Can the Leukocyte Esterase Strip Test Predict Persistence of Periprosthetic Joint Infection at Second-Stage Reimplantation?

BACKGROUND

We evaluated the reliability of intraoperative assessment of leukocyte esterase (LE) in synovial fluid samples from patients undergoing reimplantation following implant removal and spacer insertion for periprosthetic joint infection (PJI). Our hypothesis was that a positive intraoperative LE test would be a better predictor of persistent infection than either serum C-reactive protein (CRP) or erythrocyte sedimentation rate (ESR) or the combination of serum CRP and ESR.

METHODS

The records of 76 patients who received a 2-stage exchange for PJI were retrospectively reviewed. Synovial fluid was collected for LE measurement during surgery before arthrotomy in 79 procedures. Receiver operating characteristic curves were generated. Sensitivity, specificity, positive predictive value, negative predictive value, accuracy, and area under the curve (AUC) of LE, CRP, ESR, and CRP + ESR were calculated.

RESULTS

Sensitivity, specificity, positive predictive value, and negative predictive value of the LE assay were 82%, 99%, 90%, and 97%, respectively. Receiver operating characteristic analysis revealed an LE threshold of 1.5 between the first (negative) and the second (positive) level of the ordinal variable, so that a grade starting from 1+ was accurate for a diagnosis of persistent infection (AUC 0.9044). The best thresholds for the CRP and the ESR assay were 8.25 mg/L (82% sensitivity, 84% specificity, AUC 0.8416) and 45 mm/h (55% sensitivity, 87% specificity, AUC 0.7493), respectively.

CONCLUSION

The LE strip test proved a reliable tool to diagnose persistence of infection and outperformed the serum CRP and ESR assays. The strip test provides a valuable intraoperative diagnostic during second-stage revision for PJI.

The role of suction drainage in the management of peri-operative bleeding in Total and Unicomcompartmental knee arthroplasty: a retrospective comparative study

Background

Suction drainage is commonly applied after total knee arthroplasty (TKA) and unicompartmental knee arthroplasty (UKA) to reduce hematoma, swelling and to favor surgical wound healing. However, its efficacy remains controversial; thus, the purpose of this study is to evaluate drainage efficiency in the management of postoperative bleeding in TKA and UKA.

Methods

The cohort comprised 134 clinical records of patients affected by knee osteoarthritis (OA) who underwent either TKA or UKA. All the patients were subdivided into 2 groups: the first one with drainage and the second one without drainage (respectively 61 and 73 patients). For each group, hemoglobin levels in the preoperative, first, second and third postoperative day were collected. Postoperative complications such as swelling, bleeding from the surgical wound or the need for blood transfusion, were also recorded.

Results

Our results did not show any significant difference of hemoglobin levels in the first (p = 0.715), second (p = 0.203) and third post-operative day (p = 0.467) between the two groups. Moreover, no significant correlation between knee swelling or transfusion rate and the drainage was observed (p = 0.703 and p = 0.662 respectively). Besides, a significant correlation was found between bleeding from the surgical wound and the absence of drainage (p = 0.006).

Conclusions

The study demonstrates how the routine use of suction drainage does not provide substantial benefits in the postoperative blood loss management after TKA or UKA.

Trial registration

ClinicalTrials.gov NCT04508101, 09/08/2020, Retrospectively registered

Level of evidence

III

Knee Pathology before and after SARS-CoV-2 Pandemic: An Analysis of 1139 Patients

BACKGROUND

The SARS-CoV-2 pandemic drastically changed daily life activities and medical practice, leading to a reorganization of healthcare activities. People spent two months in home-isolation, changing their daily habits and undertaking a more sedentary lifestyle. Change in lifestyle is related to important consequences in knee pathologies. The aim of this study was to evaluate the outpatient activity for knee pathologies before and after lockdown in terms of incidence, severity, diagnosis, and treatment.

METHODS

Medical records of patients with knee pathology in outpatient follow-up at IRCCS Istituto Ortopedico Galeazzi in Milan (Italy) were analyzed in the time frame 4 May-4 September 2020 and compared with patients examined between 4 May and 4 September 2019.

RESULTS

A significant increase of knee diagnoses associated to patellofemoral disorders in 2020 was found (p = 0.004). In addition, physiotherapy was significantly more prescribed in 2020 than in 2019 (p = 0.012).

CONCLUSIONS

The SARS-CoV-2 pandemic lockdown did not drastically change knee pathology, but it may have had an impact on it, highlighting a summary worsening of patellofemoral disorders associated with other knee diagnoses. Further studies are required to validate this result.

Is the newest fibrin sealant an effective strategy to reduce blood loss after total knee arthroplasty? A randomized controlled study

An RCT was conducted to ascertain whether, compared to control management, topical application of a novel fibrin sealant (Evicel, J&J) in patients undergoing primary TKA reduces peri-operative blood loss. Sixty-two patients were randomized to receive topical application of Evicel (N = 31) or not (N = 31). The mean total blood loss was 1.9L(± 0.7) in the control group and 1.8L(± 0.5) in the treatment group (P = 0.4). The transfusion rate was 32.3% in the control group and 25.8% in the treatment group (P = 0.5). The transfusion rate decreased linearly with increasing preoperative Hb levels in the treatment group (P = 0.005). The results of this study suggest that topical application of this novel fibrin sealant doesn't reduce perioperative blood loss and the need for allogeneic blood transfusion.

Value of digital telethermography for the diagnosis of septic knee prosthesis: a prospective cohort study

Background

Diagnosis of peri-prosthetic infection remains challenging, often requiring a combination of different tests.

Methods

In this prospective, case–control study, the diagnostic accuracy of telethermography was evaluated in a group of seventy patients who had had a total knee replacement and were undergoing a reoperation because of infection or another implant-related problem, after a minimum of one year from implant.

Results

An average differential temperature of the affected versus not affected knee of 1.9°C was observed in infected prosthesis, compared to 0.3°C in aseptic failures. Considering a normal reference value equal or less than 1.0°C, telethermography showed an accuracy, sensitivity, specificity, positive and negative predictive value of, respectively: 0.90, 0.89, 0.91, 0.91, 0.88.

Conclusions

Digital telethermography is a reliable option for diagnosing peri-prosthetic knee infection.

Comfrey extract ointment in comparison to diclofenac gel in the treatment of acute unilateral ankle sprains (distortions)

OBJECTIVES

A previously published study comparing the efficacy of comfrey extract to a commercial diclofenac (CAS 78213-16-8) preparation in the treatment of unilateral ankle sprains is critically re-evaluated. The study was designed to show non-inferiority of the comfrey extract. The data were re-evaluated for superiority according to CPMP guidelines. The study was an observer-blind, randomised, multi-centre clinical trial with two independent treatment groups "comfrey extract" and "diclofenac gel" (parallel group design) and included a total of 164 patients (82 in the comfrey group and 82 in the diclofenac group, intention-to-treat (ITT) analysis). Key variables were the area under the curve (AUC) from Visits 1 to 2 of the difference of the tenderness values contra-lateral minus injured side (primary variable), pain assessment (Visual Analogue Scale, VAS) at rest and on movement by patient, swelling (figure-of-eight method) and ankle movement (neutral zero method). On average (mean difference comfrey extract minus diclofenac), the AUC was +61.1 h x N/cm2 greater for patients treated with comfrey extract compared to diclofenac treated patients (95% confidence interval: 19.08; 103.09 h x N/cm2). The difference between the two treatment groups was statistically significant (analysis of variance with factors "study drug", "centre", and "drug x centre interaction"). Safety was excellent in both treatment groups. The re-evaluation of the data showed superiority of the plant based ointment over the diclofenac gel in the treatment of distortions. It is encouraging and impressive to realize that a natural product seems to be an effective and safe alternative to the standard topical treatment with diclofenac.