Within our true pelvis lies the rectum, bladder, uterus, iliac vessels and lumbosacral nerve roots. Thus a pelvic fracture may lead to a major haemorrhage, neurological deficits, urogenital trauma and damage to the bowel.
Pelvic fractures can be caused by low impact and high impact injuries, however, they are mostly associated with high energy blunt trauma such as road traffic accidents (RTAs) and falls from heights. However, in the elderly, a fall from standing height often causes pelvic fractures (fragility fractures).
😷 Presentation
Symptoms vary depending on the site and severity of the fracture. It is mostly significant sharp pain in the hip that is felt.
- Pelvic deformities - abnormal positioning of the lower limbs may be noticed.
- Pain and swelling
- Bruising
- Inability to weight bear on the affected side.
- Nerve injury - damage to sacral roots may occur, presenting as pain, paraesthesia, weakness, hyporeflexia, especially in the lower limbs.
Our pelvis is made up of 2 innominate bones which themselves are comprised of 3 parts:
- Ilium
- Ischium
- Pubis
We also have a pelvic ring which is made up of the innominate bones and the sacrum. Anything sit above the pelvic inlet is considered a part of the false pelvis while anything between the inlet and outlet is considered a part of the true pelvis.
On examination, the patient may be seen to have an ecchymosis or developing haematoma in the perineal, scrotal or labial regions.
In young patients especially, they tend to have low-energy injuries which are avulsion fractures. These present with poorly localised pain that is sudden especially when performing rapid movements (such as starting to run). The pain is exacerbated when contracting muscles. Most commonly on the ASIS (sartorius), AIIS (rectus femoris), ischial tuberosity (hamstrings). These are managed conservatively unless we see significant displacement of the avulsed bone.
🔍 Investigations
3 plain film radiographs minimum is required to assess the pelvic brim. We need an AP view, inlet view and outlet view.
🏆 CT scan, if possible, will mitigate the need for plain films. It is usually done in the trauma setting as the first-line option.
A complete neurovascular assessment should also be done.
🔢 Classification
There are 3 classification systems we can use for pelvic ring injuries:
- Young and Burgess classification
- Tile classification
- Denis classification
Young and Burgess classification
This classification is grouped on the vector of the disrupting force and the subsequent degree of displacement.
- Antero-posterior compression (APC)
- I - disruption of the pubic symphysis, separation (diastasis) <2.5cm, posterior ligamentous structures are intact.
- II - disruption of pubic symphysis, diastasis >2.5cm, disruption of sacrospinous, sacrotuberous and anterior sacroiliac ligaments.
- III - same as APCII but posterior sacroiliac injury is complete.
- Lateral compression (LC)
- I - transverse/oblique fracture of the pubic ramus. Often concomitant crush fracture of the ipsilateral sacral ala.
- II - rami fracture + fracture of iliac blade with resulting crescent fragment.
- III - same as LCII but contralateral iliac wing opens to form a windswept pelvis.
- Vertical shear (VS)
- I - unilateral complete loss of attachment between the sacrum and the lower limb.
- II - same as VSI but bilateral injury is seen.
Denis classification
Describes line of fracture in sacrum with relation to sacral foramina:
- Type 1 - lateral to the foramina.
- Type 2 - transforaminal.
- Type 3 - medial to the foramina.
Tile classification
Fractures are based on the stability of the pelvic ring.
- A-type fractures - rotationally and vertically stable.
- B-type fractures - horizontally unstable but vertically stable (partially stable)
- C-type fractures - both horizontally and vertically unstable.
🧰 Management
- If it is a high energy trauma, ATLS guidelines should be followed with a primary survey to identify if any life-threatening injuries.
- Significant amount of blood loss may occur, commonly due to retroperitoneal venous plexus internal iliac arteries or intraabdominal haemorrhage → hypovolaemic shock.
- Hypotensive patient with pelvic trauma is assumed to have pelvic fracture until proven otherwise → pelvic binder should be placed for stabilisation and attempted clot formation.
- Conservative - resuscitation and haemodynamic stabilisation.
- If the patient is haemodynamically unstable → interventional radiology/laparotomy ± retroperitoneal packing.
- Operative - indications include: life threatening haemorrhage, unstable fractures, open fractures, urological injury. Stabilisation approach is done via the Young and Burgess classification with both anterior and posterior stabilisation.
Hip fractures commonly occur in elderly people by falling from a standing height. It is associated with osteoporosis especially in the elderly. In younger patients it is associated with high-energy trauma such as motor vehicle accidents and falls from height.
We consider a hip fracture to be any fracture of the femur distal to the femoral head and proximal to a level just below the lesser trochanter.
About 65,000 hip fractures occur each year in the UK and are becoming more prominent in the ageing population. The mortality rate is very high with up to 30% mortality at one year.
🦴 Anatomy
Let’s recap our hip anatomy quickly:
Our hip is a ball and socket synovial joint that is formed by an articulation between the acetabulum (pelvic portion) and the head of femur (femoral portion). It is designed for stability and weight-bearing, but as a a result compromises slightly of range of movement.
- Acetabulum - cup-like depression on the inferolateral aspect of the pelvis. It is deepened by the addition of a fibrocartilagenous cuff known as the acetabular labrum.
- Head of femur - hemispherical shape fits into the depression of the acetabulum.
The capsule of the hip attaches to the edge of the acetabulum proximally and distally it attaches to the Inter trochanter if line anteriorly and the femoral neck posteriorly.
There are some ligaments that are present to increase stability. We can classify them as intracapsular or extracapsular:
Intracapsular ligament:
Only 1 ligament is the ligament of the head of femur (aka ligamentum teres) which runs from the acetabular fossa → fovea of the femur. It contains an artery which is a branch of the obturator artery known as the artery of ligamentum teres (aka foveolar artery).
Extracapsular ligaments:
- Iliofemoral ligament - comes from the AIIS and bifurcates before inserting into the intertrochanteric line of the femur (Y-shaped). It prevents hyperextension of the hip (strongest hip ligament).
- Pubofemoral ligament - from the superior pubic rami → intertrochanteric line of the femur. It supports the capsule anteriorly and inferiority. Triangular in shape. Prevents excessive abduction and hyperextension.
- Ischiofemoral ligament - from body of the ischium → greater trochanter of the femur. Reinforces the posterior aspect of the capsule. Spiral in orientation and prevents hyperextension + holds femoral head in the acetabulum.
The hip joint is predominantly supplied by the medial + lateral circumflex femoral arteries (which are branches of the profunda femoral). These 2 arteries anastomose at the base of the neck and form retinacular arteries that supply the joint itself.
The medial circumflex femoral artery is responsible for the majority of the supply to the neck of femur. The foveal artery and gluteal arteries (both superior and inferior) also provide some additional supply to the neck. However, damage to the MCFA may result in AVN of the femoral head.
Nervous innervation is supplied by the sciatic, femoral and obturator nerves, this is also true for the knee that is why hip pain may be referred to the knee and the converse is also true.
🔢 Classification
There are 2 major classifications for hip fractures
- Intracapsular fractures - these run from the subcapital region → basocervical region (proximal to the trochanters). Ultimately these are neck of femur fractures. They can be subclassified as:
- Subcapital
- Midcervical
- Basal
- Extracapsular fractures - can also be subdivided into:
- Inter-trochanteric - between the greater and lesser trochanter.
- Sub-trochanteric - between the lesser trochanter → 5cm distally.
We have classification systems to categorise both intracapsular and extracapsular fractures.
For intracapsular fracture, we use the Garden classification system:
- Type 1 - non-displaced (stable) fracture with impaction in valgus.
- Type 2 - complete fracture but undisplaced.
- Type 3 - complete fracture with displacement in varus but still has boney contact.
- Type 4 - complete displacement.
The AO classification system is used for extracapsular fractures:
This categorises fractures by location, joint involvement, pattern and geometry.
😷 Presentation
- History of trauma
- Pain - especially when pin-rolling the leg and axial loading (pushing up from the base of the foot for example). Flexion and extension of the hip also may elicit pain.
- Referred pain to the knee is common. The groin and thigh regions are also common places for referred pain.
- Inability to weight bear
- Shortened and externally rotated leg - this is due to the pull of the external rotators (deep gluteal muscles) especially in a displaced fracture.
⚠️ Risk factors
- Older age
- Osteoporosis*
- Female sex
- Trauma - high-energy is especially prevalent in young patients.
- Medications - some drugs increase the risk of fracture while others increase the risk of falls.
- Alcohol consumption
- Levothyroxine - decreases bone density.
- Loop diuretics - impairs Ca2+ absorption in the kidneys.
- PPIs - reduce Ca2+ absorption.
- Corticosteroids - long-term use may lead to osteoporosis.
- Bisphosphonates - although it is used in the treatment of osteoporosis, long-term use is associated with atypical hip fractures.
- Sedatives - antidepressants, antihistamines etc.
- Antihypertensives - due to postural hypotension and dizziness.
- Opioids - due to sedative effects.
We can use the QFracture or FRAX caculcators to calculate the absolute risk of hip fracture to major osteoporotic fractures over 10 years.
A FRAX may indicate the patient needing a DEXA scan.
⬅️ A DEXA scan is then used to calculate a T-score which can advise
- <2.5 - give bisphosphonate (alendronate) + vitamin D supplementation.
- >2.5 - modify risk factors and repeat DEXA.
☝️ However, NICE now says that anyone with a fragility fracture and is >50 years old, they need to be referred for DEXA scan.
🔍 Investigations
🏆 Plain-film radiograph should be done with AP and lateral views.
- On the AP view look for interruption of Shenton’s line and any breach in the cortex of the bone.
- On the lateral view look for anterior displacement of the shaft/neck, any increased bone density (due to impaction), breach in the cortex.
If there is no evidence on X-ray then MRI hip should be done as these are first-line for occult hip fractures.
Routine bloods should be done such as an FBC, U&Es, coagulation screen, G&S to assess for fitness for surgery.
Anaemia is present in 50% of patients with a hip fracture.
🧰 Management
An initial management entails an A-E approach to stabilise the patient and treat any life/limb-threatening injuries. This is especially true for high-impact traumas but because of the patients at risk of low-impact injuries, they should also be assessed for such risks.
🥇 Analgesia is of course necessary. It can be either opioid analgesia or regional blocks such as a fascia-iliaca block.
- Morphine - can be given with IV infusion.
- Regional blocks - fascia-iliaca block is given to block the femoral, lateral femoral cutaneous, and obturator nerves. It is given lateral to the femoral pulse (more accurately we can divide the ASIS → pubic symphysis into thirds and then we choose the point between the lateral and medial 1/3rd and then go 1cm below)
The only definitive management is surgical:
Intracapsular fractures:
- Simply put, if it is an undisplaced fracture (Garden I or II) → internal fixation or hemiarthroplasty if unfit for IF.
- If it is a displaced fracture, arthroplasty is recommended. This may be a hemi or total. Hemiarthroplasty’s are reserved for patients who are less fit for surgery and generally have <10 years of life left. More fit patients who are more mobile will qualify for total hip replacement.
- Total hip replacement is favoured if the patient is medically fit for the procedure, able to walk with no more than the use of a stick, and are not cognitively impaired.
Extracapsular fractures:
- Stable intertrochanteric fractures → dynamic hip screw.
- An intramedullary device may be placed for reverse oblique, transverse or subtrochanteric fractures.
⭐️ Patients should be able to fully weight bear immediately post-op. This reduces the length of stay and the complications associated with prolonged immobility such as chest infection, VTE, pressures sores.
Early physiotherapy and occupational therapy is also recommended post-operatively.
🚨 Complications
- Avascular necrosis of the femoral head - especially with displaced intracapsular fractures as this disrupts the MCFA.
- MRI is used to diagnose AVN. If it has been a long time, an X-ray will show different densities of the bone.
- Discuss this more (24/01/2022)
- Non-union
- Post-operative complications:
- Pain
- Bleeding
- Leg-length differences
- Neurovascular damage
- Joint dislocation
- Peri-prosthetic fracture
- Aseptic loosening
- Infection