Sacral fractures encompass a spectrum from high-energy traumatic injuries (associated with pelvic ring disruption in ~40–50% of cases) to low-energy insufficiency fractures (increasingly prevalent in elderly, osteoporotic patients). [1-2] They are commonly underdiagnosed due to nonspecific symptoms and poor sensitivity of plain radiographs, with a mean diagnostic delay of ~24 days reported in the ED setting. [3]
1. History
- Mechanism: High-energy (MVC, fall from height, axial load) vs. low-energy (ground-level fall, no trauma) — determines fracture type and associated injuries [2][4]
- Pain location: Low back, buttock, gluteal, groin, or coxalgia; often bilateral [2-3]
- Onset and progression: Insidious onset is typical for insufficiency fractures; acute onset for traumatic fractures [2]
- Aggravating factors: Weight-bearing, ambulation, transitional movements (sit-to-stand) [5]
- Neurologic symptoms: Radiculopathy, sciatica, saddle anesthesia, bowel/bladder dysfunction, lower extremity weakness [6]
- Important negatives: Absence of antecedent trauma does not exclude fracture in at-risk patients; ask about prior radiation therapy, steroid use, and recent spinal surgery [2][7]
2. Alarm Features
- Cauda equina syndrome: Urinary retention, saddle anesthesia, fecal incontinence, bilateral lower extremity weakness — requires emergent MRI and surgical consultation [8-9]
- Neurologic deficit: New motor weakness, progressive sensory loss, or bowel/bladder dysfunction — especially with Denis Zone III fractures (central canal involvement), where neurologic injury occurs in ~57–60% [6][10]
- Hemodynamic instability: Pelvic fractures with sacral involvement may cause significant retroperitoneal hemorrhage [11]
- Spinopelvic dissociation: U-shaped or H-shaped transverse fractures with lumbopelvic instability — high-energy, often requires operative fixation [1][12]
- Displaced or comminuted fractures: Strong association with neurologic injury (OR 8.4 for displaced, OR 5.2 for comminuted) [13]
3. Medications
- Contributors to fracture risk: Long-term corticosteroids, aromatase inhibitors, anticonvulsants, proton pump inhibitors, GnRH agonists — all associated with bone loss [2][14]
- Anticoagulants: Warfarin, DOACs — assess bleeding risk in retroperitoneal hemorrhage; consider TEG for DOAC patients with active bleeding [15]
- Acute pain management: Multimodal analgesia — acetaminophen, NSAIDs (if renal function permits), opioids for severe pain; avoid excessive sedation in elderly [16-17]
- Osteoporosis pharmacotherapy: Initiate or optimize bisphosphonates, denosumab, or anabolic agents (teriparatide/romosozumab); anabolic agents prior to or in conjunction with sacroplasty improve outcomes [16][18]
- Caution: NSAIDs may impair fracture healing — use judiciously and for limited duration
4. Diet
- Calcium and vitamin D: Virtually all patients with sacral insufficiency fractures have pronounced vitamin D deficiency and manifest osteoporosis; supplementation is essential [17]
- Protein intake: Adequate protein supports bone healing and prevents sarcopenia in elderly patients
- Hydration: Important during immobilization to prevent constipation, DVT, and urinary complications
- Long-term: Mediterranean-style diet rich in calcium, vitamin D, and protein for secondary fracture prevention
5. Review of Systems
- Neurologic: Radiculopathy, numbness/tingling in lower extremities, saddle area sensation, bowel/bladder function, sexual dysfunction [6]
- Genitourinary: Urinary retention or incontinence (key CES indicator) [8][19]
- GI: Constipation (immobility-related), fecal incontinence (neurologic)
- Musculoskeletal: Concurrent pelvic pain, hip pain, thoracolumbar pain (tandem fractures occur in ~30% with TLJ fractures) [20]
- Constitutional: Weight loss, night sweats, fevers — to evaluate for malignancy or infection as alternative diagnoses [21]
- Vascular: Signs of DVT given immobility
6. Collateral History and Family History
- Collateral: Functional baseline, ambulatory status, fall circumstances, witnessed syncope, medication compliance (especially osteoporosis treatment)
- Family history: Osteoporosis, fragility fractures, metabolic bone disease
- Social context: Living situation, ability to perform ADLs, caregiver availability (critical for disposition planning), fall risk at home [22]
- 71% of patients with pelvic insufficiency fractures are not receiving adequate secondary fracture prevention — inquire about prior DEXA and treatment [22]
7. Risk Factors
- Osteoporosis — the most common cause of sacral insufficiency fractures [2]
- Age >55 years, especially postmenopausal women [2]
- Prior fragility fracture [2]
- Pelvic radiation (e.g., rectal, cervical, endometrial cancer) — 7.1% incidence of sacral fracture after chemoradiation for rectal carcinoma [7]
- Long-term corticosteroid use [2][14]
- Prior multilevel spinal fusion — SIF diagnosed ~9.5 weeks post-fusion in 24.9% of patients in one series [23]
- Rheumatoid arthritis, metabolic bone disorders, vitamin D deficiency [2]
- Pregnancy/postpartum — rare but recognized; risk factors include high birth-weight infant, excessive weight gain, rapid vaginal delivery [5]
- High-energy trauma — MVC, falls from height, axial loading [1][4]
8. Differential Diagnosis
- Sacroiliitis (inflammatory or infectious) — can mimic and even coexist with SIF; MRI findings overlap [5][24]
- Metastatic bone disease — sacral insufficiency fractures are frequently confused with metastases on imaging [21][25]
- Lumbar disc herniation / spinal stenosis — overlapping symptom profiles [21]
- Lumbosacral degenerative spondylosis [5]
- Osteitis condensans ilii [5]
- Sacral tumors (chordoma, giant cell tumor, plasmacytoma)
- Pelvic ring fracture without sacral involvement
- Sacroiliac joint infection [21]
- Hip pathology (femoral neck stress fracture, avascular necrosis) — concurrent insufficiency fractures at multiple sites are common [5]
9. Past Medical History
- Osteoporosis/osteopenia and DEXA results
- Prior fragility fractures at any site
- History of cancer and radiation therapy (especially pelvic)
- Prior spinal surgery — particularly multilevel fusion [23]
- Chronic steroid use (e.g., for RA, COPD, transplant)
- Renal disease (secondary hyperparathyroidism, renal osteodystrophy)
- Cardiovascular disease — relevant for perioperative risk if surgery needed [26]
- Anticoagulation status — impacts hemorrhage risk and surgical timing
10. Physical Exam
- Vital signs: Tachycardia and hypotension suggest hemorrhage (but elderly may have blunted tachycardia due to beta-blockers or age-related catecholamine insensitivity) [15]
- Inspection: Bruising/contusion over sacrum (in ED, contusion/abrasion is the best red flag for spinal fracture) [14]
- Palpation: Tenderness over sacrum, sacroiliac joints, and posterior pelvic ring
- Pelvic compression/distraction: Assess pelvic ring stability (perform gently, once)
- Neurologic exam:
- Lower extremity motor strength (L4–S1 myotomes)
- Sensation in saddle distribution (S2–S5)
- Perianal sensation and rectal tone (critical for CES screening) [6][8]
- Deep tendon reflexes (patellar, Achilles), bulbocavernosus reflex
- Gait assessment: If patient can ambulate — antalgic gait, inability to bear weight
- Rectal exam: Assess sphincter tone, perianal sensation — mandatory if neurologic deficit suspected [6]
11. Lab Studies
- CBC: Baseline hemoglobin (hemorrhage assessment)
- BMP/CMP: Renal function (contrast planning, medication dosing), calcium, phosphorus
- Coagulation studies: PT/INR, PTT — especially if on anticoagulants; TEG if on DOACs with active bleeding [15]
- Lactate/blood gas: Occult hypoperfusion in elderly trauma [15]
- Vitamin D level (25-OH): Virtually all SIF patients are deficient [17]
- DEXA scan: For bone mineral density assessment (not acute, but essential for management) [23]
- Urinalysis: If urinary retention or infection suspected
- Troponin: Consider in elderly patients — perioperative MI occurs in ~35% of hip/pelvic fracture patients and is often unrecognized [27-28]
- If malignancy suspected: ESR, CRP, serum protein electrophoresis, PSA, alkaline phosphatase
12. Imaging
- Plain radiographs: Low sensitivity (~28.5%) for sacral fractures; often miss nondisplaced fractures. Ferguson view (AP with 25° cephalad tilt) may improve visualization but is rarely obtained [11][29]
- CT pelvis: Standard of care for diagnosing and characterizing sacral fractures in trauma; sensitivity ~94%. Gold standard for evaluating fracture morphology and classification [1][22][29]
- MRI: Most sensitive modality (sensitivity ~98.6–99%). Shows bone marrow edema (T1 hypointense, T2/STIR hyperintense) before a discrete fracture line is visible. Preferred for: [22][30]
- Suspected insufficiency fractures with negative CT [30]
- Neurologic deficit assessment
- Differentiating fracture from metastatic disease
- Coronal STIR sequence should be standard protocol [23]
- Bone scintigraphy: Classic "Honda sign" (H-shaped uptake) is pathognomonic for bilateral sacral insufficiency fractures; largely supplanted by MRI [25]
- When imaging is unnecessary: Stable, nondisplaced fractures confirmed on CT in neurologically intact patients do not routinely require MRI [4]
13. Special Tests
- Denis Classification: [6]
- Zone I (alar): Lateral to foramina — L5 radiculopathy risk (~24%)
- Zone II (foraminal): Through foramina — sciatica (~29%), rarely bladder dysfunction
- Zone III (central canal): Saddle anesthesia, sphincter dysfunction (~57–60%)
- Modern data suggest overall neurologic injury rates are lower (~3.5%) than originally reported [13]
- AO Spine Sacral Injury Classification: Validated hierarchical system; Sacral AOSIS ≥5 generally indicates operative management [31-32]
- Rommens and Hofmann FFP Classification: For fragility fractures — FFP I–II (stable) vs. FFP III–IV (unstable, often requiring surgery) [22]
- Postvoid residual (PVR): Bedside bladder scan to assess for urinary retention in suspected CES [8]
- Cystometrography: Recommended routinely for Zone III injuries to identify neurogenic bladder [6]
14. ECG
- Indications: Obtain ECG in all elderly trauma patients — ECG abnormalities, especially atrial fibrillation, are strong independent predictors of 30-day mortality (OR 6.1) [33]
- Assess for: AF (present in ~9.5% of elderly fracture patients), ischemic changes, conduction abnormalities [33-34]
- Syncope workup: If fall was preceded by syncope, ECG is essential to evaluate for arrhythmia as the precipitating cause [15]
- Perioperative monitoring: Serial troponin and ECG recommended if surgery planned — perioperative MI occurs in ~35–40% of elderly fracture surgery patients and is frequently asymptomatic [27-28]
15. Assessment
- Sacral fractures range from stable insufficiency fractures (most common in elderly osteoporotic patients, presenting with insidious low back/buttock pain) to high-energy traumatic fractures with pelvic ring disruption and potential spinopelvic dissociation [2][12]
- Commonly underdiagnosed: Nonspecific symptoms, poor plain film sensitivity, and overlap with degenerative disease contribute to diagnostic delay [3][21]
- Severity stratification depends on fracture zone (Denis), displacement, pelvic ring stability, and neurologic status [1][31]
- Complications: Neurologic injury (3.5–60% depending on zone and displacement), chronic pain, loss of independence (64–89%), DVT/PE, and mortality of 13–27% in elderly patients with pelvic insufficiency fractures [13][22]
- Atypical presentations: SIF can present as cauda equina syndrome even without visible nerve root compression on MRI [9]
16. Treatment Plan
Initial stabilization (ED)
- ABCs, hemodynamic assessment; pelvic binder if unstable pelvic ring injury suspected
- Multimodal analgesia: acetaminophen + limited opioids; consider regional anesthesia
- Foley catheter if urinary retention
Nonoperative management (majority of stable, nondisplaced fractures): [4][17]
- Bedrest with progressive mobilization and weight-bearing as tolerated
- Multimodal pain management
- DVT prophylaxis (LMWH or DOACs)
- Osteoporosis treatment: calcium, vitamin D, and antiresorptive or anabolic agents [16]
- Physical therapy for early mobilization
Procedural/Surgical management: [17-18][31]
- Sacroplasty: For persistent pain (VAS >5) despite conservative measures in nondisplaced fractures; significant pain reduction (mean NRS 7.8 → 0.9 at 6 months) [35]
- Percutaneous iliosacral screw fixation: For displaced fractures or unstable pelvic ring injuries [2][11]
- Lumbopelvic fixation: For spinopelvic dissociation (U-type, H-type fractures) [12][36]
- Sacral AOSIS ≥5: Generally operative; AOSIS 3–4 with anterior pelvic ring injury at surgeon's discretion [31]
- Decompression: If neurologic deficit from nerve root compression, especially Zone III [6]
17. Disposition
- Admission criteria: [17][22]
- Hemodynamic instability or significant hemorrhage
- Neurologic deficit (new or progressive)
- Displaced or unstable fractures requiring surgical planning
- Inability to mobilize or manage pain (VAS >5 with immobility)
- High-energy mechanism with polytrauma
- Elderly patients unable to safely ambulate or care for themselves
- Observation: Stable fractures with moderate pain, awaiting advanced imaging or orthopedic/spine consultation
- Discharge criteria: Stable nondisplaced fracture, adequate pain control, able to ambulate (even with assistive device), neurologically intact, safe home environment, reliable follow-up
- Specialist consultation triggers: Orthopedic surgery/spine surgery for displaced fractures, pelvic ring instability, neurologic deficit, or failed conservative management; interventional radiology for sacroplasty consideration [16][18]
18. Follow Up / Return Precautions
- Follow-up timing: Orthopedic/spine follow-up within 1–2 weeks; repeat imaging at 6–12 weeks to assess healing
- DEXA scan: If not recently performed, obtain to guide osteoporosis management [23]
- Return immediately for: New or worsening numbness (especially saddle area), urinary retention or incontinence, fecal incontinence, progressive leg weakness, inability to ambulate, fever [8]
- Expected recovery: Most insufficiency fractures heal in 8–12 weeks with conservative management; sacroplasty provides faster pain relief [17][23]
- Secondary fracture prevention: Ensure osteoporosis treatment is initiated — 71% of patients do not receive adequate prevention [22]
- Fall prevention: Home safety assessment, physical therapy, medication review (especially sedatives, antihypertensives), vision screening [26]
- Counseling: Gradual return to activity; persistent pain beyond 3 months warrants re-evaluation and consideration of advanced imaging or intervention [17]
References
1. CT of Sacral Fractures: Classification Systems and Management. — Dreizin D, Smith EB. Radiographics : A Review Publication of the Radiological Society of North America, Inc. 2022.
2. Sacral Insufficiency Fractures. — Rickert MM, Windmueller RA, Ortega CA, et al. JBJS Reviews. 2022.
3. Incidence and Clinical Features of Sacral Insufficiency Fracture in the Emergency Department. — Tamaki Y, Nagamachi A, Inoue K, et al. The American Journal of Emergency Medicine. 2017.
4. Best Practices Guidelines Spine Injury. — Gregory D. Schroeder MD, Alexander R. Vaccaro MD PhD MBA, William C. Welch MD FACS FAANS FICS FAANOS, et al American College of Surgeons (2022). 2022.
5. ACR Appropriateness Criteria® Stress (Fatigue-Insufficiency) Fracture Including Sacrum Excluding Other Vertebrae: 2024 Update. — Morrison WB, Deely D, Fox MG, et al. Journal of the American College of Radiology : JACR. 2024.
6. Sacral Fractures: An Important Problem. Retrospective Analysis of 236 Cases. — Denis F, Davis S, Comfort T. Clinical Orthopaedics and Related Research. 1988.
7. Fractures of the Sacrum After Chemoradiation for Rectal Carcinoma: Incidence, Risk Factors, and Radiographic Evaluation. — Kim HJ, Boland PJ, Meredith DS, et al. International Journal of Radiation Oncology, Biology, Physics. 2012.
8. Evaluation and Management of Cauda Equina Syndrome in the Emergency Department. — Long B, Koyfman A, Gottlieb M. The American Journal of Emergency Medicine. 2020.
9. Cauda Equina Syndrome Presentation of Sacral Insufficiency Fractures. — Muthukumar T, Butt SH, Cassar-Pullicino VN, McCall IW. Skeletal Radiology. 2007.
10. Neurological Injury and Patterns of Sacral Fractures. — Gibbons KJ, Soloniuk DS, Razack N. Journal of Neurosurgery. 1990.
11. Sacral Fractures: Current Strategies in Diagnosis and Management. — Hak DJ, Baran S, Stahel P. Orthopedics. 2009.
12. Injuries and Fractures of the Sacrum-a Comprehensive Review. — El Naga AN, Gendelberg D, Theologis AA. The Journal of the American Academy of Orthopaedic Surgeons. 2025.
13. Relationship of Sacral Fractures to Nerve Injury: Is the Denis Classification Still Accurate?. — Khan JM, Marquez-Lara A, Miller AN. Journal of Orthopaedic Trauma. 2017.
14. Red Flags to Screen for Vertebral Fracture in People Presenting With Low Back Pain. — Han CS, Hancock MJ, Downie A, et al. The Cochrane Database of Systematic Reviews. 2023.
15. Best Practices Guidelines Geriatric Trauma Management. — Alicia Mangram MD FACS, Jessica M. Berdeja MD, Christine S. Cocanour MD FACS FCCM, et al American College of Surgeons (2023). 2023.
16. Sacroplasty for Sacral Insufficiency Fractures: Narrative Literature Review on Patient Selection, Technical Approaches, and Outcomes. — Singh M, Balmaceno-Criss M, Knebel A, et al. Journal of Clinical Medicine. 2024.
17. Comparative Outcome of Different Treatment Options for Fragility Fractures of the Sacrum. — Andresen JR, Radmer S, Andresen R, et al. BMC Musculoskeletal Disorders. 2022.
18. Sacral Insufficiency Fractures: Pathology, Management, and Outcomes. — Collins AP, Roddy E, Davis WT, Firoozabadi R. The Journal of Bone and Joint Surgery. American Volume. 2025.
19. Cauda Equina Syndrome: A Literature Review of Its Definition and Clinical Presentation. — Fraser S, Roberts L, Murphy E. Archives of Physical Medicine and Rehabilitation. 2009.
20. A Modified MRI Protocol for the Increased Detection of Sacrococcygeal Fractures in Patients With Thoracolumbar Junction Fractures. — Khil EK, Choi I, Choi JA, Kim YW. Scientific Reports. 2021.
21. Sacral Insufficiency Fractures: Current Concepts of Management. — Tsiridis E, Upadhyay N, Giannoudis PV. Osteoporosis International : A Journal Established as Result of Cooperation Between the European Foundation for Osteoporosis and the National Osteoporosis Foundation of the USA. 2006.
22. Chronic Pelvic Insufficiency Fractures and Their Treatment. — Gewiess J, Albers CE, Keel MJB, et al. Archives of Orthopaedic and Trauma Surgery. 2024.
23. Sacral Insufficiency Fracture: A Single-Center Experience of 185 Patients With a Minimum 5-Year Follow-Up. — Sarigul B, Ogrenci A, Yilmaz M, et al. European Spine Journal : Official Publication of the European Spine Society, the European Spinal Deformity Society, and the European Section of the Cervical Spine Research Society. 2024.
24. Sacroiliitis or Insufficiency Fracture?. — Memetoğlu OG, Ozkan FU, Boy NS, et al. Osteoporosis International : A Journal Established as Result of Cooperation Between the European Foundation for Osteoporosis and the National Osteoporosis Foundation of the USA. 2016.
25. Insufficiency Fractures of the Sacrum. — Cooper KL, Beabout JW, Swee RG. Radiology. 1985.
26. Cardiovascular Diseases, Prevention, and Management of Complications in Older Adults and Frail Patients Treated for Elective or Post-Traumatic Hip Orthopaedic Interventions: A Clinical Consensus Statement of the ESC Council for Cardiology Practice (CCP), the European Association of Preventive Cardiology (EAPC), the Association for Acute CardioVascular Care (ACVC), the Association of Cardiovascular Nursing & Allied Professions of the ESC (ACNAP), the ESC Working Group on Aorta and Peripheral Vascular Diseases (WG APVD), and the ESC Working Group on Thrombosis (WG T). — Guasti L, Fumagalli S, Afilalo J, et al. European Journal of Preventive Cardiology. 2025.
27. Perioperative Myocardial Infarctions Are Common and Often Unrecognized in Patients Undergoing Hip Fracture Surgery. — Hietala P, Strandberg M, Strandberg N, Gullichsen E, Airaksinen KE. The Journal of Trauma and Acute Care Surgery. 2013.
28. Perioperative Myocardial Infarction/Myocardial Injury Is Associated With High Hospital Mortality in Elderly Patients Undergoing Hip Fracture Surgery. — Rostagno C, Cartei A, Rubbieri G, et al. Journal of Clinical Medicine. 2020.
29. Superiority of MRI for Evaluation of Sacral Insufficiency Fracture. — Yamauchi T, Sharma S, Chandra S, et al. Journal of Clinical Medicine. 2022.
30. Comparison of Diagnostic Accuracy of Magnetic Resonance Imaging and Multidetector Computed Tomography in the Detection of Pelvic Fractures. — Henes FO, Nüchtern JV, Groth M, et al. European Journal of Radiology. 2012.
31. The Surgical Algorithm for the AO Spine Sacral Injury Classification System. — Lee Y, Lambrechts M, Narayanan R, et al. Spine. 2024.
32. Evolution of the AO Spine Sacral and Pelvic Classification System: A Systematic Review. — Kweh BTS, Tee JW, Oner FC, et al. Journal of Neurosurgery. Spine. 2022.
33. Electrocardiographic Predictors for Early Risk Stratification: 30-Day Mortality in Older Adult Trauma Patients. — Ozdemir S, Oktay MM, Tiftikci I, Altinsoy KE. Journal of Clinical Medicine. 2025.
34. Electrocardiogeriatrics: ECG in Advanced Age. — Vicent L, Martínez-Sellés M. Journal of Electrocardiology. 2017.
35. An Interim Analysis of the First 102 Patients Treated in the Prospective Vertebral Augmentation Sacroplasty Fracture Registry. — Beall DP, Shonnard NH, Shonnard MC, et al. Journal of Vascular and Interventional Radiology : JVIR. 2023.
36. Osteosynthesis in Sacral Fracture and Lumbosacral Dislocation. — Pascal-Moussellard H, Hirsch C, Bonaccorsi R. Orthopaedics & Traumatology, Surgery & Research : OTSR. 2016.