From June 2005 to December 2017, a total of 66 patients with Day type II CFD were selected and retrospectively analyzed according to the following criteria. According to different surgical methods, patients with Day type Ⅱ CFD were divided into minimally invasive percutaneous cross screw internal fixation treatment group (Group A, 40 cases) and open reduction and internal fixation treatment group (Group B, 26 cases). The eligibility criteria were: 1) Day type II crescent fracture-dislocation; 2) recipients of surgery including open or closed reduction internal fixation; 3) complete follow-up and information. Exclusion criteria included: 1) children pelvic fractures; 2) local or systemic infections; 3) severe blood vessel and nerve injury. Patient characteristics such as age, sex, injury mechanisms and fracture classification were extracted from the database. The data were analyzed anonymously and personal identifiers were completely removed. This study followed the guidelines of the “Declaration of Helsinki” and was approved by the hospital’s ethics committee. Written informed consent was obtained from all patients.
2.2 Surgical technique
In our study, the anterior ring injury could be fixed in the same incision while the posterior ring was fixed by plate through the anterior approach. The rest of the patients who needed anterior ring surgery were fixed in the supine position, then the posterior ring was fixed in the prone position. 46 cases of anterior ring injury were treated with closed reduction screw fixation, 12 cases were treated with ORIF, and the remaining 8 patients were not fixed because the anterior ring fracture did not move significantly. Among them, there were 5 cases of pubic rami fracture with pubic symphysis separation. So they were fixed with percutaneous pubic symphysis screw and pubic rami screw in one stage.
Percutaneous cross screw internal fixation (Group A): 1-2 posterior iliac cross screws combined with 1 sacroiliac joint screw fixation in prone position. If the patient was accompanied by anterior ring pubic rami fracture or pubic symphysis separation, the anterior ring injury was first fixed with pubic rami screws or/and pubic symphysis screws.
After successful anesthesia, patient was placed on the X-ray surgical bed with complete fluoroscopy. When the fracture displacement of the pelvis anterior and posterior rings were obvious, the anterior ring should be reset and fixed firstly. Then, we pushed the compressive iliac bone on the injured side outward manually or used a 5-mm Schanz nail to insert the edge of the iliac crest to assist the external rotation of the ilium for reduction. At the same time, external rotation and abduction of the hip joint could also play a role in assisting the external rotation of the injured side of the iliac bone. Once closed reduction was difficult, made a small incision of 0.5 cm at the apex of the fracture and dislocation. A the top rod was used to push the proximal dislocated part of the iliac posterior fracture to the distal end, assisted by longitudinal traction of the lower extremities. When closed reduction was completed, percutaneous screw fixation was performed. Generally, the sacroiliac joint screws fixation was performed before the posterior iliac screws fixation on the basis of correcting the vertical displacement of the posterior iliac fracture.
After the fracture was reduced, the insertion point of the posterior iliac screw on the central side of the posterior superior iliac spine was identified with the aid of fluoroscopy. The guide pin pointed to the anterior inferior iliac spine, and inserted 15° outwardly in the transverse plane and 30° downwardly in the sagittal plane. The lateral pelvic image and the obturator oblique position image should be repeatedly seen to ensure that the guide pin was located above the large ischial notch and in the center of the tear drop. Finally, the depth of the guide pin was measured by the ilium oblique position image. If necessary, the second guide pin could be inserted 1 to 2 cm above and outside from the first one. Screwed the hollow compression screw with a diameter of 6.5 mm or 7.3 mm along the guide pin, and made sure that the screw was in the iliac bone. (The operation diagram was shown in Fig 1 and typical case was shown in Fig 2).
ORIF (Group B): In 10 cases, reconstruction plates and screws were placed to fix the sacroiliac joint and the iliac fracture through the anterior ilioinguinal approach. The remaining 16 patients were treated with posterior approach. Plate and screws were used to fix the iliac fracture, and hollow screws were used to fix the sacroiliac joint. Drainage tubes were routinely placed in this Group.
2.3 Postoperative treatment
All patients underwent pelvic radiograph examination on the second day after surgery. The drainage tube was removed within 24 to 72 hours after the operation depending on the drainage fluid. The use of antibiotics according to the incision level. Anticoagulation therapy after surgery unless the patients had contraindications. Encouraged patients to perform roll-over exercises in bed one day after surgery. Partial weight-bearing exercise was performed with double crutches 3 months after the operation, and full weight-bearing walking was allowed 4 to 6 months postoperatively.
2.4 Follow-up and outcome evaluation
All patients were followed up at 6 weeks, 3, 6 and 12 months after surgery, and then followed up every year. Pelvic X-ray examination, Majeed score, physical examination, and neurological function examination were performed at each follow-up. Radiological results were graded according to the maximum residual displacement of the posterior or anterior pelvic ring injury (excellent, < 4 mm; good, 5 - 10 mm; fair, 11 - 20 mm; poor, > 20 mm) . Functional outcomes were measured at the last follow-up according to the criteria described by Majeed et al. , which is based on pain, sitting, walking, sexual intercourse, and work (excellent, 85-100 points; good, 70-84 points; fair, 55-69 points; poor, <55 points).
2.5 Statistical analysis
Statistical analysis was performed using SPSS 18.0 (SPSS Inc, Chicago, Ill). Continuous variables were expressed as mean ± standard deviation. Comparisons between groups were performed using the Student's t-test, Chi-square test, Fisher's exact test and Wilcoxon rank-sum test. P value less than 0.05 was considered statistically significant.