1/12. Lower intestinal bleeding due to aorto-enteric fistula.The case is described of a man who complained of intermittent fever and fatigue. After three digestive endoscopies and computed tomography, a 99m technetium-HM-PAO-labelled white cell scan was usefully employed to establish diagnosis. Anaerobic aortic Graft infection and anaemia due to lower intermittent occult intestinal bleeding were found. The intestinal bleeding was caused by secondary aorto-jejunal fistula. This condition is rare, but should be suspected whenever a patient with aortic prosthesis presents with occult digestive bleeding and unexplained fever.- - - - - - - - - - ranking = 1keywords = fatigue (Clic here for more details about this article) |
2/12. Fracture of the femoral component of a Brigham unicompartmental knee: a case report.We report the failure of a femoral component in a unicompartmental knee replacement 6 years after implantation. The implant fractured 15 mm from the anterior tip, and scanning electron microscopy confirmed fatigue to be the cause of failure. The clinical and laboratory findings are presented, and the causes and implications of this mode of implant failure are discussed.- - - - - - - - - - ranking = 1keywords = fatigue (Clic here for more details about this article) |
3/12. Late surgical conversion after thoracic endograft failure due to fracture of the longitudinal support wire.PURPOSE: To report complications from a thoracic endograft wire fracture and early experience with elective conversion after thoracic endografting. CASE REPORT: A 43-year-old man underwent urgent endovascular repair of a symptomatic post-traumatic thoracic aneurysm in 1999. The patient had been involved in a car accident 14 years before. He developed clinical and radiological signs of graft infection 46 months after stent-graft implantation. multidetector computed tomography confirmed a fracture of the longitudinal support wire in the Excluder thoracic stent-graft. Additionally, radiological signs of suspected endograft infection were described. Due to concerns over a potential chronic infection, the stent-graft was successfully excised, and a polyester graft was implanted 50 months after primary endovascular repair. CONCLUSIONS: Recognition or strong suspicion of endograft infection requires conversion with removal of the device. Long-term follow-up after endografting is necessary to assess material fatigue that undermines the durability of these implants.- - - - - - - - - - ranking = 1keywords = fatigue (Clic here for more details about this article) |
4/12. Trunion fracture of a fully porous-coated femoral stem. Case report.Femoral component fracture is a documented but an uncommon complication of total hip arthroplasty. A retrospective survey conducted by the American association of hip and knee Surgeons estimated the prevalence of femoral component fractures at 0.27% (172 of 64483 implants over a 5-year period ending in 1993) . There have been several case reports of fatigue fractures of the prosthetic neck distal to the Morse taper in modular implants with a cobalt alloy head and a cobalt alloy stem. Here, we present a case report of stem fracture within the Morse taper of a cobalt alloy stem coupled with a cobalt alloy head.- - - - - - - - - - ranking = 1keywords = fatigue (Clic here for more details about this article) |
5/12. Iatrogenic left atrioventricular fistula after aortic valve re-replacement.Left ventriculoatrial fistula is a very rare cardiac disorder. The case is reported of a male patient who was admitted to the authors' clinic with dyspnea and fatigue. The patient had an atrioventricular fistula between the left atrium and left ventricle, and had undergone aortic valve re-replacement for prosthesis malfunction about one year previously. The fistula was considered to be the result of iatrogenic injury related to valve re-replacement surgery.- - - - - - - - - - ranking = 1keywords = fatigue (Clic here for more details about this article) |
6/12. Fractures of cementless thin-walled cups.Cementless threaded cups are commonly used in total hip arthroplasty. A method to match the elasticity of the cup to that of natural bone is reducing the wall thickness of the implant. Despite good results with this philosophy of implantation, we recently observed 3 cases of implant fractures after the implantation of such thin-walled cups called "Bicon." We performed a thorough analysis of 1 of these cases including a histological examination and a technical failure analysis (including scanning electron microscopy) to establish the chronology and cause of the failure. Multiple fractures of the thin-walled metal-back cup were determined to be caused by fatigue. We have concluded that due to the specific material and design parameters of this cup, under adverse circumstances such as the lack of primary or secondary osteointegration, there is a risk of failure due to fatigue.- - - - - - - - - - ranking = 2keywords = fatigue (Clic here for more details about this article) |
7/12. polyethylene wear debris and long-term clinical failure of the Charite disc prosthesis: a study of 4 patients.STUDY DESIGN: A clinical case series of 4 patients undergoing anterior lumbar revision due to failure of total disc replacement surgery. OBJECTIVES: To assess the clinical significance of polyethylene wear debris in salvage surgery after initial total disc replacement, the pattern and the mechanisms of polyethylene wear in the retrieved cores, and the extent of polyethylene debris in the periprosthetic tissues obtained from 4 patients. SUMMARY OF BACKGROUND DATA: Previous in vitro wear tests have demonstrated low wear rates for lumbar artificial discs, suggesting that implant wear may not be a clinically relevant issue with total disc replacement. However, only long-term clinical investigations with analysis of retrieved implants and periprosthetic tissue can ultimately establish the significance of polyethylene wear debris for total disc arthroplasty. methods: Starting in 2004, we began routinely performing salvage procedures in patients with failed total disc replacements. We report on the short-term outcomes of 4 patients at our institution who were revised with a Charite prosthesis (DePuy spine, Raynham, MA). Wear analysis of the retrieved prosthesis and histologic examination of the periprosthetic tissue were also performed. RESULTS: All of the retrieved polyethylene cores showed evidence of wear, but the extent and severity varied among the 4 patients. Wear and fracture of the core were associated with osteolysis of the underlying sacrum in 1 patient. Histologic examination of the periprosthetic tissues confirmed the presence of wear debris lying in inflammatory fibrous tissue. In 3 of the 4 patients, implant wear was associated with an unfavorable biomechanical environment (e.g., subsidence, migration, undersizing, and adjacent fusion). The mechanisms of wear included adhesive/abrasive wear of the central domed region of the polyethylene core, as well as chronic rim impingement, resulting in rim fatigue and fracture. CONCLUSIONS: This study demonstrates the clinical significance of polyethylene wear debris and the potential for osteolysis with total disc replacements. The authors recommend that patients undergoing lumbar disc arthroplasty receive long-term follow-up to monitor the wear and functional status of their implants.- - - - - - - - - - ranking = 1keywords = fatigue (Clic here for more details about this article) |
8/12. Ingrowth of bone in failed fixation of porous-coated femoral components.In five straight-stemmed, proximally porous-coated femoral components that were retrieved at revision arthroplasty from patients who had radiographic and clinical evidence of loosening, there was growth of bone into the porous coating. The components had been inserted during a primary arthroplasty in one woman and four men. The patients ranged in age from thirty-seven to sixty-seven years. Three patients were heavy, and all five were active. All patients had had an excellent early result from the initial arthroplasty; at the one-year follow-up, the mean Harris hip score had been 91 points. pain in the hip developed in all of the patients, between one and three years after the index procedure. Initial radiographs had revealed excellent position and fixation of the prosthetic components, but the components then subsided between one and three and one-half years after the index procedure. All of the femoral components were found to be grossly loose at the revision operation. Nevertheless, all of the prosthetic components demonstrated growth of bone into 4 to 44 per cent (mean, 24 per cent) of the pore spaces available for ingrowth. Woven bone and fracture callus were found in the curettings from the proximal part of the femur. The findings in these five patients suggest that late failure of uncemented porous-surfaced femoral components can occur despite the presence of extensive ingrowth of bone. These failures may be the result of fatigue fractures of the trabeculae of the osseous ingrowth into the porous surfaces. Caution is warranted in the liberal use of these prosthetic components in heavy, active patients.- - - - - - - - - - ranking = 1keywords = fatigue (Clic here for more details about this article) |
9/12. fatigue failure of the sliding screw in hip fracture fixation: a report of three cases.Hardware failure of the sliding screw system used in hip fracture fixation is rare. The fatigue failure of the sliding screw is always related clinically to nonunion or refracture along the path of the screw. In both situations, cyclic loading of the implant exceeds its endurance limit, and failure can ensue. Three cases of failure of the sliding screw are presented: a nonunion of a basicervical fracture, a nonunion secondary to stress fracture at the plate-barrel junction, and a refracture through the femoral neck after healing of an intertrochanteric fracture. A biomechanical analysis of the stresses on the sliding screw focuses on design features such as the internal threaded region used for the compression screw or the barrel length that creates increased stresses in the screw, thus lowering the number of cycles to failure. Based on this analysis, recommendations are made concerning implant design and surgical technique.- - - - - - - - - - ranking = 1keywords = fatigue (Clic here for more details about this article) |
10/12. Aseptic loosening in total hip arthroplasty secondary to osteolysis induced by wear debris from titanium-alloy modular femoral heads.Since 1984, we have used components made of titanium alloy for total joint arthroplasty. Recently, two patients needed revision hip arthroplasty, approximately three years after the initial procedure, because of aseptic loosening secondary to severe osteolysis that had been induced by metallic debris. Although implants made of titanium alloy have many favorable qualities--most importantly, superb biocompatibility--the alloy is more susceptible to wear by particles of acrylic cement and tends to generate more polyethylene wear than do components made of stainless steel or chromium-cobalt. A new process of implanting ions has reportedly improved resistance to wear as well as fatigue properties and has enhanced the resistance to corrosion of the implants. Although, to our knowledge, only in vitro studies of this process have been reported to date, we recommend avoiding the use of components made of titanium alloy in which ions have not been implanted. We suggest considering the possibility of osteolysis secondary to appreciable metallic debris in patients who have aseptic loosening of titanium-alloy components that were not implanted with ions.- - - - - - - - - - ranking = 1keywords = fatigue (Clic here for more details about this article) |
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