Scapular notching in reverse shoulder arthroplasty: is it important to avoid it and how?

Area of Science:

• Orthopedic surgery
• Radiology
• Biomedical engineering

Background:

• Scapular notching is a radiographic finding specific to reverse shoulder arthroplasty (RSA), characterized by erosion of the scapular neck.
• The clinical and radiological significance of scapular notching remains incompletely understood.

Purpose of the Study:

• To determine the incidence and natural history of scapular notching after RSA.
• To assess the relationship between notching and functional outcomes, radiographic signs of failure, and factors influencing its development.

Main Methods:

• Retrospective review of 448 patients (461 shoulders) who underwent Grammont-type RSA.
• Clinical assessment included Constant-Murley scores and range of motion; radiographic assessment evaluated notching, humeral, and glenoid radiolucent lines.

Main Results:

• Scapular notching occurred in 68% of cases, appearing early with variable progression.
• Notching correlated with follow-up duration, patient strength, shoulder elevation, and the presence of humeral and glenoid radiolucent lines.
• Preoperative superior glenoid erosion was associated with a higher incidence of notching.

Conclusions:

• Scapular notching is a frequent complication of RSA that generally progresses.
• Notching is associated with deterioration in clinical parameters and increased radiolucent lines, suggesting potential implant loosening or failure.
• Preoperative glenoid erosion patterns are critical, influencing surgical technique and implant positioning to mitigate notching risk.