Delayed Avascular Necrosis and Fragmentation of the Lunate Following Perilunate Dislocation

Chronic Isolated Dorsal Dislocation of the Lunate. A Rare Presentation of Carpal Instability

Isolated dorsal lunate dislocation is a rare injury. Only one case has been reported previously in which the treatment was performed in the chronic stage. In this report, we present the case of a 49-year-old handworker male who presented a dorsal dislocation of the lunate after a traffic accident. He was referred to our clinic 2.5 months later due to an initial misdiagnosis. Surgical treatment was performed and consisted of an open reduction using a nerve-sparing dorsal approach. A complete rupture of the perilunate ligaments and a marked instability of the lunate were detected. Stabilisation of the scapholunate, lunotriquetral and scaphocapitate spaces with a compression screw and Kirschner wires, respectively, was performed. The persistence of pain and functional limitation after the surgery along with an insufficient reduction of the scapholunate space on the X-ray and the development of a fistula on the ulnar edge of the carpus prompted reintervention. A hardware-free total wrist arthrodesis was preferred over other procedures, such as proximal row carpectomy, owing to the important articular damage. At the 3-month follow-up, he was clinically stable, consolidation of arthrodesis was documented and he had returned to his previous activities. Isolated dorsal dislocation of the lunate is a rare lesion. There is no consensus on the management of isolated chronic dislocations of the lunate. The frequent delay in the diagnosis compromises the final outcome of reconstructive techniques and introduces the risk of residual instability, increasing the incidence of chronic pain associated with post-traumatic osteoarthritis. In the case of chronic lesions, treatment with palliative techniques, such as proximal carpectomy or joint arthrodesis, should be considered.

Transscaphoid Dorsal Lunate Dislocation: A Case Presentation and Review of the Literature

This case report describes a 74-year-old man with the rare injury of transscaphoid dorsal lunate dislocation (LD). He sustained a crushing injury with a huge amount of energy to his right wrist while working with a pressing machine. There were deep abrasions and areas of skin necrosis on the dorsum of the wrist. The patient was treated with closed reduction and a Herbert screw fixation for the scaphoid fracture. Six months postoperatively, avascular necrosis (AVN) of the lunate and scaphoid was apparent on the wrist radiographs. We offered a proximal row carpectomy to the patient, but he declined surgery because he was able to perform his activity of daily living. Dorsal LD as well as its variants has a high prevalence of AVN of the lunate. Delayed diagnosis, delayed treatment, and open reduction increase the risk of AVN development of the lunate. The level of evidence is therapeutic IV.

Avascular necrosis of the lunate secondary to perilunate fracture dislocation: Case report and review of the literature

This is a 39-year-old male, fell from a bike, left wrist with trans-styloid perilunate fracture dislocation that underwent open reduction internal fixation, 20 months after surgery the patient developed avascular necrosis of the lunate, final wrist fusion was performed secondary to the arthritic changes on the wrist. Anatomic dissection was performed and vascularity of the lunate was identified, its origin is from the volar palmar arch, when dislocated palmarly and more than 90 degrees the vessel is still intact. More than 512 patients with perilunate dislocation and perilunate fracture dislocation are included we identified in the literature transient avascular necrosis of the lunate in nine and seventeen of pure avascular necrosis of the lunate. Concluding that avascular necrosis of the lunate after perilunate dislocation or perilunate fracture dislocation is an infrequent finding especially when the volar ligaments are intact.

The Etiology and Pathogenesis of Kienböck Disease

Kienböck disease is a condition that typically occurs in the "at-risk" patient, in the "at-risk" aspect of the proximal condyle of the "at-risk" lunate. In the active male, repetitive loading causes the stress fracture that commences in the single layer proximal subchondral bone plate. The lunate fracture commences at the point the lunate cantilevers over the edge of the distal radius, and then takes on the shape of the radius. We postulate that the stress fracture violates the parallel veins of the venous subarticular plexus-leading to localized venous hypertension and subsequent ischemia and edema of the fatty marrow. The increased osseous compartment pressure further potentiates the venous obstruction, producing avascular necrosis. If the fracture remains localized, it can heal or settle into a stable configuration, so that the wrist remains functional. Fractures of the subchondral bone plate produce irregularity of the lunate articular surfaces and secondary "kissing lesions" of the lunate facet and capitate, and subsequent degeneration. The lunate collapses when the fracture is comminuted, or there is disruption of the spanning trabeculae or a coronal fracture. The secondary effect of the lunate collapse is proximal migration of the capitate between the volar and dorsal fragments, producing collapse of the entire central column. The proximal carpal row is now unstable, and is similar to scapholunate instability, where the capitate migrates between the scaphoid and lunate. The scaphoid is forced into flexion by the trapezium, however, degeneration of the scaphoid and scaphoid facet only occurs in late disease or following failed surgery. In Kienböck disease, the secondary effects of the collapsing lunate are a "compromised" wrist, including: deformity and collapse of the central column, degeneration of the central column (perilunate) articulations, proximal row instability (i.e., between the central and radial columns), and degeneration of the radial column.

Arthroscopic Reduction and Stabilization of Chronic Perilunate Wrist Dislocations

An acute perilunate wrist injury that is unreduced for more than 6 weeks results in severe disability, and even open reduction with stabilization through wide dorsal and volar approaches is technically challenging. This report describes an arthroscopic technique for reduction and percutaneous wire stabilization of a chronic perilunate wrist dislocations. The technique involves initial radiocarpal and midcarpal access through the 6R and 3-4 portals, and these portals are used for synovectomy and debridement of capsular flap tears. The midcarpal joint is accessed initially through the radiocarpal joint, and additional midcarpal portals are used for sequential perilunate adhesiolysis before carpal mobilization and reduction. A percutaneous wire drilled into the lunate is used as a joystick to manipulate the lunate into its anatomic alignment along the carpal bones, and percutaneous transcarpal wire fixation is performed to stabilize the carpus. Arthroscopic and fluoroscopic guidance is used to optimize anatomic reduction and to confirm stability. The wrist is immobilized for 6 weeks; the percutaneous wires are removed thereafter, and the wrist is mobilized. Overall, the arthroscopic technique provides a safe and reproducible method for treatment of this complex chronic injury.