Healing of surgical site after total hip and knee replacements show similar telethermographic patterns

BACKGROUND: Isolated reports indicate the efficacy of infrared thermography for monitoring wound healing and septic complications, but no long-term analysis has ever been performed on this, and there are no data on the telethermographic patterns of surgical site healing after uncomplicated total hip prosthesis and after knee prosthesis. MATERIALS AND METHODS: In this prospective, observational, nonrandomized cohort study, two groups with forty consecutive patients each, who were operated on respectively for total hip and for total knee replacements, underwent telethermographic examination of the operated and contralateral joints prior to and at fixed intervals for up to 1\ua0year after uncomplicated surgery. A digital, portable telethermocamera and dedicated software were used for data acquisition and processing. RESULTS: No thermographic difference was observed preoperatively between the affected side and the contralateral side in both groups. After the intervention, a steep increase in the temperature of the operated joint was recorded after total hip replacement and after knee replacement, with a peak mean differential temperature measured three days postoperatively between the operated and unoperated joint of 3.1\ua0\ub1\ua00.8\ub0C after total hip replacement, and 3.4\ua0\ub1\ua00.7\ub0C after total knee replacement. Thereafter, the mean differential temperature declined slowly to 0.7\ua0\ub1\ua01.1\ub0C and to 0.5\ua0\ub1\ua01.3\ub0C at 60\ua0days, and to 0.0\ua0\ub1\ua01.0\ub0C and -0.1\ua0\ub1\ua01.1\ub0C 90\ua0days post-operatively, respectively. No further changes were observed for up to 1\ua0year after surgery. Results were similar when comparing the average telethermographic values of an elliptical area where the main axis corresponded to the surgical wound. CONCLUSIONS: The surgical sites after uncomplicated total hip or total knee replacement show similar telethermographic patterns for up to 1\ua0year from surgery, and can easily be monitored using a portable, digital, telethermocamera

Reimplantation after Periprosthetic Joint Infection: The Role of Microbiology

Periprosthetic joint infection (PJI) is among the most feared orthopedic complications. Critical questions are whether the infection is completely resolved before reimplantation and what the clinical significance of positive culture is at reimplantation. The aim of this study was to determine whether a correlation exits between culture results at reimplantation after spacer insertion for hip and knee PJI and treatment failure rate. The data of 84 patients who underwent two-stage exchange arthroplasty for hip or knee PJI were reviewed and the results of intraoperative culture at reimplantation were analyzed quantitatively and qualitatively. Correlations were sought between these patterns and treatment outcome. Our data indicate no evidence for a correlation between positive culture at reimplantation and greater risk of treatment failure. Nonetheless, we noted a higher, albeit statistically not significant rate of treatment failure in patients with at least two samples testing positive. The role of microbiology at reimplantation remains unclear, but a positive culture might signal increased risk for subsequent implant failure. Further studies are needed to elucidate the implications of this finding

Evaluation of Synovial Calprotectin by Using a Lateral Flow Test for the Diagnosis of Prosthetic Joint Infections

The analysis of synovial fluid is a crucial step in the diagnosis of prosthetic joint infections (PJIs). Recently several studies illustrated the efficacy of synovial calprotectin in supporting the diagnosis of PJI. In this study, synovial calprotectin was analyzed by a commercial stool test to explore whether it might accurately predict PJIs. The synovial fluids of 55 patients were analyzed and calprotectin levels were compared to other synovial biomarkers of PJI. Of the 55 synovial flu-ids, 12 patients were diagnosed with PJI and 43 with an aseptic failure of the implant. Specificity, sensitivity, and AUC of calprotectin resulted in 0.944, 0.80, and 0.852 (95%CI: 0.971–1.00), respectively, with a set threshold of 529.5 µg/g. Calprotectin had a statistically relevant correlation with the synovial leucocyte counts (rs = 0.69, p p < 0.001). From this analysis, it can be concluded that synovial calprotectin is a valuable biomarker that correlates with other established indicators of local infection, and the use of a commercial lateral flow stool test could be a cost-effective strategy delivering rapid and reliable results and supporting the diagnostic process of PJI

Cost-benefit analysis of antibiofilm microbiological techniques for peri-prosthetic joint infection diagnosis

Abstract Background Implant-related infections, including those of peri-prosthetic joint (PJIs), osteosynthesis and other biomaterials, are biofilm-related. Pathogen identification is considered the diagnostic benchmark; however, the presence of bacterial biofilms makes pathogen detection with traditional microbiological techniques only partially effective. To improve microbiological diagnostic accuracy, some biofilm debonding techniques have been recently proposed. Aim of this health economics assessment study was to evaluate their economic impact on hospital costs. Methods Direct and indirect hospital costs connected with the routine introduction of sonication and dithiothreitol treatment applied to hip and knee PJIs and of tissue cultures were examined. In particular the consequences of diagnostic inaccuracy, the opportunities, costs, and risks of each technique were calculated. Results Considering an average of five samples per patient, processed separately with traditional tissue culture with or without sonication of prosthetic components, or pooled together using the MicroDTTect device (a close system for sample collection, transport and treatment with Dithiothreitol for microbial release from biofilm), the overall mean direct cost per patient was € 397 and € 393 for sonication or MicroDTTect, respectively, compared to € 308 for traditional tissue cultures. In terms of opportunity costs, MicroDTTect was the most effective technique, allowing for a 35% or 55% reduction in time required for sample treatment, compared to tissue cultures combined or not with sonication, respectively. Pooling together direct and indirect costs associated with false positive and negative results of the different diagnostic techniques, unnecessary medical treatments and possible medical claims, MicroDTTect or sonication become increasingly cost-effective when the extra-costs, generated by diagnostic inaccuracy of traditional tissue culture, took place, respectively, in 2% or 20% or more of the patients. Conclusions This is the first study specifically focused on the economic impact of the routine clinical use of microbiological antibiofilm sampling and processing techniques in orthopaedics. Although our results may suffer from a potential country and hospital bias, as the data collection process for direct and indirect costs is specific to each institution and country, this analysis highlights the potential economic advantage to hospitals associated with the routine introduction of antibiofilm techniques for microbiological diagnosis of PJI

The combined evaluation of fibrinogen and D-dimer levels are a helpful tool to exclude periprosthetic knee infection

: This retrospective study was undertaken to (i) define the most appropriate thresholds for serum d-dimer and fibrinogen for differentiating aseptic failure from periprosthetic joint infection&nbsp;(PJI) and (ii) evaluate the predictive value of our d-dimer and fibrinogen threshold compared to previously proposed thresholds. This observational cohort study included consecutive patients who had undergone total knee arthroplasty (TKA) revision between January 2019 and December 2020. International Consensus Meeting diagnostic criteria were used to identify patients affected by the prosthetic infection. Receiver operating characteristic curve analyses assessed the predictive value of the parameters, and the areas under the curves were evaluated. We included 125 patients with a median age of 69 years (53-82) affected by painful TKA. Fifty-seven patients (47%) had PJI. Patients with PJI had higher median d-dimer, fibrinogen, ESR, and CRP when compared to patients believed to be free of PJI. The best threshold values for d-dimer and fibrinogen were 1063 ng/ml (sensitivity 0.72, specificity 0.74) and 420 mg/dl (sensitivity 0.67 and specificity 0.82), respectively. A d-dimer level &gt;1063 ng/ml combined with a fibrinogen level &gt;420 mg/dl had a sensitivity of 0.52, and a specificity of 0.90. We found that an increased d-dimer beyond 1063 ng/ml showed a better predictive value than the previously proposed threshold. The combined determination of d-dimer and fibrinogen displayed high specificity and should be considered an excellent tool to rule out an infection. The accuracy of the proposed cutoffs is more effective than previously reported

Two-stage revision surgery with preformed spacers and cementless implants for septic hip arthritis: a prospective, non-randomized cohort study

<p>Abstract</p> <p>Background</p> <p>Outcome data on two-stage revision surgery for deep infection after septic hip arthritis are limited and inconsistent. This study presents the medium-term results of a new, standardized two-stage arthroplasty with preformed hip spacers and cementless implants in a consecutive series of adult patients with septic arthritis of the hip treated according to a same protocol.</p> <p>Methods</p> <p>Nineteen patients (20 hips) were enrolled in this prospective, non-randomized cohort study between 2000 and 2008. The first stage comprised femoral head resection, debridement, and insertion of a preformed, commercially available, antibiotic-loaded cement hip spacer. After eradication of infection, a cementless total hip arthroplasty was implanted in the second stage. Patients were assessed for infection recurrence, pain (visual analog scale [VAS]) and hip joint function (Harris Hip score).</p> <p>Results</p> <p>The mean time between first diagnosis of infection and revision surgery was 5.8 ± 9.0 months; the average duration of follow up was 56.6 (range, 24 - 104) months; all 20 hips were successfully converted to prosthesis an average 22 ± 5.1 weeks after spacer implantation. Reinfection after total hip joint replacement occurred in 1 patient. The mean VAS pain score improved from 48 (range, 35 - 84) pre-operatively to 18 (range, 0 - 38) prior to spacer removal and to 8 (range, 0 - 15) at the last follow-up assessment after prosthesis implantation. The average Harris Hip score improved from 27.5 before surgery to 61.8 between the two stages to 92.3 at the final follow-up assessment.</p> <p>Conclusions</p> <p>Satisfactory outcomes can be obtained with two-stage revision hip arthroplasty using preformed spacers and cementless implants for prosthetic hip joint infections of various etiologies.</p