Introduction: The success of total knee arthroplasty (TKA) is dependent on many factors. Postoperative extremity and component alignment are important determinants of outcome and longevity and malalignment results in higher failure rates. Computer-assisted (CAS) navigation devices were developed to improve implant positioning but their use increases the complexity of the surgery. The aim of this study is to assess the radiological outcome of conventional techniques versus CAS for TKA performed by an expert and other group performed by a beginner in CAS.

Methods: 90 patients patients with knee arthritis were prospective randomized into 3 groups: CAS performed by an expert, CAS performed during the learning curve and conventional technique (manual instrumentation) performed by an expert. Preoperative and postoperative clinical examinations were performed at four weeks, six months, and one year by an independent physician who was blinded to the surgical technique. Preoperative and postoperative radiographic measurements of the anterior-posterior mechanical axis and the sagittal tibial and femoral axes were evaluated by an observer who was blinded to the surgical technique. The Knee Society Scoring System was used to asses clinical and functional outcomes. All variables were analysed for differences between the groups either by Student’s t-test or the Mann-Whitney U test.

Results: There was no differences in implant positioning between the CAS groups. The mechanical axis of the leg was significantly better in the two CAS groups (96%, within +/−3° varus/valgus) compared with the conventional Group (78%, within +/− 3° varus/valgus). The frontal and sagittal alignment of the femoral component and the frontal tibial alignment were also more precise in the CAS groups. Improvement occurred in the Knee Society scores up to one year post-operatively and was similar for the three groups. No significant difference between the groups could be found at any time point in the study, with the mean difference being 3.5 points (95% CI;18.6 to 13.6).

Conclusions: We have not shown differences in the precise positioning of implants during the learning curve in computer-assisted total knee arthroplasty. Computer-assisted total knee arthroplasty gives a better correction of alignment of the leg and orientation of the components compared with the conventional technique. Potential benefits in the long-term outcome and functional improvement require further investigation.

Introduction and Objectives: Surgical infection is the third most frequent hospital infection (14–16%) and the first in frequency in surgical patients (38%). We present here the data on incidence of post-surgical infection in our Service over the last 11 years.

Materials and Methods: Between 1/1/1996 and 31/12/2006, we monitored, prospectively, 14,099 patients admitted to and operated on in our Service and collected epidemiological, clinical, surgical and microbiological data. We analyzed the rate of infection in programmed, urgent and deferred surgery.

Results: The mean rate of incidence of osteoarticular infection was 1.46% (0.77–1.89%) and the mean rate of incidence of non-osteoarticular infection was 1.47% (0.63–3.01%). There were 122 cases of osteoarticular infection diagnosed in programmed surgeries (8,381 patients) a percentage of 1.45% and 108 cases of osteoarticular infections in urgent surgeries (5,718 patients) a percentage of 1.88% during the period studied (p=0,23). There have been 77 cases of non-osteoarticular infections diagnosed in programmed surgical procedures, a percentage of 0.91% and 133 cases of non-osteoarticular infections diagnosed in urgent surgical procedures, a percentage of 2.32% (p< 0,05) over the last 11 years.

Discussion and Conclusions: The mean rate of osteoarticular infection is higher in urgent surgical procedures in comparison with the rate in programmed surgical procedures, but the difference is not statistically significant. The mean rate of non-osteoarticular infection in urgent surgical procedures is significantly higher in comparison with the rate of non-osteoarticular infection in programmed surgery. Our data is within the standards accepted by the scientific community. We believe that this study helps us to control our infections and serves as a guide when implementing infection therapy.