[Clinical application of dynamic locking screw in treating humeral shaft fracture].

Objective: To compare clinical effect of dynamic locking screws and common screws in treating humeral shaft fractures.

Methods: From January 2016 to October 2018, clinical data of 46 patients with humeral shaft fracture were retrospectively analyzed, which were divided into dynamic locking screw internal fixation group (treatment group) and ordinary screw internal fixation group (control group). In treatment group, there were 14 males and 10 females, aged from 20 to 61 years old with an average of (36.8±10.9) years old;22 patients in control group, there were 13 males and 9 females, aged from 19 to 60 years old with an average of (35.9±12.8) years old. Length of incision, operation time, amount of bleeding, fracture healing time and complications were compared between two groups, Constant-Murley score of shoulder joint and Mayo score of elbow joint at 3 and 9 months after operation were compared to evaluate clinical effect.

Results: Forty six patients were followed up from 9 to 43 months with an average of (18.6±7.9) months. There were no statistical differences in length of incision, operation time, amount of bleeding between two groups (>0.05);fracture healing time in treatment group was (12.2±3.2) weeks, and (15.6±4.7) weeks in control group;there was difference between two groups (<0.05). Constant-Murley score and Mayo score of elbow joint at 3 months after operation in treatment group were 84.9±5.9 and 81.8±6.7, while in control group were 74.6±9.2 and 71.5±10.7;there were differences between two groups (<0.05). There were no statistical differences in Constant-Murley score and Mayo score of elbow joint between two groups at 9 months after operation (>0.05);One patient occurred neural paralysis in treatment group;1 patient occurred delayedunion, 2 patients occurred bone nonunion and 1 patient occurred broken nail in control group;while there was no statistical difference between two groups in complication.

Conclusion: Both of dynamic locking screws and ordinary screws could effectively treat humeral shaft fractures. dynamic locking screws has an advantage in fracture healing time, and recovery of early shoulder and elbow function. However, the active time of this technology is not too long in China, further study on long-term efficacy of large samples is needed.