Comparison of the Visible Articular Surface between the Lateral Para-Olecranon Approach and Two Other Common Posterior Approaches for Distal Humeral Fracture: an Anatomical Study

Abstract

Purpose: To quantify the visible area of the articular surface of the distal humerus exposed by the lateral para-olecranon (LPO) approach and to compare this with the bilaterotricipital (BT) and olecranon osteotomy (OO) approaches. Methods: We examined 12 elbows from 6 fresh cadavers (mean age, 93.5 years; range, 90–99 years; 3 men and 3 women). Elbows on one side of the cadavers underwent the LPO approach. The opposite elbows underwent the BT approach followed by the OO approach. Macroscopically observable articular cartilage was coated with synthetic silicone resin paint under direct vision. The dissected bone was fixed on the table and photographs of the distal humerus were taken from anteriorly and posteriorly. The color-coded areas projected on 2 planes were quantified using digital photography and computer analysis software. Results: Proportions of the total visible area, summation of the anterior and posterior visible articular areas, were 25.3% ± 2.2% for the BT procedure, 46.4% ± 8.4% for the LPO procedure, and 58.5% ± 5.7% for the OO procedure, showing significant differences among the 3 procedures. The LPO procedure achieves better exposure of the posterior articular surface than the BT procedure, but the LPO procedure had limitations in the anterior visible area compared with the OO procedure. In particular, direct vision of the humeral trochlea was restricted by the presence of the olecranon. Conclusions: The LPO approach has improved visualization of the distal humeral articular surface compared with the BT approach but not as good as that achieved with the OO approach. Clinical relevance: The LPO approach is applicable to cases of AO type C1 and C2 distal humeral fractures and some cases of type C3 fracture, excluding those accompanied by complex fractures in the trochlea of the humerus. It is important to evaluate the fracture line of the humeral trochlea in preoperative computed tomography to determine whether to use the LPO or OO approach for AO type C3 fracture. Key words: distal humeral fracture, olecranon osteotomy, posterior approach for elbow