Bone loss management represents one of the most challenging issues for the orthopaedic surgeon. In most cases, stems, structural allograft, TMcones, and sleeves are adequate to allow optimal implant stability and durable fixation. In selected cases of wide metadiaphyseal bone defects, these devices do not provide proper intraoperative stability. In such scenarios, further steps are needed and include complex modular reconstruction, substitution with megaprosthesis (exposing patients at high risk of early failure) or joint arthrodesis that can yield unacceptable results. The aim of this paper is to present early results obtained with a new custom-made implant for complex metadiaphyseal bone defects management in knee revision surgery. By means of case presentations the authors would highlight the possibilities and technical notes of this novel device in complex knee revision surgery. Since2015, 8 custom-made porous titanium devices were implanted for massive bone defect management in 6 knee arthroplasty revision procedures. Five patients were staged revision for periprosthetic joint infection (PJI) and one patient underwent a staged revision for post-traumatic septic arthritis. Main demographic and surgical data were collected. Clinical (Range of Movement [ROM], Knee Society Score [KSS] and Oxford Knee Score [OKS]), radiological findings and complications were recorded at different time points and statistically evaluated. Mean follow up was 19.5 ± 9.6months.Introduction
Methods
Femoral or tibial massive bone defects (AORI F2B-F3 / T2B-T3) are common in septic total knee replacement. Different surgical techniques are described in literature. In our study we show clinical and radiological results associated with the use of tantalum metaphyseal cones in the management of cavitary bone defects in two-stage complex knee revision. Since 2010 we have implanted 70 tantalum metaphyseal cones associated with constrained or semiconstrained knee prostheses in 47 patients. The indication for revision was periprosthetic knee infection (43 cases, 91.5%) or septic knee arthritis (4 patients, 8.5%) with massive bone defect. All cases underwent a two-stage procedure. Patients were screened for main demographic and surgical data. Clinical and radiological analysis was performed in the preoperative and at 3,6 months, 1 years and each year thereafter in the postoperative. The mean follow-up was 31.1 months ± 18.8. No dropout was observed.Aim
Method
Prosthetic joint infections (PJI) occur in 0.8–1.9 % of arthroplasties, but the absolute number is increasing because of the frequency of procedures. Two stage exchange is the most effective strategy, but failures are often described. Culture of perioperative tissues during removal of arthroplasty is a standard procedure but culture during second step is equally important to define a success or a failure. We retrospectively reviewed PJI treated with two stage-exchange from January 2011 and December 2012 at “Ospedale S. Maria Misericordia”, Albenga-Italy. The procedure calls for bacterial culture not only during first step but also during reimplantation. Antibiotic treatment is prolonged after reimplantation until the cultures availability. A failure was defined by persistence of infection for positive culture or reocurrence of infection during a follow up of at least 2 years in patients with negative cultures. Three positive cultures yielding phenotypically identical organisms, or a single specimen of a virulent microorganism (e.g. Staphylococcus aureus) were required to rule out false positive for contaminants. Patients with persistence of infection were treated for 3 months with antibiotics. 86 patients underwent the two stage treatment: 45 hip and 41 knee prosthesis. The average ESR before arthroplasty removal was 59 mm/ 1st h (range 5–120), the average CRP was 3.9 mg/dl (range 0.3 – 34). Coagulase-negative staphylococci were isolated in 31 cases, Staphylococcus aureus in 19, Streptococcus spp in 8 and enterococci in 4. Gram-negatives were isolated in 4 patients and polymicrobial infection in 6 patients. In 14 patients (16%) no pathogen was identified. A positive culture during reimplantation was documented in 11 (13%) cases: 8 coagulase-negative staphylococci, 2 Staphylococcus aureus, 1 Candida sp. All patients received 3 months of therapy after surgery and 6 of them were free of infection at 2 years of follow up after the end of treatment. Among the 75 patients with negative cultures, a relapse was documented in 2 (3%), after 5 and 24 months, respectively. These cases were treated with arthrodesis and 6 weeks antibiotic treatment, with resolution of infection but poor functional results. Overall the success rate of our strategy was 92% (79/86). In patients treated with two-stage exchange, the combination of cultures at reimplantation and antibiotic suppressive treatment for 3 months in presence of positive cultures, are associated with a high rate of success. Only a prolonged follow up can rule out a relapse and agree with a true resolution of infection.
