Objective evaluation of lengthening in reverse shoulder arthroplasty

Area of Science:

• Orthopedic surgery
• Radiographic imaging
• Biomechanical analysis

Background:

• Reverse shoulder arthroplasty (RSA) necessitates precise deltoid re-tensioning for functional outcomes.
• Current methods lack objective preoperative planning and postoperative evaluation for deltoid tension and arm lengthening in RSA.
• Complications in RSA may stem from inadequate deltoid lengthening or tensioning.

Purpose of the Study:

• To introduce a standardized radiographic technique for measuring deltoid length.
• To enable preoperative planning of RSA based on objective deltoid length measurements.
• To investigate the correlation between complications and inadequate deltoid lengthening in RSA.

Main Methods:

• Radiographic review of 58 patients undergoing RSA.
• Evaluation of humeral length, arm length, and subacromial space height pre- and post-surgery.
• Comparison of operated and contralateral arms for radiographic measurements.

Main Results:

• Significant arm lengthening (23 mm) was observed post-RSA, with no significant change in humeral length.
• Statistically significant differences in subacromial space height between operated and contralateral arms.
• Lower humeral and overall arm lengthening correlated with postoperative instability (P < .0001).

Conclusions:

• A novel radiographic technique for preoperative deltoid tension planning using contralateral arm measurements is presented.
• This technique is crucial for managing complex RSA cases and assessing deltoid length postoperatively.
• Objective radiographic measures should supersede subjective intraoperative assessments for deltoid tensioning in RSA.