Investigations

1st investigations to order

plain radiographs

Test
Result
Test

Order plain radiographs in all patients with a history of a fall or trauma who present with hip pain.[53]

  • Request anteroposterior (AP) pelvic and lateral views of the affected hip.

  • Radiography will show a fracture of the proximal femur.

  • Order a radiograph of the femur if you suspect distal extension of the fracture.

  • Consider ordering any other radiographs needed at the same time to prevent the patient being moved twice (e.g., chest, looking for other bony injuries).

  • If the patient has a history of malignancy, request a full-length radiograph of the femur to identify bony metastases.[69]

Result

  • At least 90% of proximal femoral fractures will be identified on radiographs.[50][68]

  • Fracture visible on radiograph.

  • On the AP view, look for interruption of the smooth curve known as Shenton’s line (from the inferomedial border of the femoral neck to the inferior border of the superior pubic ramus), increased density of bone due to impaction, and any breach in the cortex either medially or laterally.

  • On the lateral view look for anterior displacement of the femoral shaft/neck relative to the head, increased density of bone due to impaction, and any breach in the cortex.

full blood count

Test
Result
Test

Correct anaemia as important to optimise fitness for surgery.[45][46][59][73]

  • Anaemia is present in 50% of patients with hip fracture.[72] 

  • Consider the cause and possibility of underlying malignancy.[49]​ If the fracture is unexplained, consider a diagnosis of myeloma and arrange a full blood count and blood tests for calcium and plasma viscosity or erythrocyte sedimentation rate.[49]

Practical tip

Transfusion preoperatively may be needed when the patient has cardiorespiratory disease or frailty, or is likely to lose a significant amount of blood during the procedure.

Result

  • Acceptable levels will depend on patient factors.

  • Consult local guidelines for when to transfuse.

  • A haemoglobin concentration <80 g/L (<8 g/dL) may be a reason to delay surgery.[59]

urea and electrolytes

Test
Result
Test

Correct any abnormalities as important to optimise fitness for surgery.[46][73]​ 

  • Electrolyte abnormalities are common.[45][46] 

Result

  • Acceptable levels will depend on patient factors.

  • Plasma sodium concentration <120 or >150 mmol/L (<120 or >150 mEq/L) and plasma potassium concentration <2.8 or >6.0 mmol/L (<2.8 or >6.0 mEq/L) may be a reason to delay surgery.[59]

glucose

Test
Result
Test

Important to optimise diabetes management prior to surgery.[46]

  • Hypoglycaemia may cause a collapse.

  • Hyperglycaemia may be related to stress or intercurrent illness.

  • Hyperglycaemia is not a reason to delay surgery unless the patient is ketotic and⁄or dehydrated.[59]

  • Uncontrolled diabetes may be a reason to delay surgery.[59]

Result

  • May reveal hypoglycaemia or hyperglycaemia.

  • A random plasma glucose concentration ≥11.1 mmol/L (≥200 mg/dL) indicates diabetes.[75] 

  • A plasma glucose concentration ≤3.9 mmol/L (≤70 mg/dL) indicates hypoglycaemia.[75]

group and save

Test
Result
Test

This is required as patients with hip fracture are likely to need surgery.[46]

  • Consider the patient’s baseline levels.

Result

  • Consult your hospital’s guidelines on when a transfusion is required.

coagulation screen

Test
Result
Test

Follow local guidelines to reverse any coagulopathy prior to surgery.

  • Attend to a reversible coagulopathy so that it does not cause an unnecessary delay to surgery.[59]

Result

  • May be abnormal in chronic liver disease or if the patient has severe sepsis or multi-organ failure.

ECG

Test
Result
Test

Review the ECG for signs of cardiac syncope, such as heart block, intraventricular conduction abnormalities, or inappropriate sinus bradycardia (40-50 bpm) or slow atrial fibrillation (40-50 bpm) in the absence of negatively chronotropic medications.[46][74]

  • Rarely cardiac syncope is due to tachycardia such as VT.[74]

  • Look for evidence of ischaemic heart disease, such as ST changes or new left bundle branch block, and of prolonged QT interval.[74]

  • Patients may have an increased risk of arrhythmias due to underlying electrolyte abnormalities or anaemia.[45][46] It is important to treat these early to prevent any delay to surgery. 

  • A correctable cardiac arrhythmia with a ventricular rate >120/minute may be a reason to delay surgery.[59]

Result

  • Presence of arrhythmia or myocardial infarction.

Investigations to consider

MRI pelvis

Test
Result
Test

Order if you have a high clinical suspicion of hip fracture despite a negative plain radiograph (i.e., severe pain, and/or shortened and externally rotated leg).

  • MRI has a higher sensitivity detecting occult hip fractures, and is not contingent on time between injury and imaging.[70][71]

Result

  • Presence of marrow oedema and a fracture line.

CT pelvis

Test
Result
Test

Order if you have a high clinical suspicion of hip fracture, despite a negative plain radiograph, and MRI is not available within 24 hours or is contraindicated.[45]

  • Useful for picking up alternative causes for hip pain, such as pubic rami fractures, acetabular fractures, and iliopsoas haematoma.

Result

  • Presence of a fracture.

technetium bone scan

Test
Result
Test

May be used if there is no access to an MRI or CT; however, the bone scan may be falsely negative for up to 72 hours from the time of injury.[50]​ False positives may also arise with bone scan, related to osteoarthritis, soft-tissue injury, or any other process that may increase bone turnover.[50]

Result

  • Increased uptake of radioactivity in region of fracture.

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