Floating knees: lesional and therapeutic aspects (about 74 cases) by Dr. Bensaka Mohammed in Journal of Clinical Case Reports, Medical Images and Health Sciences

Floating knees: lesional and therapeutic aspects (about 74 cases) by Dr. Bensaka Mohammed in Journal of Clinical Case Reports, Medical Images and Health Sciences 

Introduction :

The floating knee is a fracture association in the lower limb, as described by Blake and Mcbryde [1] in 1974, to designate ipsilateral fractures of the femur and tibia. It most often occurs in the context of multiple trauma causing associated brain, thoracic and abdominal lesions that endanger the patient's vital prognosis. Management must be multidisciplinary, early and optimal with the essential goals of: stabilization of vital functions in the multiple trauma patient, effective and definitive treatment allowing early recovery, maximum prevention of complications and well-conducted rehabilitation. Our work aims to clarify this traumatic entity by analyzing the lesional and therapeutic aspects and evaluating the functional results of treatment in order to compare them with those in the literature.

Materiel And Methods: 

This is a retrospective study covering all patients operated on for floating knees at the Traumatology Orthopedics Department B4 of the Hassan II University Hospital of Fez, over a period of 22 years, going from January 2010 to December 2022. We excluded our study: 1) patients aged less than 16 years; 2) patients leaving medical advice; 3) incomplete files (non-usable). At the end of our operation, 74 floating knees were retained. The data was analyzed based on an operating sheet; the statistical study was carried out on Microsoft Excel 2016 

Results:

We have noted a clear increase in the annual incidence of floating knees. The average age of our patients is 27 years with a male predominance of 91%, the left lower limb was affected in 68.05% of cases and in 03 cases (2.77%) the involvement was bilateral. Direct shock is the most incriminated in 83.33% of cases, the etiologies are dominated by public road accidents (AVP) in 66 cases or 91.66%. (Figure A) The average time of admission to the hospital was 1.5 hours, all patients underwent a complete somatic examination thus revealing the floating knee was isolated in 50% of cases, associated with other lesions in 25% and occurring in a context of polytrauma in 25% of cases. A percentage of 70.83% of fractures were open with 7 cases of vascular lesions or 9.72% (4 cases of lesions of the posterior tibial artery (PTA) and 3 cases of lesions of the tibial artery anterior (ATA)). The average ISS (Injury Severity Score) score was 22 with a predominance of associated brain lesions (30.55%), the rest were mainly skeletal lesions (22.22%), thoracic and abdominal lesions. Radiologically, it was noted that diaphyseal fractures are predominant both at the level of the femur and at the level of the tibia with a predominance of Fraser stage I fractures (70.5%). Note that comminution of the fracture site was more frequent for the tibia than for 

In our series, 28 patients (37.5%) were admitted to intensive care, including 18 serious polytrauma patients admitted for initial treatment (PEC) and 9 patients admitted for post-operative PEC; among these patients we noted 4 deaths. The average surgical intervention time is 25 hours, with extremities ranging from H2 to 03 days, the two fractures 

were operated on in a single surgical procedure, the operating timeline depends on the skin opening, the type of fracture and therefore the Surgical trt considered, thus the osteosynthesis of the tibia was the first operation step in 56 cases (75%) and in the remaining 18 cases the intervention had started with the osteosynthesis of the femur (25%). The duration of the surgical procedure was 1h50 min to 4h, an average of 152 minutes. Intramedullary nailing with reaming was the most used therapeutic method for the femur (72.22%) and tibia (66.66%). The average follow-up of our series is 50 months, we noted as complications: 5 cases (6.94%) of hemorrhagic shock on admission of which 3 patients have stabilized after resuscitation measures and 2 deaths; 7 cases (8.33%) of infection on equipment, they all involved open floating knees; 4 cases (4.16%) of malunion including 2 malunion of the tibia on open comminuted fracture stage II and one of the femur on open diaphyseal fracture stage 2; 4 cases (5.55%) of non-union including 3 septic non-union of the leg and 1 aseptic non-union of the femur; 4 cases

(5.55%) of knee stiffness. Furthermore, we did not note any thromboembolic, ligamentous or nervous complications. Fifty-two (52) patients progressed favorably towards bone union, i.e. 72.22% of cases, i.e. a time to consolidation between 3 and 4.6 months with an average of 3.2 months. Overall functional results were assessed according to Karlstrom's criteria (Figure 2).

Discussion  :

The studies influencing these results are: skin opening, joint damage in fractures classified as Fraser stage II, thus we noted 70% excellent and good results in cases of floating knee with at least one open fracture versus 91% for closed floating knees with more satisfactory results for Fraser stage I (57% excellent and good results). Floating knee can occur at any age with a predominance for young male subjects in the majority of series of literature, which is similar to our series. AVP represents the etiology of floating knee in 91.66% of cases in our series as well as in all the series of other authors. The rate of skin opening exceeds half of the cases in most series, as well as our study series and we see that open fractures predominate at the level of the tibia compared to the femur, and this is explained by the fact that at the tibial level the bone is located under the skin at the level of the antero-internal face of the leg. The majority of authors report the occurrence of floating knee in the context of polytrauma in more than 20% of cases, notably 46.1% for Zrig and 32.2% for Karlstrom with an average ISS score which remains high, which shows the seriousness of the problem. this trauma. Radiologically, Fraser type I is the most reported in the majority of series in the literature. Intramedullary nailing remains the most used therapeutic method in all series (Table 3). The most reported complications are infection, malunion, joint stiffness and nonunion. For our functional results, they are consistent with those of the literature with a predominance of excellent and good results in all studies, moreover, open fractures and Fraser stage II fractures remain with an unfortunate prognosis with acceptable to poor results.

Conclusion:

 Floating knees represent a potentially serious traumatic entity with frequent associated injuries making their multidisciplinary management requiring appropriate resuscitation measures and appropriate surgical treatment.  

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