Physical Address

304 North Cardinal St.
Dorchester Center, MA 02124

Associated ulnar fixation (ulnar styloid and metadiaphyseal fractures)


Indications

  • Ulnar styloid, ulnar metaphyseal, and ulnar metadiaphyseal fractures may be treated after reduction and stabilization of distal radius fractures (DRF).

    • If rigid fixation of a DRF results in a stable distal radioulnar joint (DRUJ), then operative fixation of an associated distal ulnar fracture is not mandatory.

    • The most common causes of instability of the DRUJ after DRF are dorsal angulation and shortening of the DRF fragments.

    • Ulnar fractures require operative repair if there is (1) an unstable DRUJ, (2) an unstable and/or irreducible fracture, (3) a large intraarticular step-off, or (4) a need to restore ulnar length and alignment.

Ulnar styloid fracture management

  • Ulnar styloid fracture is present in up to 50% to 65% of DRF patients.

  • Treat an ulnar styloid tip or midportion fracture nonoperatively because these injuries are not associated with DRUJ instability (the radioulnar ligament insertion is still intact).

  • For an ulnar styloid base fracture, if the DRUJ is stable with or without laxity, treat nonoperatively.

  • In cases of grossly unstable DRUJ with ulnar head subluxation, manage with open reduction internal fixation.

Ulnar metaphyseal fracture management

  • Ulnar metaphyseal fracture (i.e., ulnar head or distal ulnar) is present in up to 6% of DRF patients.

  • Literature has shown that comminuted fractures in elderly patients are often stable enough (after DRF fixation) for nonoperative management.

  • The Biyani Classification delineates the fracture patterns of ulnar metaphyseal fractures ( Fig. 34.1 ).

    FIGURE 34.1, Biyani Classification of ulna metaphyseal fractures. Type I: Simple extraarticular fracture with minimal comminution. Type II: Inverted T- or Y-shaped fracture with an ulnar styloid fragment, including a portion of the metaphysis. Type III: Fracture of the lower ulnar metaphysis with avulsion fracture of the ulnar styloid. Type IV: Comminuted fracture of lower ulnar metaphysis, with or without styloid fracture.

Ulna metadiaphyseal fracture management

The goal of management is to restore ulnar alignment and length and ensure DRUJ stability. Typically, a displaced fracture should be treated operatively.

Contraindications

  • Ulnar styloid fractures with a stable DRUJ do not require fixation.

  • Elderly patients with osteoporotic bone and comminuted ulnar head, metaphyseal, or neck fractures can be managed nonoperatively.

Clinical examination

  • Perform a complete skin, muscle, and neurovascular examination of the upper extremity pre- and postreduction.

  • Examine the contralateral extremity to compare forearm length (ulnar variance), range of motion (ROM), and integrity of the DRUJ.

  • The carpal tunnel and forearm compartments should be examined for signs and symptoms of compartment syndrome because fractures of both forearm bones are typically caused by highimpact injuries.

  • Examine for DRUJ instability ( Fig. 34.2 ).

    • Assess for joint laxity, subluxation, or dislocation. Joint laxity can be compared with the contralateral extremity. A palpable clunk with ulnar dislocation suggests a DRUJ injury.

    FIGURE 34.2, With the elbow flexed at 90 degrees, stress the ulna volarly and dorsally with the forearm in supination, neutral, and pronation. Repeat the examination with radial deviation of the wrist (right image). Next, compress the distal radius and ulnar head together and range the wrist from supination to pronation. Ulnar dislocation indicates a DRUJ injury that needs surgical repair.

Imaging

  • Radiographs of the wrist in posteroanterior, lateral, and oblique views should be obtained.

    • Repeat radiographic views of the wrist intraoperatively to ensure restoration of volar tilt and length of the distal radius after fixation and before examining DRUJ stability.

Evidence of druj instability

  • Ulna head is subluxed dorsally from the sigmoid notch with the arm in neutral rotation.

  • There is widening of the DRUJ on the posteroanterior view.

  • Radial displacement of ulnar styloid fragment indicates a pulling force of a detached radioulnar ligament ( Fig. 34.3 ).

    FIGURE 34.3, The ulnar styloid fragment is being pulled radially ( white arrow ) indicating the pulling force of the radioulnar ligament.

Surgical anatomy

Biomechanical anatomy

  • The distal ulna is the fixed point around which the radius rotates.

  • Pronation and supination of the wrist is achieved as the radius rotates around the ulna via the DRUJ articulation.

  • The ulnar styloid base and fovea are the insertion points of the palmar and dorsal radioulnar ligaments, which are the primary stabilizers of the DRUJ ( Fig. 34.4 ).

    FIGURE 34.4, The palmar and dorsal radioulnar ligaments are the primary stabilizers of the DRUJ. If the ulnar styloid fragment is proximal to those attachments, the DRUJ may be unstable, necessitating fixation.

  • Therefore DRUJ instability may occur with basilar ulnar styloid or intraarticular fractures because this results in disruption of the superficial (distal) attachment limbs of the radioulnar ligaments.

  • The DRUJ may maintain stability if the deep (proximal) limbs remain attached to the fovea (i.e. ligamentum subcruentum).

You're Reading a Preview

Become a Clinical Tree membership for Full access and enjoy Unlimited articles

Become membership

If you are a member. Log in here

Related Posts