Evaluating Bone Loss in Anterior Shoulder Instability

Eric C. Makhni, MD, MBA; Joseph S. Tramer, MD; Matthew J.J. Anderson, MD; William N. Levine, MD

Disclosures

J Am Acad Orthop Surg. 2022;30(12):563-572. 

In This Article

Abstract and Introduction

Abstract

Anterior shoulder instability is a common orthopaedic condition that often involves damage to the bony architecture of the glenohumeral joint in addition to the capsulolabral complex. Patients with recurrent shoulder dislocations are at increased risk for glenohumeral bone loss, as each instability event leads to the accumulation of additional glenoid and/or humeral head bone defects. Depending on the degree of bone loss, successful treatment may need to address bony lesions in addition to injured soft-tissue structures. As such, a thorough understanding of methods for evaluating bone loss preoperatively, in terms of location, size, and significance, is essential. Although numerous imaging modalities can be used, three-dimensional imaging has proven particularly useful and is now an integral component of preoperative planning.

Introduction

Glenohumeral joint stability results from a complex interplay between dynamic and static restraints that function synergistically to keep the humeral head centered within the glenoid. Both soft-tissue and bony structures are critical in maintaining a concentric joint and preventing subluxation or dislocation. Traumatic anterior instability events involve disruption of the capsulolabral complex but can also lead to damage of the bony architecture of the glenoid and humerus. Bone loss after dislocation is common, with up to 90% of patients demonstrating either a glenoid or a humeral head defect during arthroscopic evaluation for recurrent instability.[1] Even first-time traumatic subluxation events have been associated with high rates of Hill-Sachs lesions (HSLs) and osseous Bankart lesions on MRI.[2]

Successful surgical treatment of shoulder instability often requires the surgeon to consider both bony defects of the glenohumeral joint and damage to the capsulolabral complex. Failure to address significant bone loss may lead to recurrent instability, despite robust soft-tissue repairs.[3–5] Recurrent instability after arthroscopic soft-tissue procedures can be as high as 17.8% among contact athletes, and there is currently no consensus regarding the amount of bone loss beyond which a soft-tissue repair cannot reliably restore stability.[3] Accordingly, accurate characterization of glenoid and humeral bone loss, in terms of location, size, and significance, is an important component of preoperative planning and essential to minimizing the risk of recurrent dislocation.

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