What to do next if a hand X-ray shows flattening of the ulnar styloid?

Management of Flattened Ulnar Styloid on Hand X-ray

The finding of a flattened ulnar styloid on hand X-ray requires clinical correlation to determine if this represents an acute fracture or chronic finding, followed by assessment of distal radioulnar joint (DRUJ) stability through physical examination—if the DRUJ is stable, no specific treatment is needed regardless of fracture characteristics.

Initial Clinical Assessment

Determine Acute vs. Chronic Finding

• Obtain a focused history regarding recent trauma, mechanism of injury, timing of symptoms, and whether there is an associated distal radius fracture 1
• The flattened appearance may represent an ulnar styloid fracture (occurring in approximately 55% of distal radius fractures) or a chronic anatomic variant 2
• Document the presence and severity of ulnar-sided wrist pain, clicking, or instability symptoms 3

Physical Examination for DRUJ Stability

• Perform the ballottement test (piano key sign) to assess DRUJ stability by comparing dorsal-palmar translation of the ulnar head relative to the radius 2
• Test forearm rotation (pronation and supination) for pain, crepitus, or mechanical symptoms 3
• Assess grip strength and compare to the contralateral side 2
• Critical point: DRUJ stability is the primary determinant of treatment, not the presence or characteristics of the ulnar styloid fracture itself 1

Management Based on DRUJ Stability

If DRUJ is Stable (Most Common Scenario)

• No specific treatment of the ulnar styloid fracture is required 1, 4
• The American Academy of Orthopaedic Surgeons states they are "unable to recommend for or against fixation of ulnar styloid fractures associated with distal radius fractures" due to lack of evidence showing benefit 1
• Recent evidence demonstrates that neither the size, displacement, nor healing status (union vs. nonunion) of ulnar styloid fractures affects clinical outcomes when the DRUJ is stable 2, 5, 4
• If there is an associated distal radius fracture requiring treatment, manage the radius fracture according to standard protocols; the ulnar styloid can be left alone 5, 4
• Immobilization for 4-8 weeks may allow triangular fibrocartilage complex (TFCC) recovery 2

If DRUJ is Unstable (Less Common)

• This represents a Type 2 ulnar styloid nonunion pattern with DRUJ subluxation requiring surgical intervention 3
• Obtain MRI of the wrist to evaluate TFCC integrity and the extent of ligamentous injury 1
• MRI is the ideal imaging modality with sensitivity and specificity approaching 100% for TFCC tears 1
• CT may be used as an alternative to assess DRUJ stability in multiple positions (pronation, neutral, supination) 1

Surgical Indications

• Large ulnar styloid fragments (base fractures) with DRUJ instability should undergo open reduction and internal fixation 3
• Smaller fragments with DRUJ instability require fragment excision plus TFCC repair to the distal ulna 3
• The key surgical principle is restoration of DRUJ stability, not simply treating the bony fragment 3

Common Pitfalls to Avoid

• Do not assume all ulnar styloid fractures require treatment—the vast majority do not affect outcomes when the DRUJ is stable 2, 5, 4
• Do not base treatment decisions on radiographic appearance alone (fracture size, displacement, or union status)—these factors do not correlate with functional outcomes in stable wrists 2, 4
• Do not obtain advanced imaging (MRI/CT) routinely—reserve this for cases with documented DRUJ instability on physical examination 1
• Do not confuse ulnar styloid fractures with stylocarpal impaction syndrome—the latter occurs with negative ulnar variance and requires different management 6

Follow-up Recommendations

• For stable DRUJ with ulnar styloid fracture: routine follow-up as dictated by any associated distal radius fracture; no specific monitoring of the styloid is needed 5, 4
• For unstable DRUJ: urgent orthopedic referral for surgical evaluation within 1-2 weeks 3
• Patient-rated outcomes (pain, function, grip strength) remain similar regardless of ulnar styloid union status when DRUJ stability is maintained 2, 4