Fat embolism following a cemented hemiarthroplasty
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- Karadimas, E.J., Kapotas, J.B., Pachantouris, E.G. et al. Eur J Orthop Surg Traumatol (2008) 18: 147. doi:10.1007/s00590-007-0275-4
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Fat-embolism (FE) is a rare but severe complication involving the long tubular bones, presented during the second posttraumatic or post-operative day. The main characteristics are pulmonary distress, mental status disturbances and petechiae. The purpose is to present our case of fat embolism and the final outcome.
Materials and methods
A female patient, aged 72, was admitted in our hospital after a low energy fall. The examination revealed a Garden IV subcapital hip fracture. A cemented hemiarthroplasty was performed in less than 24 h after the appropriate preoperative control.
The operation finished uncomplicated, but later the same day, the patient became hyper-febrile with signs of confusion. During the first post-operative day she deteriorated further and a full investigation was performed. The improvement started the following day and petechiae were developed. She was able to follow the post-operative mobilization protocol and was discharged on the 12th post-operative day.
We present a full documented case of FE with all the triad characteristics, which recovered rapidly and fully. We consider FE a severe complication and due to the mortality rate, all the orthopaedic surgeons must be aware of the early signs.
KeywordsHip arthroplastyArthroplasty complicationsFat embolismCemented hemi arthroplasty
Embolie graisseuse après prothèse intermédiaire de hanche
L’embolie graisseuse est une complication rare mais sévère des os longs, qui s’installe au 2ème jour post-traumatique ou post-opératoire. Les caractéristiques les plus habituelles sont la détresse respiratoire, les troubles psychiques et les pétéchies. Notre but est de présenter un cas d’embolie graisseuse et le résultat final.
Matériel et Méthode
Une patiente âgée de 72 ans fut admise dans notre hôpital après une chute à basse énergie. Un diagnostic de fracture sous-capitale Garden IV fut posé. Une hémi-arthroplastie cimentée fut réalisé en moins de 24 heures après le bilan pré-opératoire approprié.
L’opération se déroula sans complications, mais le même jour, après l’opération, la patiente devint hyperthermique et présenta des signes de confusion. Au premier jour postopératoire, la détérioration de l’état général augmenta et un examen approfondi fut décidé. Une amélioration s’installa à J 2 avec apparition de pétéchies. La patiente put alors réintégrer le protocole de mobilisation postopératoire et elle quitta l’hôpital à J 12.
Nous présentons un cas totalement documenté d’embolie graisseuse avec la triade caractéristique et qui a récupéré rapidement et complètement. Nous considérons l’embolie graisseuse comme une complication grave et, en tenant compte de sa mortalité, nous estimons que tout chirurgien orthopédiste doit être attentif à l’apparition de ses symptômes précoces.
Mots clésArthroplastie de hancheComplications des arthroplastiesEmbolie graisseuseHémi-arthroplastie cimentée
Fat embolism is a known serious and life-threatening complication of traumatology, especially in long bone  and pelvic fractures . It may also occur in liposuction and articular surgery (0.1%) . The usual pattern of fat embolism occurs 8–72 h after trauma or surgery and is characterized by the triad of pulmonary distress, mental status changes, and cutaneous manifestations (petechiae) mainly around the shoulder, axilla, and in the eyes.
In the bibliography there are published sporadic cases of FE during invasive intramedullary procedures, such medullary reaming for fresh fractures of the femur  and tibia or pathological lesions [1, 18, 20, 21] during cemented and uncemented THA [4, 6, 7, 15, 22, 23] or revision , TKA , after hemiarthroplasties [8, 9, 16] and bilateral femoral lengthening . Almost all of them were referred to patients who died mainly from cardiac arrest, without the presence of the characteristic triad. The diagnosis was made by histological findings of fat embolism in the lungs and brain. Only very few of the patients survived and none of those have been presented with the full triad of symptoms.
We present, to our best knowledge, the only one of FES after a cemented hemiarthroplasty for subcapital fracture of the neck of the femur with the full triad of characteristic and full and rapid recovery.
Materials and methods
A 72-year-old woman, with free medical history, was admitted to our hospital after a low energy fall. A subcapital fracture of her right hip (Garden´s IV) was diagnosed. Pre-operative blood test investigations were normal, including Quick time 100% and Thrombofax (APTT) 36.1 s (20–40 s) and thrombocytes (253,000).
She was operated in less than 24 h of her admittance with cemented hemiarthroplasty under general IV anaesthesia. During all the stages of the operation she did not reveal any either anaesthesiological or surgical distress. The femoral canal was prepared with rasps, irrigation was used for canal lavage and a high-viscosity cement was applied after the insertion of a restrictor. During the operation, she received one unit of blood.
Her initial recovery was regular; she was under prophylactic antibiotic (Cefamandole 1 g × 4 iv) and prophylactic anticoagulant therapy with low-molecular heparin (Nadroparin Calcium 30 mg × 1). Later the same day she was hyper-febrile with 39°C and she had signs of confusion. We had been informed of the incidence but we attributed the high temperature to the blood transfusion and the slight mental disturbances to the analgesia (pethidine injections).
Thrombocytes was counted to 253,000 pre-op. they dropped gradually post-op to the first day to 151,000 and after that started increasing to 171,000 the third post-op day and to the normal 265,000 at the fifth post-op day.
The following days she was fully investigated for any pathological conditions that could be a predisposing factor for her fat embolism. The investigation reveals the following:
Troponine T test: negative, Phospolipid antibodies test: negative, Leiden’s factor: negative. Hyperhomocysteinaemia (MTHFR with PCR–RFLP) homozygous/abnormal (prone to thrombosis).
Sutures were removed on the 12th post-op day and she discharged using a walker with PWB. She was also advised to continue the enoxaparin 60 mg × 1 daily, and acetylosalicylic acid 100 mg Tabl × 1.
In recent regular followup 3 months post-op the patient did not have any residual symptoms related with her post-operative FES incidence.
The case of FE that we present after cemented hemiarthroplasty is to our best knowledge fourth in the literature and the second, which recovered fully. She was a patient with previous clear medical history and had developed the classical triad without reaching the unconscious and recovered fully and rapidly.
The first case published by Lairmore et al. . The patient had metastatic breast cancer to her proximal femur and after cemented hip hemiarthroplasty, developed sensorium that progressed to coma in association with hypoxaemia and tachypnea. Pulmonary compromise was mild and she did not demonstrated petechiae. MRI results were consistent with FES. She was in coma for 11 days without purposeful motor function. She recovered after that rapidly.
The second case of 78-year-old lady with stable angina, diabetes and metastatic breast cancer has been published in 2001 . During the cementing of the femoral canal and insertion of the prosthesis, desaturation, hypotension and cardiac arrest occurred and she died 24 h later. The diagnosis confirmed of FES by the autopsy.
The third case described by anaesthesiologists Sasano et al. . The patient with no medical history underwent cemented hip hemiarthroplasty under spinal anaesthesia for femoral neck fracture. Shortly after insertion of the prothesis a sudden oxygen desaturation, hypotension, bradycardia and cardiac arrest occurred. The patient was successfully resuscitated, but developed high-grade fever, and thrombocytopenia, as in our case, anaemia and oliguria. She did not regain consciousness and remained in a persistent “vegetative state”. The diagnosis of FES was made on the basis of clinical findings and MRI images (high intensity signals throughout the brain).
Those three cases did not present the full triad of FES (not existence of petechiae), which was fully manifested in our patient. In our case no hypotension or hypoxia or any other respiratory clinical failure has been observed and the MRI of the lung was not significant. Rare incidents of isolated cerebral FE without pulmonary involvement have been reported [14, 27, 28].
Transcardiac echocardiography  studies showed that severe embolic responses occurred while reaming pathological lesions  or during cemented arthroplasties [25, 26]. Sevitt  found fat embolism in cemented hemiarthroplasties (Thompson’s) in hip fractures, and not in uncemented (Moore’s). Clinical diagnosis was not used and the assessments were based primarily on a histological search for fat emboli at necropsy.
Experimental studies in dogs  showed that reaming a fractured bone produced minimal embolization. The presence of a fracture may decompress the pressure in the medullary canal, minimizing the release of fat into the circulation during acute internal fixation. This could help explain the low incidence of clinical FE associated with intramedullary nailing. Similar studies in dogs after cemented arthroplasty  also were found with intravascular fat in brain, heart and kidney specimens. Orsini et al.  also found in dogs that the use of the cement produced significant more cardiopulmonary fat dysfunction and the account of pulmonary fat emboli was 10 times greater at autopsy. There were no evidences that methylmethacrylate monomer was responsible for the cardiorespiratory changes in the group with the cemented implant. They demonstrated that the pressurizing effect of bone cement on producing high intramedullary pressures cause pulmonary microemboli and cardiopulmonary dysfunction. Other experimental studies  showed that intravascular fat persists in the lungs, kidneys and brain for 72 h after canal pressurization and, by itself does not cause pathological evidence of acute inflammation. Heisel et al.  in Merino sheers, showed that the amount of fat that passed into the venous draining system of the femur induced by cemented implantation was twice the amount seen with cement-less implantation. They also observed that in the cemented implantation, 8 of the 13 animals showed a peak in the fat intravasation caused by application of the cement restrictor. They emphasize the importance of a thorough preparation of the intramedullary canal, particularly when cemented fixation is performed.
In experimental studies in dogs Byrick et al.  found significant increase of cardiopulmonary dysfunction after bilateral cemented arthroplasties when no lavage was used. In the pulsatile–lavage group, the number of fat mocroemboli that were found in the lungs was reduced to 25.7% of those found in the no-lavage group. Herndon et al.  in their patient with THA found that the use of a catheter attached to suction for aspiration of the medullary contents decreased the duration of fat embolization by almost 50%. In order to reduce the risk of FES the avoidance of excessive cement pressurization, low viscosity cement, meticulous high-pressurized canal lavage and the use of a vent hole are effective techniques to minimize canal pressure .
In our case a cement restrictor was used and a good lavage with aspiration was performed before insertion of the femoral stem/prothesis. No distress was detected during the operation (normal cardio–pulmonary monitoring). The syndrome started with hyperpyrexia and mild confusion some hours after the end of the operation. The brain MRI showed appearance of multiple embolization and lung MRI slight effusion and consolidation at the lower lobes. The FE was confirmed with the petechiae, which were presented the second post-op day. It was not a severe one; she never became fully unconscious although there were findings of brain MRI and was without clinical disturbances from the lungs. The prophylactic administration of Nadroparin Calcium 4 h after the operation could be a reason for the mild severity of FE and the rapid recovery. The existence of atrial septal aneurism with patent of foramen ovale, explains the full mechanism of cerebral fat embolization.
Fat embolism is a rare clinical manifestation related with hip fractures. It could also happen in patients with good general health. Appropriate monitoring during the operation and also the following 48 h, prophylactic anticoagulant therapy and medical personnel awareness could be the factors which could interfere in FE outcome.