At what angle was the humeral head resected during the shoulder arthroplasty?

• A. 30 degrees
• B. 60 degrees
• C. 15 degrees
• D. 45 degrees of retroversion

Answer: (D)

Retroversion is how much the humeral head is rotated backward relative to the humeral shaft, and getting this angle right is crucial for a smooth, balanced shoulder prosthesis. In shoulder arthroplasty, recreating the natural twist of the humeral head helps the prosthetic ball articulate well with the glenoid and allows the soft tissues to function without excessive impingement or looseness. A common target is about 45 degrees of retroversion. This position supports good external rotation and joint stability, while avoiding posterior impingement or instability that can occur if the head is resected with too little or too much retroversion.