intra-articular distal tibial allograft and extra-articular iliac crest autograft. Although indications are not yet well defined, these bone augmentation procedures are considered in patients with glenoid bone loss, increased glenoid retroversion, previous failed posterior soft-tissue repair, and insufficient posterior capsulolabral tissue. In patients with posterior glenoid bone loss, the senior author (P.J.M.) recommends intra-articular glenoid reconstruction with a fresh distal tibial osteoarticular allograft. In patients with insufficient posterior capsulolabral tissue, the senior author prefers an extra-articular iliac crest autograft to buttress the posterior soft-tissue restraints. This technique guide outlines extra-articular iliac crest autograft treatment for recurrent posterior shoulder instability in patients with insufficient posterior soft tissues due to prior failed surgery. After an open capsulolabral repair is performed using suture anchors, the bone block is placed extra-articularly on the posterior glenoid neck.

Fig 1

The patient is positioned in the lateral decubitus position with the operative shoulder (left shoulder) and ipsilateral iliac crest prepared and draped. The operative extremity is secured in an arm holder (arrow).

Fig 2

Left shoulder in lateral decubitus position. Skin landmarks and incisions are marked to gain access to the posterior glenohumeral joint. (A) A vertical, posterior mark is made at the inferior margin of the acromion, 2 cm medial to the lateral edge, and extended distally approximately 7 cm. (B) The skin incision is made and is carried down through the subcutaneous tissue. (LAB, lateral acromial border.)

Fig 3

Dissected cadaveric shoulder showing proper placement of 1.8-mm knotless all-suture anchors (3 anchors) used to complete the soft-tissue repair of the posterior labrum on the glenoid: drill guide placed at 6-o'clock position (asterisk) (A), 7:30 clock-face position (asterisk) (B), and 9-o'clock position (asterisk) (C).

Fig 4

(A) Left shoulder in lateral decubitus position. A template (aluminum foil from suture packaging) is used to determine the size of the glenoid defect and the appropriate size of the iliac graft to harvest. (B) Left iliac crest in lateral decubitus position. The aluminum foil template is used to size the iliac crest graft before harvest.

Fig 5

(A) A 25 × 20–mm iliac tricortical autograft is harvested. (B) Two threaded K-wires are placed into the superior and inferior aspects of the graft to allow easier handling and positioning.

Fig 6

Left shoulder in lateral decubitus position. (A) The tricortical iliac crest autograft is positioned flush with the glenoid and held manually in place with 2 K-wires (arrows). (B) A 3.5-mm fully threaded stainless-steel cortical screw is inserted through the inferior 3.5-mm drill hole. A preliminary K-wire (asterisk) is placed through the center of the graft to minimize rotation during graft fixation. (C) The graft is fixated in the appropriate position flush to 1 mm lateral to the native glenoid with two 3.5-mm stainless-steel screws.

Fig 7

Postoperative radiographs of a left shoulder showing proper placement of the bone graft and fixation hardware, without signs of loosening or failure. (A) Anteroposterior glenoid (Grashey) view. (B) Scapular Y-view.