The optimal management of severe tibial and/or femoral bone loss in a revision total knee arthroplasty (TKA) has not been established. Reconstructive methods include structural or bulk allografts, impaction bone-grafting with or without mesh augmentation, custum prosthetic components, modular metal augmentations of prosthesis and tumor prosthesis. Recently metaphyseal fixation using porous tantalum cones (Zimmer, Warsaw, IN) has been proposed as alternative strategy for severe bone loss. The purposes of this study were to determine the clinical and radiographic outcomes in patients who underwent revision knee arthroplasty with tantalum cones with a minimum of 5-year follow-up.Introduction
Objectives
The use of antibiotic-loaded polymethylmethacrylate bone-cement spacers during two-stage exchange procedures is the standard in the treatment of patients with delayed prosthetic joint infection. The real antimicrobial activity of these spacers is unclear because the adherence of bacteria to cement might result in clinical recurrence of infection. The purpose of the study is to evaluate the in vitro formation of Cement disks (diameter = 6 mm) impregnated with gentamicin and colistin were submerged in bacterial suspensions of Methicillin-resistant Introduction
Materials and methods
High-dose antibiotic-loaded acrylic cement (ALAC) is used for managing periprosthetic joint infections (PJIs). The marked increase in resistant high-virulence bacteria is drawing the attention of physicians towards alternative antimicrobial formulations to the routinely used antibiotics. To date, few studies simultaneously investigated the elution properties of a broad range of antibiotics. The aim of thepresent All the ALAC samples showed a burst release of antibiotics in the first hour, progressively decreasing overtime, and elution curves strictly adhered to a non-linear regression analysis formula. Among aminoglycosides, commonly addressed as the most appropriate antibiotics to be loaded into the bone cement, the highest elution rate was that of tobramycin. Among the glycopeptides, commonly used to treat PJIs because of the prevalence of aminoglycoside resistance, vancomycin showed better elution in comparison with teicoplanin. Clindamycin, that can be associated with aminoglycosides to prepare ALACsshowed the highest absolute and relative elutions among all the tested formulations. A noticeable elution was also detected for colistin, an antibiotic of last resort for treating multi-drug resistant bacteria. The current study demonstrates theoretical advantages in the preparation of ALAC for some antibiotics notroutinely used in the clinical setting for PJIs. The use of these antibiotics based on the infecting bacteria sensitivity may represent an useful option for physicians to eradicate PJIs.
Tapered cementless femoral components have been used in total hip arthroplasty (THA) constructs for more than 20 years. The Synergy femoral component was introduced in 1996 as a second generation titanium proximally porous-coated tapered stem with dual offsets to better restore femoral offset at THA (Figure 1). The purpose of this study was to evaluate the outcome of the authors' experience using the Synergy stem at minimum 15 years of follow-up. We retrospectively reviewed a consecutive series of 102 patients (112 hips) who underwent surgery between November 1996 and October 1998 for primary THA using cementless Synergy stem with a minimum 15-years follow-up. The mean age at the time of surgery was 61 years, and the mean duration of follow-up was 16.3 years. Seventeen patients were lost at FU (8 died before the 15 years mark, 8 changed residency, 1 not willing to be seen) with no problems related to the replaced hip. Ninety-four hips in 85 patients were available for clinical and radiologic analysis. Clinical results of the 94 THAs with more than 15 years of follow-up were assessed preoperatively and postoperatively at 5, 10 and 15 years by means of standard evaluation tools: SF12, WOMAC and Harris Hip Score. Thigh pain frequency and intensity were also recorded. Radiographic analysis (Figure 2) was focused on stem alignment, bone ingrowth, radiolucent lines presence, width and progression, stress-shielding and heterotopic ossification (HTO). Student paired test and Kaplan-Meier survival analysis were used for statistical analysis.Background
Material and methods
Few studies have evaluated at a medium-term follow-up the use of semiconstrained reverse shoulder arthroplasty (RSA) for primary glenohumeral osteoarthritis, massive rotator cuff tear, or cuff tear arthropathy excluding any other shoulder disease. Moreover, data on patients' quality of life after this surgery are lacking. In this prospective cohort study, 80 patients were evaluated after an RSA for either primary osteoarthritis, massive rotator cuff tear, or cuff tear arthropathy with the Constant-Murley score (CMS), ROM, and Short Form Health Survey (SF-36). A radiologic assessment was performed pre- and postoperatively.BACKGROUND:
METHODS:
Modern total hip arthroplasty (THA) has shown a great improvement in pain, function and range of motion of patients but data on patients' quality of life after this surgery as assessed by validated tools are lacking. In this cohort study we evaluated the quality of life and functionality of 250 patients an average of 16 years (11–23) after THA using the SF-36 questionnaire, the Harris Hip Score, the WOMAC score, the Functional Comorbidity Index, and a study specific questionnaire. Models of multiple stepwise linear and logistic regression analysis were constructed to evaluate the relationships between the explanatory variables and the functional outcomes.BACKGROUND:
METHODS:
The removal of cement debris at the time of primary and revision joint replacement has been facilitated through the introduction of coloured bone cements. Up to date, few studies have evaluated the effect of methilene blue dye on physical, mechanical and pharmacological properties of cements. In this light, we evaluated the effects of adding methylene blue to bone cement with or without antibiotics (gentamicin, vancomycin or both). The addition of methylene blue to plain cement significantly decreased its mean compression (95.4±3 MPa vs 100.1±6 MPa, p = 0.03) and bending (65.2±5 MPa vs 76.6±4 MPa, p < 0.001) strengths, mean setting time (570±4 seconds vs 775±11 seconds, p = 0.01), as well as its mean elastic modulus (2744±97 MPa vs 3281±110 MPa, p < 0.001). Bending resistance decreases after the supplementation of the coloured cement with vancomycin and gentamicin (55.7±4 MPa vs 65.2±5 MPa, p < 0.001). The release of antibiotics from the bone cement was significantly decreased by the methylene blue. Indeed, the release of gentamicin alone was 385.5±26 μg in comparison to 228.2±24 μg when the methylene blue was added (p < 0.001), while the release of gentamicin in combination with vancomycin was 613±25 μg vs 498.5±70 μg (p = 0.018) when the dye was added to the same formulation. With this study we demonstrated several theoretical disadvantages of the antibiotic-loaded bone cement coloured with methylene blue, although caution should be exercised in transferring our findings to the clinical context. Based on our findings, we do not recommend methylene blue supplementation of PMMA for routine clinical use.
Pure tantalum has been proposed in orthopaedic surgery. Its chemical and physical properties have been widely studied in the past. From pure tantalum is obtained a spongy structure (Trabecular Metal Technology: TMT) that shows a full thickness porosity which is 2–3 times higher compared to other surfaces available for bone ingrowth with a three-dimensional porous arrangement in rough trabeculae. Pores (average diameter of 650 mm) are fully interconnected and represent 75–80% of the whole volume. TMT acetabular components have an elliptical shape and have an irregular external surface which both allow an optimal mechanical fit. We retrospectively reviewed 212 cases of monoblock porous tantalum acetabular cup (Hedrocel, Stratec) implanted between 1999 and 2003 in a single centre with a minimum follow-up of 9–10 years; There were 98 men and 114 women, with an average age of 65 years. They all underwent primary or revision total hip arthroplasty or to acetabular component revision alone. In all patients a monoblock porous tantalum acetabular component with polyethylene directly compression molded into cup, with or without peripheral holes for screws, was implanted. In all primary procedures the same femoral stem (Synergy, Smith and Nephew) was implanted. All patients were evaluated with a clinical examination (Harris Hip Score: HHS) and with standard radiographs of the pelvis preoperatively and 1, 3, 6 months and yearly postoperatively. The stability of the acetabular cup was determined by modified Engh's criteria. The HHS score improved from 42 preoperatively to 94 after one year; at 13 years follow-up it was 95. The subjective outcome was widely satisfying, with the majority of patients experimenting good functional recovery and return to daily activities. Osteointegration of the acetabular component was present in all X-rays controls at one year after surgery. All post-operative evidence of residual bone loss (geodes, bone defects in revisions and in displasia) were no more radiographically evident after 1 year postoperatively as the host bone quickly filled these gaps. We did not observe osteolysis nor progressive radiolucent lines at the latest follow-up. None of the cups was revised, except 3 cases, revised for infection. Both clinical and radiographic results are the same or even superior to those of coated implants. Our experience confirms that trabecular metal tantalum cups can avoid the formation of bone-implant interface membrane and consequently can avoid implant loosening. The most important advantages of TMT monoblock cups are: no potential for polyethylene backside wear, prevention of loosening and osteolysis, increased early fixation via friction, improved late biological stability, maximum bone-implant contact. High biocompatibility of porous tantalum and its elastic modulus very close to bone influence positively earlier and wider osteointegration of the implant. Larger series are needed to confirm the positive our preliminary results.
