DISLOCATION, WRIST DISTAL RADIAL ULNAR JOINT (DRUJ)

Isolated distal radioulnar joint (DRUJ) dislocations with only ligamentous involvement are uncommon injuries. In most cases, they are associated with a concomitant fracture, usually of the distal ulna or rarely of the distal radius.^1,2 The mechanism of injury depends on the direction of displacement, as dorsal DRUJ dislocations typically result from a hyperpronation force—in most cases a fall on an outstretched hand (FOOSH)—and the less common volar dislocation from a hypersupination force.^1,3 For acute DRUJ dislocations that are closed and reducible, conservative treatment that consists of closed reduction and immobilization is typically recommended. Surgery is indicated for open injuries, those that cannot be reduced closed, and when the dislocation has become chronic due missed diagnosis or patient neglect.^1,4

Definitions

• A DRUJ dislocation occurs when the articular surface of the distal ulna is displaced off the articular surface of the distal radius.

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Hand Surgery Resource’s Dislocation Description and Characterization Acronym

D O C S

D – Direction of displacement

O – Open vs closed dislocation

C – Complex vs simple

S – Stability post reduction

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D – Direction of displacement

• The primary description and characterization of DRUJ dislocations are done by noting the direction of the displacement of the distal ulna relative to the distal radius. The three possible directions of displacement are dorsal, lateral, and volar.⁵ Dorsal dislocations are the most common, while volar dislocations are extremely rare.^3,6
  • In dorsal dislocations, the mechanism of injury is believed to be a hyperpronation force, which usually results from a FOOSH. This fixes the hand to the ground and causes the ulna to rotate around it, which disrupts the volar radioulnar ligament and dorsal joint capsule. This causes extreme difficulty with wrist supination.^1,3,6
  • In volar dislocations, the mechanism is typically a hypersupination force that disrupts the dorsal radioulnar ligament and volar joint capsule. This causes extreme difficulty with wrist pronation.^1,3
• The degree of displacement of the ulna further characterizes DRUJ dislocations. In a true complete dislocation, the articular surface of the ulna is no longer in contact with the articular cartilage of the radius. If there is contact of the cartilaginous surfaces that is >50%, then this is not a true dislocation but rather a joint subluxation.⁵

O – Open vs closed

• The majority of DRUJ dislocations are closed; the skin is intact, and there is no route for bacteria to contaminate the joint space.
• Open DRUJ joint dislocations are extremely rare, but when they do occur, require urgent irrigation, debridement, open reduction, and ligament repair if the dislocation is unstable after reduction.

C – Complex vs simple

• Most DRUJ dislocations are simple, meaning that reduction is easily achieved under digital anesthetic block and is not blocked by soft tissue being interposed in the joint between the distal ulna and radial joint surfaces.
• Complex (irreducible) DRUJ dislocations are very rare, but do occur on some occasions.
  • The extensor carpi ulnaris (ECU) tendon is the most commonly interposed soft-tissue structure that blocks reduction, but other structures that may be involved include the extensor digitorum communis, extensor digiti minimi, or flexor pollicis longus tendons, or the triangular fibrocartilage complex (TFCC) or median nerve.³
  • Complex DRUJ dislocations are high-energy injuries that nearly always occur in conjunction with a fracture, most commonly with the distal radius as part of a Galeazzi fracture.¹
  • Irreducible simple dislocations without soft tissue interposition are also possible. In such cases, the ulna may be irreducible because of a bony mechanical blockage at the volar lip of the sigmoid notch of the radius.¹

S – Stability

• A stable DRUJ dislocation can be reduced and then put through an active range of motion (ROM) test under a local anesthetic block without redislocating.
• Furthermore, a stable DRUJ dislocation is stable to stress testing after reduction. This maneuver should always be done after ORIF of a Galeazzi fracture to determine the DRUJ stability.

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Related anatomy^3,4,6

• Extensor tendons
• Flexor tendons
• Radial collateral ligament
• Radioulnar ligaments (dorsal and volar)
• Intrinsic interosseous ligments
• Extrinsic radiocarpal and ulnocarpal ligaments
• Intracapsular ligaments
• Infratendinous extensor retinaculum
• Interosseous membrane
• Pronator quadratus muscle
• Sigmoid notch
• Osteology of the distal ulna and distal radius
• TFCC which is the most important stabilizer of the DRUJ

Overall incidence

• DRUJ dislocations are uncommon injuries, but their exact incidence is not well documented. In one series of 1,236 forearm fractures, 6.8% were Galeazzi fractures, indicating that a DRUJ dislocation was also present.⁷

Related Injuries/Conditions

• Distal ulna fractures
• Distal radius fractures
• Galeazzi fractures of the radius
• Essex-Lopresti fractures
• Intrinsic ligament injuries
• Extrinsic ligament injuries
• Extensor tendon ruptures
• Flexor tendon ruptures

The typical patient is a 34-year-old right-handed female equestrian athlete. During a recent competition, her horse started acting erratically and moving in unpredictable directions. Eventually, this threw the rider off her horse in an awkward way, flipping her upside down and causing her to land on two outstretched hands to break the fall. This traumatic force hyperpronated her right wrist and led to a dorsal dislocation of the DRUJ, which was followed by severe pain, swelling, and tenderness in the area.  She could not move her wrist or forearm without severe pain.  The woman subsequently removed herself from the competition to seek out medical help.

• Patients with closed DRUJ dislocations that are reduced early may be able to exercise their wrist on their own.
• However, patients with marked swelling and pain will need hand therapy to help reduce swelling and improve ROM and strength.
• Surgically repaired complex DRUJ dislocations, repaired ligaments, and unstable DRUJ dislocations will definitely need hand therapy, custom splinting, and possibly dynamic extension splints.

• Recurrent dislocations
• Stiffness
• Pain
• Infection
• Residual deformity
• Weakened grip
• Impaired ROM
• Nerve injuries 
• Vascular injuries
• Posttraumatic osteoarthritis
• Spontaneous extensor tendon rupture

• Simple DRUJ dislocations that are recognized and treated early typically have a positive outcome.^3,8,9
• In one series of 11 patients with an isolated volar DRUJ dislocation, 9 were treated with closed reduction on the same day as presentation at the ED. All of these patients had a successful outcome, as well as the 1 patient who presented >3 weeks after the injury.⁸
• Even after a late diagnosis, a good result can be obtained by open reduction and TFCC repair.⁹
• All patients with DRUJ dislocations should be warned that the DRUJ on the injured side will likely remain slightly larger than the opposite side because the stretched ligaments are likely to heal with a little extra bulk (collagen) and some loss of supination and/or pronation is not unusual.
• If not promptly recognized and treated, DRUJ dislocations can lead to significant functional disability.³

• Open and complex DRUJ joint dislocations require urgent surgical treatment.
• Up to 50% of all DRUJ dislocations are missed upon initial evaluation, especially if an associated fracture is not present or when there are no obvious signs of deformity in the ED. This highlights the need for elevated clinical suspicion and careful evaluation of radiographs after all high-energy wrist injuries.³
• Due to improved diagnostic and therapeutic techniques, the incidence of delayed diagnosis and misdiagnosis of DRUJ dislocations appears to be decreasing.⁶  A true lateral x-ray view should be used to confirm this diagnosis.³  The anteroposterior (AP) x-ray view in dorsal dislocations typically shows a widened DRUJ with divergence of the radius and ulna, whereas volar dislocations demonstrate an overlap of the radius and ulna at the DRUJ.^1,3  Any rotation of the forearm during radiographic examination will change the relative position of the ulna, which makes the diagnosis difficult.³
• CT scan:  This is the preferred advanced imaging option if the diagnosis cannot be confirmed with plain radiographs.²

New and Cited Articles

1. Carlsen, BT, Dennison, DG and Moran, SL. Acute dislocations of the distal radioulnar joint and distal ulna fractures. Hand Clin 2010;26(4):503-16.PMID: 20951900
2. Wassink, S, Lisowski, LA and Schutte, BG. Traumatic recurrent distal radioulnar joint dislocation: a case report. Strategies Trauma Limb Reconstr 2009;4(3):141-3.PMID: 19937146
3. Bouri, F, Fuad, M and Elsayed Abdolenour, A. Locked volar distal radioulnar joint dislocation. Int J Surg Case Rep 2016;22:12-4. PMID: 27016647
4. Sang, L, Liu, H, Liu, J, et al. A case report of distal radioulnar joint dislocation fixed by using mini-plate-button. Int J Surg Case Rep 2017;34:69-73. PMID: 28371634
5. Merrell G, Slade JF. Dislocations and ligament injuries in the digits. In: Wolfe, SW, Hotchkiss RN, Pederson WC, Kozin SH (eds): Green’s Operative Hand Surgery.  Philadelphia 2011: Elsevier Churchill Livingstone, pp. 291-332.
6. Qian, H, Chen, G and Liu, Z. Treatment of distal radioulnar joint dislocation with spontaneous rupture of extensor tendon by Sauve-Kapandji osteotomy assisted by wrist arthroscopy: A case series and literature review. Medicine (Baltimore) 2018;97(22):e10752.PMID: 29851780
7. Moore, TM, Klein, JP, Patzakis, MJ, et al. Results of compression-plating of closed Galeazzi fractures. J Bone Joint Surg Am 1985;67(7):1015-21.PMID: 4030820
8. Mulford, JS, Jansen, S and Axelrod, TS. Isolated volar distal radioulnar joint dislocation. J Trauma 2010;68(1):E23-5. PMID: 20065743
9. Zannou, RS, Rezzouk, J and Ruijs, AC. Non-reducible palmar dislocation of the distal radioulnar joint. Case Reports Plast Surg Hand Surg 2015;2(2):43-45.PMID: 26158121

Review

1. Carlsen, BT, Dennison, DG and Moran, SL. Acute dislocations of the distal radioulnar joint and distal ulna fractures. Hand Clin 2010;26(4):503-16. PMID: 20951900

Classics

1. Morrissy RT, Nalebuff EA. Dislocation of the distal radioulnar joint: anatomy and clues to prompt diagnosis. Clin Orthop Relat Res1979;(144):154-8. PMID: 535217
2. Weseley MS, Barenfeld PA and Bruno J. Volar dislocation distal radioulnar joint. J Trauma1972;12(12):1083-8. PMID: 4651332