What could be causing worsening foot pain in a smoker with possible psoriatic arthritis after initial improvement following back surgery within 2 weeks?

Worsening Foot Pain After Back Surgery in a Smoker with Possible Psoriatic Arthritis

The most likely cause of worsening foot pain within 2 weeks after initial improvement following back surgery is post-operative infection, particularly given the patient's smoking status and possible psoriatic arthritis, both of which significantly increase surgical complication risks.

Primary Concern: Post-Operative Infection

Infection Risk in Psoriatic Arthritis Patients

• Patients with psoriasis have a significantly increased risk for post-operative infection in orthopedic surgery, with one study of 55 arthroplasties showing substantially elevated infection rates versus patients with rheumatoid or osteoarthritis 1
• The largest case-control study found psoriasis was a risk factor for post-operative infection in hip replacement surgery, though evidence for other orthopedic procedures shows conflicting results 2, 1
• The typical pattern of initial improvement followed by worsening within 2 weeks is highly consistent with developing surgical site infection 2

Smoking as a Major Risk Factor

• Smoking dramatically increases post-operative complications, with smokers having 1.6 times higher surgical complication rates and 3.3 times higher risk of deep surgical site infections 3
• Smokers are twice as likely to require unplanned return to the operating room (OR 2.0) and have 1.8 times higher risk of hospital readmission within 30 days 3
• Smoking accelerates tissue breakdown through impaired vascular supply, local hypoxia, inflammation, and delayed wound healing—all critical factors in post-surgical recovery 4

Immediate Evaluation Algorithm

Clinical Assessment Required

• Examine the surgical site for signs of infection: erythema, warmth, purulent drainage, wound dehiscence, or fluctuance 2
• Assess for systemic signs: fever, elevated inflammatory markers (CRP, ESR), leukocytosis 2
• Evaluate perfusion status given smoking history: check for adequate blood flow that could impair healing 2

Diagnostic Workup

• Obtain wound cultures if any drainage present to guide antibiotic therapy 2
• Consider advanced imaging (MRI) if deep infection or osteomyelitis suspected, particularly if symptoms persist beyond 2 weeks 2
• Blood cultures if systemic infection suspected 2

Alternative Considerations

Psoriatic Arthritis Flare

• Uncontrolled psoriatic arthritis can cause progressive joint destruction through osteolysis and erosion, potentially affecting surgical sites and adjacent structures 1
• However, a 2-week timeframe with initial improvement makes active inflammatory arthritis less likely as the primary cause 1
• Smoking is independently associated with axial psoriatic arthritis (OR 1.4) and radiographic sacroiliitis (OR 6.6), suggesting the underlying disease may be more severe 5

Failed Surgical Intervention

• Smoking causes delayed wound healing, failed fusion, and increased re-operations in spinal surgery 4
• The initial improvement suggests some surgical benefit, making complete failure less likely but not excluded 4

Management Approach

If Infection Confirmed or Highly Suspected

• Initiate empiric broad-spectrum antibiotics immediately, typically covering Staphylococcus aureus as this is the most common pathogen in post-operative orthopedic infections 2
• Duration of 2 weeks minimum for severe soft tissue infections, longer if bone involvement 2
• Surgical debridement may be necessary if deep infection or abscess present 2

Smoking Cessation Critical

• Immediate and permanent smoking cessation is essential to prevent further complications and optimize healing 4
• Smoking cessation programs should be strongly recommended, as continued smoking will compromise any treatment efforts 6, 7

Psoriatic Arthritis Management

• If infection is ruled out and inflammatory arthritis is contributing, aggressive treatment with biologics (TNF inhibitors or IL-17 inhibitors) is essential to prevent progressive joint destruction 1, 8
• Traditional DMARDs are ineffective for axial manifestations and should not be relied upon for spinal disease 8

Critical Pitfalls to Avoid

• Do not dismiss early post-operative infection based on initial improvement—this biphasic pattern is characteristic of developing surgical site infections 2
• Do not underestimate the compounding effects of smoking and psoriatic arthritis on surgical outcomes—these are independent and additive risk factors 1, 3
• Avoid attributing all symptoms to psoriatic arthritis flare without ruling out infection, as delayed treatment of infection can lead to devastating outcomes including sepsis and amputation 2
• Do not proceed with additional interventions until infection is definitively excluded 2