Table A1.

Details of the Questionnaire.

Questions	Answer Options
1. What are you?	A. Trauma surgeon B. Trauma surgery resident C. Orthopedic surgeon D. Orthopedic surgery resident
2. For how long have you worked as a trauma or an orthopedic surgeon?	A. 0–5 years B. 6–10 years C. 11–20 years D. >20 years E. In residency
3. In which trauma care network region do you work?	A. Eastern Regional Emergency Healthcare Network B. Acute Care Network North-West C. Network Emergency Care Brabant D. Network Acute Care West E. Network Emergency Care Euregio F. Trauma Center Southwest Netherlands G. Network Acute Care Limburg H. Network Emergency Care Zwolle I. Trauma Network Middle Netherlands region J. AcuteCareNet AMC K. Acute Care Network North Netherlands
4. Which Trauma Center Level meets your hospital?	A. Level 1 (highest) B. Level 2 C. Level 3 (lowest)
5. Are pelvic and acetabular fracture operations performed in your hospital?	A. Yes, 1–20 operations per year B. Yes, 21–40 operations per year C. Yes, 41–60 operations per year D. Yeas, >60 operations per year E. No
6. Do you perform pelvic and acetabular fracture operations?	A. Yes, 1–10 operations per year B. Yes, 11–20 operations per year C. Yes, 21–40 operations per year D. Yes, >40 operations per year E. No
7. How many elderly patients (≥65 years) with a superior/inferior ramus fracture on plain radiographic imaging do you treat in your hospital (both operatively and conservatively)?	A. 1–25 patients per year B. 26–50 patients per year C. 51–75 patients per year D. 76–100 patients per year E. >100 patients per year
8. How often do you refer elderly patients with pelvic fractures after low-energy trauma to a specialized pelvic center?	A. 1–5 times per year B. 6–10 times per year C. >10 times per year D. Not applicable
9. Who generally assesses an elderly patient with a superior/inferior ramus fracture in your hospital’s Emergency Department (ED)?	A. Surgeon/orthopedic surgeon B. Surgical/orthopedic residents (not in training) C. Surgical/orthopedic residents (in training) D. Emergency physician E. Otherwise, namely:
10. In case an elderly patient with a superior/inferior ramus fracture needs to be admitted to the hospital, where will this patient be admitted?	A. Surgical ward/orthopedic ward B. Geriatric ward C. Nursing home D. ‘Primary care’ nursing home E. Otherwise, namely:
11. Is there a treatment protocol for elderly patients with a superior/inferior ramus fracture in your hospital?	A. Yes, named: B. No C. I am not aware if there is such a treatment protocol
12. Mrs. A. is a 75-year-old, independently living ASA 2 patient. She tripped and fell at home. Plain radiographic imaging showed a superior/inferior ramus fracture on the left side. Would you, based on this information, perform a CT scan in the hospital you work at?	A. No, a CT scan has no treatment consequences B. Yes, always C. Yes, if the patient has pain on palpation of the sacrum D. Yes, if the patient is very painful during mobilization E. Otherwise, namely:
13. Mrs. B. is a 77-year-old ASA 4 patient living in sheltered housing. She tripped and fell at home. Plain radiographic imaging showed a superior/inferior ramus fracture on the left side. Would you, based on this information, perform a CT scan in the hospital you work in?	A. No, a CT scan has no treatment consequences B. Yes, always C. Yes, if the patient has pain on palpation of the sacrum D. Yes, if the patient is very painful during mobilization E. Otherwise, namely:
14. Mrs. C. is a 75-year-old, independently living ASA 2 patient. She fell on the street, and plain radiographic imaging showed a superior/inferior ramus fracture on the right side. She is discharged from the ER with oral painkillers. The patient comes back to your outpatient clinic after 14 days. She mobilizes with difficulty, sits in a wheelchair, walks with a four-wheel walker indoors, and uses Paracetamol and Diclofenac. A CT scan shows an LC1/FFP3c fracture. Do you think, based on this information, the patient is eligible for surgical fixation?	A. No, I do not think this is indicated and would have little impact on this patient’s outcome B. No, I think operative pelvic fixation would be too invasive for this patient C. Yes, if the patient has evident pelvic pain during a physical exam D. Yes, only if the pain did not decrease at 6 weeks follow-up E. Otherwise, namely:
15. Mrs. D. is a 69-year-old, independently living ASA 3 patient with COPD Gold 3. She fell on the street, and plain radiographic imaging showed a superior/inferior ramus fracture on the right side. She is discharged from the ER with oral painkillers. The patient comes back to your outpatient clinic after 14 days. She mobilizes with difficulty, sits in a wheelchair, walks with a four-wheel walker indoors, and uses Paracetamol and Diclofenac. A CT scan shows an LC1/FFP3c fracture. Do you think, based on this information, the patient is eligible for surgical fixation?	A. No, I do not think this is indicated and would have little impact on this patient’s outcome B. No, I think operative pelvic fixation would be too invasive for this patient C. Yes, if the patient has evident pelvic pain during a physical exam D. Yes, only if the pain did not decrease at 6 weeks follow-up E. Otherwise, namely:
16. Mrs. E is an 81-year-old ASA 3 patient. She fell on the street, and plain radiographic imaging showed a superior/inferior ramus fracture on the right side. She is admitted to the nursing ward and has difficulty turning in bed. Transfer from bed to toilet chair is possible. She uses Paracetamol, Diclofenac and Oxynorm. A CT scan shows an LC1/FFP3c fracture. Do you think, based on this information, the patient is eligible for surgical fixation?	A. No, I do not think this is indicated and would have little impact on this patient’s outcome B. No, I think operative pelvic fixation would be too invasive for this patient C. Yes, if the patient has evident pelvic pain during a physical exam D. Yes, only if the pain did not decrease at 6 weeks follow-up E. Otherwise, namely:
17. If plain radiographic imaging shows a superior/inferior ramus fracture and the patient is treated conservatively, when would your first follow-up moment be?	A. No follow-up B. Within 1 week C. Within 2 weeks D. Within 3 to 6 weeks E. After >6 weeks
18. If plain radiographic imaging shows a superior/inferior ramus fracture and the patient is treated conservatively, when would you advise the patient to use full weight bearing?	A. Immediately, based on the patient’s pain B. After 2 to 4 weeks C. After 4 to 6 weeks D. After 6 to 8 weeks E. Otherwise, namely:
19. If a patient underwent operative fixation related to a right-sided sacrum and superior/inferior ramus fracture, when would you advise the patient to use full weight bearing?	A. Immediately, based on the patient’s pain B. 2 to 4 weeks minimal weight bearing, afterward full weight bearing C. 4–6 weeks minimal weight bearing, then full weight bearing D. 6 to 8 weeks minimal weight bearing, then full weight bearing E. Otherwise, namely: