[Occult Injuries to Posterior Pelvic Segment in Elderly Patients with Pubic Rami Fractures]

PURPOSE OF THE STUDY The incidence of pelvic fractures in geriatric population has been increasing. The diagnostic method of first choice is plain pelvic anteroposterior X-ray which, however, mostly reveals merely the pubic rami fractures. The pain caused by undiagnosed lesion of the posterior pelvic segment may substantially reduce the patient s mobility, thus also their self-sufficiency which is crucial in elderly patients. The purpose of this prospective study was to evaluate the incidence of an occult injury to the posterior pelvic ring in patients with an X-ray finding of pubic rami fractures only. MATERIAL AND METHODS Throughout a three-year period (2017-2019), the incidence of an occult injury to the posterior pelvic ring was evaluated by means of a CT scan in 50 patients aged 65 years and over, in whom the plain anteroposterior pelvic radiograph initially revealed only the pubic rami fractures. The mean age of 35 women and 15 men was 76 years (the range of 65-94 years). RESULTS In 15 patients (30%) only, the CT scan confirmed the isolated pubic rami fracture. In the remaining 35 cases (70%), the CT scan revealed an injury to the posterior pelvic segment, namely in 32 cases ipsilaterally, in one case contralaterally and in two patients bilaterally. In 4 patients (8%) only, signs of the injury to the posterior pelvic segment were subsequently found on the plain X-ray of the pelvis. DISCUSSION Diagnosis of a pubic rami fracture in geriatric patients solely based on the performed X-ray can be misleading. It has been proven in our prospective study that majority of injuries to posterior pelvic ring is not detected on the plain X-ray, which is also the conclusion arrived at by foreign authors. The CT scan alone can safely determine the actual extent of the pelvic injury. While the isolated injuries to the anterior pelvic ring show biomechanical stability, and thus are less painful and can be successfully treated non-operatively, the associated injuries to the posterior pelvic ring can cause a certain degree of instability, which has to be reflected in treatment strategy. CONCLUSIONS Injuries to the posterior pelvic segment in geriatric population are much more frequent than expected. They are, however, rarely distinguishable on a plain radiograph. Often times, only the pubic rami fractures are clearly visible. The fractures of posterior segment tend to be accompanied by a higher number of complications and a worse prognosis. A reliable method to detect these injuries is the unenhanced CT scan of the pelvis that should be performed routinely in all the patients with pubic rami fractures identified on a radiograph. In cases when pain substantially limits the mobilisation of the patients, minimally invasive surgical treatment should be considered. Key words: pelvic ring injury, pubic rami, geriatric population.