Distal Ulnar Fractures Concomitant With Distal Radius Fractures

Importance of the Problem

Displaced fractures of the distal radius (DRF) can be expected to have rupture of the linkage between the radius and the ulna, caused by either avulsion of the origin of the radioulnar ligaments from the base of the ulnar styloid, or fracture of ulnar styloid base. Of all distal ulnar fractures, 77% are associated with radial fractures.

Fracture of the ulnar styloid base disrupts the origin of the radioulnar ligaments which remains attached to the fragment. In the absence of fracture, similarly displaced fractures likely result in avulsion of the origin from the base without fracture.

Surgeons express concern about distal radioulnar joint (DRUJ) “instability” after fracture of the distal radius. In our opinion, pain in the ulnar side of the wrist pain after fracture of the distal radius is often diagnosed as “instability” for unclear and imprecise reasons. However, the term “instability” is vague and nonspecific because: (1) There is no consensus definition and (2) no reliable and accurate measurement. Palpable and reproducible subluxation and dislocation of the DRUJ with forearm rotation are uncommon in the absence of malalignment of the radius. There is both rotational and translational motion at the DRUJ with pronation and supination. Moreover, evidence shows radiographic nonunion and malalignment of a fracture of the base of the ulnar styloid does not correspond with pain intensity. This results in the risk of misinterpreting alignment on computed tomography as pathological, particularly at relative extremes of pronation and supination.

Fractures of the head or metaphysis of the distal ulna often line up and heal without specific intervention when the distal radius is aligned and secured. Open reduction and internal fixation of the ulna is considered when head, neck, and diaphyseal fractures remain notably malaligned after radius fixation. The degree of displacement that might affect symptoms and limitations is still a matter of debate and needs more evidence.

Fixation of fractures of the ulnar styloid and distal ulna is not straightforward, because of the need to avoid articular surfaces and tendons and because the bone is small and often osteoporotic. A variety of techniques are used. For ulnar styloid fixation frequently used techniques are (1) open reduction and internal fixation (ORIF) using tension band wiring; (2) plate and screw fixation; (3) screw fixation (either headless or headed); and K-wire fixation, sometimes percutaneous. For the ulnar head or metaphyseal fractures fixation is usually accomplished with a plate and screws. Loss of fixation, restriction of DRUJ motion, and iatrogenic injury of the dorsal branch of the ulnar nerve are potential harms of fixation.

Previous database studies and case series addressing fixation of distal ulnar fractures concomitant with distal radius fractures are heterogeneous in fixation techniques, and Level-1 studies are lacking.

Main Question

Is there a benefit repairing a distal ulnar fracture accompanying an operatively treated unstable distal radius fracture?

Current Opinion

In patients with a displaced distal radius fracture with an accompanying distal ulnar fracture, the level of the ulnar fracture and in case of styloid base fractures intraoperative stability tests after distal radius fixation will guide you to ulnar fixation or nonoperative treatment. Ulnar styloid tip fractures are not fixed. Fixation of a displaced ulnar styloid base fracture might be considered if the distal ulna dislocates during forearm rotation after the radial fracture is fixed in a near anatomical position. If the ulnar styloid base fracture is near its usual position, with an expected degree of distal radioulnar laxity and good alignment of the radius, there's no apparent benefit to fixing the ulnar styloid fracture.