Does implant coating with antibacterial-loaded hydrogel reduce bacterial colonization and biofilm formation in vitro?

BACKGROUND: Implant-related infections represent one of the most severe complications in orthopaedics. A fast-resorbable, antibacterial-loaded hydrogel may reduce or prevent bacterial colonization and biofilm formation of implanted biomaterials. QUESTIONS/PURPOSES: We asked: (1) Is a fast-resorbable hydrogel able to deliver antibacterial compounds in vitro? (2) Can a hydrogel (alone or antibacterial-loaded) coating on implants reduce bacterial colonization? And (3) is intraoperative coating feasible and resistant to press-fit implant insertion? METHODS: We tested the ability of Disposable Antibacterial Coating (DAC) hydrogel (Novagenit Srl, Mezzolombardo, Italy) to deliver antibacterial agents using spectrophotometry and a microbiologic assay. Antibacterial and antibiofilm activity were determined by broth microdilution and a crystal violet assay, respectively. Coating resistance to press-fit insertion was tested in rabbit tibias and human femurs. RESULTS: Complete release of all tested antibacterial compounds was observed in less than 96 hours. Bactericidal and antibiofilm effect of DAC hydrogel in combination with various antibacterials was shown in vitro. Approximately 80% of the hydrogel coating was retrieved on the implant after press-fit insertion. CONCLUSIONS: Implant coating with an antibacterial-loaded hydrogel reduces bacterial colonization and biofilm formation in vitro. CLINICAL RELEVANCE: A fast-resorbable, antibacterial-loaded hydrogel coating may help prevent implant-related infections in orthopaedics. However, further validation in animal models and properly controlled human studies is required.

Primary haematogenous septic arthritis of the wrist in immunocompetent healthy patients: a report of four cases.

Primary haematogenous nontraumatic arthritis of the wrist is uncommon. We report four such cases. All had a spontaneous onset with a delay in diagnosis. Treatment consisted of an open debridement and systemic antibiotics. Outcome appeared to be related to the delay between onset and treatment.

Postradiation soft tissue sarcoma of the shoulder: a case report.

We present a case of a postradiation soft tissue sarcoma of the shoulder in a patient with a hemiarthroplasty of the shoulder. Initially the patient was treated for an infection of the hemiarthroplasty but subsequent removal of the loose prosthesis and biopsy revealed the presence of a malignant tumour.

Neuropathic arthropathy of the shoulder and elbow associated with syringomyelia: a report of 3 cases.

We report three cases of neuropathic arthropathy secondary to syringomyelia. In two cases both the shoulder and elbow were involved. In the third case only involvement of the elbow was observed.

Septic arthritis after arthroscopic anterior cruciate ligament reconstruction: a retrospective analysis of incidence, management and outcome.

BACKGROUND: Septic arthritis after arthroscopic anterior cruciate ligament reconstruction is a rare complication. In the literature, several different managements are proposed. HYPOTHESIS: The graft can be retained during treatment of a septic arthritis after anterior cruciate ligament reconstruction. STUDY DESIGN: Case series; Level of evidence, 4. METHODS: A retrospective analysis of knee joint infections occurring after arthroscopically assisted anterior cruciate ligament reconstructions was conducted. Fifteen patients were treated for postoperative septic arthritis of the knee after anterior cruciate ligament reconstruction between 1996 and 2005. All patients underwent an urgent extensive arthroscopic debridement (wash-out and synovectomy) and parenteral antibiotics and oral antibiotics subsequently. Repetitive wash-outs were performed if necessary. The average time at follow-up for our series was 58 months (range, 9-99 months). RESULTS: Only 1 graft was removed during debridement because it was nonfunctional. All other patients retained their anterior cruciate ligament reconstruction. There was no reinfection. There were 2 traumatic reruptures. We evaluated 11 patients: in 6 patients the Lachman test showed a translation of more than 3 mm, but all patients had a firm endpoint and there was no subjective instability. Early signs of radiological degeneration were seen in 3 patients. The value for the Lysholm knee scoring scale was 83, on average, ranging from 57 to 100. Regarding the International Knee Documentation Committee score, 2 patients had a final evaluation of normal, 7 patients nearly normal, and 2 patients abnormal. CONCLUSION: The graft can be retained during treatment of septic arthritis after anterior cruciate ligament reconstruction.

Antimicrobial susceptibility of coagulase-negative staphylococci on tissue allografts and isolates from orthopedic patients.

Allograft infection occurs at a rate not different from that of similar procedures with large allografts or sterilized prosthetic devices and is usually caused by coagulase-negative staphylococci (CNS). CNS are feared for their limited antimicrobial susceptibility. We aimed at investigating this risk. CNS were isolated from 260 of 1461 allograft tissue grafts and compared with 384 consecutive clinical isolates from a general orthopedic population (258 patients). The CNS were identified and examined for their susceptibility to nine antibiotics used in routine practice. Staphylococcus epidermidis was the most commonly identified (35%) and the most resistant species of the allograft isolates. Comparing the overall antibiotic susceptibility patterns, clinical pathogens were significantly more resistant to six of the nine antibiotics (p < 0.01), namely penicillin, oxacillin, erythromycin, clindamycin, ofloxacin, and gentamicin. In conclusion, massive allograft infection is a well-known life-threatening surgical risk. However, we did demonstrate that allograft-related in contrast to orthopedic clinics-related CNS, are susceptible to commonly used first and second line antibiotics.

Resection arthroplasty of the infected shoulder: a salvage procedure for the elderly patient.

Infection of the shoulder joint is a challenging problem for the orthopaedic surgeon. Several treatment options have been proposed. Here, we evaluate the results achieved following resection arthroplasty of the shoulder in seven patients. We performed resection arthroplasty in seven cases to treat a chronic uncontrollable infection of the shoulder. Three patients had an infected shoulder arthroplasty, one had an infected non-united arthrodesis, one was treated for an infected osteosynthesis, one had an infected rotator cuff repair and one patient had a septic arthritis of the shoulder joint. All patients were reviewed after a mean of 252 days. The functional outcome was evaluated using the Constant and DASH score. C-Reactive Protein levels were determined to evaluate the presence of residual infection. Except for one doubtful result, all our patients remained free of infection and there was excellent pain relief after the resection. Nevertheless, the functional outcome was poor: the mean Constant score was 25.7 and the mean DASH score was 69.3. Resection arthroplasty of the shoulder is a valuable treatment option for infection of the shoulder, especially in older patients with a poor mental and physical condition who suffer intolerable pain.

Management of a large post-traumatic skin and bone defect using an Ilizarov frame.

The authors report the case of a 28-year old male who presented with a compound diaphyseal fracture of the tibia, which was treated with intramedullary nailing. Postoperatively he required an extensive fasciotomy for an acute compartment syndrome. The fracture evolved towards post-traumatic osteomyelitis, growing methicillin-resistant Staphylococcus aureus (MRSA), combined with a large overlying soft tissue gap. An Ilizarov frame was used to treat both the bone and the skin defect. The infected fracture was treated by resection and longitudinal bone transport. Meanwhile, the skin was gradually closed using extra rods on the frame, allowing for a transverse 'skin transport'. Both the bone and the soft tissues healed without further complications.

The value of (18)FDG-PET for the detection of infected hip prosthesis.

We compared the accuracy of fluorine-18 labelled 2-fluoro-2-deoxy- d-glucose positron emission tomography ((18)FDG PET) with that of technetium-99m hexamethylpropylene amine oxime leucocyte scintigraphy (LS) in the detection of infected hip prosthesis. Seventeen patients with a hip prosthesis suspected for infection were prospectively included and underwent (99m)Tc-methylene diphosphonate bone scintigraphy (BS), LS and an (18)FDG-PET scan within a 2-week period. Seven volunteers with ten asymptomatic hip prostheses were used as a control group and underwent BS and an (18)FDG-PET scan. Bacteriology of samples obtained by surgery or by needle aspiration and/or clinical follow-up for up to 6 months were used as the gold standard. Planar images of BS and LS (4 and 24 h p.i.) were acquired, followed by single-photon emission tomography (SPET) LS images (after 4 h). These images were scored as positive or negative by two experienced readers. The (18)FDG-PET scans of the patients were compared with the tracer distribution pattern in the asymptomatic control group and with BS. A phantom study was performed in order to identify artefacts. For this purpose, three different attenuation correction methods were tested. The combined analysis of the planar BS and LS resulted in a 75% sensitivity and a 78% specificity. The SPET LS images showed a better lesion contrast, resulting in an 88% sensitivity and a 100% specificity, while 24-h planar images were of no additional value. The analysis of PET images alone resulted in an 88% sensitivity and a 78% specificity. The combination of (18)FDG-PET and BS images resulted in an 88% sensitivity and a 67% specificity. Given the presence of small errors near the edge of the metal, which can induce significant artefacts in the corrected emission image, we decided to use the data without attenuation correction. In this preliminary study, (18)FDG-PET scans alone showed the same sensitivity as combined BS and LS, although the specificity was slightly lower.