Minimally invasive bilateral fixed angle locking fixation of the dorsal pelvic ring: clinical proof of concept and preliminary treatment results

PURPOSE: Dorsal pelvic ring fractures may result from high energy trauma in younger patients or from osteoporosis as fragility fractures in elderly patients. To date, no strong consensus exists on the best surgical technique to treat posterior pelvic ring injuries. The aim of this study was to evaluate the surgical performance of a new implant for angle-stable fixation of the posterior pelvic ring and patient outcome. METHODS: In a prospective pilot study, 27 patients (age: 39–87 years) with posterior pelvic ring fractures classified according to the AO classification (n = 5) or to the fragility fractures of the pelvis (FFP) classification (n = 22) were treated using the new implant. During a follow-up period of 1 year, surgical parameters of the implantation technique, complication rate, morbidity, mortality, preservation of patient mobility, and social independence were evaluated. RESULTS: No implant misplacement or failure was observed. Two patients developed symptomatic spinal canal stenosis at L4/L5 following mobilization. MRI diagnosis proved the implant was not responsible for the symptoms. In one case, an additional plate stabilization of a pubic ramus fracture was necessary 6 months later. There was no inpatient mortality. One patient died due to her underlying oncological disease within the first 3 months. The main outcome parameters were pain, mobility, preservation of independent living and employment. CONCLUSION: Operative instrumentation of dorsal pelvic ring fractures should be stable enough to allow for immediate weight bearing. The new locking nail implant offers percutaneous reduction and fixation options and may decrease the generally observed rate of complications. TRAIL REGISTRATION: German Clinical Trials Register ID: DRKS00023797, date of registration: 07.12.2020.