RESUMO
Cemented total hip arthroplasty was first introduced by Sir John Charnley in 1961 and it has become one of the principal fixation techniques for fixation of an implant. The surgical technique has since been modified and this has resulted in improved longevity and reliability. The clinical success of the cemented technique has varied in literature, and this has been reported as 30~40% failure to 2% failure for 14 years of follow up using the 2nd generation cement technique. Currently, the successful clinical results can be contributed to the better developed design of the femoral stem and the advancement of the 3rd and 4th generation cement fixation techniques. As society gains more elderly people, for the older patients who have osteoporosis, a wide and thin femur would be the best indication for cement fixation in order to achieve early stability and better clinical results. It is imperative to learn and practice performing the exact cement fixation technique to achieve the best clinical results.
Assuntos
Idoso , Humanos , Artroplastia , Fêmur , Seguimentos , Quadril , Longevidade , OsteoporoseRESUMO
Objective To compare the biomechanical properties of mono-segTnent pedicle instru-mentation and its combination with bone cement fixation in treatment of thoracolumbar fractures. Meth-ods Eight fresh specimens of calf spines ( T11 -L3 ) were used for development of incomplete burst frac-ture models at the vertebral body of L1. Mono-segment pedicle instrumentation and its combination with vertebroplasty were respectively applied in each specimen subsequently to restore spinal stability. A cyclic loading with pure moment of 4 Nm was applied to specimens, with load frequency of 0.5 Hz for 2 000 cy-cles. Range of motion (ROM) at flexion/extension, left/right lateral bending and left/right axial rotation of the fixated segment at different status of intact, injury, fixation and cyclic loading was determined by spinal three-dimensional instability test system. Results ROM after treatment with two fixation tech-niques and that at different directions after cyclic loading were distinctly smaller than that of intact and fractured models (P <0.05 ). Under mono-segment pedicle instrumentation combined with bone cement fixation, ROM at flexion, extension, lateral bending and axial rotation was 0.40°, 0. 53°, 0.86° and 0.55° respectively and that after cyclic loading was 0.10°, 0.07°, 0.19° and 0.08°respectively, which were all lower than those of monosegmental fixation, especially at flexion and axial rotation, with statisti-cal difference (P <0.05 ). Conclusions Both fixation techniques can provide instant stabihty of the fractured spine and have good fatigue resistance effect. However, mono-segment pedicle instrumentation is inferior to mono-segment pedicle instrumentation plus bone cement fixation in treatment of fractured verte-bral body at flexion and axial rotation.
RESUMO
PURPOSE: To analyze clinical, radiological results and survival rates of Press Fit Condylar total knee arthroplasty and compare the results of cruciate-retaining versus cruciate-substitution, and cement versus cementless fixation. MATERIALS AND METHODS: We analyzed 364 patients, 520 knees, which had undergone PFC total knee arthroplasty during the period January 1988 to January 1999. Average follow-up period was 7.1 years (3-14 years). Cases were divided into 2 categories: cruciate-retaining (CR) versus substitution (CS) and cement versus cementless fixation. The clinical results were evaluated using the Hospital for Special Surgery knee scoring system and radiological results were obtained by measuring tibiofemoral angle using Bauer's method. Survivorship analysis was performed using Kaplan-Meier method with revision for any reason as the end point. RESULTS: Clinical, radiological results and the survival rate in the cruciate substitution group were slightly better than those of the cruciate retaining group but no statistical difference was found. Survival rate in the cemented group was significantly higher than that in the cementless group. Clinical and radiological results of the cemented group were better but there was no statistical significance between the two groups. CONCLUSION: No differences were found in the postoperative results of the CR and CS groups. Survival rate in the cemented group was superior to that of the cementless group, which was used even in good bone stock and less deformed cases. This results may be related to a design problem of the cementless prosthesis.