Pubic Rami Fractures

A pubic rami fracture involves the superior pubic ramus, the inferior ramus or both. It may be isolated, with the ring intact, or associated with a posterior ring injury: a sacral fracture or an SI joint injury.

Two populations. The most common presentation is the elderly fragility fracture after a low-energy fall. It is a very common fragility fracture and an often under-recognised one. The other patient is young and has had high-energy trauma, a motor vehicle accident or a fall from height, and in them the rami fracture is often part of a major pelvic ring injury.

The rami. The superior pubic ramus connects the pubic body to the acetabulum and forms the anterior column. The inferior pubic ramus connects the pubic body to the ischium. The two pubic bones meet at the symphysis, a fibrocartilaginous joint in the midline.

The ring. The pelvis is a closed loop of sacrum, SI joints, innominate bones (ilium, ischium and pubis) and symphysis. A complete ring cannot break in only one place, so fractured rami are a reason to look posteriorly.

Where the rule bends. Osteoporotic bone can have incomplete or subtle posterior fractures, the sacral insufficiency fractures. Rami fractures frequently coexist with a sacral or SI injury, but the ring aphorism is not a law. Do not assume the fracture is isolated, and do not claim a second break automatically either: CT and the patient's function define the actual pattern.

Isolated or ring injury. The first division is whether the posterior ring is involved, and CT is essential to determine it.

• Isolated rami: superior and/or inferior rami only, with the posterior ring intact on CT
• Ring involvement: rami plus a sacral fracture (LC-1), an SI injury or contralateral rami fractures

Young-Burgess, when the ring is involved. Lateral compression is a side-impact mechanism that compresses the pelvis, and the higher the LC type, the more unstable the ring.

• LC-1: ipsilateral rami fractures anteriorly and ipsilateral sacral compression posteriorly, which may be subtle. Usually stable; the most stable LC type
• LC-2: more severe lateral compression, with rami fractures anteriorly and a crescent (iliac wing) fracture posteriorly. More unstable

Two languages. LC-1 is a Young-Burgess high-energy mechanism; FFP and OFP are fragility classifications. Do not call FFP II and LC-1 interchangeable.

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History. The mechanism sorts the patient: a low-energy fall in the elderly, high-energy trauma in the young. The pain is in the groin and anterior pelvis. Ask whether they can walk and bear weight.

Examination. Tenderness is over the pubic rami, in the groin and anterior pelvis. An isolated stable fracture usually has no deformity; pelvic compression or distraction may elicit pain, and the gait is antalgic.

• Genitourinary: blood at the meatus, for urethral injury in high-energy trauma, especially in males
• PR/PV: for associated injury

Who is at risk. High-energy rami fractures may carry a bladder or urethral injury, the limb-and-life-relevant association of the anterior ring and the one that changes the very first action at the bedside, so check for haematuria. It is a young, high-energy problem, from straddle injuries, falls astride and anteroposterior-compression patterns, not a feature of the elderly low-energy fragility fracture.

Urethral injury. Predominantly male: the longer male urethra is the one at risk. The membranous urethra at the urogenital diaphragm is the classic site in pelvic-fracture (anteroposterior) injuries, and the bulbar urethra is torn in straddle mechanisms. The signs:

• Blood at the external meatus, the cardinal sign
• Inability to pass urine
• A high-riding, boggy or impalpable prostate on rectal examination
• A perineal or scrotal "butterfly" haematoma

Bladder injury. Gross haematuria is the cardinal sign and mandates a CT cystogram, with retrograde gravity filling rather than just a passively clamped catheter. The pattern of rupture decides the treatment:

• Extraperitoneal rupture, the common pattern with pelvic-ring fractures: usually catheter drainage alone
• Intraperitoneal rupture, a free leak into the peritoneal cavity, often from a dome tear: operative repair

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The sequence.

1. AP pelvis radiograph: the rami fractures are usually visible, but the posterior injury may be missed
2. CT pelvis: essential; assesses the posterior ring, the sacrum and SI joints
3. MRI: when CT is negative but clinical suspicion is high, for the occult sacral insufficiency fracture

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Why the CT. Posterior sacral injury is common and easily missed on AP radiographs.

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What to look for posteriorly.

• Sacral compression (LC-1) may be subtle on CT: look for buckling of the sacral ala
• Sacral insufficiency fracture: the classic H-sign (Honda sign) on bone scan or MRI, from bilateral sacral ala and transverse fractures

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When the pain does not fit. Persistent immobilising pain after an apparently limited rami injury should prompt posterior-ring reassessment.

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The elderly patient with groin or buttock pain who cannot weight-bear does not always have a rami fracture.

The decision. Treatment follows what CT shows posteriorly and whether the patient can mobilise. Isolated pubic rami fractures rarely need operative fixation.

Fragility PatternPosterior Injury / High Energy

The older adult with a low-energy rami fracture. Inability to mobilise is a trigger to reassess both the diagnosis and the treatment.

1. Confirm anterior and posterior morphology with CT when clinically indicated.
2. Give prompt renal-, gastrointestinal- and delirium-conscious multimodal analgesia, opioid-sparing and with consideration of regional blocks, so that the patient can actually move. Pain that prevents mobilisation is itself a driver of mortality.
3. Mobilise from day 1 with physiotherapy, weight-bearing as tolerated and an aid (frame or walker), as pain and stability permit. The explicit aim is to break the immobility cascade.
4. Assess venous-thromboembolism risk and prescribe prophylaxis individually.
5. Start the falls, frailty and bone-health pathway (below).
6. Reassess persistent or worsening pain for occult or progressive posterior injury.

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Fragility patterns with a posterior injury. Selected nondisplaced patterns get a trial of non-operative mobilisation. Fixation is considered when displacement, dynamic instability, progressive deformity or persistent immobilising pain outweighs the operative risk.

High-energy trauma. Follow haemorrhage-control and pelvic-ring protocols according to physiology and morphology. Choose posterior and anterior fixation from the actual instability; "posterior first" is not a universal sequence.

Sacroplasty may reduce pain in selected sacral insufficiency fractures. It is not the automatic response to inability to mobilise.

Immobility is the biggest risk. Prolonged immobility leads to DVT, PE, pneumonia, deconditioning and death. Mobilise early.

Mortality. One-year mortality after an elderly pelvic fragility fracture is around 10-20%, and the best single figure is Studer's 18.5% in 132 consecutive patients of mean age 84. That is in the same range as hip fracture, which is the comparison that justifies the pathway. It is crude mortality in a very frail population, though, and no study has shown that the fracture causes the deaths rather than marking the frailty that does. An orthogeriatric model of care improves outcomes.

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Co-management. Beyond the analgesia, mobilisation and VTE risk assessment in the management protocol, orthogeriatric co-management adds:

• Delirium prevention and screening (for example the 4AT), with reorientation, sensory aids, hydration, sleep hygiene and avoidance of precipitating drugs
• Pressure-area, continence, nutrition and hydration care
• Review and deprescribing of falls-risk and sedating medications

Bone health. This fragility fracture is a sentinel event signalling high future fracture risk; in the elderly a rami fracture means osteoporosis, and it is treated. Enrol the patient in a fracture liaison service, arrange bone-density assessment and start the osteoporosis work-up. Correct calcium and vitamin-D deficiency, and select osteoporosis medication after contraindication and renal review; the choice between anti-resorptive and anabolic agents is developed in the osteoporosis topic.

Falls. Undertake a multifactorial falls assessment (gait and balance, vision, postural blood pressure, home hazards) to prevent the next fracture.

The hip-fracture parallel. National hip-fracture programmes and their best-practice standards (early surgery where relevant, orthogeriatric review, bone-health and falls assessment) increasingly bring pelvic fragility fractures onto the same audited pathway, recognising them as an equivalent frailty event rather than a benign isolated injury.

Conservative care. Mobilisation starts on day 1 with a walker or frame and daily physiotherapy. Discharge, home or to rehabilitation, comes when it is safe.

After sacroplasty. Mobilise the same day or the next, weight-bearing as tolerated, with a follow-up radiograph.

An isolated rami fracture has a good outcome if mobilised early. With ring or sacral involvement there may be chronic pain, and sacroplasty can help. Frail elderly patients have high morbidity and mortality from immobility.

Global epidemiology:

• Fragility fractures of the pelvis are rising rapidly with population ageing; the typical patient is a woman in her 80s after a low-energy fall.
• Women are affected roughly 5-6 times more often than men, reflecting postmenopausal bone loss.
• One-year mortality (around 15-20%) and loss of independence approach those of hip fracture, making this a sentinel frailty event rather than a benign injury.

Side-by-side guidance:

Related pages: Pelvic Ring Injuries is the parent topic and the one to read for the high-energy patterns and for posterior fixation technique - the rule that a ring rarely breaks in one place comes from there and is why the CT is mandatory here; Sacral Insufficiency Fracture is the posterior half of this injury and, in most of these patients, the half that actually hurts - the sacroplasty evidence carded above properly belongs to it; Sacral Fractures for the traumatic counterpart and the Denis zones; Lateral Compression Injuries for the mechanism that produces the FFP II pattern in a younger patient; Sacropelvic Fixation for the constructs used when a fragility pattern does need stabilising; Pelvic Discontinuity for the arthroplasty problem that shares this anatomy in the same age group; and Pelvic Avulsion Fractures for the adolescent injury at the other end of life that must not be confused with it radiographically.

Operative or conservative for FFP II? The dominant pattern, rami plus a non-displaced unilateral sacral fracture, sits in a grey zone. A randomised pilot found no functional, pain or mortality advantage for surgery at 1 year, but it was small and underpowered. Most centres start conservatively and fix only those who fail to mobilise.

CT for every rami fracture? CT uncovers a posterior lesion in the majority, from 54% of Studer's consecutive cohort to 96.8% of Scheyerer's selected one, yet most are still treated conservatively. The debate is whether universal CT changes management enough to justify its dose and cost, or whether it should be reserved for persistent pain or inability to mobilise.

How much sacroplasty adds. Cohort data show rapid, early pain relief, but selection bias and limited comparative data prevent a universal success percentage. There is no high-quality randomised comparison against optimised conservative care, so its true added benefit and patient selection remain debated.

Reliability of the FFP grade. Interobserver agreement on the FFP grade is only moderate, and worst exactly where it matters most: complete versus incomplete sacral fractures, the distinction that swings the operative decision.