To explore the operative effect and treatment strategies for the low distal humerus fracture.

A retrospective analysis was conducted on the clinical data of 16 patients with the low distal humerus fracture between January 2016 and January 2018 at Department of Orthopaedics, Shanghai Tongji Hospital Affiliated to Tongji University.All fractures were coronal fractures of humeral head, partly combined fractures of humeral trochlea or posterior part. Fractures were classified according to Dubberley classification as 9 cases in type Ⅰ, 3 cases in typeⅡ and 4 cases in type Ⅲ.Selection of the kind of operative approach and internal fixation was made according to the fracture type and shape. For simple coronal fractures of humeral head or combining humeral trochlea fractures, which were relatively stable, single or multiple countersunk screws fixation by the lateral approach were chosen.For humeral head coronal fractures, which combining obviously displaced comminuted humeral trochlea factures, posterolateral locking plates and countersunk screws internal fixation by the olecranon osteotomy approach were chosen. The incision and elbow soft tissues were observed within 2 weeks after operation.The radiographic evaluation of fracture reduction, bone healing, internal fixation, arthritis and elbow range of motion were made at 3, 6, 12 months after operation. The Mayo elbow functional scores were documented for analysis of elbow joint function, and compared between different surgery groups by Kruskal-Wallis H test.

The follow-up time was (22.1±9.2)months(range: 15 to 39 months). The incisions healed well in 2 weeks after operation without soft tissue infection, necrosis or vascular complications. There was no fracture reduction loss or internal fixation loosening according to radiographic evaluation 3 months after operation. One case of ectopic ossification was observed 6 months after operation and inhibited by the treatment of non steroidal anti-inflammatory drugs.One case of ulnar neuritis occurred after operation and released after removing the long screw and loosing the ulnar.Osteoarthritis images were observed at the end of follow-up.Arc of motion was (120.4±11.2) ° in flexion and (5.5±1.9) ° in extension. The Mayo score was 88.7±9.1, including 11 excellent, 4 good, and 1 fair.The Mayo score was 90.1±3.7 in Dubberley classification type Ⅰcases, 89.7±4.6 in type Ⅱ cases and 84.5±5.8 in type Ⅲ cases. There were no significant differences in Mayo scores between 3 types cases according to Kruskal-Wallis H test.

Choosing the appropriate surgical approach and composite internal fixation according to the fracture types and shapes of low distal humerus fracture, anatomic reduction of the articular surface and early functional exercise are the keys to obtain ideal curative effect.

Humeral fractures; Ulnar olecranon; Internal fixators; Coronal; Distal end of the humerus