The elbow anatomy is complex, and the peripheral nerve, blood vessel and ligament components are dense, which makes the surgical exposure of complex elbow injuries technically demanding. At present, there are mainly posterior approaches (i.e., olecranon osteotomy, triceps cleft, triceps flap flip, para-triceps approach) , medial and lateral approaches, lateral or anterolateral approaches, etc. These approaches have specific applications and advantages, but for the distal humerus surrounded by olecranon, In particular, Dubberley classification type 2A and 3A fracture lines of the distal humerus coronal fractures extend to the posterior coronal process and Dubberley type B fractures. The distal fracture is usually at the lowest point or even posterior of the articular surface, completely covered by the olecranon of the ulna. It is difficult to expose the distal fracture lines of the articular surface through the lateral or anterolateral approach. The posterior approach does not fully expose the anterior aspect, such as the radial head fossa or coronal fossa, making intraoperative fracture reduction and fixation very difficult. Hoyt et al. conducted cadaver studies and found that 95.9% of the anterior surface and 100% of the small head could be exposed by the lateral approach of elbow dislocation and reduction.

To investigate the method and clinical effect of reduction and fixation of lateral elbow dislocation in the treatment of coronal fracture of distal humerus.

From January 2019 to October 2021, 12 patients with distal humerus coronal fracture were treated by lateral incision dislocation approach reduction and internal fixation in our hospital. There were 4 males and 8 females, aged 23-80 years, with an average age of (51.67±4.90) years. The causes of injury included 6 cases of falling, 1 case of traffic injury, 2 cases of sports injury, and 3 cases of falling from height. According to Dubberley classification, there were 2 cases of type 2A, 3 cases of type 2B, 3 cases of type 3A, and 4 cases of type 3B. There were 10 cases with lateral condyle fracture. During the operation, the articular surface bone mass was reduced under direct vision, and the internal fixation was performed without head nails. If necessary, the posterior anatomical plate or hinge outer frame was attached. Antibiotics were used once before and after operation. Active functional exercise was started 3 days after operation, and the external fixator was removed after 6 weeks. The extent of intraoperative exposure, fracture reduction, articular surface smoothness (separation or step <2 mm is better) , brachial-ulnar joint matching, screw cutting, and Mayo elbow performance score (MEPS) at 3 months after operation were recorded as well as the excellent and good rate, heterotopic ossification and joint degeneration.

The average follow-up time was 7.9 months (ranging from 3 to 16 months) . The distal humeral articular surface was completely exposed in all cases. Postoperative three-dimensional CT confirmed that all patients had good articular surface reduction, separation or step <2 mm. Cut without screws. One patient developed ulnar nerve traction symptom after operation and recovered after 3 weeks. No serious complications such as vascular injury occurred in all patients. At the last follow-up, no necrosis of the humeral head was found, and 2 cases had joint degeneration and heterotopic ossification. The MEPS score was (90.0±1.38) points, of which 9 cases were excellent, 3 cases were good, and the excellent and good rate was 100%.

Lateral elbow dislocation approach can fully expose the articular surface of the distal humerus, anatomical reduction and accurate fixation under direct vision, without affecting the stability of the elbow joint, and has a good prognosis, which is worthy of promotion.