Aseptic looseningis is one of the most frequent long-term complications after joint replacement, which limits the service lire of prosthesis. A lot of studies have been focused on macrophage, osteoblast, osteoclast and fibroblast in interface membranes around prostheses recently. Aseptic loosening of orthopedic implants used in joint replacement results from bone loss that occurs through the resorptive activity of inflammatory cells activated by the presence of wear particles. Apoptosis has been observed in the periprosthetic site and it has been interpreted as a sign of resolution of inflammation suggesting that apoptosis-related events are indeed associated with periprosthetic osteolysis,targeting the Apoptosis pathway may lead to novel therapeutic approaches for the treatment of aseptic prosthesis loosening. In this thesis,the relationship between wear debris-induced apoptosis and aseptic loosening of prostheses are expounded in detail.
Apoptosis ; Humans ; Joint Prosthesis ; adverse effects ; Osteolysis ; Prosthesis Failure ; etiology

Adult ; Angina Pectoris ; etiology ; Aortic Valve Insufficiency ; complications ; Bradycardia ; etiology ; Female ; Heart Valve Prosthesis ; Humans ; Prosthesis Failure

An evaluation of the acetabular cartilage was performed grossly and histologically in a patient who had a bipolar hemiarthroploasty, which had served satisfactorily for 2 years until the femoral prosthetic head had been separated from the acetabular assembly due to creep deformation of the inner bearing polyethylene cup. This study indicates that the double-bearing bipolar prosthesis dose not necessarily have an advantage over the classical single-piece prosthesis in the prevention of acetabular cartilage wear.
Acetabulum/abnormalities* ; Cartilage, Articular/abnormalities* ; Hip Joint/abnormalities ; Hip Prosthesis* ; Human ; Male ; Middle Age ; Postoperative Complications/etiology* ; Prosthesis Failure

Acute Coronary Syndrome ; etiology ; Aortic Valve Insufficiency ; Female ; Heart Valve Prosthesis ; adverse effects ; Humans ; Middle Aged ; Prosthesis Failure

Drug-Eluting Stents ; adverse effects ; Humans ; Male ; Middle Aged ; Prosthesis Failure ; Thrombosis ; etiology

The Bjork-Shiley Monostrut valve is tilting disc mechanical valve prosthesis. This study was designed to present the long-term outcome of our experience. One hundred and thirty-seven Bjork-Shiley Monostrut valves were implanted in 101 consecutive patients from November 1983 to February 1990. There were 60 male and 41 female with mean age of 34.5 yr at the time of operation. Fifty-nine patients underwent single valve replacement, 38 had double valve, and 4 had triple valve replacement. There were six in-hospital deaths (5.9%): three from cardiopulmonary bypass weaning failure and one each from septic shock, sudden cardiac arrest, and uncontrollable bleeding. Mean duration of follow-up was 181.2+/-76.2 months. Overall survival was 86.2% at 15 yr and 83.1% at 20 yr. Patients with mitral valve replacement had 93.5% and 90.2% cumulative survival at 10 and 15 yr, respectively, while patients with aortic valve replacement had 91.1% and 86.5% cumulative survival at 10 and 15 yr. Two groups had no significant difference in survival. Double valve replacement patients had 92.2% and 84.0% survival at 10 and 15 yr, respectively. There were no significant differences in survival between the single and double valve replacement groups. Freedom from thromboembolism was noted in: 97.8%, 97.8%, 96.4% and 87.8% at 5, 10, 15 and 20 yr, respectively. Absence of endocarditis was noted in 98.6% and 94.8% at 15 and 20 yr. Absence of reoperation was 92.5% at 20 yr. In conclusion, the Bjork-Shiley Monostrut valve is reliable, with a similar incidence of valve-related morbidity as in other mechanical valves.
Adolescent ; Adult ; Anticoagulants/adverse effects ; Child ; Endocarditis/etiology ; Female ; *Heart Valve Prosthesis/adverse effects ; Humans ; Male ; Middle Aged ; Prosthesis Failure ; Survival Rate ; Thromboembolism/etiology

BACKGROUND: The aim of this study was to evaluate causes of unstable total knee arthroplasty and results of revision surgery. METHODS: We retrospectively reviewed 24 knees that underwent a revision arthroplasty for unstable total knee arthroplasty. The average follow-up period was 33.8 months. We classified the instability and analyzed the treatment results according to its cause. Stress radiographs, postoperative component position, and joint level were measured. Clinical outcomes were assessed using the Hospital for Special Surgery (HSS) score and range of motion. RESULTS: Causes of instability included coronal instability with posteromedial polyethylene wear and lateral laxity in 13 knees, coronal instability with posteromedial polyethylene wear in 6 knees and coronal and sagittal instability in 3 knees including post breakage in 1 knee, global instability in 1 knee and flexion instability in 1 knee. Mean preoperative/postoperative varus and valgus angles were 5.8degrees/3.2degrees (p = 0.713) and 22.5degrees/5.6degrees (p = 0.032). Mean postoperative alpha, beta, gamma, delta angle were 5.34degrees, 89.65degrees, 2.74degrees, 6.77degrees. Mean changes of joint levels were from 14.1 mm to 13.6 mm from fibular head (p = 0.82). The mean HSS score improved from 53.4 to 89.2 (p = 0.04). The average range of motion was changed from 123degrees to 122degrees (p = 0.82). CONCLUSIONS: Revision total knee arthroplasty with or without a more constrained prosthesis will be a definite solution for an unstable total knee arthroplasty. The solution according to cause is very important and seems to be helpful to avoid unnecessary over-constrained implant selection in revision surgery for total knee instability.
Aged ; Aged, 80 and over ; Arthroplasty, Replacement, Knee/*adverse effects ; Female ; Humans ; Joint Instability/*etiology ; Knee Joint/*surgery ; Knee Prosthesis ; Male ; Middle Aged ; *Prosthesis Failure ; Reoperation ; Retrospective Studies

OBJECTIVESTo measure the linear polyethylene wear with use of a computer-assisted two-dimensional method, and to evaluate the relationship between wear and long-term clinic-radiological findings.

METHODSBetween December 1991 and December 1995, the senior author performed 40 primary total hip arthroplasties with use of H/G porous-coated acetabular component. Radiographs of 40 H/G cementless total hip arthroplasties were examined for osteolysis, radiolucent line, cup migration and so on. To measure the linear polyethylene wear, migration in the femoral head center relative to the cup shell center was calculated on digitized consecutive radiographs with special computer software program.

RESULTSThe minimum follow-up was 10 years. Total linear wear was 2-8 mm, the mean rate of linear polyethylene wear was (0.32+/-0.31) mm/year. Twelve acetabular components (30%) were revised at an average follow-up point of 12 years. Three types of polyethylene liner failure were identified: wear-through of the polyethylene liner with resultant metallosis (5 hips), excessive wear necessitating revision (5 hips), and polyethylene liner dissociation without gross evidence of wear (2 hips).

CONCLUSIONSHigh wear rates and femoral and acetabular osteolysis have been and still are the main problems in uncemented total hip replacement. There is clear relationship between wear and acetabular osteolysis or loosening of the prostheses. The poor long-term results with these uncemented total hip arthroplasties illustrate the necessity of regular radiographic evaluation in order to detect osteolysis and liner failure, which are both generally asymptomatic until catastrophic failure appears.

Adult ; Aged ; Arthroplasty, Replacement, Hip ; methods ; Follow-Up Studies ; Hip Prosthesis ; Humans ; Middle Aged ; Osteolysis ; etiology ; Polyethylene ; Postoperative Complications ; Prosthesis Failure ; Retrospective Studies

No abstract available.
Aged ; Device Removal ; Humans ; *Intraoperative Complications ; *Lens Implantation, Intraocular ; *Lenses, Intraocular ; Male ; *Phacoemulsification ; Prosthesis Failure/*etiology ; Reoperation

Humans ; Hyperplasia ; etiology ; Male ; Middle Aged ; Prosthesis Failure ; Stents ; Tomography, Optical Coherence ; adverse effects ; Tunica Intima ; pathology