When is total knee arthroplasty indicated and what pre‑operative evaluation and peri‑operative management are recommended?

Total Knee Arthroplasty: Indications, Pre-operative Evaluation, and Peri-operative Management

Primary Indication for Surgery

Total knee arthroplasty should be performed in patients with moderate-to-severe radiographic osteoarthritis (or advanced osteonecrosis with secondary arthritis) who have moderate-to-severe pain and functional disability that persists despite completion of at least one trial of appropriate non-operative therapy. 1, 2

Mandatory Pre-operative Requirements

Before proceeding to surgery, patients must meet ALL of the following criteria:

• Radiographic confirmation of moderate-to-severe structural joint damage using validated grading systems (Kellgren-Lawrence or Tönnis classification) 1, 2

• Documented failure of at least one trial of appropriate non-operative therapy, which includes: 1

  • Physical therapy
  • NSAIDs or other analgesics
  • Intra-articular injections (glucocorticoids or viscosupplementation)

• Moderate-to-severe symptoms including pain or functional limitation that substantially impairs quality of life 1, 2

• Shared decision-making process completed between patient and surgeon, with discussion of risks, benefits, and realistic expectations 1, 2

Critical Timing Recommendation

Once the above criteria are met, proceed directly to surgery without arbitrary delays for additional non-operative treatments. 1

The 2023 ACR/AAHKS guidelines specifically recommend AGAINST delaying surgery for:

• Additional physical therapy trials 1
• Further NSAID trials 1
• Additional intra-articular injections 1
• Braces or ambulatory aids 1
• Arbitrary 3-month "cool-down" periods 1

Rationale: Patients in this defined population have already attempted prolonged conservative treatment, and further delays may lead to increased pain, worsening function, and deterioration of medical comorbidities due to limited mobility. 1

Pre-operative Risk Factor Optimization

Conditions That SHOULD Delay Surgery:

• Nicotine dependence: Conditionally recommend delaying surgery for nicotine cessation or reduction 1

• Poorly controlled diabetes: Conditionally recommend delaying surgery to improve glycemic control (though no specific HbA1c threshold is defined) 1

Conditions That Should NOT Delay Surgery:

• Obesity (any BMI level): Conditionally recommend proceeding without delay to meet rigid BMI thresholds 1

  • Patients should be educated about increased surgical risks and counseled on weight loss methods 1
  • However, lack of resources to achieve weight loss should not be an absolute contraindication 1, 3

• Severe deformity or bone loss: Proceed without delay 1

• Neuropathic joint: Proceed without delay 1

Expected Outcomes

Approximately 89% of patients achieve good-to-excellent pain relief and functional improvement lasting up to 5 years post-operatively. 2, 3, 4

The evidence demonstrates:

• Substantial pain reduction 4, 5
• Significant functional improvement 4, 5
• Enhanced quality of life 2, 4
• TKA followed by non-surgical treatment is 18.3 points more effective on KOOS scores than non-surgical treatment alone 5

Peri-operative Analgesia Recommendations

For optimal pain control, the evidence supports: 1

Primary anesthetic technique (choose one):

• General anesthesia combined with femoral nerve block 1
• Spinal anesthesia with local anesthetic plus spinal morphine 1

Supplementary multimodal analgesia:

• Paracetamol (acetaminophen) 1
• Conventional NSAIDs or COX-2 selective inhibitors 1
• Cooling and compression techniques 1
• Strong IV opioids for high-intensity pain or weak opioids for moderate-intensity pain 1

Common Pitfalls to Avoid

• Do not mandate arbitrary waiting periods (e.g., 3 months) once surgical criteria are met, as this only prolongs suffering without evidence of benefit 1

• Do not delay surgery solely for obesity or to meet rigid BMI cutoffs, as there is no evidence that achieving specific weight targets improves outcomes 1

• Do not use isolated criteria (severe pain alone or radiographic changes alone) without considering the complete clinical picture including functional limitation and failed conservative therapy 2

• Do not perform surgery in patients who have not attempted appropriate non-operative therapy first 1, 2

• Do not proceed in patients with mild radiographic OA, minimal pain/disability, or those who have not tried conservative treatment 1

Important Caveats

All recommendations from the 2023 ACR/AAHKS guidelines are conditional due to very low to low quality evidence, though expert consensus was high or unanimous for all recommendations. 1 This reflects the reality that high-quality randomized controlled trials comparing TKA to non-surgical treatment are lacking. 2, 4

The decision must ultimately be made through shared decision-making, considering individual patient circumstances, comorbidities, and personal preferences. 1, 2