Investigating Optimal Osteotomy Angles for Kienböck and Preiser Disease Using Finite Element Analysis: Stress Changes in the Lunate and Scaphoid Bones Associated With Closing Radial Wedge Osteotomy.

Abstract

Purpose: To evaluate the biomechanical effects of varying closing radial wedge osteotomy (CRWO) angles on the scaphoid and lunate using finite element analysis (FEA) and to identify the optimal osteotomy angle for treating Kienböck and Preiser diseases.

Methods: Eight fresh-frozen cadaveric upper extremities (5 men, 3 women; mean age, 89.4 years) were analyzed. Specimen-specific computed tomography-based FEA models were developed to simulate carpal alignment changes in neutral and ulnar-deviated wrist positions with simulated CRWO angles of 5°, 10°, 15°, and 20°. A physiological load of 102 N was applied to the metacarpal heads. Stress distribution was analyzed across 3 scaphoid regions (proximal, body, distal) and 2 lunate regions (radial, ulnar). Changes in equivalent stress and minimum principal stress were compared with pre-osteotomy levels.

Results: A 20° osteotomy resulted in a reduction of minimum principal stress in the lunate (-29.9%) and a decrease in the scaphoid (-9.2%). With increasing osteotomy angles, stress distribution changed with measured stress values shifting in the proximal regions of the scaphoid and radial potion of the lunate. The triquetrum exhibited varying responses, with stress measurements showing changes from +8.6% to -9.1% at lower osteotomy angles (5° to 10°) and reductions at higher angles (15° to 20°).

Conclusions: FEA-based analysis showed stress reductions in the lunate at osteotomy angles between 10° and 20°, with measurements indicating that a 20° angle resulted in the greatest measured stress reduction in both the lunate and scaphoid.

Clinical relevance: This study provides biomechanical evidence supporting CRWO for Kienböck and Preiser diseases and offers guidance on selecting osteotomy angles for improved clinical outcomes.