Traumatic Hip Dislocations in Children and Adolescents: Diagnostic Challenges and the Significance of MRI Imaging - A Multi-Center Study

doi:10.21203/rs.3.rs-4367643/v1

Download PDF

Research Article

Traumatic Hip Dislocations in Children and Adolescents: Diagnostic Challenges and the Significance of MRI Imaging - A Multi-Center Study

https://doi.org/10.21203/rs.3.rs-4367643/v1

This work is licensed under a CC BY 4.0 License

Version 1

posted

You are reading this latest preprint version

Background

Traumatic hip dislocations in children and adolescents are rare but associated with significant consequences such as secondary coxarthrosis and avascular necrosis of the femoral head. Delayed reductions are cited in the literature as a primary cause, mainly due to radiologically overlooked dislocations. The heterogeneous symptomatology and primary care in regular emergency departments complicate the diagnosis. This multi-center study aims to evaluate the various diagnostic steps and propose an improved algorithm for diagnosing traumatic hip dislocations in childhood.

Methods

This retrospective multi-center study included 76 patients aged up to 17 years with acute traumatic hip dislocations and open growth plates from 16 German hospitals. Exclusion criteria included insufficient data, positive history of hip dysplasia, and association with syndromal, neurological, or connective tissue disorders predisposing to hip dislocation. Analysis included anthropometric data and imaging (ultrasound, X-ray, MRI, CT) from 1979 to 2022. Examined parameters included gender, age, associated fractures, mechanisms of injury, initial care, time to reduction, associated injuries, and diagnostic modalities. Statistical analysis was performed using SPSS while strictly adhering to ethical guidelines.

Results

76 patients met the inclusion criteria. Primary imaging showed a clear dominance in X-ray diagnostics in one plane 46% (n = 35) and two planes 39% (n = 30). In 87% of the cases (n = 66), dislocations were diagnosed during initial presentation. Dislocations were missed in 12% (n = 9), with seven children under the age of eight years old. Fifty percent of dislocations of those under four years old were not detected. Delayed reduction occurred in 12 children (15.8%), with 8 patients undergoing reduction more than 24 hours after trauma. The reason in 12% of the cases (n = 9) was an undetected dislocation in imaging. Dislocations were particularly commonly overlooked in conventional X-rays, whereas none were missed in MRI. Fifty-four patients (71%) had associated injuries, of which 57.9% (n = 44) were diagnosed only with MRI.

Conclusion

Successful primary diagnosis of traumatic hip dislocations, which are delayed in 15% of cases and carry an increased risk of femoral head necrosis, requires an algorithm, especially for young children where dislocations are often not automatically suspected. MRI plays a crucial role in the secondary diagnostic phase due to the high incidence of associated injuries. MRI provides a more precise depiction, especially of cartilaginous acetabular avulsions and soft tissue interpositions. These findings underscore the indispensable role of MRI diagnostics in traumatic hip dislocations and a unified diagnostic algorithm.

Level of Evidence: IV

Traumatic hip dislocations

childhood

avascular necrosis

primary care

emergency departments

diagnostics

algorithm

radiographic imaging

Traumatic hip dislocations are exceedingly rare in childhood and adolescence (Macnicol, 2000; Mehlman et al., 2000; Kutty et al., 2001; Ayadi et al., 2008; Brandão et al., 2010; Bressan et al., 2014; Strüwind et al., 2018). These situations are emergent, as unrecognized dislocations or delayed treatment of non-concentric reductions are associated with early onset of secondary coxarthrosis and an increased incidence of avascular necrosis of the femoral head (AVN) (Bressan et al., 2014; Thanacharoenpanich et al., 2020). Most studies describe cases of delayed reductions (Brunner et al., 1988; Ayadi et al., 2008; Zrig et al., 2009; Sulaiman et al., 2014). Offierski et al. mentioned in their study a dislocation with concurrent femoral head injury diagnosed three months and three weeks after trauma (Offierski, 1981). Barquet et al. even describe 50% of initially overlooked cases of dislocations with concurrent ipsilateral femoral shaft fractures (Barquet, 1981). In the previous study by this research group (Braun, et al., 2023), delayed reductions occurred in 15.8% of cases. When causality is cited in literature, overlooked dislocations with conventional radiology are primarily discussed. It is speculated that this is due to pain-related difficulties and thus inadequate imaging (Mörsdorf et al., 2016), as well as to associated injuries in polytrauma cases (Sanders et al., 2010). Another explanation for overlooked dislocations is the circumstances of childhood emergency care in the context of traumatic hip dislocation. Mono-injuries significantly outweigh multiple traumas and polytraumas in children of all age groups (Braun et al., 2023). Thus, primary care typically occurs not in trauma bays but in emergency departments. Primary care in "regular emergency departments" can lead to trivialization of trauma, especially when only a minor mechanism of injury is present (Zrig et al., 2009). Furthermore, diverse mechanisms of injury can lead to dislocation, ranging from tripping in children under eight to high-velocity traumas in older children (Offierski, 1981; Braun et al., 2023). Additionally, the clinical symptomatology of patients is inconsistently described in the literature (Brandão et al., 2010; Bressan et al., 2014; Graf and Seidl, 2022). Graf et al. go as far as to say that clinical signs are not reliable enough to identify hip dislocation. Currently, conventional X-rays are established as the standard both before and after reduction. However, computed tomography (CT) and particularly magnetic resonance imaging (MRI) are attributed with a heterogeneous significance in the acute phase of traumatic hip dislocation (Vialle et al., 2005; Blanchard et al., 2016; Strüwind et al., 2018). Fabricant et al. demonstrate that ossification of the posterior acetabular wall usually occurs between twelve and thirteen years of age (Fabricant et al., 2013), and that conventional X-rays and CT scans may not effectively depict the non-ossified, developing, cartilaginous portions of the immature acetabulum (Yang et al., 2023). In summary, overlooked dislocations are associated with pain and a higher risk of complications. Overlooked dislocations lead to delayed reductions, which in turn pose the greatest risk factor for developing AVN (Mehlman et al., 2000). It remains to be noted that according to the literature, a multitude of factors can contribute to the overlooking of dislocations. The most easily modifiable variable appears to be that of diagnostics. Thus far, diagnostics are inconsistent, and the benefits of individual diagnostic methods, particularly imaging, have not been comparatively examined regarding childhood hip dislocation. Additionally, there is currently no diagnostic algorithm for suspected childhood traumatic hip dislocation. The aim of this multi-center study is to evaluate the individual steps of diagnostics with the goal of establishing an algorithm that improves the quality of diagnostics regarding traumatic hip dislocations in childhood.

This retrospective, anonymized data collection was conducted as a multi-center study. It includes 76 patients with acute traumatic hip dislocations. Patient recruitment was based on a nationwide request to 36 pediatric traumatology clinics through the network of the Pediatric Traumatology Section (SKT) of the German Society of Orthopedics and Trauma Surgery (DGOU). Out of 36 clinics, 16 clinics reported treating children and adolescents with traumatic hip dislocation during the period from 1979 to 2022 (Braun et al., 2023). For easier comparability with the largest study on this topic to date (Mehlman et al., 2000), the inclusion criteria of this study were internalized. Patients with a history and radiologically confirmed traumatic hip dislocation and open growth plates at the proximal femur at the time of injury were included.

Patients with a positive history of hip dysplasia and association with syndromal diseases (e.g., Trisomy 21), neurological conditions (e.g., Infantile Cerebral Palsy), or connective tissue disorders (e.g., Marfan Syndrome), all of which predispose patients to hip dislocation (Macnicol, 2000), were excluded. Another exclusion criterion was insufficient data availability.

From medical records, the following information was extracted: gender, age at the time of dislocation, associated fractures, mechanism of injury, initial care including diagnostic procedures, and the time interval between dislocation and reduction. Additionally, all documented associated injuries, their diagnostic procedures, and the time interval until treatment were recorded.

The following five age categories were established

1–3 years 11 months, 4 years − 7 years 11 months, 8 years − 10 years 11 months, 11 years − 14 years 11 months, and > 15 years. This classification, established by Trueta, is based on morphological changes in the femoral head and its blood supply (Trueta, 1957). This categorization had already proven effective in the previous study by Braun et al. (2023) and was thus continued. Additionally, the work of Yang et al. (2023) supports the significance of the different morphology of age groups for imaging diagnostics.

The clinical symptoms at initial presentation were derived from patient records and were examined based on the characteristics listed in the literature for posterior dislocations with hip flexion, adduction, internal rotation, and shortened ipsilateral limb, as well as for anterior dislocations with hip extension, abduction, external rotation (Herrera-Soto and Price, 2009; Zrig et al., 2009).

The documentation of primary imaging diagnostics (ultrasound, conventional X-ray, MRI, or CT) as well as documentation of whether the dislocation was recognized, was extracted from patient records. The analysis included the age-dependent distribution of these imaging diagnostics as well as the age-dependent reliability of these diagnostics. Additionally, a detailed analysis of imaging was conducted using the six-eye principle to determine whether experienced pediatric traumatologists should have recognized dislocations based on the available images. This involved examining whether potential failures to recognize were attributable to imaging issues or human error.

The reduction period was divided into the time until the first reduction attempt, regardless of its success, and the time until the final successful reduction. These periods may differ from each other due to non-congruent reductions, which can be caused by interposition or associated injuries (Thanacharoenpanich et al., 2020).

The mechanism of injury was classified into mild, moderate, and severe traumas, defined as follows

Mild traumas included running, tripping, or falls (under three meters); moderate traumas resulted from excessive speed (riding, cycling, skiing, or sledding accidents) or excessive force (soccer); severe traumas were caused by high-velocity impacts or falls (over three meters) (Braun et al., 2023). The type of trauma was subdivided into isolated dislocation (mono-injuries) as well as multiple injuries and polytraumas.

Lesions in the acetabulum were examined. The focus was on the posterior acetabulum, as injuries in hip dislocations are almost exclusively located in this area (Morris et al., 2017). It was analyzed whether the likelihood of associated injuries after hip dislocation is age-dependent. The associated injuries themselves were morphologically categorized based on available radiological imaging using the six-eye principle, as well as by assessment from experienced radiologists, into bony injuries, cartilage, labral, or combination injuries, as well as isolated dislocations without associated injuries. Special attention was paid to the modality for diagnosing associated injuries and the resulting diagnostic consequences.

The diagnostic algorithm was established through consensus among the participating authors, based on the study results.

The statistical analysis was performed using SPSS. Qualitative variables were described using absolute and relative frequencies. A bivariate analysis was conducted. Categorical variables were compared using chi-square tests (or Fisher's exact test for small datasets). Ordinal variables were compared using the linear-by-linear association test.

This study is based on the analysis of patient records and existing imaging without intervention in the treatment algorithm.

The study has received a positive ethics vote from the State Medical Association of Baden-Württemberg (F-2020 -120).

The clinical symptoms at initial presentation could only be traced in 22.3% (n = 17) of the total 76 patients based on patient records. Among them, 19.7% (n = 15) were diagnosed with posterior dislocation. Of these, only 60% (n = 9) exhibited internal rotation, 53.3% (n = 8) exhibited flexion, 20% (n = 3) exhibited adduction, and 20% (n = 3) exhibited shortening of the ipsilateral limb, as described in the literature as typical symptoms. Two patients with posterior dislocation exhibited external rotation contrary to the literature. One patient with anterior dislocation exhibited internal rotation contrary to the clinical presentation described in the literature. The second patient with anterior dislocation exhibited only flexion.

Delayed initial reductions (> 6 hours after trauma) occurred in 15.8% (n = 12) of the children. The reason for 12% (n = 9) was an overlooked dislocation in imaging. The cause was unknown in 5.3% (n = 3).

For primary imaging diagnostics conventional X-ray was used predominantly. This was divided into X-rays in one plane (n = 35), X-rays in two planes (n = 30), CT (n = 4), MRI (n = 1), and ultrasound (n = 1). Although the distribution of diagnostics is seemingly very different, considering the age groups, this is not statistically significant with a p-value of 0.7704 (Table 1). Dislocation was recognized in 87% (n = 66) of primary imaging diagnostics and overlooked in 12% (n = 9). Dislocations were predominantly overlooked in younger children, with seven overlooked dislocations occurring in children under eight years old. In children under four years old, 50% of dislocations were not recognized. The differences in recognition accuracy between age groups were significant with a p-value of 0.00637 (Table 1, Fig. 1). Among cases where dislocations were not diagnosed, 44.4% (n = 4) were on conventional X-rays in one plane, 44.4% (n = 4) were on X-rays in two planes, and 11.1% (n = 1) were on ultrasound. On MRI all dislocations were detected.

In 31.6% (n = 24), one reduction was not sufficient for final stabilization and centering of the hip joint. In 17 cases, a missed associated injury in the primary imaging was the cause. In eight children, an interposition prevented a concentric, stable reduction. This resulted in a delayed final reduction with associated injury management, if present, in one case between 6–12 hours after trauma and in 23 cases after more than 24 hours after trauma (Fig. 4).

Associated injuries to the acetabulum occurred in 54 patients. With a p-value of 0.04010, the likelihood of associated injuries in younger children was significantly lower. There were significant differences in the type of associated injuries regarding age, with a p-value of 0.001. The distribution showed an increased incidence of isolated dislocations without posterior acetabulum injury in children up to eight years old. Noticeably, avulsions of the cartilaginous acetabular rim and bone injuries increased with age (Table 1). 81.5% (n = 44) of associated injuries were diagnosed by MRI (Fig. 3). In 34 cases, intervention-requiring associated injuries were identified after reduction. In 10 cases, this occurred before reduction.

		Total (n/percent)	Age 0 - 4 years (n/percent)	Age 4-8 years	Age 8-11 years	Age 11-15 years	Age >15 years	p-Value
		76/100	(n = 10)	(n = 20)	(n = 12)	(n = 25)	(n = 9)
		76/100	13.2%	26.3%	15.0%	32.9%	11.8%
Primary diagnosis	Sonography	1/100	(n = 0)	(n = 0)	(n = 0)	(n = 1)	(n = 0)	p = 0.7704
		1.4%	0.0%	0.0%	0.0%	4.0%	0.0%
	X-ray single plane	35/100	(n = 3)	(n = 10)	(n = 5)	(n = 12)	(n = 5)
		50.0 %	30.0%	52.6%	50.0%	52.2%	62.5%
	X-ray two planes	30/100	(n = 7)	(n = 9)	(n = 4)	(n = 8)	(n = 2)
		42.9%	70.0%	47.4%	40.0%	34.8%	25.0%
	MRI	1/100	(n = 0)	(n = 0)	(n = 0)	(n = 1)	(n = 0)
		1.4%	0.0%	0.0%	0.0%	4.3%	0.0%
	CT	4/100	(n = 0)	(n = 0)	(n = 1)	(n = 2)	(n = 1)
		5.7%	0.0%	0.0%	10.0%	8.7%	12.5%
		* For five patients, no initial imaging is known or has been performed. * Quantity irrespective of whether the dislocation or accompanying injuries were identified.
Dislocation detected in initial imaging	Detected	66/100	(n = 4)	(n = 19)	(n = 10)	(n = 20)	(n = 13)	p = 0.006375
		86.8%	50.0%	86.4%	90.9%	90.9%	100.0%
	Not detected	9/100	(n = 4)	(n = 3)	(n = 0)	(n = 2)	(n = 0)
		11.8%	50.0%	13.6%	0%	(9.1%)	0.0%
	Unknown	1/100	(n = 0)	(n = 0)	(n =1)	(n = 0)	(n = 0)
		1.4%	0.0%	0.0%	9.1%	0.0%	0.0%
Associated injuries	No	22/100 28.9 %	(n = 5)	(n = 9)	(n = 3)	(n = 4)	(n = 1)	p = 0.04010
	** Yes	54/100 71.1%	(n = 3)	(n =13)	(n = 8)	(n = 18)	(n = 12)	p = 0.04010
	Without injury to the joint structure	36/100	(n = 7)	(n = 15)	(n = 4)	(n = 8)	(n = 2)	P = 0.001
		%	70.0%	75.0%	36.4%	32.0%	22.2%
	Labrum die	18/100	(n = 2)	(n = 4)	(n = 4)	(n = 5)	(n = 3)
		%	20.0%	20.0%	36.4%	20.0%	33.3%
	cartilage and bone	5/100	(n = 0)	(n = 0)	(n = 0)	(n = 4)	(n = 1)
		%	0.0%	0.0%	0.0%	16.0%	11.1%
	bone	16/100	(n = 1)	(n = 1)	(n = 3)	(n = 8)	(n = 3)
		%	10.0%	5.0%	27.3%	32.0%	33.3%
		** This also includes associated injuries outside the joint (nerve lesions, muscle hematomas, femoral head fractures, torn lig. capitis femoris, etc.)

Illustrative Cases:

Patient 1 (505) fell while sledding at the age of 3 years and 9 months. Due to severe pain and no longer being able to bear weight on the lower extremity, X-rays were taken in two planes at an external clinic on the same day. Following a suspected diagnosis of epiphysiolysis, the patient was transferred to a larger hospital. After an MRI, a diagnosis of right posterior hip dislocation was made. The subsequent closed reduction occurred more than 24 hours after the trauma. Two months after the trauma, a suspicion of partial AVN was raised during an MRI follow-up.

Patient 2 (507) slipped down a slope and rolled approximately 40 meters at the age of 9 years and 7 months. A pelvic overview X-ray was performed at an external hospital, diagnosing a right posterior hip dislocation. Closed reduction was performed within 6 hours of the trauma. The hip joint was unstable after reduction. Subsequent MRI imaging revealed the interposition of soft tissue. The hip was only stabilized after two open reductions. The first was performed through a Stoppa approach one day after the trauma. The second was through a Kocher-Langenbeck approach three days after the trauma. Additionally, a paraforaminal sacral fracture was observed at an follow-up MRI. Four months after the trauma, a follow-up MRI also lead to the diagnosis of AVN.

This multicenter study serves as a continuation of the 2023 published epidemiological study on traumatic hip dislocations in childhood (Braun et al., 2023). With 76 included patients, it currently represents the largest study on this topic to date.

The aim of this study was to evaluate diagnostic processes and it was possible to highlight significant deficits in initial diagnosis within the studied population. This reinforces existing literature, which also documents difficulties in diagnosis. The importance of diagnostics is evident in the study by Barquet et al., which reported a 50% rate of missed dislocations (Barquet, 1981). Overlooked dislocations lead to delayed reductions, which according to Mehlman et al., represent the main risk factor for AVN (Mehlman et al., 2000). To address the complexity of the issue, the individual steps of diagnostics were examined chronologically.

Literature describes clinical symptoms for posterior dislocations as flexion, adduction, internal rotation, and shortening of the ipsilateral leg, and for anterior dislocations as abduction, external rotation, and hip extension (Herrera-Soto and Price, 2009). This has been challenged in the past due to the dependence on many subjective factors (Graf and Seidl, 2022). However, the results of this study are only partially consistent with these described symptoms. This could be due to accompanying injuries leading to changes in clinical symptoms. Additionally, it must be noted that clinical symptoms were documented in only a small cohort of 17 children. However, so little of this documentation corresponds to the clinical presentation described in the literature that it should be noted that the clinical examination is undisputedly important, but should not be used as a specific sign, rather merely as a non-specific indication. And any abnormal position of the lower extremity should raise suspicion of hip dislocation (Herrera-Soto and Price, 2009). In addition, a clinical examination is challenging to perform in a child with a painful hip joint and thus its diagnostic value is limited. Consequently, movement testing should not be forced as it provides limited diagnostic information. It is crucial to proceed immediately with diagnostic imaging screening to allow for a more precise assessment of the hip region.

Sonography is becoming increasingly important in trauma-oriented clinics. It can be carried out quickly, can be used for both static and functional diagnostics, and is cost-effective. Another advantage is that children are not exposed to radiation, which is particularly important during growth. Sonography has proven to be a particularly effective tool in the evaluation of differential diagnoses such as coxitis fugax, which is the most common affliction in children's hips under the age of six to eight. Sonography, therefore, plays an important role in cases of unclear hip complaints in order to rule out differential diagnoses. However, according to current literature and our own data, sonography appears to be unsuitable as a sole primary diagnostic tool for traumatic hip dislocations in growth age. In this study, only one case was described in which sonography was used. In this one case, the dislocation was not detected. The limitations of sonography in relation to dislocation diagnostics can be explained by two factors. Firstly, this examination method is very dependent on the examiner and can quickly lead to incorrect results in inexperienced hands (Jejurikar et al., 2021). Secondly, according to Graf et al., dislocations of the hip can only be detected in children up to the age of six months due to increasing ossification. After that, sonography is only suitable for detecting an effusion or a hematoma (Graf and Seidl, 2022). However, in comparison with the opposite side of the body, this can be an unspecific indication of trauma that has taken place. It should be noted that Graf et al. focus on dislocations of DDH (Developmental Dysplasia of the Hip) hips in their study. However, it is also the only study on this topic. But there are experience reports suggesting that sonographic assessment of traumatic hip dislocations is possible. However, literature and statistical data confirming claims on this topic are currently lacking.

One notable finding is that in the current patient cohort, 15.8% (n = 12) of hip dislocations were reduced late. This is consistent with previous literature, which consistently reports delayed reductions (Ayadi et al., 2008; Brunner et al., 1988; Sulaiman et al., 2014; Zrig et al., 2009). In 12% (n = 9) of cases, the reason was a missed dislocation in imaging. In 4% (n = 3), the cause was unknown. The analysis of the available X-rays using the six-eye principle shows that experienced pediatric traumatologists should have recognized the dislocation in at least two of the nine overlooked cases. Imaging, thus, represents the decisive time factor for reduction.

In primary imaging, conventional X-rays in one plane 46.1% (n = 35) and conventional X-rays in two planes 39.5% (n = 30) are established as the standard. Other imaging modalities such as sonography, CT, or MRI only played a subordinate role to date. Overall, 12% (n = 9) of dislocations were not detected in imaging. Almost all (88.9%, n = 8) of these were overlooked in conventional X-ray diagnostics. It is striking that the dislocations were predominantly overlooked in younger children under eight years of age, in seven cases. Particularly concerning is the 50% rate of overlooked dislocations in those under four years of age.

One explanation may provide the technical limitations of X-ray diagnostics. This seems plausible when considering the bone-cartilage ratio, which only changes in favor of bone with increasing age (Zrig et al., 2009). Since only the ossified parts of the hip joint can be assessed with conventional X-rays, this diagnostic modality has limited diagnostic value in younger children and in pediatric clinicians inexperienced in child trauma. This also becomes clear in the radiological study by Fabricant et al. in which 180 healthy children's hips between the ages of four and 15 were examined (Fabricant et al., 2013). In hip dislocations during the growth period, dorsal dislocations predominate significantly (Braun et al., 2023). The study by Fabricant et al. clearly shows that ossification of the dorsal acetabular wall lags behind that of the anterior acetabular wall over the entire developmental period. It describes that the entire dorsal acetabular wall is cartilaginous between the ages of four and eight and only ossifies from the age of eight onward. Consequently, the dorsal wall is less stable up to this point compared to the anterior wall, which ossifies earlier.

This statement aligns with our findings that almost all radiologically overlooked dislocations occurred in children up to the age of eight, with a clear majority of cases under the age of four years. According to Fabricant et al.'s research results, ossification of the dorsal acetabular wall is only completed in the majority of children at the age of 13. Furthermore, it is described that the development of the posterior wall in boys occurs on average 1.5 years later when compared to girls. These observations are consistent with the findings of the previous study by this research group, conducted by Braun et al. In this study, it was found that dislocations occur more frequently in girls in younger children and more frequently in boys in older children. Fabricant et al. go so far as to say that MRI is the diagnostic tool of choice for any type of hip pain in girls up to the age of 12 and in boys up to the age of 14. No dislocations were overlooked in our study when MRI diagnostics were applied.

The algorithm depicted in Fig. 2 integrates the results of Fabricant et al. as well as the results from this study. It also takes into account the logistical effort and cost intensity that would be associated with performing an MRI on every child with hip pain. In children under four years of age, sonography is planned to rule out differential diagnoses, followed by a pelvic overview X-ray or MRI in case of suspicion.

Furthermore, considering the study results, the application of a second radiographic diagnostic level should be regarded as frequent with 39.5% of the cases. Worldwide, the principle of "as low as reasonably achievable" (ALARA) has been established in the assessment of pediatric fractures, aiming to minimize the radiation dose for both the examiner and the patient (Kaplan et al., 2016). In accordance with this guideline, if a clear indication for surgery can already be determined on one level, documentation of the second level should occur only during the operation and painlessly under anesthesia (Dresing et al., 2021).

Another aspect that became evident in the current study is that in 31.6% (n = 24) of cases, one simple reduction was not sufficient to achieve concentric, stable reduction. In 17 cases, an overlooked associated injury in the primary imaging was causative. In eight cases, an interposition prevented a concentric, stable reduction. Overall, 81.5% of associated injuries were diagnosed using MRI imaging. These findings align with previous smaller studies describing both associated injuries and interpositions of the capsulolabral complex that prevented stable reduction (Manner et al., 2012; Rubel et al., 2002; Thanacharoenpanich et al., 2020). It is crucial to note that predominantly both associated injuries and interpositions were diagnosed via MRI, and the existence or full extent of these structures was not visualized on conventional X-ray or CT due to the later complete ossification. Therefore, due to morphological considerations, CT also does not offer an advantage over MRI (Rubel et al., 2002; Strüwind et al., 2018; Yang et al., 2023). Additionally, there is what Ashman et al. term as Satisfaction of Search in Osteoradiology. They explain that the rate of detecting additional injuries in radiographic imaging decreases with the severity of the initially detected problem.

In this study, the combination of all described factors resulted in a delayed final reduction with management of associated injuries, if present, in 1.3% (n = 1) between 6–12 hours after the trauma and in 30.3% (n = 23) after more than 24 hours after the trauma. To prevent delayed inadequate reduction, which increases the potential for complications, it is therefore crucial to have a reliable diagnosis before and after reduction.

In order to determine a diagnostic algorithm, it is essential to understand the development of the pediatric hip. With this background, coupled with the results from this study, a diagnostic algorithm (Fig. 7) was developed by consensus.

The focus is on successful primary diagnosis of traumatic hip dislocation, which is delayed recognized in 15% of cases and carries an increased risk of avascular necrosis of the femoral head. Especially in the acute primary diagnostic phase, an algorithm is necessary to minimize the risk of being overlooked. This is particularly important for small children, where dislocation is not automatically anticipated in the emergency department due to the low energy involved at accident.

Due to the high incidence of accompanying injuries, MRI serves as the crucial diagnostic tool in the second diagnostic phase. MRI aligns significantly better with the child's anatomical conditions, especially concerning the depiction of avulsion of the cartilaginous acetabular rim and soft tissue interpositions. These factors highlight the timely and indispensable role of MRI diagnostics in traumatic pediatric hip dislocations and underscore the significance of MRI diagnostics in the presented algorithm.

As low as reasonably achievable (ALARA), avascular necrosis of the femoral head (AVN), computed tomography (CT), Developmental Dysplasia of the Hip (DDH), German Society of Orthopedics and Trauma Surgery (DGOU), magnetic resonance imaging (MRI), Pediatric Traumatology Section (SKT),

Authors and affiliated clinic:

Mirjam Evi Braun: Department of Orthopaedics, Olgahospital, Klinikum Stuttgart, Kriegsbergstraße 62, 70174 Stuttgart, Germany, and Center for Orthopaedics and Trauma Surgery, University Hospital Giessen and Marburg GmbH, Baldingerstrasse, Philipps-Universität Marburg, 35043 Marburg, Germany, [email protected]

Prof. Dr. Francisco Fernandez Fernandez: Department of Orthopaedics, Olgahospital, Klinikum Stuttgart, Kriegsbergstraße 62, 70174 Stuttgart, Germany, and Center for Orthopaedics and Trauma Surgery, University Hospital Giessen and Marburg GmbH, Baldingerstrasse, Philipps-Universität Marburg, 35043 Marburg, Germany, [email protected]

Lena Riha: University Hospital, Hoppe-Seyler-Strasse 1, Tübingen 72076, Germany, [email protected]

Prof. Dr. med. Hagen Schmal: Department of Orthopedic Surgery and Traumatology, Freiburg University Hospital, Albert Ludwigs University Freiburg und University Hospital Odense, Dep. Of Orthopedic Surgery, Denmark, [email protected]

Prof. Dr. Peter Schmittenbecher: Department of Pediatric Surgery, Städtisches Klinikum Karlsruhe, Moltkestr. 90, 76133 Karlsruhe, Germany, [email protected]

Prof. Dr. med. Dorin Schneidmueller: Department of Pediatric Trauma Surgery and Pediatric Orthopaedics, BG Unfallklinik Murnau, Professor Küntscher Str. 8, 82418 Murnau, Germany [email protected]

Dr. med. Christoph Strüwind: Department of Trauma Surgery Klinikum Garmisch-Partenkirchen, and Department of Trauma Surgery BG Unfallklinik Murnau, Professor Küntscher Str. 8, 82418 Murnau, Germany, [email protected]

Philipp Schwerk: Department of Pediatric Surgery, University Hospital Dresden – Technical University of Dresden, Fetscherstraße 74, 01307 Dresden, Germany, [email protected]

Dr. Sebastian Reineke: Clinic for Pediatric Surgery & Pediatric Urology and Center for Children with Severe Burn Injuries, Gesundheit Nordhessen Holding AG, [email protected]

Univ.-Prof. Dr. med. Dr. rer. nat. Frank Traub: Department of Orthopedics and Traumatology, University Medical Center Mainz , [email protected]

Prof. Dr. med. Christoph Ihle: Department of Trauma and Reconstructive Surgery, Eberhard-Karls-University Tuebingen, BG Unfallklinik, 72076 Tuebingen, Germany, [email protected]

Prof. Dr. med. Justus Lieber: Department of Pediatric Surgery and Pediatric Urology

University Children's Hospital, Hoppe-Seyler-Strasse 1, Tübingen 72076 Germany, [email protected]

Dr. med. Christina Wack: Center for Orthopaedics and Trauma Surgery, University Hospital Giessen and Marburg GmbH, Baldingerstrasse, Philipps-Universität Marburg, 35043 Marburg, Germany, [email protected]

Dr. Hauke Rüther: University Medical Center Göttingen; Clinic for Trauma Surgery, Orthopaedics and Plastic Surgery, [email protected]

Prof. Dr. Florian Baumann: University Medical Centre Regensburg, Franz-Josef-Straus-Allee 11, 93053 Regensburg, Germany, [email protected]

Prof. Dr. med. Ingo Marzi: Department of Trauma Surgery and Orthopaedics ,University Hospital, Goethe University Frankfurt,Theodor-Stern-Kai 7, 60590 Frankfurt am Main, Germany, [email protected]

Lewin-Caspar Busse: Department of Trauma Surgery and Orthopaedics ,University Hospital, Goethe University Frankfurt,Theodor-Stern-Kai 7, 60590 Frankfurt am Main, Germany, [email protected]

Dr. med. Ludger Tüshaus: Department of Pediatric Surgery, University Medical Center Schleswig-Holstein, Campus Lübeck, 23538 Lübeck, Germany; [email protected]

Dr. Miriam Adrian: Clinic for Pediatric Surgery, University Hospital Mannheim, Faculty of Heidelberg, Mannheim, Germany, [email protected]

Dr. med. Florian Bergmann: Department of Pediatric Surgery, Dr. von Hauner Children’s Hospital, Ludwig-Maximilians-Universität München, Lindwurmstrasse 4, 80337 Munich, Germany, [email protected]

Dr. Alexander Graf: Department of Trauma Medicine and Orthopaedics, Special Orthopaedic Surgery,

Ortenau Klinikum Offenburg – Kehl, [email protected]

Univ. Prof. Dr. med. Martin M. Kaiser: University Clinic and Polyclinic for Pediatric Traumatology and Pediatric Surgery, Department of Operative and Conservative Pediatric and Adolescent Medicine (DOKKJ), Universitätsklinikum Halle (Saale), [email protected]

PD Dr. Oliver Loose: Department of Orthopaedics, Olgahospital, Klinikum Stuttgart, Kriegsbergstraße 62, 70174 Stuttgart, Germany, and Department of Trauma Surgery, University Medical Centre Regensburg, Franz-Josef-Straus-Allee 11, 93053 Regensburg, Germany, [email protected]

Author Contribution

M.E.B. assumed the primary authorship role in this study, meticulously crafting the study´s design, the main manuscript text and meticulously preparing the figures. F.F.F. and O.L. played integral roles in shaping the study's design. L.R. contributed significantly to the translation process. H.S. provided key insights in interpreting the data.C.W. serves as the corresponding author.Each author made substantial contributions to the manuscript, approved the submitted version and agreed both to be personally accountable for the author's own contributions and to ensure that questions related to the accuracy or integrity of any part of the work, even ones in which the author was not personally involved, are appropriately investigated, resolved, and the resolution documented in the literature.

ASHMAN, C. J., YU, J. S. & WOLFMAN, D. 2000. Satisfaction of search in osteoradiology. American Journal of Roentgenology, 175, 541-544.
AYADI, K., TRIGUI, M., GDOURA, F., ELLEUCH, B., ZRIBI, M. & KESKES, H. 2008. Les luxations traumatiques de la hanche chez l’enfant. Revue de chirurgie orthopédique et réparatrice de l'appareil moteur, 94, 19-25.
BARQUET, A. 1981. Traumatic hip dislocation with fracture of the ipsilateral femoral shaft in childhood: Report of a case and review of the literature. Archives of orthopaedic and traumatic surgery, 98, 69-72.
BLANCHARD, C., KUSHARE, I., BOYLES, A., MUNDY, A., BEEBE, A. C. & KLINGELE, K. E. 2016. Traumatic, posterior pediatric hip dislocations with associated posterior labrum osteochondral avulsion: recognizing the acetabular “fleck” sign. Journal of Pediatric Orthopaedics, 36, 602-607.
BRANDÃO, G. F., AMÉRICO, L. R. D., SOARES, C. B. G., FARIA, R. G. C. & TEIXEIRA, L. E. M. 2010. Traumatic posterior dislocation of the hip in children: report on five cases. Revista Brasileira de Ortopedia (English Edition), 45, 196-199.
BRAUN, M. E., LOOSE, O., SCHMITTENBECHER, P., SCHNEIDMÜLLER, D., STRÜWIND, C., SCHWERK, P., REINEKE, S., TRAUB, F., IHLE, C. & LIEBER, J. 2023. Epidemiology and injury morphology of traumatic hip dislocations in children and adolescents in Germany: a multi-centre study. European journal of trauma and emergency surgery, 1-11.
BRESSAN, S., STEINER, I. P. & SHAVIT, I. 2014. Emergency department diagnosis and treatment of traumatic hip dislocations in children under the age of 7 years: a 10-year review. Emergency Medicine Journal, 31, 425-431.
BRUNNER, C., GYSIER, R. & MORGER, R. 1988. Traumatische Hüftluxation beim kind. Zeitschrift für Kinderchirurgie, 43, 174-175.
DRESING, K., FERNÁNDEZ, F., STROHM, P., SCHMITTENBECHER, P. & KRAUS, R. 2021. Röntgendiagnostik bei Frakturen im Kindes-und Jugendalter–Konsensusbericht des wissenschaftlichen Arbeitskreises der Sektion Kindertraumatologie der DGU. Der Unfallchirurg, 124, 427.
FABRICANT, P. D., HIRSCH, B. P., HOLMES, I., KELLY, B. T., LORICH, D. G., HELFET, D. L., BOGNER, E. A. & GREEN, D. W. 2013. A radiographic study of the ossification of the posterior wall of the acetabulum: implications for the diagnosis of pediatric and adolescent hip disorders. JBJS, 95, 230-236.
GRAF, R. & SEIDL, T. 2022. Sonographie der Säuglingshüfte: Prinzipien, Durchführung und therapeutische Konsequenzen, Georg Thieme Verlag.
HERRERA-SOTO, J. A. & PRICE, C. T. 2009. Traumatic hip dislocations in children and adolescents: pitfalls and complications. JAAOS-Journal of the American Academy of Orthopaedic Surgeons, 17, 15-21.
JEJURIKAR, N., MOSCONA-MISHY, L., RUBIO, M., CAVALLARO, R. & CASTAÑEDA, P. 2021. What is the interobserver reliability of an ultrasound-enhanced physical examination of the hip in infants? A prospective study on the ease of acquiring skills to diagnose hip dysplasia. Clinical Orthopaedics and Related Research, 479, 1889.
KAPLAN, D. J., PATEL, J. N., LIPORACE, F. A. & YOON, R. S. 2016. Intraoperative radiation safety in orthopaedics: a review of the ALARA (As low as reasonably achievable) principle. Patient safety in surgery, 10, 1-7.
KUTTY, S., THORNES, B., CURTIN, W. & GILMORE, M. 2001. Traumatic posterior dislocation of hip in children. Pediatric emergency care, 17, 32-35.
MACNICOL, M. F. 2000. The Scottish incidence of traumatic dislocation of the hip in childhood. Journal of Pediatric Orthopaedics B, 9, 122-124.
MANNER, H. M., MAST, N. H., GANZ, R. & LEUNIG, M. 2012. Potential contribution of femoroacetabular impingement to recurrent traumatic hip dislocation. Journal of Pediatric Orthopaedics B, 21, 574-578.
MEHLMAN, C. T., HUBBARD, G. W., CRAWFORD, A. H., ROY, D. R. & WALL, E. J. 2000. Traumatic hip dislocation in children: long-term followup of 42 patients. Clinical Orthopaedics and Related Research®, 376, 68-79.
MORRIS, A. C., JONATHAN, C. Y. & GILBERT, S. R. 2017. Arthroscopic treatment of traumatic hip dislocations in children and adolescents: a preliminary study. Journal of Pediatric Orthopaedics, 37, 435-439.
MÖRSDORF, P., LAUER, A., HISTING, T., POHLEMANN, T. & BURKHARDT, M. 2016. Die Traumatische Hüftgelenkluxation eines 6‑jährigen Jungen: Selten, aber anspruchsvoll. Der Unfallchirurg, 4, 350-354.
OFFIERSKI, C. 1981. Traumatic dislocation of the hip in children. The Journal of bone and joint surgery. British volume, 63, 194-197.
RUBEL, I. F., KLOEN, P., POTTER, H. G. & HELFET, D. L. 2002. MRI assessment of the posterior acetabular wall fracture in traumatic dislocation of the hip in children. Pediatric radiology, 32, 435-439.
SANDERS, S., TEJWANI, N. & EGOL, K. A. 2010. Traumatic Hip Dislocation. Bulletin of the NYU hospital for joint diseases, 68.
STRÜWIND, C. M., VON RÜDEN, C., THANNHEIMER, A., BÜHREN, V. & SCHNEIDMUELLER, D. 2018. Relevance of MRI after closed reduction of traumatic hip dislocation in children. Zeitschrift für Orthopädie und Unfallchirurgie, 156, 586-591.
SULAIMAN, A. R., MUNAJAT, I. & MOHD, E. F. 2014. Outcome of traumatic hip dislocation in children. Journal of Pediatric Orthopaedics B, 23, 204-205.
THANACHAROENPANICH, S., BIXBY, S., BREEN, M. A. & KIM, Y.-J. 2020. MRI is better than CT scan for detection of structural pathologies after traumatic posterior hip dislocations in children and adolescents. Journal of Pediatric Orthopaedics, 40, 86-92.
TRUETA, J. 1957. The normal vascular anatomy of the human femoral head during growth. The Journal of Bone & Joint Surgery British Volume, 39, 358-394.
VIALLE, R., ODENT, T., PANNIER, S., PAUTHIER, F., LAUMONIER, F. & GLORION, C. 2005. Traumatic hip dislocation in childhood. Journal of Pediatric Orthopaedics, 25, 138-144.
YANG, D., LEE, J., ORELLANA, K., BATLEY, M., SYED, A. N. & SANKAR, W. 2023. Traumatic hip dislocations in a pediatric cohort: The importance of advanced imaging. Journal of Children's Orthopaedics, 18632521231164990.
ZRIG, M., MNIF, H., KOUBAA, M. & ABID, A. 2009. Traumatic hip dislocation in children. Acta Orthopaedica Belgica, 75, 328.

No competing interests reported.

Download PDF

Version 1

posted

You are reading this latest preprint version

Traumatic Hip Dislocations in Children and Adolescents: Diagnostic Challenges and the Significance of MRI Imaging - A Multi-Center Study

Status:

Version 1

Abstract

Figures

Background

Materials and Methods

Results

Illustrative Cases:

Discussion

Conclusion

List of abbreviations

Declarations

Author Contribution

References

Additional Declarations

Status:

Version 1