What preoperative evaluations and interventions are necessary for a patient to be cleared for a total hip replacement surgery?

Preoperative Clearance for Total Hip Replacement

To be cleared for total hip replacement, you must undergo mandatory preoperative anesthesia assessment, complete routine laboratory testing (complete blood count and electrolytes), have an ECG performed, optimize any anemia with hemoglobin >9 g/dL (or >10 g/dL if you have heart disease), and ensure proper management of anticoagulation medications. 1

Essential Laboratory Investigations

Routine testing required for all patients:

• Complete blood count (CBC) - mandatory to assess for anemia and infection 1
• Urea and electrolytes - mandatory to evaluate kidney function and electrolyte balance 1
• Electrocardiogram (ECG) - required in all elderly patients 1

Conditional testing (only if clinically indicated):

• Coagulation studies - only needed if you have bleeding disorders or take anticoagulants 1
• Chest radiograph - only if you have newly diagnosed heart failure or pneumonia 1

Anemia Management Protocol

Approximately 40% of hip replacement patients present with preoperative anemia, which significantly increases risk of postoperative complications. 1

Your hemoglobin must meet these thresholds:

• If Hb <9 g/dL: Consider preoperative blood transfusion 1
• If Hb <10 g/dL AND you have ischemic heart disease: Consider preoperative transfusion 1
• If Hb 10-12 g/dL: Two units of blood should be crossmatched 1
• If Hb is normal: A grouped blood sample is sufficient 1

The expected hemoglobin drop during surgery is approximately 2.5 g/dL, making preoperative optimization critical to avoid myocardial and cerebral ischemia. 1, 2

Anticoagulation Management

If you take aspirin (33% of patients do):

• May be withheld during hospital stay unless needed for unstable angina or recent transient ischemic attacks 1
• Increases bleeding risk when combined with other blood thinners 1

If you take clopidogrel (4% of patients):

• Generally NOT stopped on admission, especially if you have cardiac stents 1
• Expect marginally greater blood loss during surgery 1, 2
• Do NOT receive prophylactic platelets 1

If you take warfarin (5% of patients):

• INR must be <2 for surgery 1
• INR must be <1.5 for spinal/epidural anesthesia 1
• Follow your hospital's specific warfarin management protocol 1

If you take direct oral anticoagulants (DOACs like rivaroxaban, apixaban, dabigatran):

• Must be stopped 2-5 days before surgery depending on your kidney function and the specific medication 1
• Timing varies based on creatinine clearance, age, and concomitant medications 1
• No heparin bridging is needed except in very high thrombotic risk cases 1

Platelet Count Requirements

Your platelet count determines anesthesia options:

• Platelet count 50-80 × 10⁹/L: Relative contraindication to spinal/epidural anesthesia 1
• Platelet count <50 × 10⁹/L: Requires preoperative platelet transfusion 1

Comorbidity Assessment

Approximately 70% of hip replacement patients have ASA physical status 3-4, with multiple medical conditions requiring optimization. 1

The most common comorbidities requiring preoperative evaluation:

• Cardiovascular disease (35% of patients) 1
• Respiratory disease (14%) 1
• Cerebrovascular disease (13%) 1
• Diabetes (9%) 1
• Malignancy (8%) 1
• Renal disease (3%) 1

Additional assessments needed:

• Musculoskeletal abnormalities (osteoarthritis, kyphoscoliosis, fixed flexion deformities) 1
• Skin condition and pressure areas 1
• Dentition status 1
• Hearing aids 1

Medication Review

If you are over 60, you likely take multiple medications (20% of people over 70 take more than five medications), which increases risk of adverse drug reactions. 1

Your medication list must be reviewed for:

• Inappropriate dosing given your age and kidney function 1
• Potential drug interactions 1
• 80% of adverse drug reactions in this population are potentially avoidable 1

Electrolyte Optimization

Specific electrolyte abnormalities to correct:

• Hypokalemia: Associated with new onset rapid atrial fibrillation perioperatively 1
• Hyperkalemia: May indicate rhabdomyolysis if you were immobilized after falling 1
• Hyponatremia: Common (17% of patients), may indicate infection or result from thiazide diuretics 1

Infection Screening

White blood cell count interpretation:

• Leukocytosis and neutrophilia are common (45% and 60% respectively) and may be reactive to trauma 1
• Leukocytosis >17 × 10⁹/L: Likely indicates infection (commonly chest or urinary tract) requiring treatment before surgery 1

Critical Pitfalls to Avoid

• Do NOT proceed with spinal/epidural anesthesia if you have insufficient anticoagulation discontinuation time, especially if you take dabigatran and are over 80 years old or have kidney failure 1
• Do NOT delay surgery for clopidogrel cessation, particularly if you have drug-eluting coronary stents 1
• Do NOT skip preoperative anesthesia assessment - this is mandatory for planning anesthetic technique, assessing perioperative risk, and optimizing your condition 1