Intramedullary nailing for floating knee injury complicated by pulmonary fat embolism: A case report and literature review

Abstract

A 28-year-old man involved in a serious motorcycle accident was admitted to our hospital with comminuted fractures of the ipsilateral femoral shaft and tibial shaft, as well as multiple fractures of the right lower limb, including the proximal fibula, medial malleolus, and the third and fourth distal metatarsals. In addition, the patient suffered a skin contusion and laceration of the right foot. On the first day of admission, this patient suddenly developed tachycardia, pyrexia, and tachypnoea, and was immediately transferred to the ICU for further treatment due to a CT-diagnosed pulmonary fat embolism (FE). As a symptomatic treatment, he received a prophylactic dose of low-molecular-weight heparin for 10 days, after which his condition improved. A Doppler ultrasound of the lower leg and a follow-up chest CT angiography were performed, which excluded any remaining thrombus and verified that the pulmonary FE had improved without deterioration. Closed-reduction and retrograde intramedullary nailing were performed for the femoral shaft fractures, while antegrade intramedullary nailing was performed for the tibial shaft fractures under general anaesthesia. In the three-year follow-up, the patient had recovered with good function of the right limb, without any respiratory discomfort. Both the femoral and tibial shaft fractures finally resolved without any further treatment. Ipsilateral femoral and tibial shaft fractures should undergo surgical stabilisation as early as possible to avoid pulmonary FEs. It is still controversial whether intramedullary nailing is suitable for floating knee injuries complicated by pulmonary FEs. However, if patients with pulmonary FEs require intramedullary nailing, we suggest that surgery should be performed after at least one week of anticoagulant use, when patient vital signs are stable and there is no sign of dyspnoea. In addition, patients should try to avoid reaming during the operation to prevent and decrease "second hit" for the lung.

Keywords: Damage control orthopaedics; Fat embolism syndrome; Floating knee injury; Intramedullary nailing; Pulmonary fat embolism.

Fig. 1

Male 28 years old, a. ipsilateral comminuted femoral shaft and tibial shaft fracture of right side (a float knee injury) b. 3D reconstruction CT of the right lower extremity after injury showed medial malleolus fracture and talus fractures c. 3D reconstruction CT of the right foot after injury showed the third and fourth distal metatarsus fracture. d-e. Chest CT angiography of one day after inpatient showed peripheral pulmonary embolism with both inferior lobar artery filling defect (as show by deep red arrow). f-i. X-ray of one day post-operation show good alignment of femoral shaft and tibial shaft fracture following close reduction and intramedullary nail fixation. j-l. Outlook of right lower limb one week post-operation show well healing without sign of infection. m-q. X-ray of one year post-operation show good heal of femoral shaft and tibial shaft fracture following close reduction and intramedullary nail fixation.

Fig. 2

a-f. 3 years postoperations follow-up show good function of right hip and knee joint. g-j. X-ray of 3 years postoperations showed good union of ipsilateral comminuted femoral shaft and tibial shaft fracture of right side.