An Anatomical Study on Canine Cadavers Investigating the Caudolateral Approach Involving the Elevation of the Anconeus Muscle and Splitting of the Triceps Brachii Muscle for the Potential Treatment of T-Y Humeral Fractures

Due to the complex anatomical structure of the distal humerus, elbow joint, and the soft tissue mantle (the triceps brachii muscle, large nerves, and vessels), fractures of the distal humerus and humeral condyle are difficult to treat. In most cases, strong instrumentation is needed to stabilize the fractures. To improve exposure of the distal humerus and humeral condyle, we proposed a caudolateral approach that involves elevating the anconeus muscle and splitting the triceps brachii. This study presents the results of using this approach in 16 canine cadavers. After exposing the distal humerus and maximally flexing the elbow joint, photographs were taken of the condyle from the same distance before and after olecranon osteotomy. The visible surface area of the articular cartilage was then calculated in square pixels after calibrating the photographs. It was possible to reach the distal and middle humerus in all cases. The only vital structure that could be easily identified and protected in all cadavers was the radial nerve. The visible area of the articular surface of the humeral condyle increased after olecranon osteotomy. The A₀ (visible area before osteotomy) was significantly smaller than the A₁ (visible area after osteotomy) in all dogs (<i>p</i> < 0.001). The ratio of A₀ to A₁ ranged from 57% to 67% in 15 dogs (median: 64%, interquartile range (IQR): 61-66%), with a very high value of 85% observed in one dog. This experiment used cadavers with intact elbows. This could limit the study's findings because the effectiveness of the proposed access in reducing T-Y fractures was not assessed. The caudolateral approach is a valuable alternative to other methods for treating T-Y humeral fractures in dogs. Olecranon osteotomy widens access to the condyle. Further studies are needed to evaluate the necessity of olecranon osteotomy in clinical cases.