Acute Distal Radioulnar Joint Instability

Key Points

•

All fractures of the distal radius should be evaluated with a physical exam to test for concurrent instability at the distal radioulnar joint.
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Radiographs that show excessive radial shortening, widening at the distal radioulnar joint, or a large ulnar styloid fracture should raise suspicion for instability.
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Most cases of instability can be managed with immobilization of the forearm in the position of stability.
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Cases in which stability cannot be maintained with immobilization are indicated for pinning of the forearm or repair of the ulnar structures.

Panel 1: Case Scenario

A 28-year-old man fell from a ladder at 14 ft and presented with a dorsally displaced and shortened distal radius fracture. The fracture was repaired with a volar plate and immobilized in a short arm splint. At the first follow up visit, the patient complains of a clunking sensation with rotation of the forearm. How can one diagnose acute instability of the forearm preoperatively or intraoperatively? How is acute distal radioulnar joint instability treated?

Importance of the Problem

Stability at the distal radioulnar joint (DRUJ) is imparted by the bony congruity of the sigmoid notch and the ulna and by the integrity of the soft tissue constraints of the triangular fibrocartilage complex (TFCC), radioulnar ligaments, and interosseous membrane (IOM). Dynamic stabilizers such as the pronator quadratus and extensor carpi ulnaris play a minor role. Instability at the DRUJ may result from several causes:

(1)

Simple dislocation from hyperpronation or hypersupination
(2)

Essex-Lopresti dislocation from longitudinal rupture of the IOM
(3)

Galeazzi fracture-dislocation from diaphyseal radial fracture
(4)

Distal radius fracture and rupture of the soft tissue stabilizers

The aim of the following chapter will focus on those associated with distal radius fractures—a common fracture representing 16% of skeletal failures. Fractures of the distal radius are often associated with an additional soft tissue injury. Studies reporting on wrist arthroscopy in distal radius fractures have estimated that concomitant TFCC injuries occur in 43%–84% of cases. Those with a complete TFCC rupture were more likely to develop instability at the DRUJ and experienced an inferior outcome. Significant morbidities associated with residual instability of the DRUJ include poor strength, reduction in range of motion, pain, and premature arthrosis.

Main Question

What is the most effective diagnostic approach and treatment for acute DRUJ instability associated with DRF (including TFCC lesions)?

Current Opinion

No consensus exists on the optimal method of diagnosis or treatment. Most surgeons would likely agree that an anatomic reduction of the distal radius is critical. Generally, intraoperative clinical exam is performed after fixation using rotation or translation maneuvers. Radiographs may suggest instability if the radial articular segment is severely shortened, if the DRUJ is seen to be wide on the posteroanterior view, or if the radius is grossly dislocated from the ulna on the lateral view ( Figs. 1 and 2 ). If instability is discovered treatment options include immobilization in the position of stability, radioulnar pinning, or repair of the TFCC/ulnar styloid.

Finding the Evidence

Pubmed (Medline) search was performed using keywords “distal radius” and “distal radioulnar joint” and “dislocation” or “instability.”
Bibliography of eligible articles.
Articles not in English, French, or German were excluded.

Quality of the Evidence

Level I: 2 studies
Level II: 1 study
Level IV: 4 studies

Findings

Despite not being a commonly studied lesion, a few high-quality evaluations have reported on the prognosis and treatment of acute instability of the DRUJ associated with distal radius fracture. However, diagnosis was most commonly performed with the ballottement test, which is a subjective evaluation; thus making the long-term consequences of a positive test difficult to interpret. The following studies are summarized in Table 1 with more recent studies described in detail below.

Table 1

Selected Studies Evaluating Distal Radioulnar Joint Instability With Distal Radius Fractures.

LoE	Author	Study Aim	Number of Patients	Method of Diagnosis	Conclusion
I	Kim et al.	Determine if intraoperative laxity was associated with adverse outcome after distal radius fracture	84	Ballottement test	Laxity did not affect outcome at 1 year, but groups were treated differently
I	Lee et al.	Compare conservative vs operative treatment for laxity of DRUJ	157	Ballottement test. CT scan	No difference in outcome at 1 year
II	May et al.	Determine if ulna styloid size or displacement was associated with DRUJ instability	166	Ballottement test. Radiographs. CT scan	Size and displacement were associated with instability
IV	Stoffelen et al.	Determine the effect of instability on outcome score	272	Ballottement test, forearm rotation and compression test	Instability had a worse outcome
IV	Lindau et al.	Determine if TFCC tear was associated with DRUJ instability	51	Ballottement test	Unstable DRUJs often had peripheral TFCC tear
IV	Solgaard	Describe prognosis of distal radius fractures	154	Ballottement test	DRUJ pain and or instability was the most frequent problem at 3.5 years
IV	Frykman	Gross description of outcomes of distal radius fractures	430	Ballottement test	19% of all fractures complained of pain or instability at DRUJ. Ulnar styloid fracture has worse outcome