Editor’s note:  The following article is a review of a video available via the AAOS Orthopaedic Video Theater (OVT). AAOS Now routinely reviews OVT Plus videos, which are vetted by topic experts and offer CME. For more information, visit aaos.org/OVT.

Posterior shoulder dislocations are uncommon injuries that are often difficult to diagnose without a high index of suspicion. Typical mechanisms for these dislocations include seizures, electrical shocks, or anteriorly directed shoulder trauma.

Management involves acute reduction of the humeral head. However, other pathology, such as a reverse Hill-Sachs deformity, may be present due to compression of the anteromedial humeral head against the hard glenoid rim. Surgical indications for these defects depend on clinical presentation. In comparison to traditional lesions, reverse Hill-Sachs defects contain higher amounts of anterior humeral head cartilage damage. As such, usual treatment techniques in the literature have focused on soft-tissue filling of the defect.

The AAOS OVT video “Open Allograft Reconstruction of the Proximal Humerus Using Custom 3D Printed Cutting Guide” demonstrates the use of a 3D-printed cutting guide for osteochondral allograft reconstruction of a large reverse Hill-Sachs lesion in the setting of recurrent posterior shoulder instability. Preoperative CT scans of the humeral head are used to develop a template for a custom cutting guide and enable donor allograft to be cut to a near anatomic fit into the recipient’s humeral head.

The patient in the mentioned case was male, was 33 years old, and presented with complaints of shoulder pain and weekly dislocations occurring over the past few years. Most notably, he had a known history of seizures but was not on medical treatment. On physical examination, the patient demonstrated limited range of motion in forward flexion and external/internal rotation. Preoperative imaging demonstrated a reverse Hill-Sachs deformity with significant humeral head bone loss. Using 3D reconstruction of the lesion, the surgeon devised a plan for bony resection and ideal osteochondral graft placement.

A standard deltopectoral approach was used to access the shoulder joint. The capsule was opened to expose the glenoid labrum, and inspection revealed posterior labral tearing at the 7 and 8 o’clock positions. After preparing the posteroinferior glenoid, the surgical team placed suture anchors to secure the labrum. The reverse Hill-Sachs lesion was then debrided to obtain a bleeding surface.

On the back table, the allograft was secured in the custom 3D-printed cutting guide with Kirschner wires. The team prepared it by removing soft tissue off the proximal humerus and then cut using a sagittal saw. The graft was transferred, pinned in place, and secured with two subchondral screws. Near anatomic graft fit was obtained. A posterior load shift maneuver confirmed a stable shoulder, and closure proceeded in a standard fashion. At 6 months, radiographs demonstrated no evidence of graft failure.

This video is a detailed and technically excellent demonstration of the intraoperative technique for open allograft reconstruction of the proximal humerus using a custom cutting guide. It assists viewers to identify a reverse Hill-Sachs lesion, comprehend the pathophysiology of shoulder instability, and understand how careful reconstruction of a bony defect restores arc of motion. The authors’ decision to use 3D printing includes benefits such as anatomic fit of the donor graft, improved workflow efficiency, and satisfactory clinical outcomes. Overall, this video will be of high educational value to both novice and expert orthopaedic surgeons.

Neil Jain, MD, is a postdoctoral orthopaedic surgery research fellow at St. Luke’s University Health Network in Bethlehem, Pennsylvania.

Michael DeRogatis, MD, MS, is an orthopaedic surgery resident at St. Luke’s University Health Network in Bethlehem, Pennsylvania.

Video details

Title: Open Allograft Reconstruction of the Proximal Humerus Using Custom 3D Printed Cutting Guide
Authors: Anthony Mitchell, MD; Matthew J. DiPaola, MD, FAAOS; Brian Richard Quaranto, MD; Paul Mercado, BS
Published: October 10, 2023
Time: 5:46
Tags: Shoulder and Elbow, Shoulder Instability, 3D Printed, Allograft

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