Which part of the glenoid cavity is most susceptible to osteoarthritis?

Anatomical Susceptibility of the Glenoid Cavity to Osteoarthritis

The anteroinferior portion of the glenoid cavity is most susceptible to osteoarthritis development in the shoulder joint. Based on the available research evidence, this area experiences the highest rates of cartilage defects and degenerative changes.

Patterns of Glenoid Wear in Osteoarthritis

• Glenoid wear in osteoarthritis commonly presents with eccentric deformation in both anteroposterior and superoinferior directions 1
• The anteroinferior region (approximately the 3 o'clock position) is particularly vulnerable to cartilage defects, which can progress to osteoarthritis 2
• Morphological studies have demonstrated that cartilage defects in the glenoid are typically located directly anteriorly at the 3:07 clockface position (range 2:10-4:05) 2

Types of Glenoid Deformity in Osteoarthritis

Glenoid deformity in osteoarthritis can be classified into several patterns:

• Type-0: Lines at the base of the coracoid process and glenoid rim run parallel 1
• Type-1: Lines intersect below the inferior glenoid rim 1
• Type-2: Lines intersect between the inferior glenoid rim and glenoid center 1
• Type-3: Lines intersect above the base of the coracoid process 1

Biomechanical Factors Contributing to Glenoid Wear

• Eccentric inferior glenoid wear is frequent in osteoarthritis and occurs independently from retroversion deformity 1
• Approximately 47% of osteoarthritis patients show combined posterior and inferior glenoid wear patterns 1
• These wear patterns alter biomechanics and can accelerate the progression of osteoarthritis 3

Clinical Implications

• Understanding the pattern of glenoid wear is critical for surgical planning in shoulder arthroplasty 3
• Glenoid morphology directly impacts the choice of prosthetic components and surgical techniques 4
• Normalization of glenoid version in both transverse and coronal planes may reduce eccentric loading of prosthetic components, potentially reducing loosening 1

Molecular Basis of Glenoid Cartilage Degeneration

• Osteoarthritic glenoid cartilage shows an inflammatory and catabolic phenotype compared to the anabolic phenotype seen in shoulders with instability 5
• Several genes (CCL3, CHST11, GPR22, PRKAR2B, and PTGS2) show elevated expression in osteoarthritic glenoid cartilage 5
• These molecular changes may provide insight into the progression from shoulder instability to degenerative arthritis 5

Imaging Considerations

• Pre-operative imaging is essential to characterize glenoid morphology before shoulder arthroplasty 3
• Assessment should include evaluation of central bone loss, posterior bone loss, retroversion, biconcavity, inclination, osteophyte formation, and bone quality 3
• These imaging findings directly influence surgical decision-making and technique selection 6

Understanding the preferential involvement of the anteroinferior glenoid in osteoarthritis has important implications for both conservative management and surgical planning, particularly when considering shoulder arthroplasty options for advanced disease.