1/22. Crushed stents in benign left brachiocephalic vein stenoses.Two hemodialysis patients presenting with left venous arm congestion due to benign catheter-induced stenosis of the left brachiocephalic vein were treated by angioplasty and stent placement. External compression of the stents was responsible for rapid recurrence of the symptoms. No osseous or vascular malformation could be identified. Mechanical constraints induced by respiratory chest wall motion and aortic arch flow-related pulsation are proposed to explain this observation. This potential hazard should be considered when stent placement into the left brachiocephalic vein is advocated.- - - - - - - - - - ranking = 1keywords = motion (Clic here for more details about this article) |
2/22. Two-stage operation for treatment of a large dissecting popliteal cyst after failed total knee arthroplasty.A symptomatic popliteal cyst after total knee arthroplasty (TKA) is rare, occurring most frequently as a result of intra-articular knee pathology. We present a case of a large dissecting popliteal cyst 7 years after TKA with symptoms of severe calf pain and functional disability. The symptomatic cyst was excised completely in a first-stage operation, and the severely worn TKA was corrected by a second-stage surgical procedure. The patient in this report was pain free and had satisfactory range of knee motion 5 years after the index revision TKA, without recurrence of effusion or popliteal cyst formation.- - - - - - - - - - ranking = 1keywords = motion (Clic here for more details about this article) |
3/22. The Ilizarov method for failed knee arthrodesis following septic TKR.knee arthrodesis is a well-recognized salvage procedure in patients with infected total knee arthroplasties. If a fusion is achieved, it offers the opportunity for a stable lower limb and eradication of infection, but at the expense of knee motion. However, knee arthrodesis in this setting may be difficult to achieve because of poor bone stock, persistent infection, soft tissue compromise, and often the poor general health of the patient. We report two cases of failed knee arthrodesis following periprosthetic infection where a fusion was successfully achieved with open debridement and a hybrid advanced Ilizarov fixator.- - - - - - - - - - ranking = 1keywords = motion (Clic here for more details about this article) |
4/22. Posterior femoral impingement causing polyethylene failure in total knee arthroplasty.Several reports in the literature describe dislocation and fractures of the meniscal bearings as a result of polyethylene failure after total knee arthroplasty. In this case of an asymptomatic patient with a clinically uneventful 7-year follow-up, who died a year later of an unrelated cause, we found impressive damage of the polyethylene components. This damage, at the posterior corner of the meniscal bearing elements, was caused by regrowth of the posterior femoral osteophytes. The primary osteophytes had been resected adequately during the arthroplasty. These osteophytes are related to a bone-polyethylene impingement that occurs at >110 degrees of knee flexion. The possible range of motion of an artificial joint, owing to its design, is less than the range of flexion sometimes reached clinically by the patient. This is a problem that should be solved by the industry in the near future.- - - - - - - - - - ranking = 1keywords = motion (Clic here for more details about this article) |
5/22. Successful thrombolysis of st. Jude medical aortic prosthesis with tissue-type plasminogen activator in a pregnant woman: a case report.Mechanical valve thrombosis is a life-threatening event. pregnancy is associated with a hypercoagulable state that further emphasizes the importance of adequate anticoagulation. This is associated with a therapeutic dilemma. Continued anticoagulation with warfarin throughout the first trimester can result in fetopathic effects, while replacement of warfarin by heparin between 6 and 12 weeks of gestation does not completely prevent the risk of valve thrombosis. There are a small number of reported cases of pregnant women with prosthetic heart valve thrombosis under low molecular weight heparin and consecutive lytic therapy. The authors report a 33-year-old pregnant woman with a St. Jude Medical aortic prosthesis, anticoagulated with a therapeutic dosage of low molecular weight heparin from 6 weeks of gestation, who developed prosthetic heart valve thrombosis at 17 weeks of gestation. A thrombolysis with recombinant tissue-type plasminogen activator (50 mg for 2 hours) was performed. Under thrombolysis, ST-segment elevation in leads II, III, aVF, V5, and V6 developed electrocardiographically with a maximal creatine kinase (CK) of 349 U/L (CK-MB isoenzyme of 48 U/L). echocardiography revealed normal function of the St. Jude Medical aortic prosthesis 2 hours after thrombolysis and normal wall motions. Short-course thrombolytic therapy appears to be an effective alternative to surgical intervention for the treatment of thrombotic dysfunction of valve prostheses in pregnancy.- - - - - - - - - - ranking = 1keywords = motion (Clic here for more details about this article) |
6/22. Excessive prosthetic valve motion: a sign of dehiscence.Prosthetic valve malfunction can be suspected frequently and dehiscence suspected occasionally from chest radiography. The wide availability of chest radiography makes recognition of the radiographic findings associated with valvular dehiscence important. This case highlights that partial valve dehiscence can be diagnosed occasionally by chest radiography.- - - - - - - - - - ranking = 4keywords = motion (Clic here for more details about this article) |
7/22. Valve adaptation as a cause of disc opening reduction in mechanical heart valves: the case of the Lillehei-Kaster valve.At fluoroscopy a decreased disc motion in mechanical heart prostheses is often a sign of valve thrombosis. On occasion, however, despite an exhaustive diagnostic work-up, common causes of prosthetic valve thrombosis are not found. In these cases the valve disc abnormalities are thought to be due to functional changes. We here report our experience with 5 consecutive patients carrying the Lillehei-Kaster prosthesis who had this fluoroscopic finding that was lately attributed to "valve physiologic adaptation". The time of onset, differential diagnosis and clinical/hemodynamic impact of valve adaptation are discussed.- - - - - - - - - - ranking = 1keywords = motion (Clic here for more details about this article) |
8/22. Thrombolysis for prosthetic valve malfunction: case report and review.A 40 year old female with severe mitral valve stenosis, underwent mitral valve replacement by single disc valve 4 years ago. She presented at this admission with a new onset of congestive heart failure. The prothrombin time was inadequate with international normalized ratio (INR) 1.43. Transthoracic echocardiography revealed high pressure gradient across the mitral valve. fluoroscopy demonstrated restrictive opening of single disc motion. Intravenous thrombolysis was given for presumptive diagnosis of prosthetic valve thrombosis. The patient gradually improved and did not have to undergo surgical correction.- - - - - - - - - - ranking = 1keywords = motion (Clic here for more details about this article) |
9/22. polyethylene wear and acetabular component orientation.BACKGROUND: polyethylene wear contributes substantially to both periprosthetic osteolysis and aseptic loosening after total hip arthroplasty. Acetabular component orientation has been shown to affect the range of motion of the hip as well as contact stresses. A series of studies was designed to test the hypothesis that acetabular component orientation can affect the magnitude and direction of polyethylene wear. methods: A finite-element model was used to compute contact stresses during a normal gait cycle. Wear at the end of each gait cycle was calculated with use of the sliding-distance-coupled finite-element formulation. The wear that was calculated with use of finite-element analysis was validated by comparison with the findings of hip wear simulator studies with the acetabular liner oriented to simulate 45 degrees and 55 degrees of abduction. In a clinical study, fifty-six patients who underwent sixty hip arthroplasties with use of a single prosthetic design were followed for as long as five years. Radiographs were analyzed to measure the abduction angle of the acetabular component and polyethylene wear. RESULTS: The finite-element analysis predicted increased peak contact stresses with an increased abduction angle and reduced peak contact stresses with an increased anteversion angle. Linear wear rates ranging from 0.036 to 0.045 mm/million cycles were also predicted, and increased acetabular abduction angles were predicted to be associated with higher linear wear rates. In the hip wear simulator studies, significantly different wear rates were found between the cups with acetabular abduction angles of 45 degrees and 55 degrees (mean, 17.2 compared with 21.7 mg/million cycles; p < 0.01). In the clinical study, radiographic analysis revealed significant correlation between the acetabular abduction angle and the linear polyethylene wear rate. A 40% increase in mean linear polyethylene wear was seen in cups with an abduction angle of >or=45 degrees. The direction of wear was more medial (by 9.4 degrees ) in cups with an abduction angle of <45 degrees. CONCLUSION: All three studies presented here underlined the importance of optimizing the position of the acetabular component. Careful attention to acetabular position may help to minimize wear.- - - - - - - - - - ranking = 1keywords = motion (Clic here for more details about this article) |
10/22. Abciximab treatment for obstructive prosthetic aortic and mitral valve thrombosis in the presence of large thrombi, cardiogenic shock, and acute evolving embolic stroke.Obstructive thrombosis of left-sided mechanical prosthetic valves is a life-threatening complication. Intravenous thrombolytic therapy is contraindicated due to risk of clot embolization and surgical treatment is often required for hemodynamically unstable patients. We report for the first time the successful use of abciximab in the management of a patient in cardiogenic shock with multiple prosthetic valve obstructive thrombosis and evolving embolic stroke. Serial Doppler echocardiography and cinefluoroscopy demonstrated resolution of thrombi, improvements in transvalvular gradients and improvement in leaflet motion. This observation suggests abciximab should be considered as a therapeutic option in the treatment of obstructed prosthetic heart valves.- - - - - - - - - - ranking = 1keywords = motion (Clic here for more details about this article) |
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