Pure traumatic unstable radiocarpal dislocation over pre-existing ulnar impingement syndrome, extensively arched carpus and medially rotated scaphoid: An exceptional and complex case report.

Introduction And Importance: Radiocarpal dislocation is a rare and severe injury that demands urgent diagnosis and treatment. In this case report, we present the unique scenario of a 32-year-old male who suffered a traumatic pure unstable radiocarpal dislocation. This dislocation was associated with ulnar impingement syndrome, an extensively arched carpus, and a medially rotated scaphoid. The complexity of this injury underscores the importance of timely intervention and comprehensive management.

Case Presentation: The patient had a pre-existing short ulnar head with radial-sided deformity, radioulnar convergence, negative ulnar variance, erosive scalloping of the distal radius, subchondral sclerosis of the ulnar head, scapholunate diastasis, and distal radioulnar joint (DRUJ) diastasis. Following a high-velocity motor vehicle accident, the initial treatment involved closed reduction and radio-metacarpal external fixation. Additionally, surgical intervention was required for an open dislocation of the metatarsophalangeal (MTP) joint of the left hallux.

Clinical Discussion: The subsequent management of this complex case included the Sauvé-Kapandji procedure, ulnolunate and ulnotriquetral ligamentoplasty using the palmaris longus tendon, and scapholunate fusion. The patient reported no prior wrist instability or injury upon awakening, but mild mechanical wrist pain persisted after exertion. Follow-up assessments revealed residual pain during prono-supination, along with slightly limited radial inclination. This exceptional case highlights the biomechanical challenges and the need for a multidisciplinary approach in treating such injuries.

Conclusion: To the best of our knowledge, this is the first documented instance of a traumatic pure unstable radiocarpal dislocation associated with ulnar impingement syndrome, an extensively arched carpus, and a medially rotated scaphoid. Despite the complexity, proper bone healing and favorable functional outcomes were achieved through meticulous surgical management. This case underscores the importance of individualized treatment strategies for rare and challenging wrist injuries.