A 3D-Printed Model of a Titanium Custom-Made Talus for the Treatment of a Chronic Infection of the Ankle.

Osteoarticular infections are challenging and difficult to treat. The use of innovative technologies like 3D printing already employed in other types of surgeries and pathologies can suppose a great asset to tackle the problem and improve functional results. We present a case of an osteoarticular infection of an ankle treated with a custom-made titanium talus made with 3D metal printing technology: A 63-year-old patient, with chronic infection of the ankle. A 2-staged surgery was performed, with a hand-made cement spacer used during the first stage and the implantation of a custom-made titanium talus with an arthrodesis nail in the second stage. After a 2-year follow-up, a good clinical evolution was achieved, with no signs of reactivation of the infection, no pain, good skin condition and optimal functionality: functional gait pattern without pain and any external aids.

Higher accuracy of genotypic identification compared to phenotyping in the diagnosis of coagulase-negative staphylococcus infection in orthopedic surgery.

PURPOSE: To determine whether Repetitive Extragenic Palindromic PCR (rep-PCR) genotyping can improve the diagnosis of coagulase-negative staphylococcal (CoNS) orthopaedic infections in comparison to phenotyping. METHODS: Prospective study comparing the results of phenotypic/genotypic (rep-PCR) testing in patients with suspected CoNS infection. Each strain was analysed using both methods. Strains identified as identical in ≥2 samples were considered as pathogenic. RESULTS: 255 CoNS strains from 52 surgical episodes were included. Infection was diagnosed by phenotyping in 38(73%) cases and by genotyping in 40(77%). The Kappa index was 0.59. Sensitivity, Specificity, Positive Predictive Value (PPV) and Negative Predictive Value (NPV) for phenotyping (vs. rep-PCR) were: 88%, 75%, 92%, and 64%. 5/14(36%) of cases not considered as true infections by phenotyping were diagnosed as infections with genotyping. In a subgroup of 203 strains from 41 surgical procedures with orthopaedic implants, the kappa index was 0.68. Sensitivity, Specificity, PPV, and NPV for phenotyping were: 93%, 73%, 90% and 80%. Again, 2/10 episodes in which CoNS were considered non-infective by phenotyping were diagnosed as infected by genotyping. CONCLUSIONS: Rep-PCR genotyping can identify identical CoNS strains that differ in their phenotype and should be used as a complementary technique. One-third of infected cases may be misdiagnosed without genotypic analysis.

Relationship between skin and urine colonization and surgical site infection in the proximal femur fracture: a prospective study.

PURPOSE: Antibiotic prophylaxis is routinely used in the surgical management of proximal femur fractures. The role of bacterial colonization of the skin and urine in the development of deep surgical site infections (SSI) is yet to be elucidated. This study aimed to evaluate the role of previous skin and urine colonization in the development of deep SSI after a proximal femoral fracture surgery. METHODS: We conducted a prospective observational study in 326 patients > 64 years old, who were scheduled to surgery. Cultures from skin samples of the surgical site and from urine were performed prior to the procedure, and cefazoline was administered as prophylaxis. RESULTS: Skin microbiota was isolated in 233 (71.5%) cases; 8 (2.5%) samples were positive for other bacteria, and 85 (26%) were negative. Of 236 urine samples, 168 were negative or contaminated (71.2%), and 68 (28.8%) were positive, being 58/236 for Enterobacterales (24.6%). Acute deep SSI were diagnosed in nine out of 326 patients (2.7%), and two (22%) were infected by Gram-negative bacilli. Of the 9 cases, normal skin microbiota was isolated in 7 (78%), and the remaining two were negative. Seven cases had negative or contaminated urine cultures, and the one with E. coli did not correlate with SSI bacteria. CONCLUSION: In our elderly hip fracture population, most patients harbored normal skin microbiota, and Enterobacterales urine cultures were positive in one-quarter of cases. There was no relationship between skin colonization, urine culture, and deep SSI. We therefore do not believe that our patients would benefit from modifying the current antibiotic prophylaxis.

Subcutaneous Radiographic Measurement: A Marker to Evaluate Surgical Site Infection Risk in Elderly Hip Fracture Patients.

Objectives: Obesity is a documented comorbidity that is prevalent in the elderly population and a known predictor for surgical site infection (SSI). Body mass index is a convenient method to classify obesity, but it fails to account for fat distribution. The objective of our study was to evaluate the association between surgical site infection and a subcutaneous radiographic measurement (SRM) in elderly hip fracture patients. Materials and Methods: A retrospective case-control study was conducted to compare SRMs at the hip in patients diagnosed with surgical site infection after hip fracture surgery with patients that were not diagnosed with surgical site infection. Each case was matched to two controls. An SRM was defined as the distance from the tip of the greater trochanter to the skin following a perpendicular line to the femoral diaphysis in anteroposterior hip radiographs. Clinical diagnosis of acute surgical site infection was based on Tsukayama criteria. Results: Patients with an SRM greater than 6.27cm had a 7-fold increase in the odds of surgical site infection (OR=7.42, 95% Confidence Interval (CI)=3.01-18.28, p<0.001) compared to those with smaller measurements. The odds ratio (OR) for infection of patients with an ASA score of 3 was 15.82(95% CI=5.11-48.9, p-value<0.001) A statistically significant difference between cases and controls was also found when SRM at the hip was analyzed as a continuous variable. Patients with an infection had a 2.24cm (95% CI=1.59 - 2.90; p<0.001) greater mean SRM. Conclusion: Results of our study suggest an association between the SRM at the hip and the risk of SSI in elderly patients with surgically treated hip fractures. SRM may be a helpful tool for evaluating the risk of SSI in elderly hip fracture patients.

Periprosthetic joint infection by Propionibacterium acnes: Clinical differences between monomicrobial versus polymicrobial infection.

OBJECTIVE: To compare a series of monomicrobial Propionibacterium acnes (P. acnes) knee and hip periprosthetic joint infection (PJI) cases with cases of polymicrobial PJI which included P. acnes. We hypothesized that the presence of a polymicrobial P. acnes infection would lead to worse outcomes than those in cases of monomicrobial P. acnes PJI. METHODS: Retrospective multicentre study. All patients with hip or knee PJIs including P. acnes diagnosed from August-2002 to July-2013 in two university hospitals were included. We collected demographic data, McPherson classification, local signs of infection (swelling or wound drainage), laboratory and histological data, surgical management, antibiotic treatment and outcomes. Data were compared between two groups: cases of monomicrobial P. acnes PJI, and cases of polymicrobial PJI involving P. acnes. RESULTS: Thirty-eight patients who presented with 38 PJIs were included; median age was 71 (IQR:62.5-79); 21 were men (55%); median follow-up was 42 months (IQR:17.5-58). Local signs of infection were present in 14 patients (36.8%); ESR>30 mm/h in 14 patients (36.8%); CRP>1 mg/dl in 15 patients (39.5%); 11 out of 25 patients (44%) had positive preoperative cultures from joint aspiration. Positive histologic studies (Feldman's criteria) were found in 5 out of 28 patients (17.8%). Twenty-four patients (63%) had monomicrobial PJIs; 14 patients (37%) had polymicrobial PJIs. There were no significant outcome differences between monomicrobial and polymicrobial PJIs cases; overall, the success rates were 79.2% and 85.7% respectively (P > 0.05). CONCLUSIONS: We did not find any significant differences between monomicrobial and polymicrobial P. acnes PJI outcomes. ESR, CRP and histologic study are established parameters for diagnosing PJI which did not prove useful in P. acnes PJI.