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 Table of Contents  
Year : 2022  |  Volume : 14  |  Issue : 1  |  Page : 98-101

Bilateral floating knee: A rare case report

Department of Orthopaedics, Government Royapettah Hospital, Chennai, Tamil Nadu, India

Date of Submission11-Jun-2021
Date of Acceptance25-Dec-2021
Date of Web Publication15-Jun-2022

Correspondence Address:
Dr. Sabari Selvam
Department of Orthopaedics, Government Royapettah Hospital, Chennai - 600 014, Tamil Nadu
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Source of Support: None, Conflict of Interest: None

DOI: 10.4103/jotr.jotr_50_21

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Ipsilateral fractures of the femur and tibia have been called “floating knee” injuries and may include combinations of diaphyseal, metaphyseal, and intra-articular fractures. These are often high-energy injuries and most frequently occur in the polytrauma patient. Many of these fractures are open, with associated vascular injuries. Surgical stabilization of both fractures and early mobilization of the patient and the extremity produce the best clinical outcomes. This rare case report is of 43-year-old female from an urban setup in Chennai who underwent an Road Traffic Accident (RTA) and sustained injuries that lead to a bilateral floating knee. She was initially managed as per principles of damage control orthopedics and stabilized with knee spanning external fixators on either side. On further stabilization of the patient, bilateral definitive fixation was done in a staged manner. The patient finally regained full functional range of motions on either limb and was completely rehabilitated within 3 months.

Keywords: Bilateral, damage control orthopedics, floating knee, Fraser

How to cite this article:
Ganesh J, Selvam S. Bilateral floating knee: A rare case report. J Orthop Traumatol Rehabil 2022;14:98-101

How to cite this URL:
Ganesh J, Selvam S. Bilateral floating knee: A rare case report. J Orthop Traumatol Rehabil [serial online] 2022 [cited 2022 Dec 9];14:98-101. Available from: https://www.jotr.in/text.asp?2022/14/1/98/347366

  Introduction Top

In 1975, Blake and McBryde 10[1] established the concept of the “floating knee” to describe ipsilateral fractures of the femur and tibia. The floating knee is a complex injury and is typically more than a simple ipsilateral fracture of the tibia and femur and may involve both extra-articular and intra-articular fracture patterns. Fraser et al. classified the floating knee into three types 11 [Figure 1]. Type 1 includes extra-articular fractures of the femur and tibia. Type 2A refers to extra-articular fractures of the femur and articular involvement of the tibia. Type 2B refers to articular fractures of the femur and extra-articular involvement of the tibia. Type 2C includes articular fractures of both the femur and tibia. These classification systems serve to describe the skeletal elements of the injury but do not account for injuries to the soft tissues.
Figure 1: Fraser classification

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A floating knee after high-energy mechanism may be associated with massive hemorrhage, particularly if the fractures are open and/or if an associated arterial injury is present. Most patients with a floating knee also have concurrent injuries, which may be life-threatening. Some patients present in critical condition.[2] Advanced Trauma Life Support (ATLS) principles of airway, breathing, and circulation are initiated on presentation, followed by the stepwise ATLS algorithm for evaluation and care after trauma. After the patient is clinically stabilized, a secondary and tertiary evaluation is undertaken to assess for other injuries. Feron et al.[3] reviewed 172 cases of floating knee in a multicenter setting and reported 38% with severe head injury, 25% with combined head-thorax injury, and 68% with other limb fractures. Associated injuries in the polytrauma patient affect the management and prognosis. In particular, floating knee patients with vascular injuries have worse Karlstrom functional outcomes than patients without vascular injuries. Furthermore, patients with concurrent head injuries have higher risk of pulmonary complications, and early stabilization of lower extremity long bone fractures has been shown to mitigate these adverse events.

A systematic approach is needed to evaluate the floating knee, which should start with a thorough history of the mechanism of injury.[4] Radiographs of the involved extremity from the hip to the ankle should be ordered to characterize the fracture and to assess for subluxation or dislocation of the knee, which occurs infrequently. Morbidly obese patients are at higher risk of dislocation. Clinical examination includes evaluation of any wounds and documentation of motor and sensory neurologic function and vascular status.[5] Up to 80% of these injuries may be open. Feron et al. reported 38% with an open femur fracture and 57% with an open tibia fracture. Appropriate antibiotic coverage for open wounds should be based on the energy of injury, complexity of wounds, degree of contamination, and setting where the injury occurred.

  Case Report Top

Our case report involves around a 43-year-old female with no medical history who underwent a typical RTA wherein she was riding as the pillion rider on a motor cycle and was hit by a large truck and possibly run over by it. She was immediately brought to our trauma casualty and after initial ATLS assessment was found to be clinically stable and was stabilized using temporary splints and radiographically assessed. General examination revealed no other significant injury. On physical examination, the patient was totally unable to step on or move his both lower limb. There was a significant swelling around her both knees with no skin defect. Bilateral distal pulses were well palpable.

Through initial radiographs, she was diagnosed to have a Type I Fraser classification on the right side and Type IIa Fraser classification on the left side which indicated high velocity injuries on both sides [Figure 2]. Initial assessment also revealed vascular integrity of both limbs and closed nature of injury.[6] After vital stabilization, the patient was managed along the lines of damage control orthopedics, and knee spanning external fixation was applied on either side on day 1 itself [Figure 3].
Figure 2: Preoperative X-Rays

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Figure 3: Post exfix X-ray

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Postoperatively, the patient's initial hemoglobin was found to be 7.2 and was further stabilized using blood transfusion. Further investigations such as erythrocyte sedimentation rate, C-reactive protein, lactate dehydrogenase, and liver and renal profiling were done and were found to be slightly elevated. As per the physicians, the patient was further managed. Prophylaxis for deep-vein thrombosis (DVT) in the form of low molecular weight heparin was started, and the patient was started with In-Bed Physiotherapy also. On posttrauma day 15, the patient was further taken up of elective plating of the completely extra-articular right side and open reduction with distal femur plating was done for femur along with closed interlocking intramedullary nailing was done for tibia [Figure 4].
Figure 4: Post exfix clinical picture

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Serial sterile dressings were done regularly for the patient and repeated laboratory values turned out to be normal. The patient was also further continued on DVT prophylaxis and started on higher antibiotics. On posttrauma day 20, the patient was further taken up for elective supracondylar femur nailing of the left thigh [Figure 5], following which the patient was now started on knee mobilization exercises on the right side. On posttrauma day 30, the patient underwent the last final surgery for the left proximal tibia for which an open reduction and a single lateral buttress plating was done through a minimally invasive approach [Figure 6].
Figure 5: Post second surgery – Right-side X-ray

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Figure 6: Post third surgery - Left side X-ray

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In total, the patient underwent four major surgeries, i.e., the external fixation, plating for right femur + nailing for right tibia, followed by nailing for left femur and plating for left tibia [Figure 7]. Finally, on posttrauma day 40, the patient was able to mobilize with the help of a walker and was able to go to the toilet herself without any aid.
Figure 7: Post final surgery – X-ray and clinical picture

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The patient was rigorously given physiotherapy and bilateral knee flexion extension, quadriceps strengthening, and abductor strengthening exercises were done. The patient was regularly followed up, and the follow-up period was generally uneventful. The patient was allowed for full weight-bearing without walker on posttrauma day 70. She was able to resume her daily work-related activities by posttrauma day 90.

Serial follow-up X-rays revealed good callus formation and bony union. The patient was in follow-up at regular intervals at 2 weeks, 1 month, 3 months, 6 months, and 1 year. On each follow-up, clinical and radiological assessment was done. Radiological assessment was done by X-ray to assess bony union. Functional assessment was done using modified Karlström and Olerud score after bony union was confirmed. Knee Lysholm scoring was done at 6 months and a score of 88 was obtained.

  Discussion Top

Although Floating Knee Injuries is a rare entity, with increasing population and the rise in motor vehicle accidents its becoming more common nowadays, there is a rise in incidence of these injuries. Management protocol for these patients involves hemodynamic stabilization, followed by surgical fixation. Following the principles of damage control orthopedics, overall patient stabilization is priority, and skeletal stabilization is done by fixators at first and final definitive fixation is to be done once patient is stable.

Rethnam et al.[7] treated floating knee injuries (FKI) with intramedullary nail for most of extra-articular fracture and plate for most of intra-articular fracture and found that the fracture union time and functional recovery were better in those patients who were treated with intramedullary nail.

Theodoratus et al.[8] in their study recommended intramedullary nail as a method of choice for the treatment of ipsilateral diaphyseal tibia and femur fracture except open Grade 3b and c fracture.

Dwyer et al.[9] compared four treatment modalities to fix FKI and concluded that excellent-to-good results were obtained when shaft femur and tibia fractures were treated with intramedullary nail or combined modality (intramedullary nail for femur fracture and cast brace for tibia fracture), and poor results when both fractures were treated with external fixator. The incidence of amputation was reported up to 27% in FKI which had massive soft-tissue crushing, severe infection, and neurovascular injuries.

Knee stiffness remains the main complication after treatment. Decreased range of motion and diffuse pain persists years after treatment and fracture healing.[10] Although early range of motion and knee physiotherapy can somehow decrease the knee stiffness, final outcome is still unpredictable. Although soft-tissue damage and type of fracture may affect the functional outcome, final results are totally variable in literature. Manipulation under general anesthesia remains the next treatment option.

Complications related to union are also frequently common in FKI. Malunion (17%) was main problem in study conducted by Kulkarni et al.,[11] while delayed union was a complication mainly noted in study conducted by Yadav et al.[12] The functional assessment after the treatment of FKI is evaluated by most authors using the Karlström and Olerud grading system. In order to simplify it, most surgeons consider a satisfactory outcome as those cases with excellent or good results, and an unsatisfactory outcome as those with just acceptable or poor results. Using these criteria, most series described excellent and good results (86% by Karlström et al.,[4] 72% by Veith et al., 81% by Anastopoulos et al., and 65% by Gregory et al.).[13] The present case also showed excellent functional outcome.

  Conclusion Top

A rare occurrence of bilateral and simultaneous occurrence of floating knee in an urban setup is on the rising trend due to ever increasing number of motorcycle accidents, the management of which requires a multidisciplinary and patient-oriented approach. Initial manage through damage control orthopedics rather than definitive fixation is the most vital management step as far as polytrauma patients are concerned. Early postoperative rehabilitation and mobilization prevents most untoward complications expected out of such a major injury. Although a clear management protocol cannot be drawn up for such major and complicated cases, our case serves as an example on the likely management protocol for such major injuries.

Declaration of patient consent

The authors certify that they have obtained all appropriate patient consent forms. In the form the patient(s) has/have given his/her/their consent for his/her/their images and other clinical information to be reported in the journal. The patients understand that their names and initials will not be published and due efforts will be made to conceal their identity, but anonymity cannot be guaranteed.

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Conflicts of interest

There are no conflicts of interest.

  References Top

Blake R, McBryde A Jr. The floating knee: Ipsilateral fractures of the tibia and femur. South Med J 1975;68:13-6.  Back to cited text no. 1
Kao FC, Tu YK, Hsu KY, Su JY, Yen CY, Chou MC. Floating knee injuries: A high complication rate. Orthopedics 2010;33:14.  Back to cited text no. 2
Feron JM, Bonnevialle P, Pietu G, Jacquot1 F. Traumatic floating knee: A review of a multi-centric series of 172 cases in adult. Open Orthop 2015;Suppl 1 / M11:356-60.  Back to cited text no. 3
Vallier HA, Super DM, Moore TA, Wilber JH. Do patients with multiple system injury benefit from early fixation of unstable axial fractures? The effects of timing of surgery on initial hospital course. J Orthop Trauma 2013;27:405-12.  Back to cited text no. 4
Rethnam U, Yesupalan RS, Nair R. The floating knee: Epidemiologyprognostic indicators & outcome following surgical management. J Trauma Manag Outcomes 2007;1:2.  Back to cited text no. 5
Karlström G, Olerud S. Ipsilateral fracture of the femur and tibia. J Bone Joint Surg Am 1977;59:240-3.  Back to cited text no. 6
Rethnam U, Yesupalan RS, Nair R. Impact of associated injuries the floating knee: Aretrospective study. BMC Musculoskelet Disord 2009;10:7.  Back to cited text no. 7
Theodoratos G, Papanikolaou A, Apergis E, Maris J. Simultaneous ipsilateral diaphyseal fractures of the femur and tibia: Treatment and complications. Injury 2001;32:313-5.  Back to cited text no. 8
Dwyer AJ, Paul R, Mam MK, Kumar A, Gosselin RA. Floating knee injuries: Long-term results of four treatment methods. Int Orthop 2005;29:314-8.  Back to cited text no. 9
Nouraei MH, Hosseini A, Zarezadeh A, Zahiri M. Floating knee injuries: Results of treatment and outcomes. J Res Med Sci 2013;18:1087-91.  Back to cited text no. 10
Kulkarni MS, Aroor MN, Vijayan S, Shetty S, Tripathy SK, Rao SK. Variables affecting functional outcome in floating knee injuries. Injury 2018;49:1594-601.  Back to cited text no. 11
Yadav V, Suri HS, Vijayvargiya M, Agashe V, Shetty V. “Floating knee,” an uncommon injury: Analysis of 12 cases. Rev Bras Ortop (Sao Paulo) 2019;54:53-9.  Back to cited text no. 12
Ran T, Hua X, Zhenyu Z, Yue L, Youhua W, Yi C, et al. Floating knee: A modified Fraser's classification and the results of a series of 28 cases. Injury 2013;44:1033-42.  Back to cited text no. 13


  [Figure 1], [Figure 2], [Figure 3], [Figure 4], [Figure 5], [Figure 6], [Figure 7]


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