The aim for surgical treatment of unstable Tile B2 & C1 pelvic ring injuries is an anatomical reduction to allow early weight-bearing, pain relief and to prevent future pelvic asymmetry. So, we usually used combined posterior & anterior ring fixation, relying on the fact that anterior pelvic ring adequate reduction and fixation better augment posterior ring fixation and enhance overall pelvic stability. However, anterior ring fixation requires a second incision with a longer operation time and more blood loss. The main disadvantage of the second incision is the higher risk of wound infection, either superficial or deep, which questions its necessity and raises concerns about the possibility of isolated posterior ring fixation in managing Tile B2 & C1 pelvic ring injuries with good outcomes.

The fundamental algorithm was the questionable need for additional anterior ring fixation in managing Tile B2 and C1 pelvic ring injuries combined with posterior ring fixation, whether the incidence of postoperative complications, radiological and clinical outcomes differed between these two groups. After reviewing the literature, we found a lack of knowledge in the prospective assessment of such outcomes between the two fixation groups. So, This RCT aims to reach a satisfactory result and prove or deny the questionable need for anterior ring fixation in managing Tile B2 and C1 pelvic ring injuries. Our hypothesis was that PR fixation is at least as good as APR fixation.

Type of Study: Prospective randomized controlled clinical trial Randomization technique: Block Randomization. Study Setting: The operations were held in Ain Shams university hospitals. Study Period: From 2019 till 2020.

Study Population:

Inclusion Criteria:

Tile B2 and C1 pelvic ring injuries Nakatani zone II pubic rami fractures with intact inguinal ligament Age between 16-60 years old Recent pelvic ring injuries less than three weeks

Exclusion Criteria:

Tile A pelvic ring injuries Nakatani zone I & III pubic rami fractures neglected pelvic ring injuries exceeding three weeks Age less than 16 years and older than 60 years

Sampling Method: convenient sample. Sample Size: 40 feet subdivided randomly via Block Randomization into 2 groups, 20 feet for each group.

Group A: Patients treated by combined posterior and anterior ring fixation Group B: Patients treated by posterior ring fixation alone

Ethical Considerations: were followed by obtaining the hospital Research Ethics Committee approval and written informed consents from the patients.

Study Tools:

The patients were evaluated by the following: -

All patients were subjected to:

I. Pre-operative:

Written consent.

Complete ATLS protocol:

Primary survey: airway, breathing, circulation and disability with complete exposure, including: CXR and pelvis anteroposterior view Secondary survey: head to toe examination, complete cervical clinical and radiological clearance and detailed AMPLE history

Detailed history:

History-taking included age, mode of trauma, physiological status, haemodynamics, associated internal organ injuries, medical comorbidities and detailed surgical history.

Complete Orthopaedic examination:

Full and thorough examination of the patient was done from head to toes with complete inspection, palpation and range of motion examination of the whole body, together with detailed neurovascular examination of both lower limbs.

X-Rays pre and post-operative Preoperative: to assess the fracture pattern, location and for surgical planning.

Postoperatively: to assess the quality of reduction immediate postoperative and at each follow up visit (two weeks, six weeks, three months, six months and one year) to follow up union rate, fixation failure, secondary dislocation and secondary loss of reduction.

CT pelvis preoperative will be done to accurately describe fracture pattern, identify occult radiological instability and more comprehensive surgical planning.

Evaluation of the patients by clinical Majeed pelvic scoring system

II.Operative technique Group A: combined posterior and anterior ring fixation Group B: Isolated Posterior ring fixation

III. Postoperative management and evaluation:

We followed a partially assisted weight-bearing protocol for six weeks for both groups (using axillary or forearm crutches that take about 50% of the body weight through the injured lower extremity). In addition, we did x-ray films & neurovascular examination postoperatively.

Follow-up visits were at two weeks, six weeks, three months, six months & 1-year postoperative.

We performed radiological and clinical assessments: Radiological using Matta & Tornetta radiological principles via plain x-ray pelvis showing both hips: anteroposterior, inlet and outlet views & CT pelvis if available; we evaluated five criteria on X-ray films postoperatively: residual posterior displacement, vertical displacement, pubic symphyseal translation, sagittal rotation, and gapping of the sacroiliac joint; according to the grading of Matta and Tornetta, we classified the results into Excellent (less than or equal 4 mm), Good (4-10 mm), Fair (10-20 mm), and Poor (more than 20 mm). In addition, clinical assessment by Majeed pelvic scoring system evaluated and calculated at each follow-up visit with the mean value presented, Postoperative complications and need for another operation were evaluated.

In week two, we encouraged passive and active-assisted hip ROM. Then we started an unassisted weight-bearing and physiotherapy program to strengthen abductors and quadriceps muscles in week six. While complete full weight-bearing and return to work were after three months. After six months, a full radiological and clinical assessment were done + return to pre-injury mobility status and athletic sports. Finally, after one year, we did clinical and radiological reevaluation.

IV- Statistical analysis of data.

V- Outcome measures of interest:

Primary outcomes: radiological (using Matta & Tornetta radiological principles) & clinical outcomes (using the Majeed pelvic scoring system), and postoperative complications.

Secondary outcomes: operative time, amount of blood loss, intraoperative assessment of reduction, need for another operation, length of hospital stay, ability to weight bear postoperative, and pain control metrics.

Inclusion Criteria:

• Tile B2 and C1 pelvic ring injuries
• Nakatani zone II pubic rami fractures with intact inguinal ligament
• Age between 16-60 years old
• recent pelvic ring injuries less than three weeks

Exclusion Criteria:

• Tile A pelvic ring injuries
• Nakatani zone I & III pubic rami fractures
• neglected pelvic ring injuries exceeding three weeks
• Age less than 16 years and older than 60 years

Patients and physicians allocated to each intervention group were aware of the allocation; however, the data analysts and the outcome assessors were kept blinded to the allocation.