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

A Novel Method of Treatment of Small Osteolabral Avulsions Associated with Posterior Fracture dislocation of the Hip

Small osteolabral avulsions of the hip can be easily missed, and postreduction stress testing and a computed tomography (CT) scan of the hip should be done to look for these injuries. The usual modality of treatment of these unstable osteolabral avulsions is suture anchors, Herbert screws or spring plates. But when the bony avulsion is small, the use of these implants becomes a tedious job. We present a novel technique of fixing small osteochondral avulsion fractures not amenable to fixation using screws or spring plates. We performed a retrospective analysis of 57 cases of patients who underwent open reduction and internal fixation for posterior fracture dislocation of the acetabulum, and we identified 6 cases of small posterior labral osteochondral fragments leading to instability. These injuries were fixed using a novelmethod. Themean Harris Hip Score at the final follow-up was of 92.5. Fixation of osteochondral avulsions associated with posterior hip fracture dislocation can be a difficult task if the bony fragment is small. Our technique is a simple, cost-effective and reliable way of fixing such avulsions with satisfactory outcomes.

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.

Epidemiology and injury morphology of traumatic hip dislocations in children and adolescents in Germany: a multi-centre study

OBJECTIVE

Traumatic hip dislocations are very rare in childhood and adolescence. The aim of this multi-centre study is to analyse the current epidemiology and injury morphology of a large number of traumatic hip dislocations in children. This can provide a better understanding of childhood hip dislocations and contribute to the development of a therapeutic approach in order to prevent long-term impacts.

METHODOLOGY

This retrospective, anonymised multi-centre study included patients, aged up to 17 years, with acute traumatic hip dislocations and open growth plates. The patients came from 16 German hospitals. Exclusion criteria included insufficient data, a positive history of hip dysplasia, or an association with syndromal, neurological or connective tissue diseases predisposing to hip dislocation. An analysis was carried out on the patients' anthropometric data and scans (X-ray, MRI, CT), which were collected between 1979 and 2021. Gender, age at the time of dislocation, associated fractures, mechanism of injury, initial treatment including time between dislocation and reduction, method of reduction, treatment algorithm following reduction and all documented complications and concomitant injuries were evaluated.

RESULTS

Seventy-six patients met the inclusion criteria. There were two age peaks at 4-8 years and 11-15 years. There was an increased incidence of girls in the under-eight age group, who had mild trauma, and in the group of over-eights there were more boys, who had moderate and severe trauma. Dorsal dislocation occurred in 89.9% of cases. Mono-injuries dominated across all age groups. Concomitant injuries rarely occurred before the age of eight; however, they increased with increasing ossification of the acetabulum and appeared as avulsion injuries in 32% of 11-15-year-olds. Of the 76 patients, 4 underwent a spontaneous, 67 a closed and 5 a primary open reduction. A reduction was performed within 6 h on 84% of the children; however, in around 10% of cases a reduction was not performed until after 24 h. Concomitant injuries needing intervention were identified in 34 children following reduction. Complications included nerve irritation in the form of sensitivity disorders (n = 6) as well as avascular necrosis (AVN) of the femoral head in 15.8% of the patients (n = 12).

CONCLUSIONS

Traumatic hip dislocations are rare in childhood and adolescence and have high complication rates. The most severe complication, femoral head necrosis, occurred in 16% of cases. Minor injuries, especially in younger children, are enough to cause a dislocation. Posterior dislocation was more frequent and primarily occurred as a mono-injury; however, concomitant injuries must be considered with increasing age. Children continue to experience delayed reductions. The length of time until reduction, age and the severity of the concomitant injury play a role in the development of femoral head necrosis; however, this topic requires additional investigation.

Traumatic hip dislocations in a pediatric cohort: The importance of advanced imaging

Purpose

Given that pediatric traumatic hip dislocations are relatively rare, the purpose of the current study is twofold: first, to contribute a significant cohort to the existing corpus, and second, to provide evidence toward the role that computed tomography and magnetic resonance imaging could play in identification and management of this type of injury.

Methods

A retrospective review was conducted of all patients with traumatic hip dislocation who presented from 2012 to 2022 at a tertiary-level pediatric trauma center. Data regarding demographics, mechanism of injury, imaging, and treatment were tabulated. Outcomes of interest included immobilization length, concomitant injuries, imaging performed and findings, and rates of avascular necrosis, pain, and stiffness. Concomitant injuries were identified using imaging, clinical, and operative notes. Differences between categorical variables were compared using chi-square analysis or Fischer-exact testing, while continuous variables were compared using Student t tests or Wilcoxon rank sum tests when appropriate.

Results

Thirty-four patients were identified. Postreduction, 28 patients had a cumulative 17 magnetic resonance imaging, 19 computed tomographies, and 1 intraoperative arthrogram. Of these, 16 patients had 19 injuries identified on advanced imaging that were missed on initial radiographs. Eleven of these patients went on to operative treatment. In eight of these, postreduction advanced imaging helped guide the decision for surgery. In four patients, magnetic resonance imaging was necessary to fully characterize injury to the posterior acetabular rim after initial identification on computed tomography. Magnetic resonance imaging was also used to rule out one computed tomography-diagnosed acetabular fracture.

Conclusion

Magnetic resonance imaging is valuable to fully define associated rim and intra-articular injuries following initial treatment of pediatric traumatic hip dislocations.

Level of evidence

Level IV diagnostic study.

Surgical Hip Dislocation in Pediatric and Adolescent Patients

LEVEL OF EVIDENCE

V, Expert opinion.

Percutaneous Reduction of Intra-Articular Posterior Wall Acetabular Rim Fragment: Surgical Technique and Case Series With an Average Follow-Up of 2 Years

Small posterior wall rim fractures are typically stable; however, if incarcerated in the joint, they must be removed. It is possible to reduce the morbidity associated with open approaches by addressing these incarcerated fragments in a percutaneous manner. This allows the restoration of joint congruity and removal of the osteochondral fragment from the joint space. The following report details the surgical technique to accomplish this, and the results of a case series of patients who underwent this technique. The advantages include limiting the morbidity of an open approach. However, the surgeon must be prepared to convert to an open approach if percutaneous removal does not accomplish the goals of surgery-a concentric, stable hip joint.

Traumatic hip dislocation in the paediatric population: A case series from a specialist centre

INTRODUCTION

Traumatic hip dislocation is a rare injury in the paediatric population. It can occur after high energy trauma, but also after lower energy injuries especially in younger children. Posterior dislocation is the most common pattern of hip dislocation. In most cases, closed reduction is successful, but occasionally open reduction is required to achieve concentric reduction. The aim of our study was to present the 10-year experience from a Level-1 Trauma Paediatric Hospital and to comment on how our experience correlates with the current literature.

PATIENTS AND METHODS

This is a retrospective case series of all paediatric patients (< 16 years old) with a traumatic hip dislocation presented and/or treated at our institution, between the 1^st of January 2010 and 31^st August 2020.

RESULTS

Thirteen cases of traumatic hip dislocation were identified. There were 7 females. The mean age was 9.8 years. Typically, younger patients were involved in lower energy injuries. The direction of hip dislocation was posterior in ten cases. Associated injuries were seen in eight patients. All cases underwent closed reduction, which was successful in nine cases. Mean time to reduction was 6.8 hours. Post reduction imaging with CT and/or MRI was performed in all cases. There was residual subluxation in three cases, requiring open reduction. In one case with unrecognised undisplaced physeal injury, closed reduction resulted in a Delbet type 1 hip fracture. Two cases developed avascular necrosis (AVN).

CONCLUSIONS

Traumatic paediatric hip dislocation is a rare injury. A target of 6 hours for reduction should be employed as this will reduce the risk of AVN in those who have not permanently damaged the vessels at the time of injury. We advocate all attempts for closed reduction to be performed in an operating theatre with the use of an image intensifier to help identifying associated injuries and confirm concentric reduction. If closed reduction fails, open reduction is required. Post-reduction MRI is an important adjunct to recognise associated soft tissue injuries. Follow up of patients should continue for 2 years as a minimum to help detect AVN.

Recurrent traumatic hip dislocation in an 8-year-old boy

Pediatric traumatic hip dislocations (PTHD) are rare and represent around 5% of all pediatric dislocations. Associated bony or soft tissue injury can occur as often as 17%–25% of the time. We report a case of an 8-year-old boy presenting a posterior hip dislocation after a low-energy trauma, which was initially managed with closed reduction and bed rest for 1 week. Two days after hospital discharge, he suffered a recurrent posterior hip dislocation. He was now managed with 4 weeks of bed rest and lower limb skin traction followed by 1 week of no weight-bearing on crutches. With 6 months of follow-up, he is asymptomatic, walking autonomously, with complete and painless range of motion of the affected hip and no major radiographic changes. Pediatric traumatic hip dislocation is a rare and challenging injury that should be managed promptly. Currently, there is no protocol concerning treatment in the literature and its largely dependent of patient and parents' cooperation.

High-Energy Fractures of the Pelvis and Acetabulum in Pediatric Patients

Fractures of the pelvis and acetabulum, although uncommon in the pediatric cohort, represent a range of injuries with similarities to those seen in the adult cohort but with key differences that are important for the treating physician to be aware of to allow for systematic evaluation and management of these potentially life-threatening injuries. As the pediatric skeleton matures, changes in anatomy and physiology influence injury pattern, diagnosis, treatment, and complications. High-energy fractures of the pediatric pelvis are particularly concerning given the reported mortality rates ranging from 3.2% to 18%, with severe fracture patterns being associated with visceral injury in up to 60% of patients. The unique complexity of pediatric patients requires a multidisciplinary team to fully address their care. A systematic approach to the initial evaluation and diagnosis of pediatric patients with fractures of the acetabulum or pelvic ring aids in choosing between surgical and nonsurgical management of these fractures and avoiding complications unique to the maturing skeleton. We present such an approach to assist the practitioner who infrequently treats these uncommon injuries.

Femoral head fracture in an adult patient with isolated posterior labrum avulsion recognized through the 'fleck' sign: technical tips

Femoral head fractures in adults are known to be frequently associated with femoral neck fractures, acetabular fractures and sciatic nerve neurapraxia. Here, we report for the first time in the English medical literature the case of a 30-year-old patient having a Pipkin Type II comminuted femoral head fracture associated to an isolated acetabular labral osteochondral avulsion. This entity was diagnosed preoperatively through the presence of the acetabular ‘fleck’ sign recently described in adolescents with hip dislocation. This was of paramount importance knowing the key role of the acetabular labrum in physiological hip functioning. Therefore, a high index of suspicion of complete posterior acetabular labrum avulsion should be raised in front of a hip computed tomography scan showing the acetabular fleck sign even in an adult patient. This finding is important in posing the surgical indication and in completing the preoperative surgical planning in cases of femoral head fractures and dislocations.

Arthroscopic Treatment of a Posterior Labral Interposition after a Pediatric Hip Dislocation-A Case Report

We report the case of a 13-year-old boy, who suffered a posterior hip dislocation from playing soccer. Closed reduction was performed urgently. Because of a nonconcentric hip after closed reduction, further imaging was done. An intra-articular bony fragment was identified. Arthroscopic treatment was performed. Through an anterior portal we were able to locate the intra-articular bony fragment, which was located within the region of the fovea. After lifting of the caudal enfolded labral complex, we were able to remove the fragment. Evidence of a grade 3 cartilage defect was present at the femoral head. We were able to reduce the enfolded posterior labral complex, which was stable afterwards without the necessity of additional suture fixations. The concentric hip reduction was confirmed on an anteroposterior view of the hip postoperatively. The patient was instructed to toe tip weight-bearing for 6 weeks with limited range of motion to 60° of hip flexion. Eight weeks after surgery, he was free of pain and discomforts. From our experience, the arthroscopic intervention after pediatric hip dislocation associated with intra-articular bony fragments or posterior labral complex injuries, represents to be a preferred minimally invasive method in contrast to open surgical procedures.

Spontaneous Healing of a Bucket-Handle Posterior Labral Detachment After Hip Dislocation in a Five-Year-Old Child: A Case Report

CASE

We report the case of a 5-year-old girl who sustained a traumatic hip dislocation and a spontaneous reduction that was complicated by nonconcentric reduction and a large bucket-handle labral detachment. This injury was managed, via an anterior approach, with capsulotomy and reduction of the large interposed labral tear with an attached osteochondral fragment from the posterior aspect of the acetabulum. No additional surgical treatment was employed for the labral tear.

CONCLUSION

The patient ultimately demonstrated radiographic healing and an asymptomatic, clinically stable hip. This case illustrates the spontaneous healing of a large posterior labral detachment in a young pediatric patient with a good outcome at 2.5 years after injury.

Analysis of Acetabular Ossification From the Triradiate Cartilage and Secondary Centers

BACKGROUND

Acetabular development is a complex process that involves both endochondral growth from the triradiate cartilage (TRC) and intramembranous growth from the primary and secondary ossification centers of the innominate bones. Ponseti and others have described these centers including their contribution toward the development of normal acetabular shape. Prior studies have not utilized advanced imaging to study the appearance and closure of these secondary centers. The purpose of this study was to determine the chronological age at which the secondary ossification centers of the acetabulum appear and close and where there are any sex differences.

METHODS

Patients who underwent abdominal and pelvic computed tomography (CT) scans between January 2009 and December 2014 at a pediatric hospital were retrospectively reviewed. Patients between age 6 and 16 years with adequate imaging of acetabulum were included. CT scans were assessed for the appearance and closure of the 3 acetabular secondary ossification centers [anterior (os pubis), superior (os ilium), and posterior (os ischium)] and closure of the TRC.

RESULTS

A total of 159 CT scans met inclusion criteria (66 males and 93 females). The median age of appearance of the secondary ossification centers was: posterior (10.1 females, 12.8 males), anterior (10.7 females, 13.4 males), and superior (11.1 females, 13.6 males). The median age of closure of the secondary ossification centers was: posterior (12.8 females, 13.6 males), anterior (12.8 females, 13.9 males), superior (14.5 females, 13.9 males), and TRC (14.5 females, 14.3 males). Most ossification centers in females appeared and closed approximately 2 to 3 years before males.

CONCLUSIONS

Secondary ossification centers in the acetabulum appear sequentially (first posterior, then anterior, then superior), with almost all centers closing just before TRC. Closure occurs earlier in females than males. Knowledge of these centers and their closure patterns allows better radiologic readings (especially CT studies) and understanding of acetabular growth, allowing more informed management of childhood hip conditions including dysplasia, trauma, and over-use sports injuries.

LEVEL OF EVIDENCE

Level III-Diagnostic.