Diagnosis and Management of Persistent Trapezoid Dislocation Following Surgical Treatment of Second through Fifth Carpometacarpal Fracture Dislocation

Abstract

This case report highlights a persistent palmar trapezoid dislocation requiring return to the operating room following closed reduction and percutaneous pinning of second through fifth carpometacarpal joint fracture dislocations in the setting of ipsilateral distal radius fracture and distal radioulnar joint injury. The dislocation was identified on postoperative computed tomography imaging and required open reduction via dorsal approach. We offer this report to improve recognition of this rare presentation and to emphasize the importance of careful evaluation of intraoperative and postoperative imaging.

Trapezoid dislocation is a rare carpal injury with potentially severe functional implications. Given the strong ligamentous and bony support that the trapezoid receives from surrounding structures, including the dorsoradial ligament, scaphoid, trapezium, thumb metacarpal, and index metacarpal, trapezoid dislocation is uncommon and typically associated with either direct or indirect high-energy trauma.¹ These dislocations occur more commonly in a dorsal direction because of the stronger volar ligaments relative to the dorsal ligaments, which include the volar trapezio-trapezoid ligament.^2,3 Additionally, the trapezoid has a smaller footprint volarly than dorsally, with stronger ligamentous support palmarly as well. Given the rarity of this injury, there is a paucity of documented cases, with under 30 cases reported in the literature, the majority of which are dorsal dislocations.3, 4, 5, 6, 7, 8, 9 This case report offers another example of a palmar trapezoid dislocation previously noted in a few case examples.3, 4, 5, 6, 7, 8, 9 Furthermore, there have been some reports of trapezoid dislocations combined with other carpal fractures and/or carpometacarpal (CMC) dislocations, but there have been few, if any, reports of a volar trapezoid fracture dislocation combined with a radial shaft fracture and multiple CMC dislocations.⁹ Written informed consent was obtained from the patient for publication of this case report and accompanying images.

Case Report

The patient is a 20-year-old man with a medical history of anxiety who presented after high-energy trauma from a motorcycle crash at 40–50 miles per hour. The patient had a head strike and loss of consciousness. He experienced multiple traumatic injuries, including a subdural hemorrhage, right femoral shaft fracture, left Galeazzi fracture dislocation, as well as left index through small finger metacarpal base fracture dislocations. Upon initial X-ray imaging (Fig. 1), there was no clear radiographic evidence of trapezoid dislocation. However, on computed tomography (CT) imaging, a palmar trapezoid dislocation was noted (Fig. 2). The orthopedic resident attempted closed reduction and splinting under hematoma block with interval improvement in alignment of the carpometacarpal dislocations and distal radioulnar joint (DRUJ) (Fig. 3). On day 2 of his hospital admission, once cleared by the neurosurgical and intensive care unit teams, the patient underwent a right retrograde femoral shaft intramedullary nailing in addition to treatment for his left upper-extremity injuries. Using the interval between the FCR and brachioradialis, the radial shaft fracture was reduced, and a compression plate was applied. The DRUJ was found to be well reduced and stable. Attention was then turned to the CMC dislocations. The index metacarpal required a dorsal incision with approach via extensor carpi radialis brevis and extensor carpi radialis longus interval, with open reduction via axial traction to reduce the second carpometacarpal dislocation. K-wires were applied to the index and long metacarpals and the capitate, whereas the ring and small metacarpals were pinned to the hamate (Fig. 4). Pairs of K-wires were placed through the individual metacarpal necks as well, one radial to ulnar and one ulnar to radial. The trapezoid appeared to be reduced at this time on both mini-C-arm and full C-arm, but to ensure adequate reduction, a CT scan was obtained after surgery and demonstrated persistent palmar dislocation of the trapezoid (Fig. 5). Additionally, the patient complained of numbness/tingling in the radial three digits after surgery, which he did not report after his initial injury. As a result, the patient was taken back to the operating room for reduction of the trapezoid 2 days after his index procedure and release of the carpal tunnel. The transverse K-wire between the long and index fingers was removed, and the longitudinal K-wires in the index and middle finger metacarpals were retracted to the metacarpal level. The trapezoid was found on fluoroscopy and noted to be dislocated. A volar carpal tissue incision was made, the transverse carpal ligament was released, and a small nick was made in the volar tissue to visualize the trapezoid, but dorsally directed pressure was unsuccessful in reducing the trapezoid. There was a notable hematoma in the carpal tunnel. The previous dorsal incision was extended, and dissection was carried down to the extensor retinaculum, which was incised over the extensor pollicus longus. The ERCL and extensor carpi radialis brevis were identified and retracted. Using freer elevators, Hohmann retractors, and a dental pick, the trapezoid was then able to be reduced. A K-wire from the trapezium was placed into the trapezoid. A second K-wire was placed from the index metacarpal metaphyseal flare, through the trapezoid, and into the scaphoid, after which, the trapezoid was no longer mobile. Additional retrograde K-wires were then readvanced into the index and long metacarpals as before, and the transverse K-wire was replaced into the index and long metacarpal (Fig. 6). He was seen for follow-up at 9 days post-op as well as subsequently at 3 weeks post-op, with follow-up x-rays included below (Fig. 7). His trapezoid remained well reduced, and his K-wires remained in place with appropriate alignment. He subsequently was seen again at 6 weeks follow-up, at which point, his K-wires were removed; he was placed into a removable splint and was allowed to begin active range of motion as tolerated. Following this, the patient attended his 10-week follow-up for his femur fracture, but then missed all further follow-ups for both injuries and did not reschedule these appointments.

Figure 1.

Initial radiographs obtained in the emergency department including posterior anterior (PA) view of wrist A, lateral wrist B, AP hand C, and lateral hand D, demonstrating a distal third radial shaft fracture, DRUJ injury, and second to fifth CMC dislocations.

Figure 2.

Computed tomography obtained postsplinting and reduction attempt, demonstrating palmar trapezoid dislocation on coronal A, sagittal B, C and axial D views. 3D reconstructions of the CT shown in E and F.

Figure 3.

Postsplinting and reduction radiographs including lateral view A and posterior anterior (PA) view B.

Figure 4.

Postoperative posterior anterior (PA) A and lateral B radiographs with percutaneous pinning of the CMC dislocations and distal radius plate.

Figure 5.

Postoperative CT scan with sagittal A, D and coronal B, C demonstrating persistent dislocation of trapezoid. Figures E and F represent 3D reconstruction views of CT.

Figure 6.

Postoperative posterior anterior (PA) A and lateral B radiographs demonstrating interval reduction of the trapezoid and K-wire fixation.

Figure 7.

Three-week follow-up radiographs including a posterior anterior (PA) A and lateral B view.

Discussion

Palmar trapezoid dislocations have been described in the literature. Chang et al³ discuss a 49-year-old man who sustained an isolated palmar trapezoid dislocation along with a distal radius fracture and DRUJ dislocation.³ After initial treatment in an external fixator, CT demonstrated persistent palmar trapezoid dislocation. On day 7 of his visit, he underwent open reduction and percutaneous pinning trapezoid dislocation through a horizontal dorsal incision, in addition to distal radius fixation. Reduction was obtained with the wrist in slight dorsiflexion and dorsal manipulation of the trapezoid body with longitudinal traction. Keith et al⁴ reported on two cases of trapezoid dislocation with concurrent CMC dislocations, both occurring from striking a steering wheel at high speed. The first patient, a 25-year-old man, had a dorsal trapezoid dislocation along with second to fourth CMC dislocations shown on CT scan. The index CMC had interposed volar tissue, and the patient required open reduction with placement of K-wires and ligamentous repair. The other patient, a 54-year-old woman, presented with a dorsal scaphotrapezio-trapezoid dislocation with the trapezoid rotated 180°, as well as CMC dislocations shown on CT. She also underwent open reduction with K-wires and ligamentous repair via a dorsal approach. Larson et al⁵ reported a volar dislocation associated with acute carpal tunnel syndrome, as did Calfee et al,⁸ which is similar to our patient, who slowly developed symptoms consistent with carpal tunnel syndrome a few days after injury, with the persistent volar dislocation of the trapezoid. The patient in our report required open reduction via a combined volar–dorsal approach to the trapezoid. There is scant prior literature describing approaches to the trapezoid, although two studies describe a dorsal approach centered over the second CMC joint for surgical management of trapezoid fractures.^10,11 The persistent palmar dislocation was suspected but not confirmed until three-dimensional imaging was obtained. He returned to the operating room and was treated appropriately with open reduction using Hohmann retractors and a dental pick. This report provides another example of palmar trapezoid dislocation and offers a method to reduce the trapezoid. In addition, it raises the importance of careful attention to intraoperative and postoperative imaging. As noted by other authors, such as Safran et al,⁶ this case underlies the utility of advanced imaging, namely CT, in the diagnosis and monitoring of these injuries. This case also highlights the importance of being vigilant, as this is one of the first reported cases of a volar trapezoid dislocation in conjunction with multiple CMC dislocations and a radial shaft fracture. Patients experiencing from high-energy trauma are apt to experience multiple injuries, and one must be careful not to miss less-common injuries in light of the more obvious injuries.

Conflicts of Interest

No benefits in any form have been received or will be received related directly to this article.