ObjectiveTo evaluate the effectiveness of posteromedial double plates in the treatment of complex olecranal fracture. MethodsBetween September 2011 and July 2015, 13 patients with complex olecranal fractures were treated with posterior olecranon locking compression plate and medial mini-plate. There were 8 males and 5 females with an average age of 41.6 years (range, 22-68 years). Injury was caused by traffic accident in 4 cases, falling from height in 6 cases, and crush by object in 3 cases. According to the Mayo classification, fracture was rated as Mayo type ⅡB in 5 cases and as Mayo type ⅢB in 8 cases. Of 13 cases, 7 had Regan-Morrey type Ⅲ coronoid fractures, including 5 anterior dislocations of the elbow joint and 2 posterior dislocations. The time between injury and admission ranged from 1.5 to 10.0 hours (mean, 5.7 hours). At last follow-up, the elbow function was assessed according to the Broberg-Morrey evaluation criteria. X-ray films was performed to observe fracture healing. ResultsAll incisions healed at first stage and no neural complications occurred. The patients were followed up 9-38 months (mean, 22.1 months). All patients achieved bone union at 3.0-5.5 months (mean, 3.7 months) according to X-ray results. Subluxation of radial head and mild heterotopic ossification occurred in 1 patient respectively, who had no uncomfortable symptoms of movement disorder, elbow instability and pain, and no special management was performed. At last follow-up, the flexion and extension range of motion (ROM) of the elbow was 95-130° (mean, 116.4°); the rotation ROM of the forearm was 150-175° (mean, 170.8°); and the elbow function was excellent in 4 cases, good in 7 cases, and fair in 2 cases, and the excellent and good rate was 84.6%. No internal fixation failure, elbow stiffness, or traumatic arthritis occurred. ConclusionFor complex olecranal fractures, an early and stable anatomic reconstruction of trochlear notch in the olecranon with posterior olecranon locking compression plate and medial mini-plate can obtain good effectiveness in joint functions.