When should an MRI of the wrist be ordered after a soft‑tissue injury with normal plain radiographs?

When to Order MRI After Soft Tissue Wrist Injury

Order MRI without IV contrast when initial radiographs are normal but clinical suspicion for fracture or soft tissue injury remains high, particularly if pain persists beyond 2 weeks or if there is concern for ligamentous injury, tendon pathology, or occult fracture. 1, 2

Initial Diagnostic Approach

• Begin with standard 3-view or 4-view radiographs (posteroanterior, lateral, oblique, and scaphoid view) as the mandatory first-line examination 1, 2
• Look specifically for scapholunate diastasis >4 mm, dorsal tilt of lunate >10°, and any subtle cortical disruptions 1, 3
• If radiographs are normal but clinical findings suggest significant injury (persistent tenderness over anatomic snuffbox, inability to bear weight through wrist, or point tenderness over specific carpal bones), proceed directly to MRI rather than empiric casting 2, 3

Specific Indications for MRI Without IV Contrast

High-Priority Scenarios (Order MRI Immediately)

• Worsening pain 2 weeks post-injury despite negative initial radiographs - this is a red flag demanding advanced imaging to rule out occult fracture, ligamentous injury, or bone contusion 2
• Clinical suspicion for scaphoid fracture with negative radiographs - MRI has 94.2% sensitivity and 97.7% specificity for occult scaphoid fractures and can detect concomitant scapholunate ligament tears 1, 2, 3
• Suspected ligamentous injuries (scapholunate or lunotriquetral ligament tears) - these can present with normal radiographs but cause progressive instability and require early diagnosis to prevent chronic wrist instability and arthritis 2, 4
• Suspected tendon injuries - MRI has 92% sensitivity and 100% specificity for flexor tendon injuries and can show the level of tendon retraction and associated pulley injuries 4

Moderate-Priority Scenarios (Consider MRI Within Days to Weeks)

• Persistent radial-sided pain with normal radiographs - to evaluate for tendinopathy, ligamentous injury, or early inflammatory changes 2
• Suspected triangular fibrocartilage complex (TFCC) injury - MRI directly visualizes the TFCC and can detect tears that explain ulnar-sided pain 1, 5
• Clinical findings not explained by radiographs - one study showed MRI changed diagnosis in 55% of patients and changed management in 66% when radiographs didn't explain symptoms 1, 6

What MRI Detects That Radiographs Miss

• Occult fractures - particularly scaphoid, distal radius, and other carpal bones that are radiographically invisible 1, 2, 6
• Bone bruises/contusions - 56 bone bruises were found in one study of 155 patients with "normal" radiographs 6
• Ligamentous injuries - scapholunate ligament tears, lunotriquetral ligament injuries, and TFCC perforations 1, 2, 6
• Tendon pathology - including flexor and extensor tendon injuries, tenosynovitis, and pulley injuries 4, 7
• Early avascular necrosis - MRI is the only modality sensitive enough to detect early-stage post-traumatic avascular necrosis 5, 8

Alternative to MRI: When to Consider CT Instead

• CT without IV contrast is an acceptable alternative when MRI is contraindicated, unavailable, or when metallic implants produce artifact 1, 3
• CT is preferred for complex carpal fracture-dislocations, hook of hamate fractures, and preoperative planning for intra-articular distal radius fractures 1, 3
• However, CT cannot evaluate concomitant ligamentous injuries unlike MRI, which is a critical limitation in soft tissue wrist injuries 1, 4

The Traditional "Cast and Wait" Approach Is Outdated

• The older approach of placing patients in a short arm cast and repeating radiographs at 10-14 days results in delayed diagnosis and may lead to functional impairment 1, 2
• Early MRI (within days of injury) is more cost-effective because it reduces unnecessary immobilization, shortens periods of being unable to work, and allows for more differentiated treatment 9
• In one study, MRI-based therapeutic decisions shortened the period of being unable to work in 16 of 54 patients and eliminated the need for radiological follow-up in 35 of 56 cases 9

Critical Pitfalls to Avoid

• Do not rely on 2-view radiographs alone - this is inadequate for detecting wrist fractures, and even 3-view series can miss important pathology 2, 4
• Do not dismiss persistent pain after negative radiographs - in four out of five patients with normal X-rays, MRI identified pathological findings 6
• Do not delay MRI if clinical suspicion is high - waiting 2 weeks for repeat radiographs can miss the window for optimal treatment of ligamentous injuries and occult fractures 2, 9
• Avoid ordering MRI with IV contrast - there is no evidence to support its use in acute hand and wrist trauma 1

Practical Clinical Algorithm

1. Obtain 3-4 view radiographs immediately after injury 1, 2
2. If radiographs show fracture, proceed with appropriate fracture management; consider MRI if ligamentous injury is suspected 1
3. If radiographs are normal but high clinical suspicion (anatomic snuffbox tenderness, inability to bear weight, point tenderness over carpal bones), order MRI without IV contrast within 1-4 days 2, 3, 9
4. If radiographs are normal and clinical suspicion is moderate, consider short-term immobilization with re-evaluation in 7-10 days; if pain persists or worsens, order MRI immediately 2
5. If MRI reveals occult fracture or ligamentous injury requiring repair, refer to hand surgery or orthopedics 2

Evidence Quality Note

The ACR Appropriateness Criteria (2019) provides the strongest guideline-level evidence for this approach 1, supported by prospective research showing that 80% of "wrist sprains" with normal radiographs have identifiable pathology on MRI 6. The traditional "cast and wait" approach has been superseded by evidence demonstrating superior clinical and economic outcomes with early MRI 9.