What is the most likely diagnosis for a 17-year-old with right dorsal wrist pain that worsens with wrist extension, without carpal tunnel signs, and began mildly one week ago?

Dorsal Wrist Capsular Impingement or Extensor Retinaculum Impingement

The most likely diagnosis is dorsal wrist capsular impingement (DWCI) or extensor retinaculum impingement, both of which characteristically present with dorsal wrist pain that worsens with wrist extension in young patients. 1, 2

Clinical Presentation

This 17-year-old's presentation is classic for these conditions:

• Dorsal-central wrist pain that is specifically provoked by wrist extension is the hallmark symptom, reported in 100% of DWCI cases 1 and characteristic of extensor retinaculum impingement 2
• Young age (mean presenting age 19.6 years for extensor retinaculum impingement) 2
• Subacute onset (1 week is early, but symptoms typically present after repetitive extension activities)
• No carpal tunnel signs appropriately excludes median nerve pathology

Key Physical Examination Findings to Confirm

Look for these specific findings:

• Tenderness over the dorsal-central wrist, particularly at the distal border of the extensor retinaculum 2
• Pain with passive terminal wrist extension (present in 100% of DWCI cases) 1
• Possible extensor tendon synovitis or thickening on palpation 2
• Pain reproduction with weight-bearing in extension (push-up position, plank position) 3

Diagnostic Approach

Start with plain radiographs as the initial imaging study, per ACR guidelines 4, 5. However, recognize that:

• Radiographs will likely be normal or nonspecific in these soft-tissue impingement conditions
• MRI has limited diagnostic utility for DWCI—it was obtained in only 66% of surgically confirmed cases and showed inconsistent findings with poor correlation to intraoperative pathology 6, 1
• MRI may identify occult dorsal ganglion cysts (76% of dorsal wrist pain cases in one study), partial scapholunate tears, or dorsal capsulitis 3

If radiographs are normal and symptoms persist beyond 4-6 weeks of conservative treatment, obtain MRI without IV contrast to exclude other pathology (occult ganglion, scapholunate ligament injury, osteoid osteoma) 5, 3, 7.

Initial Management

Begin conservative treatment immediately without waiting for advanced imaging:

• Activity modification: Avoid repetitive wrist extension and weight-bearing activities (push-ups, planks, gymnastics)
• NSAIDs for 2-4 weeks 8
• Wrist splinting in neutral position to prevent terminal extension
• Consider corticosteroid injection if symptoms persist beyond 4 weeks 1, 2

Important Caveats

• Do not assume inflammatory arthritis based solely on MRI findings of synovitis or bone marrow edema—these can be present with mechanical impingement 7
• Avoid prolonged NSAID use (>4-6 weeks) due to renal toxicity risk 7
• Surgical referral is warranted if conservative treatment fails after 3 months—arthroscopic debridement of redundant dorsal capsular tissue or partial resection of the distal extensor retinaculum shows excellent outcomes with complete pain relief and return to activity 1, 2

Alternative Diagnoses to Consider

If the clinical picture doesn't fit perfectly:

• Occult dorsal ganglion cyst (most common cause of dorsal wrist pain on MRI—84% prevalence) 3
• Scapholunate ligament injury (though less likely with only 1 week of symptoms)
• Intersection syndrome (pain more proximal, 4-6 cm proximal to wrist joint)
• De Quervain tenosynovitis (radial-sided, not dorsal-central) 9