[Shoulder joint instability after primary arthroplasty]

Area of Science:

• Orthopedic Surgery
• Biomechanical Engineering

Background:

• Shoulder instability, encompassing subluxation and dislocation, is a frequent complication following shoulder arthroplasty.
• Instability can manifest in various directions (anterior, posterior, inferior, cranial) due to imbalances in muscular forces, capsular stabilizers, and bony anatomy.
• Pre-existing conditions like posterior glenoid wear in osteoarthritis can predispose to early subluxation.

Purpose of the Study:

• To investigate the incidence and characteristics of instability as a complication in shoulder revision surgeries.
• To evaluate the outcomes of revision shoulder arthroplasty compared to primary procedures, specifically concerning instability.

Main Methods:

• Analysis of 44 shoulder revision surgeries to identify the most common complications.
• Assessment of patient outcomes using the Constant Score (average 41.9).

Main Results:

• Instability was identified as the most frequent complication in the studied cohort of shoulder revision surgeries.
• Revision surgery outcomes, as indicated by the Constant Score, suggest that excellent results seen in primary arthroplasties are not typically achieved.
• Both anterior and posterior instability were observed, in addition to late cranialization of the rotator cuff-deficient shoulder.

Conclusions:

• Instability is a significant complication in shoulder revision surgery.
• Revision shoulder arthroplasty yields lower functional outcomes compared to primary procedures.
• Comprehensive assessment and management of various instability types are crucial in revision shoulder arthroplasty.