Objective  To compare the effect of posterolateral plate and anterolateral locking plate in surgical treatment for extraarticular distal humeral shaft fractures.
  Methods  A retrospective casecontrol study was made on 52 patients with extra-articular distal humeral shaft fractures admitted in Tianjin Hospital from January 2014 to October 2016. There were 32 males and 20 females, with the age from 18 to 56 years ［(36.9±10.9)years］. According to the AO/OTA classification, there were 15 patients with type A, 32 type B, and 5 type C. Twentythree patients were treated with osterolateral locking plate (Group A) and 29 with anterolateral locking plate (Group B). Operation time, bone union time, range of motion of the elbow, Mayo elbow performance score and complication rate were evaluated.   Results  All patients were followed up for 12-20 months ［(13.7±2.2)months］. Operation time was (79.8±9.6)minutes in Group A and (85.0±11.6)minutes in Group B (P＞0.05). Bone union time was (4.1±1.0)months in Group A and (4.1±1.0)months in Group B (P＞0.05). Degrees of elbow extension was 3.9°(0.0°, 5.0°) in Group A, and 4.4°(0.0°, 5.0°) in Group B (P＞0.05). Degrees of elbow flexion was 127.4°(125.0°, 132.50°) in Group A and 128.5°(122.5°, 132.5°) in Group B (P＞0.05). Mayo elbow performance score was 91.0 (90.0, 93.5) points in Group A and 90.2(90.0, 92.5)points in Group B (P＞0.05). Radial nerve damage was noted after operation, showing no significant difference between two groups ［2 patients (9%) in Group A and 3 patients (10%) in Group B］(P＞0.05),  and the symptoms were recovered in all patients within 3 months.   Conclusions  Both the posterolateral and anterolateral locking plate are effective in surgical treatment for extra-articular distal humeral shaft fractures. However, the posterolateral plate can be placed closer to the distal end of the humerus and the multi-directional locking design is more stable, which has advantages for the patient with fracture line close to the elbow joint.