Abstract
We report the case of treatment delay for an early onset of pulmonary embolism due to thrombosis in the femoral vein occurred in a traumatic anterior hip dislocation. Mistakes interpretations of clinical findings and pre-operative chest CT-angiography has endangered our patient's life because of the medical report was focused only on acute traumatic injuries. After all, we were not able to find in the literature any similar report that could explain the pathogenesis of this early onset and help us in the patient management. We have tried to list a number of practical suggestions to use in emergency room in these situations.
Keywords: Pulmonary thromboembolism, Femoral vein thrombosis, Traumatic anterior hip dislocation
1. Introduction
Traumatic anterior hip dislocations are uncommon and account for less than 11% of all hip dislocations.1 Antero-superior dislocation is even less common (<10% of the anterior ones) because of the mechanism of trauma: extreme abduction, extension and external rotation.1
This is considered an orthopedic emergency that should be treated within a 6-h period to decrease the rate of osteonecrosis of the femoral head.2 If a neurovascular deficit is present the reduction should be done as soon as possible.
2. Case report
A 28-year-old man was transferred to our hospital following a motorbike accident.
During prehospital emergency medical services transport he received temporary supplemental oxygen through nasal cannula, 100 mcg fentanyl IV, and 1 gr tranexamic acid IV because he was considered to be at risk of haemorrhage due to the extent of trauma.
On admission, approximately 1 hour and half later, he was conscious (GCS 14), vital signs were stable and considered within normal limit by emergency physician (blood pressure 130/77, heart rate 92, respiration rate 26, temperature 36.2 °C and pulse oximetry 93% on room air). His past medical history was unremarkable. The right leg was lying in abduction and external rotation. There was also sign of close left femur fracture. Distal neurovascular function was intact.
The FAST protocol and chest X-ray resulted negative for acute injuries. Skeletal radiographs confirmed anterior dislocation of the right hip-joint with ipsilateral fracture of the greater trochanter and left femur shaft fracture.
Hip reduction in emergency department was attempted many times under conscious sedation using a total of 8 mg midazolam IV and 100 mcg fentanyl IV and was unsuccessful.
Three hours after the admission urgent CT angiography (CTA) of the pelvis was done. It showed dislocation and compression of right femoral vessels (Fig. 1). Furthermore the “bone window” excluded the possibility of a right femoral neck fracture and revealed non-displaced fracture of left acetabulum.
Fig. 1.
Selected images from a Pelvic-CTA (axial-view during portal venous-phase). (a)Findings at the level of dislocated right femoral head: marked narrowing of femoral artery (arrowheads) and hidden femoral vein (arrow) compared to the contralateral ones that are patent at this level (curved arrow). (b)A slice just below shows dilation of the right femoral vein (arrow).
He didn't received deep venous thrombosis prophylaxis because shortly afterwards an emergency orthopedic surgery was expected.
At the same time pulmonary CTA was performed. Medical report didn't find any abnormalities.
About four hours and half after admission, closed manipulation under general anaesthesia achieved reduction of the right hip-joint. Afterwards the patients were treated by close reduction and internal fixation with intramedullary nail of the left femur during the same surgical procedure.
After surgery the patient was haemodynamically stable and trasferred to ICU to allow for close monitoring.
He was mechanically ventilated more or less 14 hours. Before extubation he repeated pelvis and chest CTA.
CTA of the pelvis showed increasing flow of femoral artery and thrombosis in the femoral vein, as well as reduction of right hip and minimally displaced greater trochanter fracture can be appreciated with the “bone windows” (Fig. 2).
Fig. 2.
(a,b) Pelvic-CTA (portal venous-phase) after removal of vessels compression: axial view slices at two different levels showed increasing enhancement in the femoral artery (arrowheads) and thrombosis in the femoral vein (arrow). (c) Coronal-view of proximal right femur after reduction.
Chest CTA was significant for multiple emboli in the right and left pulmonary artery, as well as in their lobar and segmental branches. Looking at preoperative pulmonary CTA again, multiple clots were already present and misdiagnosed. Comparing the images, an increase in filling defects occurred after the surgery (Fig. 3, Fig. 4).
Fig. 3.
(a,b)Preoperative chest-CTA (axial view-arterial phase) showed a thrombus limited to the left pulmonary artery (arrow),while the basal segmental branches remain mostly normal. (c)Enlargement of the basal segmental branches arteries with multiple intraluminal filling defect were significant for embolism in the postoperative axial-view.
Fig. 4.
(b) Pulmonary CTA (coronal view - arterial phase) showed an increase embolism in the posterior segmental branches arteries of lower lobes after surgery compared to the preoperative ones (a).
A color-flow Doppler ultrasound also confirmed the presence of deep vein thrombosis (DVT) of right posterior tibial veins. Transthoracic echocardiography did not show any signs suggestive of right ventricular strain.
Anticoagulation therapy was started immediately with subcutaneous low-molecular-weight heparin (enoxaparin), at a dose of 1 mg/kg, as well as oral warfarin. Enoxaparin therapy was continued for three days until a therapeutic international normalized ratio of >2.0 with the warfarin was achieved. The patient reported no known personal or family history of coagulation disorders or prior venous thromboses. Thrombophilia laborartory testing didn't detect any abnormalities.
After extubation an oxygen therapy was applied to assist the patient breathing spontaneously and the progressively suspendend in about 36 hours. The patient remained clinically silent even after removing oxygen support.
The greater trochanter and acetabular fractures were managed conservatively. He was discharged after 10 days.
Anticoagulation treatment with warfarin for six months was prescribed. The lesion was scanned by color-flow Doppler ultrasound at intervals of 6 weeks, 3 and 6 months: at the last check the vein was completely recanalized without further thrombus extension. The patient remained asymptomatic without evidence of thromboembolic morbidity.
X-ray showed a healing greater trochanter fracture at his 8-week follow-up, as well as the acetabular fracture at 12-weeks. After that he was mobilised full weight bearing as tolerated with physiotherapy. The fracture progressed to union without complication and at the time of last follow-up, 6 months after surgery, radiographic healing occurred. The patient had a complete recovery and managed to return to his normal activities.
3. Discussion
Vascular complication due to anterior hip dislocations are extremely rare and only few cases are published.3, 4, 5, 6, 7, 8, 9, 10
We found in the literature only one case of traumatic anterior hip dislocations associated to venous thromboembolism.11 It happened in a patient with risk factors for thrombosis (oral contraceptive pills and prothrombin 20210 gene mutation) and delayed hip reduction (approximately after 14 hours).
We were not able to find any report in the literature concerning traumatic anterior hip dislocation associated to early onset of pulmonary thromboembolism (PTE).
Due to early onset we investigated our patient for risk of thrombophilia: the test was found to be negative.
The exact DVT etiology was uncertain, thus we can only speculate on its pathogenesis. It is possible that the high-energy trauma has been slightly damaged the endothelium of the vein. This intimal lesion combined with venous stasis due to occlusion of the vein by the dislocated femoral head could cause an venous thrombosis. Moreover, hypercoagulability is a well-known condition that occurs immediately after the trauma,12 and represents the third aspect of the Virchow triad that contributed to the risk of thrombosis.13
DVT possibly could also have aggravated due to the use of tranexamic acid that is administered to trauma patients with significant haemorrhage or considered at risk of such in the protocol of prehospital transport.14
The possibility that traction-countertraction and release during many attempt to reduction in emergency department, may have contributed to the development of an early PTE disseminating the clots in the circulatory system is speculative but plausible.
After this experience the Authors recommend:
-
1.
Support the thigh on pillows may partially relieve the pressure on the femoral vessels if the hip is anterior dislocated.7
-
2.
Reduce the hip joint under general anaesthesia: the sedation in emergency department is most often not adequate to successfully reduce the joint and excessive manipulation may lead to trauma of the circumflex or retinacular vessels bringing to avascular necrosis,15 as well as may disseminate the clots in the circulatory system.
-
3.
Pelvis CTA before hip reduction to see vascular involvement and exclude with “bone windows” an occult femoral neck fracture, an absolute contraindication to closed reduction. If thrombus is present in the compressed veins, a temporary IVC filter placement and anticoagulation should be considered before hip reduction. Administration of DVT prophylaxis may prevent thrombosis in these cases above all if delay in reduction is anticipated. This would have to be weighed against the perceived likelihood of bleeding from other suspected injuries.11
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4.
Pulmonary CTA before hip reduction should be done if vein obstruction is showed by pelvis CTA and if index of suspicion for PTE is high: on arrival, respiratory rate of 26/min and SpO2 of 93% cannot be taken as normal. In addition to the search for acute lesions it is important to exclude PTE even if the patient is clinically silent, condition possible especially if he is sedated. Mistakes in interpretations of vital signs and pre-operative chest CTA, focused only on acute traumatic findings, has endangered our patient's life and led to wrong therapeutic choices. The decision to treat the left femur fracture with intramedullary nail during the same procedure has certainly worsened the pulmonary situation with fat emboli.
The authors would like to emphasize the role of multidisciplinary team approach to a trauma patient necessitates the involvement of various medical and surgical specialists to avoid mistakes when as trauma surgeons, the tendency is to remain focused on the musculoskeletal trauma.
We hope these handy advices would help the management of traumatic anterior hip dislocation in a emergency department.
Conflicts of interest
On behalf of all authors, the corresponding author states that there is no ethical problems or conflict of interest regarding this study. All the materials used for this study are commonly and usually already in the stock of our institution. No funds or grants have been received for this study.
Conflict of interest and financial disclosures
None.
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