Infection in the modular prosthesis reconstruction for oncological bone loss: a growing risk

Options for limb salvage surgery include reconstruction with massive allograft, prosthetic reconstruction and rotationplasty techniques. The latter procedure is not easily accepted by the patient, while allograft reconstruction show some concern regarding long term results: fracture and cartilage degeneration proved to be relative frequent complications of this surgery, and instability is another complication following ligament sacrifice during oncological resection. Megaprostheses have been largely used and from custom-made prostheses we have moved forward to a large variety of modular implants. Longevity of implants is a concern with megaprostheses, but we will focus on the rate of infection in our experience. The new Megasystem C (Waldemar Link) modular prosthesis have been used in our institution from June 2001. We operated 199 patients, with Our experience of a new prosthesis modular system used from June 2001 is reported. We performed till March 2007 199 prostheses, 177 of which were megaprostheses, 16 composite prostheses (6 proximal femur, 11 proximal tibia) and 6 were total femoral replacement. Surgical superficial infection were observed in 3 patients, and resolved with wound surgical treatment. Deep late infection developed in 15 patients (7.5%) and required several accessory surgical interventions. Staphylococcus was involved alone or in association to polymicrobial infection in 73% of the cases. Meticillin resistant bacteria were present alone or associated in more than 60% of the patients. Infection was managed with debridment alone in 3 patients; the other 12 patients were operated and the prosthesis removed with insertion of a antibiotic loaded cement spacer (Vancocin 1 gr every cement dose). In two patients due to poor skin closure an arthrodesis nail (Waldemar Link) was implanted. Another patients was not reimplanted due to poor medical condition. Seven patients ha been operated with implantation of a new prosthesis. The last 3 patients are still under antibiotic treatment and the haematological values do not permit reimplantation. Even if the infection rate in our experience is not higher than other reports in the same kind of patient, the very high rate of meticillin resistant bacteria should recall attention for the emerging risk of serious complications and should lead to better use of antibiotic prophylaxis