The so called “floating knee” is the result of ipsilateral fractures of femur and tibia. The definition of floating knee dates back to 1974, when Blake and Mc Bryde proposed it in order to move the attention from the skeletal plane of the lower limb to the articular and vasculonervous plane of the knee, where complications are more frequent and dreadful: lesions of popliteal artery or sciatic nerve, stiffness or instability of the knee. The timing of surgical treatment is still debated: in fact it may be immediate but provisional, with necessity of a second operation, or delayed but definitive. Also the strategy of osteosynthesis may be controversial, because of the association of fractures. We present a series of 3 cases (among them there were also 2 ipsilateral fractures of patella) with both femur and tibia treated by osteosynthesis with plate (1 case, with complications) or nail (2 cases, without complications): the patients were followed-up clinically and with X-rays for 1 year. Our experience confirms the gold standard for this kind of fractures is locked intramedullary nailing, retrograde for femur and antegrade for tibia.
The authors describe a new, original technique of intra-medullary nailing (originally designed for the Gamma nail system, now also suitable for other nailing systems) for the management of pertrochanteric and subtrochanteric fractures using a minimally invasive approach to the proximal femur. In this approach, the intramedullary nail is placed using a percutaneous Kirschner wire as a guide, so that the procedure has been called “Percutaneous Nailing System” (PNS). The entry portal is selected at the proximal femur using the Kirschner wire, then a series of cannulae is placed through a small cutaneous incision (15 mm). This dilatator system protects the soft tissue during the reaming procedure (usually only necessary in the proximal femur, not in the diaphysis) and the insertion of the femoral nail. From April 2001 to January 2004, 120 patients were treated with this new technique. They have been followed up and retrospectively compared to 60 patients operated with the standard technique. The comparison between the two groups was based on the surgical procedure (operation time and total blood loss) and the post-operative period (complications, length of hospitalisation). With the minimally invasive technique the operation time was on average 15 min and the blood loss, measured as the difference in pre- and postoperative haemoglobinaemia, was on average 1 point, with no need for blood transfusion: these values were less than half in comparison to the standard technique. The study shows the advantages of this minimally invasive technique, which can also be applied to fractures of the femoral diaphysis.
