Which device has a neck shaft angle range of 135-155 degrees?

Which device has a neck shaft angle range of 135-155 degrees?

• A. Univers II and Apex Cups
• B. RCR implants
• C. CA Humeral Head
• D. RTSA components

Answer: (A)

Understanding neck shaft angle range helps explain how the humeral component is oriented relative to the shaft to restore proper shoulder biomechanics. The neck shaft angle is the angle between the humeral shaft axis and the neck/head axis, and it influences head position, deltoid tension, offset, and overall range of motion. Having a range that spans 135 to 155 degrees gives surgeons flexibility to match a patient’s anatomy and achieve optimal soft-tissue tension and joint mechanics. This broad range can improve alignment, ROM, and stability while aiming to minimize impingement. The Univers II and Apex Cups are designed to accommodate this 135–155 degree range, so they offer the necessary geometric versatility. Other devices either have a fixed angle or are not configured to support this broad range, making them less suitable for achieving that specific neck-shaft orientation.

Understanding neck shaft angle range helps explain how the humeral component is oriented relative to the shaft to restore proper shoulder biomechanics. The neck shaft angle is the angle between the humeral shaft axis and the neck/head axis, and it influences head position, deltoid tension, offset, and overall range of motion.

Having a range that spans 135 to 155 degrees gives surgeons flexibility to match a patient’s anatomy and achieve optimal soft-tissue tension and joint mechanics. This broad range can improve alignment, ROM, and stability while aiming to minimize impingement.

The Univers II and Apex Cups are designed to accommodate this 135–155 degree range, so they offer the necessary geometric versatility. Other devices either have a fixed angle or are not configured to support this broad range, making them less suitable for achieving that specific neck-shaft orientation.