The concentrations of levofloxacin achieved in cancellous and cortical bone tissue and in synovial tissue are greater than the breakpoint for susceptible organisms, which is < or =2 mg/L.

IV, cohort study.

The use of locking plates relies on novel mechanical and biological concepts: the bone healing is endochondral because of the elasticity of the constructs. Preoperative planning is required to determine the fracture reduction strategy and select the implants. The type of plate and the type of screws and their position determine the mechanical properties of the construct. Failure of locking plate fixation is a new phenomenon that differs from conventional plate fixation. These are brought on by inadequate planning, which is made worse when minimally invasive surgery is performed. Often, the fracture is not reduced correctly (leading to malunion), the implant length is incorrect, or the screw type, number, location and implantation sequence are inappropriate. Together these can result in an overly rigid construct with poor healing and implant failure or the opposite, an overly flexible construct that can compromise healing. The return to weight bearing after fracture fixation must be adapted to the type of fracture and construct. While locking plates provide better bone purchase, especially in osteoporotic bone, "en bloc" pulling out of the implant is possible. Delayed fractures at the end of the plates are also possible but can be avoided by making the correct biomechanical choices during fixation. For epiphyseal fractures, there are risks of cut-out and impaction of locking screws in cancellous bone related to the fracture pathology. In the long-term, locking plates can be difficult to remove; however, specialized instrumentation can make this easier.

In 1975, Blake and McBryde established the concept of ‘floating knee’ to describe ipsilateral fractures of the femur and tibia.1 This combination is much more than a bone lesion; the mechanism is usually a high-energy trauma in a patient with multiple injuries and a myriad of other lesions.After initial evaluation patients should be categorised, and only stable patients should undergo immediate reduction and internal fixation with the rest receiving external fixation.Definitive internal fixation of both bones yields the best results in almost all series.Nailing of both bones is the optimal fixation when both fractures (femoral and tibial) are extra-articular.Plates are the ‘standard of care’ in cases with articular fractures.A combination of implants are required by 40% of floating knees.Associated ligamentous and meniscal lesions are common, but may be irrelevant in the case of an intra-articular fracture which gives the worst prognosis for this type of lesion.Cite this article: Muñoz Vives K, Bel J-C, Capel Agundez A, Chana Rodríguez F, Palomo Traver J, Schultz-Larsen M, Tosounidis, T. The floating knee. EFORT Open Rev 2016;1:375-382. DOI: 10.1302/2058-5241.1.000042.

The degree of penetration of an antibiotic into the infection site is an important factor in its therapeutic efficacy, particularly in bone and joint infections. In the present study, we examined the bone tissue penetration of cefepime at a dose of 2 g, and the results were correlated to microbiological data to estimate the clinical efficacy of cefepime in bone infections. In this open-label, single-arm, noncomparative study, subjects of similar age, body weight, height and creatinine clearance who were undergoing elective total hip replacement received a single, parenteral 2 g dose of cefepime. Plasma samples were collected simultaneously with bone tissue samples 1.5 hours later, on average, and analyzed by a validated high performance liquid chromatography assay. Ten patients (7 women and 3 men; mean age, 78 years; mean body weight, 57 Kg; mean creatinine clearance, 56 mL/min) were enrolled. The mean +/- SD plasma concentration of cefepime at the time of bone removal was 72.9 +/- 24.4 microg/mL. The mean +/- SD cefepime concentrations were 73.5 +/- 16.2 microg/mL in cancellous bone tissue and 67.7 +/- 17.0 microg/mL in cortical bone tissue. The mean +/- SD ratios of cefepime concentration in bone and plasma (bone/plasma) were 1.06 +/- 0.23 for cancellous bone tissue and 0.87 +/- 0.37 for cortical bone tissue. Cefepime exhibits an excellent diffusion into bone tissue, with concentrations achieved in both cancellous and cortical bone tissue greater than the minimum concentrations required to inhibit the growth of 90% of strains (MIC90) of most of the susceptible pathogens commonly involved in bone infections.