Objective To compare the clinical efficacy of external fixator and locking plate internal fixation via middle volar minimally invasive approach in the treatment of distal radius fractures.Methods A retrospective case-control study was conducted on the clinical data of 51 patients with distal radius fractures admitted from October 2014 to August 2016.There were 21 males and 30 females,aged 41-78 years (mean,57 years).According to the random number table method,the patients were divided into minimally invasive plate group (25 cases) which adopted locking plate internal fixation via middle volar minimally invasive approach and external fixator group (26 cases) with closed reduction of external fixator.The AO classification of the fractures in minimally invasive plate group was as follows:A2 in four cases,A3 in five cases,B1 in four cases,B2 in two cases,B3 in seven cases,and C1 in three cases.The AO classification of the fractures in external fixator group was as follows:A2 in three cases,A3 in six cases,B1 in five cases,B2 in three cases,B3 in seven cases,and C1 in two cases.The total incision length,operation time,intraoperative blood loss,preoperative and postoperative radial height,palmar inclination angle,ulnar deviation angle,pain visual analogue score (VAS),wrist active motion range (palmar flexion,dorsal extension,pronation,supination,radial deviation,and ulnar deviation),relative contralateral grip force,and wrist function Mayo score were compared between the two groups.Results There were no significant differences in the total length of incision,operation time,intraoperative blood loss,VAS 3 d after operation,radius height,ulnar deviation,and radius height,palm inclination and ulnar deviation at 14 months after operation between the two groups (P ＞ 0.05).The palmar inclination was (9.6-± 0.6) ° in the minimally invasive plate group and (7.9 ± 0.6) ° in the external fixator group (P ＜ 0.05).The wrist active motion range (palmar flexion,dorsal extension,pronation,supination,radial deviation,and ulnar deviation) and relative contralateral grip strength 3 months after operation in the minimally invasive plate group were significantly better than those in the external fixator group (P ＜ 0.05).However,the Mayo score of wrist function at 14 months after operation was (88.7 ± 12.7)points in the minimally invasive plate group and (88.7 ± 13.1)points in the external fixator group (P ＞ 0.05).Minimally invasive plate group showed median nerve stimulation in one case.External fixator group showed redness around the nail,increased temperature,and increase secretion of the infection in one case,and joint stiffness in one case after external fixation removal.But all symptoms were improved or resolved after treatment.Conclusion Both locking plate via minimally invasive approach and external fixator can achieve good results in the treatment of distal radius fractures,but the former method has better effects on early functional recovery than the latter one.