Objective:To compare anatomical locking plate fixation with versus without reconstruction of the coracoclavicular ligament in the treatment of acute and old Neer Ⅱb unstable distal clavicle fractures.Methods:From January 2015 to November 2020, 80 Neer Ⅱb distal clavicle fractures were treated at Department of Orthopaedics, The First Hospital Affiliated to China Pharmaceutical University. There were 49 males and 31 females, aged from 32 to 78 years (average, 47.8 years). Of the 50 fresh fractures, 25 were treated by internal fixation with anatomical locking plate of distal clavicle plus reconstruction of the coracoclavicular ligament with suture anchor (reconstruction group A) while the other 25 by only internal fixation with anatomical locking plate of distal clavicle (non-reconstruction group A). Of the 30 old fractures which had not got united over 3 weeks after injury, 15 were treated by internal fixation with anatomical locking plate of distal clavicle plus reconstruction of the coracoclavicular ligament with suture anchor (reconstruction group B) while the other 15 by only internal fixation with anatomical locking plate of distal clavicle (non-reconstruction group B). At 1, 3 and 6 months postoperatively, Constant-Murley scale and visual analogue scale (VAS) were used to evaluate shoulder function and pain. X-ray follow-ups were conducted to measure the coracoclavicular distance and observe fracture union and complications at the last follow-up.Results:All the 80 patients were followed up for 6 to 24 months (average, 13.8 months). For reconstruction group A and non-reconstruction group A, respectively, the union time for fresh fractures was (11.7±2.8) weeks versus (13.4±1.3) weeks, the rate of coracoclavicular distance increase 12.7%±6.2% versus 14.2%±8.0%, the Constant-Murley score 92.2±4.4 versus 90.9±5.7, showing no statistically significant difference between the 2 groups (all P>0.05). For reconstruction group B and non-reconstruction group B, respectively, the union time for old fractures was (12.8±1.9) weeks versus (19.4±6.7) weeks, the rate of coracoclavicular distance increase 12.3%±6.7% versus 21.5%±13.1%, the Constant-Murley score 93.0±5.9 versus 83.5±8.5, showing statistically significant differences between the 2 groups (all P<0.05). Conclusions:For fresh Neer Ⅱb distal clavicle fractures, simple anatomical locking plate fixation can achieve satisfactory curative efficacy without additional reconstruction of the coracoclavicular ligament. However, for old Neer IIb distal clavicle fractures, additional reconstruction of the coracoclavicular ligament can better maintain the stability of the acromioclavicular joint, reduce the risk of internal fixation failure, and achieve better outcomes.