(From the July 2015 Issue of PediatricsOnline)
Traumatic posterior hip dislocations and subluxations are typically treated with a closed reduction in pediatric patients. For patients who have a congruent hip reduction, the course of treatment typically ends here. However, a new study published in the Journal of Pediatric Orthopaedics indicates that this course of treatment is missing near-complete avulsion of the posterior labrum in cases where an acetabular “fleck” sign is visible in the postreduction CT scan.
A team of researchers from Nationwide Children’s Hospital is the first to describe the acetabular “fleck” sign, which was consistent with osteochondral avulsion of the posterior labrum in all cases in the study.
“During surgery, all of these patients were noted to have a labral injury pattern not previously recognized,” says Kevin Klingele, MD, chief of the Department of Orthopaedics at Nationwide Children’s and senior author on the paper.
Eight patients had postreduction computed tomography scans revealing a posterior acetabular wall “fleck” sign, which is suggestive of osteochondral injury. The small bony fragment was consistently displaced at least 2-3 mm in all patients, with the majority of the posterior wall remaining intact.
Notably, the closed reduction for seven of eight of these patients was congruent. In the first case, the closed reduction was not congruent, so an open reduction was completed. During surgery, the labral avulsion was found. In the next case, the patient had a congruent closed reduction, but surgery was indicated for repair of a femoral head fracture. Again, labral avulsion was found during the operation.
“The majority of patients in the study had congruent hip reduction, but a significant injury was still found,” Dr. Klingele says. “We recommend a high level of suspicion for this type of labral pathology and surgical repair when the acetabular fleck sign is identified with hip subluxation or dislocation.”
According to Dr. Klingele, studies in adults have shown that untreated labral insufficiencies are associated with joint problems down the road, and this may be true for pediatric patients as well.
The incidence of labral pathology in pediatric patients after traumatic hip dislocation is unknown, however. This study begins a new discussion on the management of these patients.
“Based on what I’ve seen and the reproducibility of the findings of this study, if I see the fleck sign, I will open,” Dr. Klingele explains. “And so far, when I do, I’ve found labral pathology — even in cases of a congruent hip reduction.”
Further research is needed to determine if arthroscopic repair is an option for these patients. Currently, the open procedure is the preferred treatment, says Dr. Klingele, who is also an adjunct assistant professor of Orthopaedic Surgery at The Ohio State University.
More discussion and research is also needed to study the potential role for MRI in postreduction scans compared to CT scans, Dr. Klingele adds. The reproducibility of the MRI in the setting of an acute traumatic injury currently makes it less accurate than a CT scan.
Blanchard, C. Kushare I, Boyles A, Mundy A, Beebe AC, Klingele KE. Traumatic, posterior pediatric hip dislocations with associated posterior labrum osteochondral avulsion: Recognising the acetabular “fleck” sign. Journal of Pediatric Orthopaedics. 2015 Apr 22. [Epub ahead of print]