Surgical Management of a Lateral Compression (LC)III Pelvic Ring Fracture With Type I Crescent Fracture-Dislocation: A Case Report

Lateral Compression (LC) pelvic ring fractures represent the most common pattern of pelvic ring injury in the Young-Burgess classification. The Crescent fracture is an uncommon subtype characterized by an iliac wing fracture that disrupts the posterior sacroiliac (SI) complex, creating a crescent-shaped fragment that is inherently rotationally unstable and associated with long-term complications including chronic pain and sexual dysfunction. LC fractures result from a laterally directed force and are subclassified (I-III) based on the degree of posterior ring disruption. We present the case of a 42-year-old male polytrauma patient treated at a Level I trauma center, who sustained an LCIII pelvic ring fracture following a 5-meter fall, comprising comminuted bilateral anterior ring fractures and a posterior ring disruption with a left type I crescent fracture involving the SI joint, with impaction of the mobile iliac fragment into the sacral ala, and a right sacral ala fracture (Dennis I). No neurological, genitourinary, or additional injuries beyond those described were identified at admission. Preoperative planning included computed tomography (CT) with three-dimensional (3D) reconstruction and a synthetic sawbone pelvic model for implant simulation and plate pre-contouring. Definitive surgical treatment on post-trauma day 10 used a modified Stoppa approach combined with a left iliac window, with de-impaction of the sacral ala and external rotation of the crescent fragment prior to sequential fixation with anterior reconstruction plating, an LCII corridor screw, and bilateral iliosacral screws. At eight-week follow-up, the patient reported no pain, no functional limitation, and no sexual dysfunction, achieving a Majeed Pelvic Score of 96/100, consistent with an excellent functional outcome. This case highlights the critical role of meticulous preoperative planning, multidisciplinary teamwork, and management at a dedicated pelvic trauma center in achieving optimal outcomes in complex LCIII crescent pelvic fractures.