Monteggia fracture, as initially described by Giovanni Battista Monteggia ^[1], is an anterior dislocation of radial head with a fracture of the proximal ulna. Jose Luis Bado classified this complex injury into four types ^[2]. However, the classification did not include certain injuries (radial head fracture, distal humerus fracture, interosseous membrane rupture, and DRUJ injuries), which was later grouped under Monteggia variants. In their systemic review, Artiaco et al. ^[3] described a new comprehensive locker-based classification system in which he has included most of the injuries associated with Monteggia fracture. In this case report, we present a rare case of proximal radioulnar joint dislocation, proximal ulna fracture (Monteggia fracture) with TFCC injury and DRUJ instability. This case illustrates that distal radioulnar joint instability and TFCC tear may be associated with a Monteggia fracture-dislocation.

A 24-year-old female, right-hand dominant software engineer fell onto her outstretched hand and presented with pain, swelling, and deformity around the left elbow. Initial radiographs showed a closed Monteggia fracture-dislocation (proximal shaft of the ulna with anterior dislocation of the radial head – Bado type 1) (Fig. 1a). Under regional anesthesia, the fracture was fixed with LCDCP, and the radial head was reduced by closed means (Fig. 1b). Intraoperatively, we noticed a click at the wrist with pronosupination, and fluoroscopic imaging showed a subtle reducible dorsal subluxation of the distal radioulnar joint. Hence, we performed a closed reduction of DRUJ, and she was given an above elbow slab in full supination. After 3 weeks of the index procedure, the POP cast was removed, and radiographs showed well-reduced radial head and well-aligned ulna fracture. She was started on active and passive range of motion exercises for the elbow and wrist. However, she had persistent wrist pain and stiffness after 2 weeks of physical therapy. Range of motion in the elbow was 0–130o, wrist movements dorsiflexion 0–50o, palmar flexion 0–40o, supination – nil, and pronation 0–40o. Subsequently, we investigated the patient using an MRI, which showed dorsal subluxation of the ulna with TFCC tear in the ulnar attachment of the volar radioulnar ligament (Fig. 2). The patient was counseled for arthroscopic TFCC repair and DRUJ stabilization. She underwent wrist arthroscopy assessment through standard portals, and the volar TFCC was repaired using Arthrex Micro Lasso and FiberWire (Fig. 3). The DRUJ was stabilized with 1.6 mm K-wire.
At 3 weeks following the second surgery, we removed the K-wire, and she was started on physiotherapy. The patient was routinely followed up thereafter. At her latest follow-up of 3 months, her range of motion in the wrist was dorsiflexion 0–45o and palmar flexion 0–20o. The forearm movements were pronation 0–80o and supination 0–50o (Fig. 4). All her movements were pain free. The patient was comfortable, and her radiographs showed a healing proximal ulna fracture. Wrist radiographs showed a well-reduced DRUJ.

Our patient had peripheral TFCC tear with a Bado Type I Monteggia fracture-dislocation. This injury pattern has not been discussed before in the literature and may represent a less common Monteggia variant. Only two cases of frank DRUJ dislocation associated with this fracture have been reported in the literature, with the disruption of distal interosseous membrane being mooted as a reason [4, 5]. However, there was no IOM injury in our case. The pattern of injury in our patient may be explained by the Locker concept ^[3]. Artiaco et al. have suggested three lockers in the forearm (DRUJ, PRUJ, and MRUJ). The authors could explain the various described fracture-dislocations of the forearm based on a combination of disruption of these linkages.
The pathogenesis of Monteggia fracture-dislocation has not been established yet. In general, being a double/concomitant injury, it is challenging to explain the pathomechanics ^[6]. However, based on the locker concept, a twisting injury of the forearm with the IOM as a pivot could result in DRUJ injury associated with Monteggia fracture-dislocations such as in our patient. Six reports in the literature have described simultaneous PRUJ and DRUJ dislocations but without any long bone injury [7, 8, 9, 10, 11, 12]. This injury pattern was described as “crisscross” by Leung et al. by the relative position of the radius and ulna on plain radiographs ^[7].
Missed DRUJ/TFCC injuries can result in persistent wrist pain ^[13]. Therefore, the various Monteggia fracture variants need to be identified and treated. While treating forearm injuries, it is imperative to examine both the wrist and elbow joints thoroughly ^[14]. The initial clinical and radiographic evaluation of the wrist may have been compromised in our patient, as attention was focused on the proximal radial dislocation and the ulnar shaft fracture, with the presumed diagnosis of a Monteggia fracture-dislocation.
In an acute setting, pain and anxiety are major limiting factors in identifying subtle findings. Therefore, proper AP and lateral radiographic views of these joints are needed with specific diligence to joint congruity ^[14]. When in doubt, opposite wrist X-rays should be taken for comparison. Acquiring further imaging studies, such as magnetic resonance imaging, are warranted if there is diagnostic uncertainty or if plain radiographs are inadequate.
Intraoperatively, accurate reduction (length and rotation) of the ulna fracture provides adequate stability to PRUJ and DRUJ ^[15]. These often are managed conservatively with splinting/immobilization. There are rare exceptions like IOM rupture where proximal and distal joint stabilization would be necessary in addition to the long bone fixation. In our patient, although the DRUJ was reduced and splinted during the index procedure, the patient had persistent symptoms and warranted TFCC repair with DRUJ stabilization.
Triangular fibrocartilage complex injury is a common etiology of ulnar-sided wrist pain following fall. It can be frequently missed when associated with other concomitant injuries. Less favorable outcomes for resuming pre-injury and grip strength recovery may be attributed to late detection and management. Arthroscopic suture repair using the outside-in technique has encouraging results in peripheral TFCC tears ^[16]. In our patient, the TFCC tear was successfully treated with arthroscopic TFCC repair and percutaneous DRUJ pinning. At the latest follow-up (3 m), she has regained good forearm rotation and elbow ROM.

In treating Monteggia fracture-dislocations, high index of suspicion is needed in cases where clinical findings suggest DRUJ instability. Missed TFCC tears and DRUJ instability can cause long-term disability. Hence, they should be evaluated at the earliest in Monteggia fracture-dislocations with wrist pain or DRUJ subluxation. In addition, DRUJ stabilization and TFCC repair can produce reliable results in these types of injuries.

TFCC directly connects the distal radius with the ulnar fovea and styloid process, thus providing DRUJ stability. While treating forearm injuries, it is imperative to examine both the wrist and elbow joints thoroughly. Accurate maintenance of length and rotation provides adequate reduction of the DRUJ and most of these injuries are managed conservatively with immobilization. In rare instances with persistent DRUJ instability, timely surgical management provides excellent results.