Traumatic Complex Scaphoid Dislocation With Radial Carpal Disruption: A Case Report

A significant amount of axial force must be applied to the wrist to cause a scaphoid dislocation without secondary fractures. Only a handful of such cases have been reported over the last century. Among these rare cases, scaphoid dislocations with associated axial carpometacarpal and midcarpal dislocations are even more rare. This article presents a case of scaphoid dislocation with radial carpal disruption and describes its diagnostic and therapeutic protocol.

The patient is a 39-year-old right-handed laborer with history of tobacco and substance use who presented to the emergency department for evaluation of persistent left wrist pain following injury 2 weeks prior. He reported a left wrist injury after falling on an outstretched hand while participating in recreational sports activities; the patient was upended while jumping in midair and fell onto his outstretched left wrist. Examination revealed no open wounds with significant swelling over the wrist. The wrist was ulnarly deviated at rest with limited passive and active range of motion. Finger motion was maintained. The patient also endorsed numbness in the median nerve distribution.

Standard 3-view x-rays were obtained that showed disassociation of the relationship among the carpal bones, with loss of normal carpal arcs, abnormal orientation of the scaphoid bone, widening of the scapholunate interval space, and displacement of the capitate bone proximally within the scapholunate space. Also, the relationship between the left long and ring finger metacarpal was disrupted (Figure 1). Further evaluation with a computed tomography (CT) scan and 3D reconstruction (Figure 2) demonstrated the significant scaphoid dislocation, with volar positioning of the scaphoid relative to radial styloid, scapholunate disassociation with a proximal displacement of the capitate into the scapholunate space, widening of the scapholunate space (measured 1.8 cm), and dorsal displacement of the long and ring carpal metacarpal head alignment (roughly by 1 cm).

We performed open reduction and percutaneous pinning of the left axial carpal dislocations, carpometacarpal dislocations, left carpal tunnel release, and scapholunate ligament reconstruction with dorsal intercarpal ligament with the use of bone anchors.

Two 0.062 K-wires were placed across the metacarpal bases transversely to maintain the height of the second and third metacarpals relative to the fourth and fifth. Another 0.062 K-wire was placed across the triquetrum and hamate and into the capitate. A 0.045 K-wire was placed from the triquetrum into the lunate. We subsequently reduced our scaphoid and the scapholunate joint under direct vision and passed one 0.045 K-wire radial to ulnar from the scaphoid into the lunate, just distal to the radial styloid, and an additional 0.045 K-wire from the scaphoid into the capitate. We then passed an additional 0.062 K-wire through the radial styloid into the scaphoid and capitate to help hold the length of the radial side of the wrist and hand. Finally, we repaired the scapholunate ligament and augmented it with the dorsal intercarpal ligament, and we used 2 bone anchors.

All procedures followed were in accordance with the ethical standards of the responsible committee on human experimentation (institutional and national) and with the Helsinki Declaration of 1975, as revised in 2008. Informed consent was obtained from all patients included in the study. Additional informed consent was obtained from all patients for which identifying information is included in this article.

Ultimately, hardware was removed 5 weeks following the procedure. At 1-year follow-up patient complained of mild wrist stiffness but demonstrated acceptable finger motion.

The pathway of the axial force transmission has been described by Richard et al¹, starting from between the third and fourth metacarpals and the capitohamate joint, pushing the capitate proximally into the scapholunate space and displacing the scaphoid. The damage to the scaphoradial, scapholunate, and scaphohamate ligaments allows the scaphoid dislocation and rotation.² If only radioscaphocapitate and lunotriquetral ligaments are injured, the scaphoid and lunate are seen to migrate in union, but the additional destruction of the scapholunate allows volar divergent movement of the scaphoid and lunate. The hand position necessary for this axial loading is described as forced hyperextension with ulnar or radial deviation, which often results from a person holding onto an object at the impact of injury.

Leung et al further delineated the categories of scaphoid dislocation as being primary-secondary, simple-complex, partial-complete, and volar-dorsal.³ Primary is a dislocation directly inflicted by the injury versus indirectly in a secondary; complex includes distal row disruption versus simple that does not. Partial indicates a dislocation of only the proximal pole versus complete, and volar-dorsal notes the direction of the displacement. When the scaphoid is displaced volarly, the median nerve can be compressed, leading to an acute carpal tunnel syndrome as seen in the present case.

There are only several similar cases reported. Richards et al¹ described a 49-year-old woman with a scaphoid dislocation with an axial dislocation of the carpus between the capitate and hamate bones, for which the capitohamate and scapholunate joints were reduced and internally fixed 2 weeks after the injury. Kanaya et al⁴ reported a 51-year-old man with an isolated scaphoid dislocation to the radial side of the radial styloid process due to a crushing injury with the wrist in volar flexion. The initial closed reduction was unsuccessful, and an open reduction and internal fixation through the dorsal approach allowed adequate stabilization.

Pedrazzini et al² described a 39-year-old professional pianist with scapholunate disassociation with radial styloid and triquetral fractures to the left wrist after a motor vehicle accident. A dorsal approach was used for an open reduction. Both the radial styloid process and the scaphocapitate diastasis were reduced and stabilized using K-wires. Injured ligaments were repaired used a bone anchor and a dorsal capsulodesis, similar to the present case.

Isolated scaphoid dislocation with radial carpal disassociation represent a rare injury pattern. Successful outcomes require early fixation and ligament repair. The report of these extremely rare injuries should be encouraged to collect high-quality data on appropriate diagnostic and therapeutic options.⁵

Affiliations: ¹Division of Plastic and Reconstructive Surgery, Rush University Medical Center, Chicago, IL 60607, USA; ²Division of Plastic and Reconstructive Surgery, Cook County Health, Chicago, IL 60607, USA.

Correspondence: Charalampos Siotos, MD; charalampos_siotos@rush.edu

Disclosures: The authors have no relevant financial or nonfinancial interests to disclose.