A computed tomography based study on rotational alignment accuracy of the femoral component in total knee arthroplasty using computer-assisted orthopaedic surgery

Rotation of the femoral component in total knee arthroplasty (TKA) is of high importance in respect of the balancing of the knee and the patellofemoral joint. Though it is shown that computer assisted surgery (CAOS) improves the anteroposterior (AP) alignment in TKA, it is still unknown whether navigation helps in finding the accurate rotation or even improving rotation. Therefore the aim of our study was to evaluate the postoperative femoral component rotation on computed tomography (CT) with the intraoperative data of the navigation system. In 20 navigated TKAs the difference between the intraoperative stored rotation data of the femoral component and the postoperative rotation on CT was measured using the condylar twist angle (CTA). This is the angle between the epicondylar axis and the posterior condylar axis. Statistical analysis consisted of the intraclass correlation coefficient (ICC) and Bland-Altman plot. The mean intraoperative rotation CTA based on CAOS was 3.5° (range 2.4–8.6°). The postoperative CT scan showed a mean CTA of 4.0° (1.7–7.2). The ICC between the two observers was 0.81, and within observers this was 0.84 and 0.82, respectively. However, the ICC of the CAOS CTA versus the postoperative CT CTA was only 0.38. Though CAOS is being used for optimising the position of a TKA, this study shows that the (virtual) individual rotational position of the femoral component using a CAOS system is significantly different from the position on a postoperative CT scan

The patella in total knee replacement: technical aspects on the femoral side.

The influence of femoral component positioning on patellar tracking is critical. The various possibilities of modifying the position of the femoral component relative to the distal femoral epiphysis are analyzed, and the ideal positioning in the medio-lateral, antero-posterior, and proximal-distal directions is described. Special emphasis is placed on the rotational positioning of the femoral component

In-vitro and in-vivo study of biofilm disruption strategies for the treatment of prosthetic joint infections

Prosthetic joint infection (PJI) is a devastating complication of joint replacement surgeries, affecting 0.5 to 2% of patients following a hip or a knee arthroplasty. Its treatment is complicated by the rapid formation of bacterial biofilms on the implants’ surfaces. Biofilms are bacterial communities enveloped in a complex self-produced matrix that isolates bacteria from their environment, leading to an increased tolerance to antimicrobials. Therefore, new therapeutic options targeting biofilms are in development to improve the outcome of PJI. The objectives of this work were to investigate biofilm disruption using a standard irrigation technique (pulsed-lavage) or an enzyme combination targeting the matrix of the biofilms, and its impact on the susceptibility of bacteria to antibiotics. Pulsed-lavage and the enzymatic combination were studied in two successive in-vitro studies, using a model of biofilms grown on titanium alloy substrates. Our experiments showed that the successive application of biofilm disrupting treatments and antibiotics, used at clinically relevant concentrations, was synergistic. Considering these encouraging results, an in-vivo model of PJI was developed to study the use of the enzymatic combination as an adjuvant to a treatment with debridement, systemic antibiotics, and implant retention. Regrettably, the addition of the enzymatic combination did not appear to improve the outcome of the treatment. However, these experiments open new perspectives to optimize the use of enzymes in this setting, and the tools developed for this work could prove useful to investigate the application of other strategies for the treatment of PJI.(BIFA - Sciences biomédicales et pharmaceutiques) -- UCL, 202

Dangerous Slimes: How Bacterial Biofilms Make You Sick and How to Combat Them

Yes, we can house dangerous slimes called biofilms in our bodies. They can cause severe infections anywhere in our bodies. They contain bacteria hidden and hibernating in a protective matrix. This makes them really difficult to treat. They like to stick on implanted material like prostheses or catheter. They can also persist on your teeth, in your ears, even sometimes in your lungs. Luckily, researchers are very aware of this problem. They are experimenting with diverse solutions to try to destroy these biofilms. Are you curious about their brilliant ideas? Then follow us to learn more about how biofilms make you sick and how we try to combat them

Outcome of total knee arthroplasties after renal transplantation

The fate of total knee arthroplasty in renal graft recipients is unknown. We retrospectively reviewed the outcome of 16 total knee arthroplasties (TKAs) performed after renal transplantation in 12 renal graft recipients from February 1997 to December 2003. The patients (mean age 63) were submitted to a clinical evaluation using the Knee Society Score (KSS) and a radiological evaluation using the Knee Society Total Knee Arthroplasty Roentgenographic Evaluation. The follow-up period averaged 65 (range 25-107) months. No knee had to be revised and one patient died during the follow-up period. The mean knee score was 97.1 (range 93-100) and the mean function score was 87.7 (range 60-100). The alignments of the prosthetic components were correct for all but one patient who, however, kept a good knee score (95). No case of aseptic loosening or osteolysis was detected at last X-rays examination. We conclude that TKA is a safe and symptomatically effective treatment of knee osteonecrosis or severe osteoarthritis in renal graft recipients and should thus be proposed in this population when symptomatology becomes significant. Long-term follow-up studies are necessary to confirm this initial report