Traumatic pediatric hip dislocations are uncommon and can occur following minor trauma. This injury may be overlooked, as pediatric hip dislocations can reduce spontaneously prior to medical attention. In this scenario, the presenting hip radiographs may provide evidence of a prior transient hip dislocation episode by demonstrating signs of a nonconcentric hip reduction, and prompt further evaluation with advanced imaging. We present a rare case of a traumatic posterior hip dislocation with spontaneous nonconcentric reduction in a child. CT and MRI revealed a block in concentric reduction by the avulsed and entrapped posterior acetabular labrum and contiguous epiphyseal fragment. This case highlights the imaging characteristics of this rare injury, and the importance of early diagnosis to guide surgical management.

Irreducibility is a rare complication of pure posterior hip dislocation requiring surgical intervention.

We present a case of a 22-year-old female with posterior hip dislocation following a motor vehicle accident. Despite unsuccessful closed reduction attempts, open surgical reduction successfully released the incarcerated muscles and achieved reduction. Follow-up examinations showed excellent functional outcomes without complications.

Irreducibility remains a rare complication of traumatic posterior hip dislocation. Three possible entities can cause soft tissue incarceration: labral buttonholing, intra-articular osteochondral bodies, and entrapment of the piriformis muscle. The posterior-lateral approach provides excellent exposure of the posterior hip structures, but it carries the risk of injury to the medial circumflex artery. After successfully reducing the dislocation, it is essential to perform a computed tomography (CT) scan to detect any osteochondral lesions, including femoral head impaction. Functional outcomes are better with early mobilization and prompt resumption of weight-bearing. However, femoral head osteonecrosis complicates 52.9 % of hip dislocations reduced beyond 6 h, whereas it occurs in only 4.8 % of dislocations reduced within this timeframe.

This case underscores the importance of prompt recognition and appropriate surgical intervention for irreducible hip dislocations to prevent further complications and optimize patient outcomes.

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.

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.

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).

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 posterior hip dislocations in children and adolescents requires emergent closed reduction. Postreduction imaging is necessary to assess the concentricity of reduction and structural injuries to the hip. There is no a consensus for which imaging is a modality of choice in such condition. The purposes of this study are to describe magnetic resonance imaging (MRI) findings of traumatic posterior hip dislocations and to compare the effectiveness of MRI with computerized tomography (CT) in detecting structural abnormalities of the hip that impact patient management.

This study is a retrospective review of imaging in traumatically dislocated hips in patients who were treated at our institution. All CT and MRI imaging were reviewed and specific osseous and soft tissue injuries documented by consensus among 2 musculoskeletal pediatric radiologists who interpreted the MRI and CT scans of each patient in a blinded manner.

In total, 27 patients (23 males, 4 females) with mean age of 12.5 years (range, 2 to 19 y) with postreduction MRI were evaluated. MRI findings revealed femoral head injuries in 17 (62.9%), posterior labral entrapments in 6 (22.2%), posterior labral tears in 17 (62.9%), posterior wall fractures in 15 (55.5%), fracture of the posterior unossified part of acetabulum in 4 (14.8%), and ligamentum teres injuries in 8 (29.6%). Of 16 patients who had postreduction CT scans, 6 (37.5%) had femoral head fractures, 9 (56.3%) had posterior wall fractures, and 8 (50%) had intra-articular osseous entrapments. All bony fractures and intra-articular entrapment could be seen on MRI imaging. In 16 patients with both CT and MRI, posterior acetabular injury was detected in 10/16 (62.5%) on MRI and 9/16 (56.3%) on CT. Three patients with entrapment of labrums identified on MRI could not be seen on CT scan. One patient with persistently unstable hip after reduction had an entrapped unossified portion of acetabular fracture which was seen on MRI but not on CT.

MRI is superior to CT scan for detection of structural injuries in children and adolescents with traumatic hip dislocation. The unique structural injuries included entrapment of posterior labrum and posterior unossified acetabular fractures could be seen only at MRI. These findings will impact surgical decision making of these injuries.

Level IV.

Nonconcentric reduction of hip posterior dislocation caused by the acetabular labrum rim fracture is rare. There has been very little study on the feasibility of arthroscopically treatment and medium and mid-term evaluation to this pathology. The objectives of the current study were: (1) Is the arthroscopically assisted technique feasible to this manage this injury? (2) What is the effectiveness of arthroscopic treatment for nonconcentric reduction of hip posterior dislocation caused by acetabular labrum rim fracture.

Arthroscopically assisted procedure is an alternative treatment modality for nonconcentric reduction of hip posterior dislocation caused by acetabular labrum rim fracture.

Thirteen of 257 posterior hip dislocations who were admitted to our hospital from February 2008 to March 2017 were included: 9 males and 4 females, with an average age of 23.7 (15-36) years. All of them underwent hip posterior dislocation and nonconcentric reduction related to acetabular labrum rim fracture. All of them had arthroscopic reduction and fixation of the rim fracture. Visual Analogic Score (VAS) score, modified Harris score, Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) score and the last follow-up radiographs were analyzed respectively. Postoperative complication and the need for secondary operation were recorded during the process.

The incidence rate of this pathology was nearly 5%. Twelve out of 13 patients were followed up for an average of 42 (range, 26-68) months. At the final follow-up, VAS score was decreased from 5.2±0.9 (range, 4.0-6.1) preoperatively to 0.5±0.5 (range, 0.0-1.0) (p<0.0001), modified Harris score and WOMAC score were increased statistically significant from 32±8 (range, 28-40) and 30±5 (range, 25-35) to 94±5 (range, 89-99) and 95±4 (range, 91-99) respectively (p<0.0001). All patients have had completely concentric reduction and returned to activities of daily life. There was not any hip arthroscopic complication such as sciatic nerve injury and intra-abdominal fluid extravasation. Besides, there were no aseptic necrosis and revision case.

Arthroscopically assisted procedure is an alternative treatment modality for nonconcentric reduction of hip posterior dislocation caused by the acetabular labrum rim fracture without surgical dislocation procedure. Good clinical results can be achieved without any complications related to the surgical procedure.

Level IV, therapeutic case series.

To investigate the effectiveness of arthroscopic treatment for irreducible hip posterior dislocation caused by acetabular labrum bony Bankart lesions.

Between February 2008 and August 2016, 11 patients with irreducible hip posterior dislocation caused by acetabular labrum bony Bankart lesions, were treated with arthroscopic reduction and fixation of bony Bankart lesions. There were 7 males and 4 females, with an average age of 23.7 years (mean, 15-36 years). The injury was caused by traffic accident in 8 cases and falling from height in 3 cases. The interval between hip dislocation and the first manual reduction was 2-8 hours (mean, 5.3 hours) and between the first manual reduction and arthroscopic surgery was 6-31 days (mean, 12.8 days). The preoperative visual analogue scale (VAS) was 5.2±0.9, the modified Harris score was 32±8, and the Western Ontario and McMaster University Osteoarthritis Index (WOMAC) was 30±5.

The operative time was 90-150 minutes (mean, 120.9 minutes), with no hip arthroscopic surgery related complications. All incisions healed by first intention. All patients were followed up 26-68 months (mean, 42.7 months). Postoperative X-ray films showed that all hip joints were reduction; CT showed that the reduction of posterior acetabular wall fracture was satisfactory. And all fractures healed at last follow-up with no avascular necrosis of the femoral head or osteoarthritis. At last follow-up, the VAS score was 0.5±0.5, the modified Harris score was 94±5, and the WOMAC score was 95±4. There were significant differences in those indexes between pre- and post-operation ( P<0.05).

The irreducible hip posterior dislocation caused by acetabular labrum bony Bankart lesions is rare. Arthroscopic therapy has the advantages of less trauma, quick recovery, and less complications.

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.

Traumatic posterior hip dislocation in children is a rare injury that typically is treated with closed reduction. Surgical treatment is typically recommended for nonconcentric reduction with joint space asymmetry with entrapped labrum or an osteochondral fragment. The surgical hip dislocation (SHD) approach allows for full assessment of the acetabulum and femoral head and has been our preferred surgical strategy. The purpose of this study was to (1) describe the intra-articular pathologic findings seen at the time of SHD; and (2) to investigate hip pain, function, and activity level of a cohort of children and adolescents after open treatment of a posterior hip dislocation using the SHD approach.

Following IRB approval, 23 patients who sustained a traumatic posterior hip dislocation between January 2009 and December 2013 were identified. In 8/23 (34.8%) patients there was evidence of nonconcentric reduction after closed treatment and surgical treatment was performed using the SHD approach. Seven male and 1 female (mean age, 11.2 y; range, 6 to 14.6 y) were followed for an average of 28 months (range, 13 to 67 mo). The modified Harris Hip Score (mHHS) and the University of California Los Angeles activity score assessed clinical hip outcome and activity level at minimum of 1 year after surgery.

Six patients were treated after an acute trauma, whereas 2 were treated after recurrent dislocations. Five patients were involved in motor vehicle accidents and 3 in sports-related injuries. Intraoperative findings include posterior labral avulsion in all patients, fracture of the cartilaginous posterior wall (n=3), and femoral head chondral injuries (n=5) and fracture (n=1). The labral root was repaired using suture anchor technique in 7/8 patients and resected in 1. In 2 patients, labral repair was complemented by screw fixation of the posterior wall. All but one patient (mHHS=94) reported maximum mHHS. The University of California Los Angeles activity score was 10 for 5/8 patients and 7 in 3 patients. No case of femoral head osteonecrosis was noted. One patient developed an asymptomatic heterotopic ossification.

When open reduction is recommended for the treatment of intra-articular pathologies and hip instability following traumatic dislocation of the hip in children and adolescents, the SHD is an excellent approach that allows surgical correction of the damaged bony and soft-tissue structures including repair of the capsule-labral complex, and reduction and internal fixation of the cartilaginous posterior wall and femoral head fractures.

Level IV.

Posterior hip dislocation in children and adolescents may involve the non-ossified posterior acetabular wall. Plain radiographs and computed tomography (CT) have been shown to underestimate injury to the unossified acetabulum as well as associated soft-tissue structures.

The purpose of this study was to describe findings on radiographs, CT and magnetic resonance imaging (MRI) after posterior hip dislocation in a series of adolescents and to report the intraoperative findings, which are considered the gold standard. Measurements of the posterior wall length using MRI and CT scans were also performed.

After institutional review board approval, 40 patients who sustained a traumatic posterior dislocation of the hip between September 2007 and April 2014 were identified. Inclusion criteria were (1) age younger than 16 years old and (2) availability of MRI obtained following closed reduction of the hip. Eight male patients and one female patient with an average age of 13.2 years (range: 10.1-16.2 years) underwent hip MRI following posterior dislocation. Seven of the nine patients also underwent evaluation by CT. Plain radiographs, CT scans and MRI were evaluated in all patients by a single pediatric radiologist blinded to surgical findings for joint space asymmetry, posterior wall fracture, femoral head fracture, labrum tear, complete or partial ligamentum teres rupture and presence of intra-articular fragments. Six patients underwent surgical treatment and the intraoperative findings were compared with the imaging findings.

CT identified all bone injuries but underestimated the involvement of posterior wall fractures. Assessment of the posterior wall size and fracture displacement was possible with MRI. All surgically confirmed soft-tissue injuries, including avulsion of the posterior labrum, were identified preoperatively on MRI. The measurement of posterior wall length was not statistically different using CT and MRI.

Intraoperative pathological findings at the time of open surgical treatment were universally recognized on MRI but not on CT scans. MRI should be considered for evaluation of the hip following closed reduction for the treatment of a posterior dislocation in children and adolescents as it reliably allows assessment of intra-articular pathology without the risk of radiation exposure.

Minor trauma may cause hip dislocation in young children because of physiologic hip joint laxity and the soft cartilaginous structure of the acetabulum. In this work, we report on a 22-month-old boy with right-sided traumatic posterior hip dislocation and ipsilateral distal femoral fracture because of an outdoor motor vehicle accident. The patient was treated with emergency closed reduction and one and a half hip spica under general anaesthesia. The femoral fracture and hip dislocation were healed smoothly without any complication. Traumatic hip dislocation is rare in children, which may occur after trivial trauma. Prognosis is better in younger patients with low-energy trauma and in cases treated early.

We report the case of a 34-year-old female patient who, six week following her acetabular fracture ORIF through an extended iliofemoral approach, presented with anterolateral incomplete dislocation of the femoral head. In the absence of joint incongruence as demonstrated on radiographs and CT images, a capsular tightening was performed via the anterior Hueter approach. This capsular plasty stabilized the hip for 2 years, but gradual osteoarthritis deterioration resulted in the need for arthroplasty. At the 2-year follow-up, this secondary arthroplasty showed satisfactory result. The substantial muscle exposure of the lateral aspect of the acetabulum and the circumferential capsulotomy related to the use of the iliofemoral approach were retained as factors promoting this complication. In case early postoperative mobilization is impossible, temporarily maintaining the limb in abduction and flexion can be recommended after an extended iliofemoral approach with circumferential capsulotomy.

Irreducible hip dislocation following capsular and labral entrapment is a rare condition. We report a case of irreducible posterior traumatic pure hip dislocation where reduction was successfully achieved only with open surgery. An analysis of this case in the light of the published literature recalls the different etiologies of irreducible traumatic dislocation of the hip and the requirement for open surgery.