SEARCH · Search PubMed
Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.
Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.
Problems are encountered in using standard prostheses in developing countries, especially when the prostheses need repair and the amputees cannot come back to the workshop. Very simple, low cost and durable prostheses can solve this problem. The solution described has worked well with villagers in some rural areas of Thailand, where the inexpensive prosthesis permits walking bare-foot and through water and mud.
The accuracy of implantation is an accepted prognostic factor for the long-term survival of unicompartmental knee prostheses (UKP). We developed a non-image-guided navigation system for UKP implantation without any extramedullary or intramedullary guiding device. The 30 patients operated on with the navigation system (group A) were matched to 30 patients operated on with the conventional technique (group B) using age, sex, body mass index, preoperative coronal mechanical femorotibial angle, and severity of the preoperative degenerative changes. All patients had a complete radiological examination in the first 3 months after the index procedure, with anteroposterior and lateral plain knee radiographs and anteroposterior and lateral long leg radiographs. Coronal femorotibial mechanical angle and both coronal and sagittal orientations of the femoral and tibial components were measured. There were no significant differences in the mean numerical values of all measured angles except for the sagittal orientation of the tibial component, with a significant excessive posterior tibial slope in group B. There was a significant increase in the rate of prostheses implanted in the desired angular range for all criteria except the coronal mechanical femorotibial angle in group A. An optimal implantation with all optimal items was obtained by 18 cases in group A and 6 cases in group B. Navigated implantation of a UKP with the used, non-image-based system improved the accuracy of the radiological implantation without any significant inconvenience and with little change in the conventional operative technique. The only inconvenience was a 20-min longer operative time. This improvement could be related to a longer survival of such implanted prostheses.
AIM: With this prospective study we analysed the occurrence of a heparin-induced thrombocytopenia type II (hit type II) using unfractioned heparin (UFH) or low-molecular-weight heparin (LMWH) as postoperative thrombosis prophylaxis after primary total hip or knee replacements. Furthermore the postoperative course of the platelet count with UFH and LMWH was investigated. MATERIAL AND METHODS: In a prospective study we looked at the platelet count of 504 primary endoprothesis patients until the 9. postoperative day. 252 patients got UFH (3-mal 5000 IE Liquemin), 252 patients got LMWH (Clexane 40 opd) as thrombosis prophylaxis. RESULTS: 5 patients of the UFH-group developed a HIT type II (incidence 2%; 95%-confidence interval 0.7-4.5) after 9.8 (7-16) days. Within the LMWH-group we saw just one case (incidence 0.4%; 95%-confidence interval 0-2.1). The drop of the platelet count was on average 64% (40.9-81.6). Within the 498 patients without a HIT type II just 2 patients had a drop of the platelet count between the 5. and 9. postoperative day of more than 15% referring to the preoperative value (24% and 33%). CONCLUSION: The incidence of a HIT type II after the use LMWH seems to be lesser than after the use of UFH. The postoperative platelet count shows a typical course after a total joint replacement. With deviations of that a HIT type II must be excluded.
The goal of blood management in orthopedic and trauma surgery is to minimize exposure to allogenic blood transfusion in elective surgical procedures. Pre-, intra- and postoperative techniques are available. In a retrospective study at our department we could show, that postoperative reinfusion in primary knee arthroplasty is an effective way to avoid allogenic blood transfusion. We evaluated two groups of totally 40 patients. Group I (20 patients) underwent collection of postoperative drainage blood and reinfusion (blood conservation system, CBC II ConstaVac, Stryker instruments), group II (20 patients) was treated without postoperative reinfusion. Group II required per patient 1.3 units of allogenic blood (totally 26 units), group I needed only 0.25 units of allogenic blood per patient (totally 5 units) by using the same guidelines for transfusion in both groups. There were similar preoperative and postoperativ hemoglobin and hematocrit levels in both groups. We recommend the use of postoperative reinfusion in addition with other blood saving techniques to reduce allogenic blood transfusion in primary knee arthroplasty.
Explore the source record for details and available documents.
We have assessed the bone cuts achieved at surgery as compared to the planned cuts produced during computer assisted surgery (CAS) using a CT-free navigation system. In addition, two groups of matched patients were compared to assess the post-operative mechanical alignment achieved. Fourteen patients received a LCS total knee replacement (TKR) using the Vector Vision module and 14 received a TKR using a conventional method of extramedullary alignment jigs. The deviation in each plane (valgus-varus, flexion-extension and proximal-distal) was calculated. For the tibia the mean deviation in coronal plane was 0.21 degrees of varus (SD=1.37) and in the sagittal plane was 1.29 degrees of flexion (SD=3.73) and 0.24 mm of resection distal to the anticipated cut (SD=2.14). For the femur the mean deviation in the coronal plane was 0.88 degrees (SD=2.2) of valgus and in the sagittal plane the mean deviation was 0.3 degrees (SD=2.91) of extension. In the transverse plane there was a mean deviation of 0.07 degrees (SD=1.57) of external rotation. There was a mean deviation of 2.33 mm of proximal resection (SD=2.9) and 1.05 mm of anterior shift (SD=2.81). On comparing the two groups, no statistically significant differences were found for the angles between the femoral component and the femoral mechanical axis, the tibial component and the tibial mechanical axis, the femoral and tibial mechanical axis and the femoral and tibial anatomical axis. This study has presented preliminary data regarding the efficacy of a particular navigation system with regards to improving upon the accuracy of component position with the long-term aspiration of improving upon TKR longevity. A further randomised controlled trial with greater numbers of cases and controls would improve upon our knowledge as to the efficacy of the Vector Vision system and a power analysis based upon the findings of this pilot study has suggested that at least thirty subjects be included in each group.
Explore the source record for details and available documents.
Prosthetic assemblies for lower limb amputees are highly engineered and consist of several components each with its own failure mechanism. This paper describes the dynamic testing of HDPE rotational moulded sockets in a specially designed machine which mimics normal gait. Thus the components are subjected to all main loadings occurring during a stride such as axial loading and A-P bending about the knee and ankle. Machine details as well as the other components of the system are described. SACH feet appear to be vulnerable by rapid wear and structural component failures at less than 100,000 cycles were observed. The sockets are much less vulnerable and stand up to simulated loading of 1350 N for approximately 400,000 cycles. Metal components such as the foot bolt may also fail in fatigue if not properly tightened. References to proposed ISO standards are also included.
INTRODUCTION: Correct alignment of the leg is one of the significant factors for the outcome after TKA. Previous studies have shown that the use of a navigation system can improve the alignment. However, for the positioning of the femoral component no validated data are available. This article presents the first results of a controlled, prospective and randomised trial comparing navigation versus free-hand implantation in TKA with special reference to the rotation of the femoral component. METHODS: Since January 2003, all patients with primary arthrosis of the knee admitted to our hospital for TKA have been followed prospectively. For this first analysis, data were collected over a period of 5 months. Apart from the usual clinical evaluations, all patients had CT of the leg prior to the operation and 1 week postoperatively. Measurement of axis and rotation was performed by staff members of the X-ray department who had no knowledge of the operation technique (navigation vs. free-hand). RESULTS: Twenty five sets of CT scans have been analysed, from 12 navigated operations and 13 freehand procedures. All 12 of the navigated knees were within the interval of +/-3 degrees varus/valgus deviation, but only 8 of the 13 non-navigated knees met this criteria. The analysis of the rotation position of the femoral component revealed no difference between the two groups. CONCLUSION: By using an intraoperative navigation system, the accuracy of the alignment in TKA can be improved. Long-term studies will have to be carried out to verify whether this will lead to a lasting benefit for the patient. Concerning the rotation position of the femoral implant, no conclusion can be made regarding the recommended rotation position at this point of the study.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
The conventional total contact suction AK prosthesis presents several disadvantages, such as difficulty in wearing the socket in a sitting position, difficulty in obtaining a favourable disposition of the stump soft tissues in the socket and difficulty in avoiding stump perspiration problems. In an attempt to solve these disadvantages, a new AK prosthesis with a thermoplastic double socket was developed at the Tokyo Metropolitan Rehabilitation Center for the Physically and Mentally Handicapped. The double socket is composed of an external socket attached to the lower parts and a detachable internal socket, and appears to solve all the disadvantages of the conventional prosthesis. This prosthesis is called the TC prosthesis, and abbreviation for the Tokyo Metropolitan Rehabilitation Center. The first model of this prosthesis, (TC-1) has a metal valve. A new rubber sheet valve was developed to solve several disadvantages of the metal valve in the TC-2 prosthesis. Since November 1978 the TC-1 has been fitted to 295 AK amputees, including 9 bilateral AK amputees, and since March 1980, 145 AK amputees have received the TC-2, including 6 bilateral amputees. Satisfactory results have been obtained with both prostheses.
Explore the source record for details and available documents.