Abstract:

Objective To investigate the epidemiological and forensic characteristics of rotator cuff injuries caused by road traffic accidents, and to explore the timing and influencing factors of disability assessment of rotator cuff injuries. Methods A retrospective analysis was conducted on 173 cases of rotator cuff injury caused by road traffic accidents. Factors analyzed included the time of post-injury assessment, the degree of functional loss of shoulder joint movement in six directions, the treatment methods, the presence or absence of combined shoulder injuries and the type of combined shoulder injuries, and the type of rotator cuff injury. The Kruskal-Wallis test and Wilcoxon rank sum test were used to analyze the differences in functional loss among the six directions of shoulder joint movement. The t-test was used to compare the differences in functional loss between the conservative treatment and the surgical treatment, as well as between cases with and without combined shoulder injuries. One-way analysis of variance （ANOVA） and Student-Newman-Keuls （SNK） test were used to analyze the differences in functional loss of shoulder joint movement among the injury types of contusion, mild tear, moderate tear and severe tear. One-way ANOVA and least significant difference （LSD） test were used to analyze the differences according to the number of involved rotator cuff tendons （1, 2, 3, or 4 tendons） and post-injury assessment time （3-<6 months, 6-<9 months, 9-<12 months, and ≥12 months）. Results The median assessment time after injury was 290.00 days. Among the six directions of shoulder joint movement, statistically significant differences in the degree of functional loss were observed between abduction up, extension back and external rotation compared with adduction, as well as between external rotation and forward flexion up （P<0.05）. There was no statistically significant difference in the degree of functional loss between conservative treatment and surgical treatment, or among different post-injury assessment times （P>0.05）. However, there were significant differences between the non-combined shoulder injury and combined shoulder injury, different types of rotator cuff injuries, and the different numbers of involved rotator cuff tendons （P<0.05）. Treatment methods had no significant effect on the degree of functional loss of shoulder joint movement, whereas combined shoulder injuries, more severe rotator cuff injuries, and involvement of a greater number of rotator cuff tendons were associated with more severe functional loss of shoulder joint movement. Conclusion Rotator cuff injuries caused by road traffic accidents exhibit the epidemiological and forensic characteristics including delayed diagnosis after injury, prolonged post-injury assessment time, and the rotator cuff injuries being mainly mild to moderate tears （≤3 cm） and involving 1 or 2 tendons. Combined shoulder injuries are mostly characterized by greater tuberosity fractures of the humerus, long head of the biceps tendon injuries and shoulder dislocations. The recommended timing for disability assessment in cases involving rotator cuff tears and/or surgical treatment should be appropriately extended. The presence or absence of combined shoulder injuries, the types of rotator cuff injury, and the number of involved rotator cuff tendons should be emphasized in forensic clinical identification.

Key words: forensic medicine, wounds and injuries, rotator cuff injury, degree of functional loss, disability assessment, influencing factor