Differentiation of anteroposterior pelvic compression type I and II injuries and severity evaluation

Abstract

Objective To investigate the reliability of using the pubic symphysis diastasis of 25 mm and anterior separation distance of sacroiliac joint to differentiate anteroposterior compression (APC) type I and II injuries as well as assess the injury severity. Methods A total of 11 (seven males and four females) fresh cadaver specimens with 22 hemipelvis were collected. The pelvic APC injury test models including fixed hemipelvis (restricted group) and unfixed hemipelvis (non-restricted group) were established, with 11 hemipelvis in each group according to the random number table method. Meanwhile the specimens were divided into male group (14 hemipelvis) and female group (eight hemipelvis), simulating APC type injury external rotation hemipelvis. The public symophysis interval and anterior interval of sacroiliac joint of the original pelvis, the pubic symphysis diastasis and anterior diastasis of sacroiliac joint after anterior tibiofibular ligament failure, as well as the affected pelvis ligament and sacral ligament injury were recorded and compared between the restricted and non-restricted groups, male and female groups. Results There were no significant differences in the public symphysis interval of the original pelvis and anterior interval of sacroiliac joint between the restricted group and the non-restricted group (P>0.05). The pubic symphysis interval of the original pelvis was [(5.13±0.61)mm] in male group and (4.03±0.84)mm] in female group (P 0.05). In terms of anterior interval of sacroiliac joint, there was significant difference between male and female groups (P 0.05). In the restricted group, sacrotuberous ligament injuries were found in four patients, and sacrospinous ligament injuries in five, whhile there were no obvious sacrospinous ligament and sacrotuberous ligament injuries in non-restricted group. There were 10 specimens with the pubic symphysis diastasis ≥23.36 mm and 10 specimens with the diastasis distance of anterior sacroiliac joint ≥9.82 mm (46%), and there were 15 specimens with at least the pubic symphysis interval ≥23.36 mm or the anterior interval of sacroiliac joint ≥9.82 mm (68%). Conclusions The public symphysis interval ≥ 23.36 mm or anterior interval of sacroiliac joint ≥ 9.82 mm can distinguish anteroposterior compression I from II injuries, and the combination of the two criteria can be beneficial to assessment of pelvic injury severity. Key words: Pelvis; Ligaments; Injury classification