Worrying Presence of Asymptomatic Bacterial Colonisation on Implanted Orthopedic Devices.

Background Bacterial infection after hardware implantation in orthopedic and trauma surgery is devastating, resulting in increased hospital costs and stays, multiple revision surgeries, and prolonged use of antibiotics. The present study aims to determine whether a symbiotic relationship between the human organism and bacteria in hardware implantation may be present, without clinically evident infection. Materials and methods We studied explanted devices for microbiological analysis, using the sonication technique, from patients who underwent surgical removal of musculoskeletal hardware for mechanical reasons. None of the patients included in the study had clinical or biochemical signs of infection. Results Forty-nine patients were enrolled. Cultures tested positive for bacteria in 42.8% of the 49 patients (21 of 49). In 13 patients, Gram-positive bacteria were isolated, while Gram-negative bacteria were isolated from nine patients. The most frequent bacterial species found was Pseudomonas aeruginosa, with six positive cultures (28.5%). Coagulase-negative staphylococci were isolated from ten implants (47%). Conclusion A pacific coexistence between humans and bacteria is possible following the implantation of metallic devices for trauma or orthopedic ailments. It is still unclear how strong or unstable this equilibrium is.

"Heterotopic ossification after total hip arthroplasty through direct anterior approach without a dedicated orthopaedic table or direct lateral approach: a quasi-randomized single-center study".

INTRODUCTION: Heterotopic ossifications (HO) are common after total hip arthroplasty (THA). The invasiveness of surgical approaches plays a relevant role in HO development. The aims of this study were to assess the development of HO 6 months after THA through direct lateral approach (DLA) or direct anterior approach (DAA) without a dedicated orthopaedic table and to assess the clinical impact of HO. METHODS: This is a single-center IRB-approved, quasi-randomized prospective cohort, observational imaging study. Fifty patients underwent primary THA through DLA and 50 through DAA. Age, sex, BMI and side of the affected hip were collected. At the 6 post-operative month the Harris Hip Score (HHS) and the presence of HO (scored through the Brooker classification system) were assessed. RESULTS: There was no significant difference in the demographic data between groups. Operative time was significantly higher in the DAA group (72 ± 10 min vs. 58 ± 8 min: p < 0.03). At 6 post-operative months the incidence of HO was 14% in the DAA group and 32% in the DLA group (p = 0.02). Severe HO (Brooker 3-4) were significantly more common in the DLA group (p = 0.04). There was no significant difference in the HHS of patients with HO between the DAA and DLA groups. There was no association between poorer clinical outcomes and the severity of HO. CONCLUSION: The DAA without a dedicated orthopaedic table is associated with a significant lower incidence of HO than the DLA 6 months after elective THA. Except for the surgical approach, no other factors correlated with the occurrence of HO. Even though a lower HHS was found with severe HO, the correlation between severity of HO and clinical outcomes did not reach statistical significance.

A Modified Technique for Two-Stage Revision in Knee PJI Treatment.

Knee PJIs represent one of the most important complications after joint replacement surgery. If the prerequisites for implant retention do not subsist, the surgical treatment of these conditions is performed using one-stage and two-stage revision techniques. In this study, an implemented two-stage revision technique was performed, adopting antibiotic calcium sulfate beads and tumor-like debridement guided by methylene blue, such as described for the DAPRI technique. The aim of the present study is to compare the implemented two-stage revision technique with the standard technique in order to assess its effectiveness. METHODS: Twenty patients affected by knee PJIs were prospectively enrolled in the study and underwent an implemented two-stage revision technique (Group A). Data collected and clinical results were compared with a matched control group treated with a standard two-stage technique (Group B). For each patient, the time of the reimplantation and length of antibiotic systemic therapy were recorded. Each patient underwent routine laboratory tests, including inflammatory markers. RESULTS: In Group A and in Group B, inflammatory markers normalized at 6.5 ± 1.1. weeks and 11.1 ± 2.3 weeks, respectively (p < 0.05). Also, the difference in length of antibiotic therapy and time to reimplantation were significantly shorter in Group A (p < 0.05). No recurrence of infection was found in Group A at the last follow-up. DISCUSSION: The implemented two-stage revision technique demonstrated a faster normalization of inflammatory markers, as well as a decrease in reimplantation time and duration of antibiotic therapy, compared to the traditional technique. The use of calcium sulfate antibiotic beads and tumor-like debridement seems to improve the results and reduce the time of healing. CONCLUSION: The implemented two-stage revision technique seems to improve the results and reduce the time of healing. This leads to a more rapid and less stressful course for the patient, as well as a reduction in health care costs.

Do serum markers correlate with invasiveness of the procedure in THA? A prospective randomized study comparing direct anterior and lateral approaches.

BACKGROUND: Advantages of minimally invasive approaches for total hip arthroplasty are still matter of debate. Serum markers have been assessed as objective method to quantify muscle damage after surgery but in literature ambiguous results have been reported. The aim of this prospective randomized study was to: 1) compare serum markers elevation between a minimally invasive direct anterior approach (DAA) and a direct lateral approach (DLA); 2) to establish a correlation between serum markers increase and other perioperative variables. HYPOTHESIS: A lesser elevation of markers could be found in patients who underwent a minimally invasive DAA. PATIENTS AND METHODS: Seventy patients were enrolled and randomly divided in two groups according to the type of the approach. All patients were treated with the same implant by the same surgeon and received the same rehabilitation protocol. Demographic data, preoperative Harris Hip Score (HHS) and operative time were recorded. Myoglobin, creatine kinase MB (CK-MB), troponin I, C-reactive protein (CRP), haemoglobin (HB) and pain levels were measured pre- and postoperatively. RESULTS: Mean postoperative rise were 524.9±134.6 and 667.8±409.5 for myoglobin, 4.8±2.5 and 6.6±3.7 for CK-MB, and 16.9±5.3 and 15.4±6.4 for PCR, in DAA and DLA groups, respectively. In both groups, postoperatively values were significantly higher than preoperatively (p<0.05). Comparing the two groups, no significant differences in serum markers elevations were found. A significantly lower postoperative pain was found in DAA group than in DLA group (2.9 vs. 4.2 and 2.7 vs. 3.6 in second and third day, respectively (p<0.05)). No significant correlation was present between the serum marker elevations and age, BMI, HHS, operative time, HB or pain levels (p>0.05). CONCLUSION: Serum markers of muscle damage and inflammation increased in the postoperative period without significant differences between DAA and DLA, even though overall trend was higher in DLA group. The DAA group had significantly lower levels of postoperative pain. No significant correlation between pain and serum markers levels was found. LEVEL OF EVIDENCE: I; randomized study.

Neurogenic Heterotopic Ossification of the Hip after Brain Injury. Function Recovery Preserving Hip Joint: A Case Report.

Introduction: Up to 30% of patients with spinal cord injury and to 20% of patients with traumatic brain injury develop neurogenic heterotopic ossification (NHO). Patients develop restriction in joint range of motion (ROM) and impairment in activities of daily life. When neurological recovery occurs, joints dysfunction represents the cause for patients' autonomy loss. Case Report: We present the case of a 39-year-old Caucasian male involved in a car accident and experienced 14 days of post-traumatic coma. After rehabilitation, no residual motor or sensory neurological deficit was present, but bilateral NHOs surrounding hip joints developed. Seventeen months after trauma, the patient was admitted to our institute. He was confined to bed, absolutely unable to walk, stand or sit. Radiological evaluation consisted in Antero-Posterior X-ray view only, due to the inability to open up his hips for lateral views, and 3D computed tomography scan. "Functional resection" of the ossifications was performed and rehabilitation started from day 1 after surgery. At the final follow-up 24 months from the second operation high grade of clinical satisfaction was reported. The patients were able to walk independently, to put on his socks, and to drive a car and bike. Painless right and left hip ROM was, respectively, 100° and 90° for flexion, 10° for extension, 35° and 30° for abduction, and near normal internal and external rotation. The patient referred that further improvement in mobility and fluency was still present day by day. Conclusion: The rarity of the condition frequently bring to a delay in treatment and the absence of specific guidelines made treatment still dependent on surgeon experiences. A multidisciplinary approach is essential for success. Surgeons should be aware that it is important to refer patients to specialized center, because early resection could provide excellent results, preserving hip, and restoring function and patient independency.

Detection of α-defensin in synovial fluids by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry as an innovative and cost-effective assay for improved definition of periprosthetic joint infections.

RATIONALE: Detection of α-defensins in synovial fluid is gaining more and more interest in the field of correct diagnosis of periprosthetic joint infections (PJIs). At present, they can be assessed by a quantitative enzyme-linked immunosorbent assay which is expensive and time-consuming and by a qualitative lateral flow immunoassay which is rapid but quite expensive and whose clinical sensitivity is debated. Thus, developing an alternative rapid, accurate, and low-cost assay for α-defensins is important to make α-defensins actionable as novel key clinical markers. METHODS: Synovial fluid (SF) samples were obtained from 18 patients undergoing revision of primary joint arthroplasty. Of these, eight met the 2013 Musculoskeletal Infection Society (MSIS) criteria for PJIs, the remaining were classified as aseptic failure. Microbiological analysis and Synovasure assays were carried out on all samples. Sample preparation and the matrix-assisted laser desorption/ionization time-of-flight (MALDI-TOF) mass spectrometry (MS) settings were adjusted to detect human neutrophil peptide (HNP)-1, -2 and -3 and to obtain optimal results in term of sensitivity and stability. RESULTS: MALDI-TOF MS was able to detect HNPs in SF from septic patients. No signals for HNPs were detected in SF from aseptic failure. The limits of detection (LOD) were 2.5 and 1.25 µg/mL for HNP-2 and HNP-1, respectively. The turnaround time of the analysis is 20 min, and SF samples are stable at -20°C for up to 3 days. Assay sensitivity, specificity, and positive and negative predictive values (PPV and NPV) were 100% for all parameters. On the same SF samples, the Synovasure assay showed lower sensitivity specificity, and PPV and NPV of 87.5%, 90%, 87.5% and 90%, respectively. Microbiological analysis of SF confirmed the presence of bacteria only in SF MSIS-positive patients. CONCLUSIONS: The reported MALDI-TOF MS assay was able to detect and differentiate HNPs in SF samples and showed a slightly better diagnostic accuracy than the Synovasure assay.