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Fixation is used to treat more than two-thirds of proximal femur fractures. The mortality rate is about 25% at one year in these patients, who have an average age of about 80 years. This is mainly due to aging, but also to a gradual deterioration of general health (especially if the operation has been delayed, or after a long stay in the surgical ward) and to local complications (displacement, infection, hematoma). Two fixation devices (a sliding screw plate and a trochanteric nail) have been designed for mini-invasive treatment with fluoroscopic guidance and an incision smaller than 50 mm. The aim is to respect the soft tissues and thereby to avoid local complications, diminish pain, and facilitate early weight-bearing Hospital discharge is possible after 3 or 4 days. Laboratory experiments have shown the satisfactory resistance of the implant and bone at full weight bearing A preliminary series of 30 patients showed the feasibility of these techniques. Primary fusion was achieved in 27 cases. There were no infections and no bleeding, despite antiplatelet treatment. The techniques have now been optimized and multicenter studies are held to determine their real benefit. Fracture fusion and hip motion should be at least as good as with open surgery (90 to 96% fusions, albeit influenced by the precise position of the implants and by osteoporosis). Mortality may be slightly reduced, thanks to immediate operation, early discharge, and fewer local complications. The cost of treatment could also be significantly reduced by the shorter hospital stay. In a few years' time, mini-invasive treatment may become the standard for elderly patients with proximal femur fractures.

Antibiotic-loaded bone cements (ALBC) were initially used empirically, both for the treatment of infected prostheses and for antibioprophylaxis. We conducted in vitro and animal studies as a prerequisite for proper clinical evaluation. We measured gentamicin diffusion from methacrylate bone cement, and found that the concentration in surrounding fluid was significantly above the minimal inhibitory concentration (MIC). We then implanted ALBC in the proximal femora of 100 ewes, in conditions close to those of total hip replacement (THR). Antibiotic concentrations in bone were above 4 x MIC for more than 6 months. We subsequently measured antibiotic concentrations in drainage fluid, blood and urine samples from 50 patients undergoing THR. Concentrations were over 20 x MIC in periprosthetic fluid, but were below the detection limit in blood after 24 hours and in urine after one week. The blood concentration was less than 1 mg/l--far below the ototoxic and nephrotoxic threshold (8 mg/l). Having established antibiotic bioavailability, we then examined the clinical efficacy of ALBC. We participated in several studies, including a French multicentric review of 342 THR procedures (direct and two-stage exchanges). ALBC was beneficial in both settings, with an 85% infection control rate. This included patients with very severe infections (multiresistant strains, severe osteolysis) treated with two-stage exchanges; and moderate infections treated by direct exchange. (This latter procedure offers fewer complications, more durable functional results, a shorter hospital stay and lower treatment costs.) We also used ALBC for antibioprophylaxis in over 2000 THR procedures, and noted no complications. This method is now being assessed in more than 200 000 cases contained in the Swedish THR Register. The experimental methods that we developed (laboratory studies, animal implantation, clinical pharmacokinetics) set the groundwork for clinical studies of gentamicin ABLC, and also allowed us to develop other ALBC formats, containing vancomycin, for example (restricted to salvage therapy). We also used these methods to evaluate antibiotic-loaded bone substitutes (calcium and carbon phosphates), designed not only to control infectious osteitis but also to replace osteolytic bone.

Reconstruction after major resections of malignant tumors can be achieved by association of prostheses and of massive allografts. In 34 patients, we could reconstruct: the proximal femur in 21 cases, after an average resection of 180 mm, with a "composite" allograft prosthesis (with a bone graft around the stem) or a "composite and combined" allograft prosthesis (in which the femur allograft was associated with the trochanteric tendons, to facilitate the reinsertion of the glutei muscles); 10 hemipelvis in which the cup was inserted in an hemipelvic allograft; 3 proximal femurs and acetabulum (with composite cups and stems). In comparison with metallic reconstruction prostheses, composite prostheses improved function, limited complications, and increased longevity. The association of allografts and prostheses not only allows reconstructions which could be hardly achieved with only prostheses (especially for the pelvis), but also improves functional result and longevity, thanks to the biological fixation of the osseous and tendinous allografts. Considering our 15 years follow up in oncology, we have now extended these procedures to the major bone losses of the femur and pelvis following iterative revisions of standard prostheses for arthritis.