Assessing proximal humerus cortical bone thickness for total shoulder arthroplasty: A cadaveric study

Area of Science:

• Orthopedic Surgery
• Biomechanical Engineering
• Anatomy

Background:

• Reverse total shoulder arthroplasty (RTSA) relies on humeral osteotomy at the anatomic neck.
• Bone quality (cancellous and cortical) is critical for accurate implant sizing in RTSA.
• Limited data exists on proximal humerus bone quality transition zones.

Purpose of the Study:

• To measure and analyze proximal humerus bone quality transition zones.
• To understand implications for implant sizing in RTSA.
• To assess bone quality using a novel indentation depth probe.

Main Methods:

• Utilized an indentation depth probe on 45 cadavers post-humeral osteotomy.
• Measured cortical rim thickness in superior, inferior, anterior, and posterior quadrants.
• Analyzed relationships between location, age, sex, osteoporosis, cancer, and cortical thickness.

Main Results:

• Cortical bone thickness was not significantly affected by sex, osteoporosis, or cancer.
• Age impacted only the posterior cortical bone thickness (p=0.04).
• Significant differences found between inferior-anterior (p=0.003) and inferior-posterior (p=0.001) cortical thickness.

Conclusions:

• Cortical bone thickness exhibits variability across different aspects of the proximal humerus.
• Age is a significant factor influencing posterior cortical bone thickness.
• A single assessment point may be insufficient for characterizing bone quality in RTSA.