The Univers II and Apex TSA stems share which range of inclination variability?

• A. 110-125 inclination variability
• B. 140-160 inclination variability
• C. 90-110 inclination variability
• D. 125-140 inclination variability

Answer: (D)

Inclination variability here refers to how much the neck-shaft angle of the humeral stem can vary to fit a patient’s anatomy while maintaining proper biomechanics in a total shoulder arthroplasty. The Univers II and Apex TSA stems are designed with a similar neck-shaft geometry, allowing a range of adjustment that centers around the typical anatomic orientation. Specifically, they share a neck-shaft inclination range of about 125 to 140 degrees. This range lets the surgeon restore appropriate humeral head height and offset, maintain rotator cuff tension, and minimize impingement or abnormal loading. Straying outside this window can lead to malalignment, altered soft-tissue tension, and suboptimal function.