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Forearm fracture-dislocations (Galeazzi and Monteggia)


Indications

  • Radius and ulna fracture-dislocations require operative treatment in the adult population.

    • The forearm unit consists of the ulna and radius, which are held together proximally at the proximal radioulnar joint (PRUJ), at the interosseous membrane (IOM) along the shaft, and distally at the distal radioulnar joint (DRUJ). Because of their intimate relationship, displaced proximal or midshaft fractures of one bone may result in a dislocation of the other.

  • Galeazzi fracture-dislocation is characterized by a radial shaft fracture, typically at the junction of the middle and distal thirds, and dislocation of the DRUJ. Dorsal ulnar dislocation of the DRUJ results from pronation and wrist extension. Volar ulnar dislocation of the DRUJ (less common) is the result of forced supination or a direct ulna blow. DRUJ instability arises when the triangular fibrocartilage complex (TFCC) tears from its foveal attachment or there is an ulnar styloid base fracture (with intact TFCC).

    • Operative fixation of the radial shaft fracture typically results in a reduced, stable DRUJ. After radius fracture fixation, evaluation of DRUJ stability will guide management as follows:

      • If stable: Perform long-arm cast immobilization in slight supination.

      • If unstable: Perform DRUJ transfixion.

      • If unstable and irreducible DRUJ: Perform (1) open reduction and internal fixation of styloid fracture, or (2) open removal of interposed soft tissue and TFCC repair. Protect both repairs with DRUJ transfixion.

  • Monteggia fracture-dislocation is characterized by a proximal ulna shaft fracture with an accompanying dislocation of the PRUJ. The goal of treatment is to maintain an anatomically reduced radial head, which is best accomplished with restoration of ulna length and alignment. The Bado Classification describes subtypes of this fracture-dislocation pattern ( Fig. 35.1 ):

    • Type I (60% of fractures, mostly children): Proximal or middle third ulna shaft fracture (apex anterior angulation) with anterior dislocation of the radial head.

    • Type II (15% of fractures, mostly adults): Proximal or middle third ulna shaft fracture (apex posterior angulation) with posterior dislocation of the radial head. The Jupiter Classification describes subtypes:

      • IIA: The ulna fracture involves the distal olecranon and coronoid process.

      • IIB: The ulna fracture is at the metaphyseal-diaphyseal junction distal to the coronoid.

      • IIC: The ulna fracture is diaphyseal.

      • IID: The ulna fracture extends to the midshaft or distal.

    • Type III (20% of fractures): Ulna metaphysis fracture (distal to coronoid process) with lateral dislocation of the radial head.

    • Type IV (5% of fractures): Proximal or middle third ulna and radial head fractures with dislocation of the radial head in any direction.

    FIGURE 35.1, The Bado Classification describes subtypes of Monteggia fracture-dislocations based on the direction of the radial head displacement ( black arrows ). (A) Type I – anterior dislocation, (B) Type II – posterior dislocation, (C) Type III – lateral dislocation, (D) Type IV – dislocation in any direction with radial head fracture ( bolt ).

Contraindications

  • Grossly contaminated wounds require initial washout and debridement before definitive fixation.

  • Hemodynamic instability or life-threatening injuries take precedence before operative fixation.

Clinical examination

  • Perform a complete skin, muscle, and neurovascular examination of the upper extremity (pre/postreduction and pre/postoperatively).

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

  • Evaluate the forearm compartments for signs and symptoms of compartment syndrome.

  • It is imperative to examine the DRUJ and PRUJ for dislocations after operative repair of forearm fractures.

Imaging

  • Anteroposterior and lateral plain radiographs of the wrist, forearm, and elbow are indicated for forearm fractures.

  • Galeazzi fracture-dislocation ( Figs. 35.2 ):

    • On anteroposterior view, evaluate for an apex medial angulated radius fracture, radial shortening (typically > 5 mm), and widening of the DRUJ.

    • On lateral view, evaluate for an apex dorsal angulated radius fracture and dorsal dislocation of ulna head.

    • Evaluate for ulna styloid base fracture.

    FIGURE 35.2, Radiograph of Galeazzi fracture-dislocation showing anterior-posterior view with (A) apex medially angulated radius fracture ( yellow arrow ), radial shortening, and DRUJ widening ( green arrow ), and lateral view showing (B) apex dorsal angulated radius fracture ( blue arrow ) and dorsal dislocation of ulna head ( red arrow ).

  • Monteggia fracture-dislocation ( Fig. 35.3 ):

    • Evaluate for bony abnormalities.

    • Congruency of the radiocapitellar joint is assessed with the radiocapitellar line (RCL). The RCL (a longitudinal line traveling down the center of the radius) should pass through the center of the capitellum in all views (in adults).

    • If intraarticular involvement (Jupiter type IIA), radial head fractures (Bado type IV), or severely comminuted fractures are suspected, then computed tomography (CT) may be helpful.

    FIGURE 35.3, Radiograph of Monteggia fracture-dislocation showing lack of congruency of the radiocapitellar joint in the (A) anteroposterior view and (B) lateral view. The radiocapitellar line (RCL; yellow dotted line ) is drawn down the shaft of the radius and should pass through the center of the capitellum. This Bado type I shows an ulna fracture with an apex anterior angulation ( blue arrow ) and anterior dislocation of the ulna head ( red arrow ).

Surgical anatomy

Bony anatomy

  • Both radius and ulna have characteristic bows that permit pronation and supination of the forearm. The morphology of these bones must be respected when performing fixation, or the patient will experience significant limitations in ROM, dexterity, and strength.

  • The radius has a 10-degree radial bow in the coronal midshaft and a 5-degree sagittal bow in the proximal third.

  • The ulna has a slight posterior apex bow along its entire length.

  • The midportion of the ulna has a triangular cross-section. The posterior apex portion is largely subcutaneous (and palpable) and separates the extensor and flexor compartments.

Articular anatomy

Distal radioulnar joint

See Fig. 35.4 for a depiction of the distal radioulnar joint.

  • It involves the synovial joint between the concave sigmoid notch of the radius and the convex ulna head.

  • It is primarily stabilized by the volar and dorsal radioulnar ligaments (component of the TFCC), and secondarily by the IOM and pronator quadratus (PQ).

  • The TFCC consists of a central articular disk, meniscal homologue, radioulnar ligaments, ulnocarpal ligaments, and extensor carpi ulnaris (ECU) tendon sheath. The radioulnar ligaments of the TFCC attach at the fovea, which is located at the base of the ulna styloid.

FIGURE 35.4, The primary stabilizing structures of the triangular fibrocartilage complex (TFCC) are the palmar and dorsal radioulnar ligaments, which insert onto the base of the ulna styloid. The distal radioulnar joint (DRUJ) is injured and may be unstable, with injury to these structures or fracture of the ulnar styloid proximal to their insertion.

Interosseous membrane

The IOM disperses axial load forces to the forearm.

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