Value of the synovial C-reactive protein test in the diagnosis of total hip and knee periprosthetic joint infections: A case-control study.

INTRODUCTION: The diagnosis of periprosthetic joint infection (PJI) can be challenging and rests on several principles. The use of diagnostic biomarkers, such as the synovial C-Reactive Protein (CRP), seems promising. The purpose of this study was to determine whether synovial CRP was a more discriminating test than serum CRP for the diagnosis of hip and knee PJI. MATERIALS AND METHODS: In total, 194 patients were included in this single center prospective study: 42 primary arthroplasties (control group [CG]), 111 revisions for aseptic prosthesis (aseptic revision group [ARG]), and 41 revisions for septic prosthesis (septic revision group [SRG]) based on the Musculoskeletal Infection Society (MSIS) criteria. RESULTS: The serum and synovial CRP levels were significantly higher in the SRG than the other two groups (SRG serum CRP=75.6mg/L vs. ARG serum CRP=6mg/L and CG serum CRP=2.7mg/L, p<0.001; SRG synovial CRP=31.5mg/L vs. CG synovial CRP=2.6mg/L and ARG synovial CRP=1.7mg/L, p<0.001). The positive likelihood ratios (LR+) were very similar for both the synovial CRP cut-off value of 4.4mg/L (LR+=7.04; sensitivity [Se] 82.5%, specificity [Sp] 88.3%) and the serum CRP cut-off value of 9mg/L (LR+=6.3; Se 87.5%, Sp 86.1%). CONCLUSION: This study showed that synovial CRP testing was not more discriminating than serum CRP in the diagnosis of hip and knee PJI. A serum CRP level greater than 9mg/L was a sign of PJI. LEVEL OF EVIDENCE: III; case-control study.

Implementation and results of an enhanced recovery (fast-track) program in total knee replacement patients at a French university hospital.

INTRODUCTION: In total knee replacement (TKR) surgeries, "fast-track" or enhanced recovery after surgery (ERAS) programs are being developed, but their impact on care pathway quality and safety has not been fully explored in the French literature. The present study aimed to compare results in TKR between fast-track and conventional pathways, addressing the following questions: (1) Are 90-day rates of complications, readmission and surgical revision higher with fast-track? (2) Is mean length of stay (LoS) shorter with fast-track? (3) Are postoperative pain and clinical results improved by fast-track? And, (4) are patients and care staff satisfied with these new programs? HYPOTHESIS: Implementing fast-track for TKR in a university hospital center is beneficial for the patient and does not impair the quality and safety of care. PATIENTS AND METHOD: A case-control study was performed using a retrospective analysis of prospectively collected data. A fast-track program was implemented for TKR by modifying the care pathway. This involved instituting a therapeutic education consultation, optimizing blood sparing, modifying surgical practices, and hastening early mobilization thus actively involving patients in their own management. Between January 2017 and January 2019, 216 patients with a mean age of 69.23±7.80years and mean BMI of 30.15±4.79kg/m2 were included in the fast-track group, with 335 matched patients included in the conventional group. RESULTS: At 90days, there were no significant inter-group differences in rates of infection (fast-track=1.39%, conventional=0.90%; p=0.34), readmission (fast-track=3.24%, conventional=3.58%; p=0.49), or surgical revision (fast-track=2.78%, conventional=2.69%; p=0.298). The visual analog scale (VAS) pain rating was 1.56±1.36 in the fast-track group versus 5±2.41 in the conventional group; p<0.001. LoS was 3.17±1.59days in fast-track versus 7.25±1.85days in the conventional group; p<0.001. Ninety-five percent of patients and 96% of care staff were satisfied with the fast-track program. DISCUSSION: Fast-track implementation ensured quality and safety of care; it did not increase the rate of complications in primary TKR. Mean length of stay was drastically reduced. Both patients and care staff were very satisfied with these new procedures. LEVEL OF EVIDENCE: III; case-control study.

Reduced wear in vitamin E-infused highly cross-linked polyethylene cups: 5-year results of a randomized controlled trial.

Background and purpose - Vitamin E-infused polyethylene is a relatively new material in joint arthroplasty; there are no long-term reports, and only few mid-term results. Using radiostereometric analysis (RSA), we primarily determined whether vitamin E-infused highly cross-linked polyethylene (HXLPE/VitE) acetabular cups show less wear than ultra-high molecular weight polyethylene (UHMWPE) acetabular cups at 5 years after total hip arthroplasty (THA). We also assessed whether wear rates correlate with increasing cup inclination angles or cup sizes.Patients and methods - This is a 5-year follow-up of our previously reported randomized controlled trial of 62 patients with 3 years' follow-up, who received THA with either an HXLPE/VitE or a UHMWPE acetabular cup. At 5 years, 40 patients were analyzed (22 in the HXLPE/VitE and 18 in the UHMWPE group).Results - HXLPE/VitE cups continued to show less cumulative femoral head penetration than UHMWPE cups (HXLPE/VitE: 0.24 mm, UHMWPE: 0.45 mm; p < 0.001). Distribution of wear was also more even with HXLPE/VitE cups than with UHMWPE cups (p = 0.002). Moreover, the difference in PE wear between 1 and 5 years in both groups showed no statistically significant correlation with increasing cup inclination angles or cup sizes. Finally, no osteolysis and implant loosening occurred, and no revision surgeries were required.Interpretation - Wear rates continue to be lower in HXLPE/VitE cups than in UHMWPE cups at 5 years of follow-up without correlation with increasing cup inclination angles or cup sizes. Finally, HXLPE/VitE cups may have the potential to prevent osteolysis and implant loosening.