Traumatic Ulnar Carpal Translocation, Distal Radioulnar Joint Subluxation with Occult Perilunate Injury

Background  Perilunate injuries pose a significant treatment challenge, particularly when initially missed or underestimated. These injuries have a multitude of variations as propagation of the injury may be through ligaments and/or bone, with more recent appreciation given to nondislocated perilunate injuries. Case Description  We present a new variant of perilunate injuries, not dislocated (PLIND). This occult ligamentous perilunate injury was associated with ulnar carpal translocation, radiocarpal subluxation, and distal radioulnar subluxation. The extent of injury was fully appreciated intraoperatively, with only subtle clues present on preoperative exam and imaging, emphasizing the high index of suspicion required to identify these injuries. Clinical outcome at 1-year follow-up was very satisfactory. Literature Review  PLIND consist a distinct subset within the spectrum of perilunate injuries in which there is no observed disruption of the capitolunate relationship. Based on few cases reported in the literature (attributable to their rare occurrence and likely additional lack of awareness surrounding the injury pattern), current recommendations for surgical management include arthroscopic or open approach to appropriately address osseous and ligamentous injuries. Clinical Relevance  Recognition of PLIND injuries is challenging given the lack of frank dislocation of the capitate head on the lunate, as observed in classic perilunate injuries. Heightened clinical suspicion in patients with consistent mechanism and presentation, followed by timely surgical management, may limit sequelae of persistent instability and arthritis. Our case contributed to relevant literature by presenting a previously undescribed PLIND variant combined with radiocarpal instability, ulnar carpal translocation, and distal radioulnar subluxation.