# CT-Based Finite-Element Analysis of the Optimal Olecranon Osteotomy Angle for Tension Band Wiring

## TL;DR

This study finds that a 20° distal angle during olecranon osteotomy provides the best compression for bone healing when using tension band wiring.

## Contribution

The study identifies the optimal osteotomy angle for maximizing interfragmentary compression in tension band wiring fixation.

## Key findings

- A 20° distal angle produced the highest contact pressure (317 kPa) across the osteotomy surface.
- The articular-side pressure was also highest at the 20° distal angle (206 kPa).
- More distal angles increased the ratio of articular-side to total pressure, reaching 80% at 40° distal.

## Abstract

Background: Olecranon osteotomy is commonly used for surgical exposure in distal humeral fractures, with subsequent fixation typically performed using tension band wiring (TBW). However, the optimal osteotomy angle for maximizing interfragmentary compression remains unclear.

Methods: Using finite-element analysis of a 30-year-old male's elbow CT data, we analyzed seven osteotomy angles relative to the ulnar axis: 20° proximal (P20), 10° proximal (P10), vertical (V), 10° distal (D10), 20° distal (D20), 30° distal (D30), and 40° distal (D40). Wire tightening force (30N) and triceps traction force (100 N) were applied sequentially. Contact pressure was measured across the entire osteotomy surface and the articular half.

Results: The 20° distal angle (D20) produced maximum contact pressure (317 kPa) across the entire osteotomy surface compared to other angles (P20: 237 kPa, P10: 295 kPa, V: 276 kPa, D10: 259 kPa, D30: 171 kPa, D40: 130 kPa). Articular-side pressure was also highest at D20 (206 kPa). The ratio of articular-side to total pressure increased progressively with more distal angles, from 23% (P20) to 80% (D40).

Conclusions: A 20° distal osteotomy angle provides optimal biomechanical conditions for TBW fixation, maximizing interfragmentary compression essential for bone healing. This finding may guide surgical technique selection to improve clinical outcomes.