In a patient with left foot pain that worsens when walking barefoot, who had a prior bunionectomy and infusion and an x‑ray to evaluate for hardware loosening, should a non‑contrast CT scan of the left foot be obtained to assess for hardware loosening?

CT Without Contrast is Appropriate for Evaluating Hardware Loosening After Bunionectomy

In this patient with post-bunionectomy pain and equivocal x-rays, obtaining a non-contrast CT scan of the left foot is appropriate and supported by evidence to definitively assess for hardware loosening.

Rationale for CT Imaging

The ACR Appropriateness Criteria 1 establish that while radiography is the initial imaging modality for chronic foot pain, CT without IV contrast is "usually appropriate" as the next imaging study after negative or equivocal radiographs in patients with chronic foot pain of suspected osseous origin 1. Your patient has already completed the appropriate first step (x-ray), and the clinical concern specifically involves hardware complications—an osseous/mechanical issue.

Why CT is Superior in This Context

Multi-detector CT has demonstrated strong diagnostic performance for orthopedic hardware complications, with:

• 95% specificity for detecting hardware complications 2
• 88% positive predictive value 2
• Significantly superior detection compared to radiography alone (ROC area 1.00 vs 0.84, P < .05) 2

The study by 2 specifically identified hardware loosening as one of the complications effectively detected by CT, alongside nonunion, malplacement, and perihardware fractures.

Clinical Algorithm for Post-Surgical Foot Pain

When evaluating post-bunionectomy pain:

1. Initial radiographs (already completed) - assess for obvious hardware failure, fracture, or malalignment
2. If radiographs are negative or equivocal AND pain persists → Proceed to CT without contrast 1
3. CT provides definitive assessment of:
   • Hardware position and integrity
   • Bone-hardware interface (loosening)
   • Occult fractures
   • Nonunion at osteotomy sites 3, 4

Important Clinical Considerations

Multiple Pain Generators May Coexist

Hardware prominence causing soft tissue irritation is a common pain source in operated feet 5. However, don't assume hardware is the only issue—peroneal tendon impingement 6, nonunion 4, and other complications can occur simultaneously.

Barefoot Pain Pattern

The fact that pain worsens when walking barefoot suggests mechanical irritation, which could be:

• Prominent hardware impinging on soft tissues
• Instability from hardware loosening
• Nonunion with motion at the osteotomy site

CT vs MRI Decision

While MRI is excellent for soft tissue evaluation, CT without contrast is the preferred modality when hardware complications are the primary concern 1, 2. MRI would be considered if soft tissue pathology (tendon tears, nerve entrapment) becomes the leading differential after CT.

Common Pitfalls to Avoid

• Don't delay advanced imaging if x-rays are equivocal and symptoms persist—this prolongs disability and may allow complications to worsen
• Don't assume all post-surgical pain is "normal healing"—persistent pain beyond 3 months warrants investigation 1
• Don't order MRI first when hardware assessment is needed—metal artifact degrades image quality and CT is more specific for osseous/hardware evaluation 2

The CT scan will provide the definitive anatomic information needed to guide treatment, whether that involves hardware removal, revision surgery, or conservative management.