tobramycin and Prosthesis-Failure

Loosening of an artificial joint prosthesis is a painful and debilitating condition that can be treated only by re-operation. Re-operations accounted for approximately 15% of all hip replacement operations performed in Denmark between the year 1995 and 2010. The process of loosening is often accompanied by destructive inflammation and osteolysis, which leads to insufficient bone stock that often requires extensive bone grafting. Impacted morselized bone graft is a well-established method for improving the amount and quality of bone stock that ensures sufficient stability and anchorage of the revision implants. Among bone graft options, the autologous bone graft is considered the gold standard. It is naturally biocompatible, but its use in revision surgery is curtailed by its limited volume and by considerable donor site morbidity. Allograft bone is readily available and is the most commonly used graft material. However, it has been shown that the incorporation of allograft bone into the host bone is not always complete, and substantial fibrous tissue formation has been described. A reason for this may be that allograft bone is a foreign tissue, which, contrary to autogenic bone, may induce an immunogenic response that leads to increased fibrous tissue formation. Furthermore, the fresh-frozen allograft has minimal osteoinductive and no osteogenic capacity. The studies in this thesis have investigated ways of improving the incorporation of allograft bone by adding osteoinductive cells from the periosteum and reducing the immunogenic load of the allograft bone by rinsing. Furthermore, the impact of antibiotic protection of the bone graft has been evaluated. The same experimental implant model was used in all three studies. This model enables evaluation of early implant fixation and osseointegration of an uncemented implant surrounded by impacted morselized bone graft. Unloaded gap implants were inserted into the metaphysis of the proximal tibia (Study I) and distal femur (Study II and III) in dogs. The observation period was four weeks and the bone-implant specimens were evaluated by mechanical tests and histomorphometry. Study I compared the fixation of grafted implants where the morselized allograft bone was either rinsed in saline or not. Since the majority of immunogenic factors in allograft bone are present in the blood, the marrow and fat, the objective of this study was to investigate whether rinsing of the allograft bone would lower the immunogenic l

Topics: Administration, Topical; Allografts; Animals; Anti-Bacterial Agents; Antibiotic Prophylaxis; Arthroplasty, Replacement, Hip; Biomechanical Phenomena; Bone Transplantation; Dogs; Hip Prosthesis; Periosteum; Prosthesis Failure; Prosthesis-Related Infections; Reoperation; Tobramycin; Transplantation, Autologous; Transplantation, Homologous

Previous in vitro research on addition of antibiotics to bone cement has found no statistically significant deterioration in mechanical properties. However, no clinical studies have compared the performance of tobramycin-laden bone cement with that of standard bone cement (Simplex P).. 23 patients (25 hips) were randomized to receive an Exeter (Stryker Orthopaedics) femoral stem cemented with either Simplex P (standard) or Simplex T (tobramycin-laden) cement. There were 2 years of follow-up, with scheduled radiostereometric (RSA) examinations.. All stems migrated distally and showed some degree of retroversion. No clinically significant differences in stem subsidence or retroversion were found between the Simplex T and Simplex P cement groups after 2 years. Overall subsidence was less than in previous studies, probably due to a postponed initial post-surgical examination. Rates of subsidence in both cement groups were consistent with those from previous studies of Exeter stems.. Subsidence of the femoral stem after 2 years was similar in the Simplex T (tobramycin-laden) and Simplex P (standard) groups.

Topics: Aged; Aged, 80 and over; Anti-Bacterial Agents; Arthroplasty, Replacement, Hip; Biomechanical Phenomena; Bone Cements; Female; Femur; Follow-Up Studies; Hip Joint; Hip Prosthesis; Humans; Longitudinal Studies; Male; Methylmethacrylate; Middle Aged; Prosthesis Failure; Radiostereometric Analysis; Retrospective Studies; Tobramycin; Treatment Outcome

For patients undergoing 2-stage exchange for the treatment of periprosthetic joint infection (PJI) following total knee arthroplasty, the long-term risk of reinfection and mechanical failure and long-term clinical outcomes are not well known. The purpose of our study was to determine the long-term clinical results of 2-stage exchange for PJI following total knee arthroplasty.. We identified 245 knees that had undergone total knee arthroplasty and were subsequently treated with 2-stage exchange due to infection during the period of 1991 to 2006; the cohort had no prior treatment for PJI. Major, or 4 of 6 minor, Musculoskeletal Infection Society (MSIS) diagnostic criteria were fulfilled by 179 (73%) of the knees. The cumulative incidence of reinfection and of aseptic revision, accounting for the competing risk of death, were calculated. Risk factors for reinfection were evaluated using Cox proportional hazards regression. Knee Society Score (KSS) values were calculated. The mean age at spacer insertion was 68 years; 50% of the patients were female. The mean follow-up was 14 years (range, 2 to 25 years) following reimplantation.. The cumulative incidence of reinfection was 4% at 1 year, 14% at 5 years, 16% at 10 years, and 17% at 15 years. Factors that were predictive of reinfection included a body mass index of ≥30 kg/m (hazard ratio [HR], 3.1; p < 0.01), previous revision surgery (HR, 2.8; p < 0.01), and a McPherson host grade of C (HR, 2.5; p = 0.04). The cumulative incidence of aseptic revision for loosening was 2% at 5 years, 5% at 10 years, and 7% at 15 years. Femoral (HR, 5.0; p = 0.04) and tibial (HR, 6.7; p < 0.01) bone-grafting at reimplantation were predictive of aseptic failure. The most common complications were wound-healing issues, requiring reoperation in 12 (5%) of the knees. The rate of death at 2 years following reimplantation was 11%. The mean KSS improved from 45 at PJI diagnosis to 76 at 10 years following reimplantation (p < 0.01).. Long-term reinfection rates following 2-stage exchange for PJI after total knee arthroplasty were similar to those of shorter-term reports and were maintained out to 15 years. Mechanical failure rates were low if bone loss was addressed at the time of reimplantation. Improvements in clinical outcomes were maintained at long-term follow-up.. Therapeutic Level IV. See Instructions for Authors for a complete description of levels of evidence.

Topics: Adult; Aged; Anti-Bacterial Agents; Arthroplasty, Replacement, Knee; Bone Resorption; Clinical Protocols; Drug Therapy, Combination; Female; Gentamicins; Humans; Knee Prosthesis; Male; Middle Aged; Prosthesis Failure; Prosthesis-Related Infections; Reoperation; Retrospective Studies; Risk Factors; Staphylococcal Infections; Tobramycin; Treatment Outcome; Vancomycin; Young Adult

Topics: Absorbable Implants; Administration, Topical; Aged, 80 and over; Cataract; Cataract Extraction; Dexamethasone; Female; Glucocorticoids; Humans; Lens Implantation, Intraocular; Lens, Crystalline; Lenses, Intraocular; Macular Edema; Phacoemulsification; Prosthesis Failure; Retinal Vein Occlusion; Tobramycin; Tomography, Optical Coherence

Clinical trials have used antibiotic impregnated impacted bone allograft in revisions of infected arthroplasties. By this method high local antibiotic concentration and good control of infection was achieved. Toxicity studies, however, suggest that high local antibiotic concentration can impair osteoblast replication. We therefore asked whether impregnating morselized allograft bone with different quantities of tobramycin before impaction would impair implant fixation. We implanted three cylindrical (10 mm × 6 mm) porous-coated titanium implants into the distal femurs of 12 dogs. The implants were surrounded by a circumferential gap of 2.5 mm into which a standardized volume of morselized allograft bone, with or without tobramycin, was impacted. In each animal, the bone graft was impregnated with either 0 mg (control), 50 mg (low dose), or 200 mg (high dose) of tobramycin per 1 mL of bone graft. At the end of the 4 weeks experimental period, the implants with surrounding bone were evaluated by histomorphometric analysis and mechanical push-out test. We found no difference between the treatment groups regarding new bone formation, bone graft resorption, or implant fixation. There was, however, a tendency toward a decrease in implant fixation with higher tobramycin dose. The present study is unable to provide evidence on whether the use of topical tobramycin with allograft is safe or whether it indeed can impair implant fixation. The tendency toward an impaired implant fixation warrants further preclinical studies. Its current clinical use should be weighed against its possible positive effects on preventing infection in complicated revisions.

Topics: Allografts; Animals; Anti-Bacterial Agents; Biomechanical Phenomena; Bone Transplantation; Delayed-Action Preparations; Dogs; Female; Models, Animal; Osseointegration; Prostheses and Implants; Prosthesis Failure; Prosthesis-Related Infections; Reoperation; Titanium; Tobramycin

A 55-year-old man had uneventful phacoemulsification with implantation of a 3-piece silicone intraocular lens (IOL). Postoperative medications included antibiotic-steroid drops and ointments. Eight months postoperatively, the patient started having recurrent episodes of anterior chamber inflammatory reaction. Suspicion that lens instability was causing the reactions led to a lens repositioning procedure 11 months after the initial surgical implantation and again at 13 months. Eighteen months postoperatively, the IOL had a "greasy" film. Despite antiinflammatory and antibiotic treatment, the clinical outcome did not improve. Twenty-seven months after implantation, the lens was exchanged with a hydrophilic acrylic IOL. The course after the exchange was uneventful. The explanted lens was examined by gross and microscopic evaluations, scanning electron microscopy, energy-dispersive X-ray spectroscopy, and gas chromatography-mass spectrometry (GC-MS) using electronic ionization. Gross and microscopic evaluations confirmed the presence of a thin, oily film covering the IOL optic surface. Surface analyses at the level of the oily substance showed unspecific peaks of sodium, chloride, and potassium. The GC-MS analysis showed the presence of compounds characteristic of hydrocarbons, including docosane, tricosane, and tetracosane, which are commonly found in the vehicle of ophthalmic ointments. The GC-MS analysis of 1 ointment used postoperatively found matching peaks, suggesting deposition of those compounds on the IOL.

Topics: Device Removal; Dexamethasone; Electron Probe Microanalysis; Gas Chromatography-Mass Spectrometry; Humans; Lens Implantation, Intraocular; Lenses, Intraocular; Male; Microscopy, Electron, Scanning; Middle Aged; Ointment Bases; Ointments; Phacoemulsification; Postoperative Complications; Prosthesis Failure; Reoperation; Silicone Elastomers; Tobramycin

We evaluate the rate of osteotomy healing, implant stability, and eradication of infection when an extended trochanteric osteotomy, with interval placement of an antibiotic-impregnated cement spacer and delayed osteotomy fixation, is used to treat the chronically infected total hip arthroplasty. Thirteen cases were followed for a minimum of 2 years. All patients had complete healing of the extended trochanteric osteotomy within 6 months. At an average follow-up of 39 months, recurrent infection occurred in 3 (23%) patients. Femoral component subsidence of 5 mm occurred in 2 patients, both of which had recurrent infection. Extended trochanteric osteotomy with interval placement of an articulating antibiotic-impregnated cement spacer and delayed osteotomy fixation permits reliable healing of the osteotomy.

Topics: Adult; Aged; Aged, 80 and over; Arthroplasty, Replacement, Hip; Bone Cements; Chronic Disease; Debridement; Device Removal; Female; Follow-Up Studies; Humans; Male; Middle Aged; Opportunistic Infections; Osteotomy; Postoperative Complications; Prosthesis Failure; Radiography; Reoperation; Retrospective Studies; Surgical Wound Infection; Tobramycin; Wound Healing

In this report a case of periprosthetic fracture of the femur associated with deep prosthetic infection after a total hip arthroplasty is treated in a novel way that allows for stabilization of the fracture and the delivery of local antibiotics. The technique allows the surgeon to stabilize the fracture and deliver antibiotics locally with a cement-coated Enders nail. This technique is useful in this combination of difficult problems as it facilitates the goals of eradicating infection, alleviating pain and improving function.

Topics: Aged; Anti-Bacterial Agents; Arthroplasty, Replacement, Hip; Bone Cements; Bone Nails; Drug Delivery Systems; Femoral Fractures; Fracture Fixation, Intramedullary; Humans; Male; Prosthesis Failure; Prosthesis-Related Infections; Tobramycin; Treatment Outcome; Vancomycin

Deep infections occur in 1-5% of all patients undergoing total knee arthroplasty, and may result in failure of the prosthesis and subsequent arthrodesis. Two-stage reimplantation is often successful, but depends upon the presence of good soft tissue coverage. We have treated 9 patients in whom chronic infection developed which required removal of the prosthesis, debridement, and implantation of antibiotic impregnated spacers for control. These patients all had poor quality soft tissue cover precluding prosthesis reimplantation. The use of muscle flaps resulted in 7 of the 9 patients having successful reimplantation of a prosthesis and remaining free of infection in a follow-up ranging from 1-5 years.

Topics: Adult; Aged; Bacterial Infections; Female; Humans; Knee Prosthesis; Male; Middle Aged; Muscles; Prostheses and Implants; Prosthesis Failure; Prosthesis-Related Infections; Reoperation; Salvage Therapy; Surgical Flaps; Tobramycin; Vancomycin

The management of an infected total knee implant is a major challenge to the orthopaedic surgeon. This article reviews the use of antibiotic-PMMA spacer block in two-stage reimplanation of septic total knee arthroplasties. In addition to serving as an antibiotic delivery system between the time of component removal and reimplantation, the antibiotic-impregnated spacer block imparts mechanical stability to the joint and decreases the morbidity during the period before reimplantation. This temporary "interposition arthroplasty" facilitates the patient's ambulation and also simplifies dissection at the time of reimplantation. Furthermore, osteoporotic bone at the time of resection becomes firm, good-quality bone by the time of reimplantation.

Topics: Aged; Drug Implants; Female; Gentamicins; Humans; Knee Joint; Knee Prosthesis; Male; Middle Aged; Prosthesis Failure; Reoperation; Staphylococcal Infections; Tobramycin