Traumatic dislocation of the hip joint in children

Acetabular "Fleck" Sign: Outcomes of Surgical Repair

BACKGROUND

Traumatic, posterior hip dislocations in the pediatric population are typically managed by closed reduction to achieve a concentric hip joint. The presence of an acetabular "fleck" sign, despite concentric reduction, has been shown to signify significant hip pathology. The purpose of this study was to evaluate the outcomes of open labral repair through a surgical hip dislocation (SHD) in a consecutive series of patients with an acetabular "fleck" sign associated with a traumatic hip dislocation/subluxation.

METHODS

A retrospective review of patients between 2008 and 2022 who presented to a single, level 1 pediatric trauma center with a traumatic posterior hip dislocation/subluxation was performed. Patients were included if they had an acetabular "fleck" sign on advanced imaging and underwent open labral repair through SHD. Medical records were reviewed for sex, age, laterality, mechanism of injury (MOI), and associated orthopaedic injuries. The modified Harris hip score (mHHS) was utilized as the primary clinical outcomes measure. Patients were assessed for the presence of heterotopic ossification (HO) and complications, including implant issues, infection, avascular necrosis (AVN), and post-traumatic dysplasia.

RESULTS

Twenty-nine patients (23 male, average age: 13.0±2.7 y; range: 5.2 to 17.3) were identified. Eighteen injuries were sports related, 9 caused by motor vehicle accidents, and 1 pedestrian struck. All patients were found to have an acetabular "fleck" sign on CT (26 patients) or MRI (5 patients). Associated injuries included: femoral head fracture (n=6), pelvic ring injury (n=3), ipsilateral femur fracture (n=2), and ipsilateral PCL avulsion (n=1). At the latest follow-up (2.2±1.4 y), all patients had returned to preinjury activity/sport. Three patients developed asymptomatic, grade 1 HO in the greater trochanter region. There was no incidence of AVN. One patient developed post-traumatic acetabular dysplasia due to early triradiate closure. mHHS scores showed excellent outcomes (n=21, 94.9±7.4, range: 81 to 100.1).

CONCLUSIONS

The acetabular "fleck" sign indicates a consistent pattern of osteochondral avulsion of the posterior/superior labrum. Restoring native hip anatomy and stability is likely to improve outcomes. SHD with open labral repair in these patients produces excellent clinical outcomes, with no reported cases of AVN.

LEVEL OF EVIDENCE

Level IV-therapeutic.

Clinical Outcomes and Associated Pathologies Following Pediatric Traumatic Hip Dislocations: A Systematic Review of the Literature

INTRODUCTION

Pediatric traumatic hip dislocations are a rare condition that can have devastating short and/or long-term outcomes and associated pathologies (APs), including associated injuries (AIs) and long-term adverse events (LTAEs), with negative long-term sequelae. Currently, there are little data that exist on the rate of APs, with the most notable being avascular necrosis (AVN), for pediatric traumatic hip dislocations. The purpose of this systematic review is to evaluate the outcome relative frequency of dislocation direction, reduction type, and rate of APs for traumatic hip dislocations in the pediatric population.

METHODS

A systematic review on the topic of traumatic hip dislocations in the pediatric population was performed using PubMed, ScienceDirect, Web of Science, CINAHL, and MEDLINE databases from database inception to March 30, 2023. Inclusion criteria was full-text English articles, addressed traumatic hip dislocations, and pediatric patients (<18 y old).

RESULTS

A total of 24 articles (n=575 patients) met final inclusion criteria from a total of 219 articles retrieved from the initial search. For the average age of the included patients with reported age (n=433 patients), the frequency weighted mean was 9.50 years±1.75 years with a frequency weighted mean follow-up time of 74.05 months ±45.97 months (n=399 patients). The most common dislocation direction was posterior (86.4%), the most common treatment type was closed reduction (84.5%), AVN was the most common type of LTAEs (15.5% of APs), and labral/capsular injuries and acetabular fractures were the most common type of AIs (14.0% and 9.4% of APs, respectively). There were a combined total of 414 APs (72%) out of 575 total patients.

CONCLUSION

Pediatric traumatic hip dislocations are associated with a high rate of AIs and LTAEs (72%, 414 APs out of 575 patients). AVN, labral/capsular injuries, and acetabular fractures are the most common APs after pediatric traumatic hip dislocations. Pediatric hip dislocations are usually posterior and commonly managed through closed reduction.

LEVEL OF EVIDENCE

III, Systematic Review.

Traumatic Obturator Hip Dislocation with Marginal Femoral Head Fracture in a 15-Year-Old Adolescent: A High-Energy Trauma-A Case Report and a Review of the Literature

We report the case of a 15-year-old boy brought to the emergency department after a bike accident, complaining of an isolated left hip pain. The X-rays showed an obturator hip dislocation treated by closed reduction under general anaesthesia, followed by 6 weeks of discharge. The follow-up MRI performed 6 weeks after the trauma showed an avascular femoral head necrosis, for which we performed multiple retrograde femoral head drilling, completed by the injection of autologue stem cells from the iliaq crest. One year later, the patient has no hip pain, no joint limitation, and can practice BMX at a high level again. The purpose of this report is to make the physicians aware of this rare problem that may be damaging for hip function, especially in young people.

Traumatic, Posterior Pediatric Hip Dislocations With Associated Posterior Labrum Osteochondral Avulsion: Recognizing the Acetabular "Fleck" Sign

BACKGROUND

Traumatic dislocation of the hip is uncommon in the pediatric population. Concentric reduction is usually achieved by closed means. Open reduction may be needed if there is femoral head fracture, incarcerated fragment, or incomplete reduction due to soft tissue entrapment. We present a series of 10 patients who sustained a posterior hip dislocation or subluxation with associated osteochondral avulsion of the posterior labrum. During surgery they were noted to have a labral injury pattern not previously recognized. Such treatment was dictated by postreduction advanced imaging, which revealed a consistent acetabular "fleck" sign indicative of this labral injury, which has not been previously described in literature.

METHODS

We performed a retrospective case review of patients with traumatic posterior hip dislocation/subluxation, treated operatively for a suspected associated labral tear and fractures.

RESULTS

Ten patients (2 girls and 8 boys) were identified. Average age was 12.7 years. Eight patients had postreduction computed tomography scans, which revealed a posterior acetabular wall "fleck" sign, suggestive of osteochondral injury. The small bony fragment was consistently displaced at least 2 to 3 mm in all patients with majority of the posterior wall remaining intact. Closed reduction was felt to be congruent in 7 of the 10 patients. All patients were treated operatively for exploration and stabilization of the suspected posterior labrum pathology and associated injuries using a surgical hip dislocation. A consistent pattern of labral pathology was seen in all patients, with disruption of the posterior labrum from the superior 12 o'clock attachment to detachment at the inferior 6 o'clock location. Reattachment of the osteochondral labral avulsion was performed with suture anchors along the posterior rim, and the associated femoral head fractures were also addressed with internal fixation. Two patients had inadequate follow-up and were excluded, the average follow-up for the remaining 8 patients was 9.8 months (range, 6 to 26 mo). There were no findings of avascular necrosis in any of the 8 patients.

CONCLUSIONS

Posterior hip dislocation in children may produce an acetabular "fleck" sign on advanced imaging, which in a stable, concentrically reduced hip has been treated without surgery in the past. Acetabular fleck sign may represent a near-complete avulsion of the posterior labrum as seen in our series. We recommend a high suspicion for this type of labral pathology and surgical repair when acetabular "fleck" sign is identified with hip subluxation or dislocation. Traumatic, posterior hip dislocations in young patients may be associated with significant labral pathology. Acetabular "fleck" sign on advanced imaging may predict such pathology.

LEVEL OF EVIDENCE

IV, retrospective study.

Traumatic hip dislocation in childhood

Traumatic dislocation of the hip in childhood is uncommon and can be a consequence of minor trauma. The authors report a series of 35 dislocations in skeletally immature patients. Most were isolated posterior dislocations without acetabular lesions. In 75% of cases, reduction of the dislocation was easy. Nine children required surgery to remove interposed joint capsule and/or osteochondral fragments to achieve anatomic reduction. Outcomes were generally good, except in one patient in whom a displaced fracture of the femoral physis was followed by total head avascular necrosis. One case of partial necrosis had a satisfactory outcome. Epiphyseal necrosis, though uncommon, appeared to be inconsistent to prevent and hard to predict. Bone scan seems to be more effective than MRI for the detection of necrosis.

Imaging of traumatic dislocation of the hip in childhood

BACKGROUND

Traumatic hip dislocation in childhood is a rare consequence of violent trauma. After reduction, outcome is usually favourable although epiphyseal necrosis can occur. Reduction must be carried out as soon as possible and is achieved easily, although if the labrum is involved, surgery may be required to achieve complete reduction.

OBJECTIVE

To analyze a retrospective series of traumatic hip dislocations in children, describing the therapeutic and imaging strategy.

MATERIALS AND METHODS

A total of 42 patients were studied. Their mean age was 10 years 3 months. All relevant radiographic, CT, MRI and radionuclide bone scan examinations were reviewed. Special attention was paid to associated lesions.

RESULTS

In 22 patients the dislocation was caused by low-energy trauma. Road traffic accidents accounted for 17 dislocations. An acetabular fracture was present in six patients and the femoral head was fractured in three. Reduction was easily achieved in 31 patients. In 11 patients the postreduction radiograph and CT showed joint space asymmetry secondary to labral entrapment. Only two patients developed epiphyseal necrosis.

CONCLUSIONS

It has been difficult to define and evaluate accurate principles for a medical imaging strategy in this group of patients. Analysis of plain radiographs is essential before and after reduction of the joint, and it is important to perform postreduction CT in every patient whose joint space remains widened. A radionuclide bone scan should be performed between the second and third weeks after injury to assess epiphyseal vascularity. With the use of specific sequences, MRI may be an alternative modality to assess epiphyseal vitality.

Traumatic hip dislocation in childhood. A report of 26 cases and review of the literature

Twenty-six cases of traumatic hip dislocation in children are presented. Although closed reduction was achieved in most instances, open procedures had to be employed in two cases of soft tissue interposition and in a patient with ipsilateral fracture of the femoral shaft. In 16 patients, with a follow-up averaging 14 years, the incidence of complications (avascular necrosis, coxa magna and arthrosis) was significant. Factors predisposing to abnormal results were delayed reduction and severe trauma. Neither the method of immobilization nor the interval without weight-bearing over 4 weeks were of influence. Principles of treatment are suggested.