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.
In order to improve hydroxyapatite (Ha) quality as a bone substitute, two types of Ha were developed based on a new and original technique: Ha with graduated porosity (G-Ha) and porous “carbonated” Ha (C-Ha). Ha cylinders were implanted into the femoral diaphysis of NZW rabbits. Before implantation the materials were characterised by XRD, porosimetry, SEM and thermic and mechanical analysis. Macroscopic, radiographic and histologic analysis were performed on the specimens at standard intervals after surgery (1-3-6- and 12 months). G-Ha proved to be morphologically more similar to bone tissue because of the graduated porosity that mimes the two natural components of bone (cortical-scarce porosity and spongious-high porosity). The C-Ha was chemically more similar to bone because of the CO3- substitution, which is a normal substitute in natural bone. Both materials achieved good mechanical strength, in particular the pseudo-cortical portion of G-Ha. Interconnected porosity was also observed in both materials. Newly formed bone appeared earlier in C-Ha (1–3 months). At 1 year C-Ha demonstrated quiescent bone and significant degradation. The G-Ha was scarcely reabsorbed but showed active osteogenesis in the surrounding living bone. Graduated porosity improved the mechanical interaction with bone over time, while the carbonation improved the temporal interaction and Ha resorption. Porous Ha was found to be a promising bone substitute and also a reliable drug-delivery carrier.
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.
Bone Loss is the main problem in failed total hip arthroplasties. Revision surgery must be conformed to the degree of the bone loss. Since 1986, 330 cases of failed THA underwent to revision surgery. Different solutions were adopted according to Paprosky femoral defects classification. In type I, a primary cementless stem was implanted (23%). In type II and IIIa, were proximal fixation is still possible to achieve, Mid PCA-Howmedica (5%) and modular S-ROM-J&
J revision stems (18%) were implanted. In all the other degree of bone loss (IIIb–IV) cementless distal fixation stems, Long PCA-Howmedica (17 %), Wagner-Sulzer (18 %) and modular (MP-Link, Profemur-Wright) (19 %), were used. Patients were clinically and radiographically evaluated by HHS and according to Engh’s criteria. Best results were observed in Type I group (HHS=90). Long and mid PCA stems presented poor clinical (HHS=60) and radiographical results and required re-revision in 15% of cases. Intermediate results were observed in Wagner prostheses. Modular revision stems showed best results although earlier F-U. (HHS=80). Of these, re-revision surgery was performed in two cases, one of which because of infection and the other one due to severe thigh pain. Cementless modular stems seem to be the most suitable technique. Distal fixation associated with proximal fill permit to manage the majority of femoral bone defects minimizing bone grafts. The modular stems, allow to conform the design of the components to the bone defects permitting to achieve primary stability (press-fit), restoring the centre of rotation and muscles tension, reducing pain and restoring hip function.
