How to manage knee pain after total knee replacement?

Management of Knee Pain After Total Knee Replacement

The first step in managing knee pain after total knee replacement should be a plain radiograph (X-ray) of the knee to evaluate for complications, followed by appropriate diagnostic and therapeutic interventions based on the suspected cause of pain. 1

Initial Evaluation

• Plain radiographs (X-rays) of the knee should be obtained first in all patients with pain after total knee arthroplasty (TKA) to assess component positioning, alignment, and potential complications 1
• Joint aspiration should be performed after reviewing the X-ray if infection is suspected, as this is the most serious complication of TKA (occurring in 0.8-1.9% of cases) 1
• Clinical assessment should focus on differentiating between common causes of post-TKA pain:
  • Infection (may present with night pain, pain at rest, warmth, erythema) 1
  • Aseptic loosening (typically pain on weight bearing) 1
  • Component malrotation or instability 1
  • Periprosthetic fracture 1
  • Soft tissue impingement or tendinopathy 2

Management Algorithm Based on Suspected Cause

1. When Infection is Suspected:

• Obtain knee radiographs followed by joint aspiration for cell count, culture, and sensitivity 1
• If aspiration cultures are positive for infection:
  • Proceed to surgical management as per AAOS guidelines 1
  • Additional imaging with MRI or CT with contrast may be considered but is not required before surgical intervention 1
• If aspiration results are negative/inconclusive but infection is still suspected:
  • Repeat joint aspiration 1
  • Consider nuclear medicine studies (Tc-99m 3-phase bone scan and In-111 WBC scan) 1

2. When Aseptic Loosening is Suspected:

• After negative infection workup, obtain CT of the knee without IV contrast 1
• Fluoroscopy may be helpful to detect radiographically occult loosening 1
• Tc-99m 3-phase bone scan may be appropriate to evaluate for loosening 1

3. When Component Rotation Issues are Suspected:

• CT scan without IV contrast is the imaging modality of choice 1
• MRI without contrast may be considered as an alternative 1

4. When Periprosthetic Fracture is Suspected:

• Obtain radiographs followed by CT without IV contrast for definitive evaluation 1
• MRI without contrast may be appropriate in some cases 1

5. When Soft Tissue Pathology is Suspected:

• MRI without contrast or ultrasound are equally appropriate for evaluating soft tissue abnormalities such as quadriceps or patellar tendinopathy, arthrofibrosis, or nerve impingement 1

Pain Management Strategies

• Implement multimodal analgesia including:

  • Acetaminophen (paracetamol) as baseline therapy 3
  • NSAIDs or COX-2 inhibitors if not contraindicated 3
  • Opioids should be reserved as rescue medications 3

• For acute postoperative pain management:

  • Consider adductor canal block and peri-articular local infiltration analgesia 3
  • A single intraoperative dose of IV dexamethasone may reduce inflammation and pain 3

• For chronic pain (>3 months after surgery):

  • Address pain catastrophizing and psychological factors that may contribute to persistent pain 4
  • Monitor for signs of low-grade inflammation (elevated C-reactive protein) which may indicate ongoing inflammatory processes 4
  • Optimize physical therapy to improve range of motion and function 4

Common Pitfalls and Caveats

• Up to 20% of patients may experience chronic postoperative knee pain after TKA, requiring careful evaluation and management 4
• Many patients report that the worst pain period occurs during the first 2 weeks at home after discharge, highlighting the importance of adequate pain management education and planning 5
• Inadequate information about analgesics and non-pharmacological pain management methods at discharge is common and contributes to poor pain control 5
• Negative perceptions about analgesic use may lead to undertreatment of pain 5
• Higher pain severity is associated with decreased satisfaction and reduced mobility, which can negatively impact recovery 5
• Soft tissue impingement in the intercondylar notch can cause pain that may be relieved by excision of hypertrophic fibrous tissue 2

Follow-up Recommendations

• For asymptomatic patients with TKA, routine follow-up with knee radiographs is appropriate 1
• For patients with persistent pain despite initial management, consider referral back to the orthopedic surgeon for further evaluation 1
• Annual weight-bearing radiographs are recommended for detecting subclinical wear in the prosthesis 1