Abstract
Objectives: To perform a systematic review of the literature on unstable distal clavicle fractures in order to determine the preferable treatment method.
Data sources: A literature search for articles on keywords “distal clavicle fracture treatment” and “Lateral end fracture of the clavicle” written in English and published between January 1990 and August 2015 was reviewed from the PubMed database.
Study selection: The articles written in English and non-English articles with an English abstract were also included. A bibliographical review of the included articles was performed to find omitted studies. Studies dealing with non-union (pseudo-arthrosis) and arthroscopic methods were excluded. Open fractures, pediatric fractures, mid-shaft, medial clavicle fractures, and complicated cases were excluded. Non-English articles without an English abstract were excluded. Eighty-six articles representing 1812 surgeries were selected.
Data extraction: The manuscripts were classified in accordance with their level of evidence and surgery type. All manuscripts were closely examined with regard to functional scores (including Constant scores, UCLA and ASES scores), union rates and complication rates.
Data synthesis: The mean nonunion rate, complication rate, and mean functional scores were calculated for each treatment modality. The extracted data were accumulated and the mean rates were calculated to evaluate and compare different treatment modalities. The means of the groups were analyzed using analysis of variance (ANOVA) and the Bonferroni post hoc test. The pearson correlation coefficient was used to analyze whether a significant correlation exists between the parameters. Two-tailed hypothesis was considered in the analyses, and the significant differences were accepted if p value was .05 or less. SPSS 18.0 software for Windows (SPSS, Inc., Chicago, IL, USA) was used in the evaluation of statistical analyses.
Results
A total of ten types of treatment modalities was compared according to results of constant scores, union rates and complication rates. ANOVA test results showed significant differences between the groups with respect to union rate and complication rate (p=0.000 and p=0.000 respectively), while there were no statistically significant differences between the groups regarding to constant scores (p= 0.301). According to Bonferroni post hoc test the differences were caused by conservative treatment modalities in both union and complication rates.
Regarding Pearson correlation test; there were no statistically significant correlation between constant scores with other scores (p=0.551, r=0.069 and p= 0.147, r= -0.168 for union rate and complication rate respectively). However, there were statistically significant correlation between union and complication rates (p=0.000, r=-0.408).
Conclusions: There is no difference between the surgical treatment methods, the conservative treatment method was found to be statistically different (worse) than all other methods.
When the treatment modalities were arranged according to highest results of constant scores, union rates and the lowest scores of complication rates ; the distal clavicle anatomic plate (precontoured plate) with /without CC sling and CC-sling(alone ) were the most preferable modalities according to benefited result relation. Thus, these techniques might be preferable.
Keywords: Distal clavicle fracture, Lateral end clavicle fracture, Neer type II distal clavicle fracture, Unstable distal clavicle fracture.

Key words: distal clavicle fractures, Treatment modalities, unstable distal clavicle fractures, distal end clavicle fractures