Rationale

Distal radius fractures are one of the most common injuries of the upper extremity and ulnar styloid fractures can be present in nearly 60% of cases.¹,² However, the impact of an ulnar styloid fracture on DRUJ instability and wrist function in the setting of a concomitant distal radius fracture is as yet unclear and there remains contradictory evidence reported in the literature.²–⁴ In particular, the impact of the location of ulnar styloid fracture, base versus nonbase, is important to understand: the attachment of the superficial limb of the triangular fibrocartilage complex (TFCC) gives the theoretical risk of increased DRUJ instability with ulnar styloid base fractures. DRUJ instability is an independent risk factor for poorer clinical outcomes and so must be avoided at all costs.⁵

Clinical comment

Understanding the radiographic parameters associated with DRUJ instability after locked volar plating will help guide clinicians to predict those injury patterns requiring early intervention.

Available literature and quality of the evidence

Literature remains sparse on this topic, and although prospective studies have been reported in the literature, none was randomized.²,⁴,⁶,⁷ The majority of studies are retrospective case series.⁸

Findings

The majority of clinical studies found that the presence and/or nonunion of an ulnar styloid fracture did not affect DRUJ stability,²,⁴,⁶–⁸ wrist range of motion (ROM),²,⁹ grip strength,² and clinical outcome measures such as the Modified Mayo Wrist Score (MMWS),²,⁹ Michigan Hand Outcomes Questionnaire (MHQ),⁷ and/or the Disabilities of the Arm, Shoulder, and Hand Questionnaire (DASH).²,⁹ Moreover, in those patients who received volar locked plating, Souer et al. found that untreated ulnar styloid base fractures that were initially displaced >2 mm did not demonstrate negative sequelae with respect to function or outcome.⁶ Furthermore, although untreated ulnar styloid fractures trended toward decreased grip strength, flexion, and ulnar deviation in their patient cohort, the insignificance of ulnar styloid fracture location and displacement on DRUJ instability was confirmed by Kim et al.² These findings were also consistent with Lindau et al.’s study that reported no negative outcomes associated with ulnar styloid fractures despite an association between complete peripheral TFCC tears and DRUJ instability.¹⁰ Potential bias may be present in the literature, however, as Kazemian et al. and Sammer et al. excluded patients that were identified with ulnar styloid fractures and intraoperative DRUJ instability after volar plating of the distal radius.⁴,⁷

Contrary studies include a biomechanical study that found ulnar styloid fractures into the fovea caused DRUJ instability and reported only partial recovery of stability with anatomic fixation.¹¹ Additionally, in a mixed cohort of conservatively and operatively managed distal radius fractures, Kramer et al., May et al., and Stoffelen et al. found higher pain scores, DRUJ instability, and decreased ROM with ulnar styloid fractures.¹,¹²,¹³

Resolution of clinical scenario

• The radiographic presence of an ulnar styloid fracture irrespective of size and displacement is not necessarily associated with DRUJ instability or worsened clinical outcomes in the setting of a distal radius fracture that has undergone open reduction internal fixation.²,⁴,⁶–⁹
  
• Intraoperative assessment of the DRUJ after distal radius volar plating should be undertaken to assess for residual DRUJ instability and, if present, instability should be addressed at that time.⁴,⁷

Rationale

The DRUJ requires strong soft tissue support for stability as the bony architecture confers minimal inherent structural support.¹⁴ The TFCC is the primary soft tissue support agreed upon in the literature and is composed of various components of which the volar and dorsal radioulnar ligaments are of particular importance.¹⁵ Persistent DRUJ instability leads to incongruent contact on the cartilaginous surfaces and subsequently post‐traumatic arthritic wear may ensue causing pain, weakness, and decreased ROM. Although other nonarticular DRUJ reconstructions are reported in the literature, they have been limited by their poor biomechanical restoration of DRUJ kinematics and stability.¹⁶ Consequently, reconstruction of both the volar and dorsal radioulnar ligaments is favored to restore the primary restraints and kinematics of the DRUJ.

Clinical comment

Understanding the effectiveness of reconstructing both volar and dorsal radioulnar ligaments in restoring DRUJ stability and symptom relief will help guide patients to make an informed decision about postoperative surgical expectations.

Available literature and quality of the evidence

Literature remains sparse on outcomes from anatomical volar and dorsal radioulnar ligament repairs, and all reported studies are retrospective case series with varied outcome measures and inconsistent follow‐up.¹⁷–²³ The largest series reported 48 patients,²⁰ while the longest follow‐up averaged approximately nine years.²¹ Although the original reconstruction proposed by Adams and Berger was the basis for most volar and dorsal radioulnar ligament reconstructions,¹⁷ modifications were performed by many authors making true procedural comparisons difficult.¹⁹,²⁰,²² In addition, some patients required concurrent procedures, making delineation of the effect of the ligamentous reconstruction alone difficult.¹⁷,²³

Findings

All studies reported that the vast majority of patients improved DRUJ stability after the procedure with greater than 78% of patients having objective clinical resolution of DRUJ instability (range: 55–100%).¹⁸,²¹,²³ Mayo Wrist Scores also improved,¹⁹,²¹,²² as did DASH¹⁸,¹⁹ and Patient‐Rated Wrist Evaluation (PRWE) scores.¹⁹,²³ Pain typically decreased¹⁷,²² allowing the majority of patients to return to pre‐injury work or recreational activities.¹⁸

Recovery of postoperative motion was less predictable with some authors reporting loss of the pronation–supination arc,¹⁷

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