What are the key considerations for risk assessment in patients undergoing surgical total joint replacement?

Risk Assessment for Surgical Total Joint Replacement

All patients undergoing total hip or knee arthroplasty are at high risk for venous thromboembolism and require systematic preoperative risk stratification focusing on infection risk, bleeding risk, and medical optimization. 1

Patient-Specific Risk Factors Requiring Careful Consideration

High-Risk Conditions for Prosthetic Joint Infection

The following conditions substantially increase infection risk and warrant careful preoperative optimization or reconsideration of surgical timing: 1

• Active infection (strongly caution against proceeding with surgery given the risks) 1
• Immunocompromised status including inflammatory arthropathies (rheumatoid arthritis, systemic lupus erythematosus), drug-induced immunosuppression, radiation-induced immunosuppression, transplant recipients, and cancer patients 1
• Previous joint infection at any site 1
• Uncontrolled diabetes (controlled diabetes is moderate risk) 1
• Malnutrition 1
• Renal disease 1
• Liver disease (hepatitis, cirrhosis) 1
• Peripheral vascular disease 1

Moderate-Risk Conditions Requiring Optimization

Proceed only after careful consideration and optimization of: 1

• Anticoagulation status/active thromboprophylaxis 1
• Autoimmune disease 1
• HIV status (proceed only after careful consideration of control and risks) 1
• Institutionalized patients 1
• Previous bariatric surgery 1
• Anemia 1
• Tobacco use 1
• Alcohol use 1
• Mental health disorders (including depression) 1
• Heart failure 1

Preoperative Laboratory and Diagnostic Testing

Essential Blood Tests

Strong evidence supports obtaining the following preoperative blood tests: 1

• Serum erythrocyte sedimentation rate (ESR) 1
• Serum C-reactive protein (CRP) 1
• Serum interleukin-6 1
• Hemoglobin and hematocrit to assess for preoperative anemia 1, 2

When both ESR and CRP are negative, infection is unlikely; positive results for either warrant joint aspiration. 1, 3

Urinary Tract Screening

Preoperative urine must be sterile before proceeding with surgery. 1 If any bacteriuria is present preoperatively, the risk of bacteremia is dramatically increased and antibiotic treatment of the bacteriuria is required before manipulation of the urinary tract or joint surgery. 1

Dental and Skin Screening

Consider dental screening and MRSA/skin decontamination as part of preoperative evaluation. 2 The most critical period for hematogenous seeding of total joint implants is the first 2 years after joint replacement. 1

Type and Screen Considerations

Routine type and screen (T&S) is not necessary for unilateral total joint arthroplasty patients in specialty surgical hospitals. 4 However, T&S should be routinely ordered for:

• Simultaneous bilateral total hip arthroplasty (transfusion rate 21.1%) 4
• Simultaneous bilateral total knee arthroplasty (transfusion rate 3.1%) 4
• Unilateral total hip arthroplasty only if additional risk factors present (transfusion rate 2.7%) 4

Unilateral total knee arthroplasty has a 0% transfusion rate and does not require routine T&S. 4

Venous Thromboembolism Risk Assessment

Universal High-Risk Status

All patients undergoing total hip or knee arthroplasty are at high risk of venous thromboembolism. 1 There is no evidence that clinical assessment can identify groups at low enough risk to justify no prophylaxis. 1

VTE Prophylaxis Recommendations

For elective hip replacement, LMWH is preferred over adjusted-dose warfarin (INR target 2.5, range 2.0-3.0) because it has been found more effective in preventing asymptomatic VTE. 1 The risk of bleeding at the surgical site and wound hematoma may be greater with LMWH than with adjusted-dose warfarin. 1

For elective knee replacement or hip fracture surgery, LMWH or adjusted-dose warfarin is recommended. 1

Fondaparinux 2.5 mg SC once daily initiated 6±2 hours after surgery demonstrated superior efficacy compared to enoxaparin in knee replacement (VTE rate 12.5% vs 27.8%, relative risk reduction 55%, P<0.001). 5

Duration of Prophylaxis

The risk for DVT persists for up to 2 months following total hip replacement surgery, with continuing risk of 12-37% identified in trials evaluating prophylaxis beyond hospital stay. 1 Prophylaxis should be continued for approximately 5 weeks for total hip replacement. 1

Timing Considerations for Intra-Articular Injections

Limited evidence suggests intra-articular injection done before total joint arthroplasty may have a time-dependent association for increased risk of prosthetic joint infection. 1 Consider delaying surgery after recent joint injections.

Metabolic and Weight Optimization

Preoperative metabolic optimization and weight control should be addressed during risk assessment. 2 Obesity is a recognized risk factor for thromboembolic complications in abdominal surgery patients and likely applies to joint replacement. 5

Obstructive Sleep Apnea Screening

Screen for obstructive sleep apnea as part of comprehensive preoperative evaluation. 2 This condition may affect perioperative management and anesthetic considerations.

Critical Pitfalls to Avoid

• Never proceed with surgery in the presence of active infection or untreated bacteriuria 1
• Do not assume low infection risk based solely on absence of obvious clinical signs - chronic infections may present with pain alone without inflammatory signs 3, 6
• Do not withhold VTE prophylaxis based on clinical risk stratification - all total joint patients are high risk 1
• Do not ignore preoperative anemia - it is an independent risk factor requiring correction 1, 2
• Do not overlook immunosuppressed states including inflammatory arthropathies, which substantially increase infection risk 1