Implantation Of Total Knee Prosthesis Research Articles

Acute arrest of hematopoiesis induced by infection with Staphylococcus epidermidis following total knee arthroplasty: A case report and literature review.

Infection is one of the most severe complications of total knee prosthesis implantation. The present study reported the case of a 74-year-old female that developed a Staphylococcus epidermidis infection following a cemented total knee arthroplasty. A routine blood test revealed neutropenia and anemia, while S. epidermidis was detected in the peripheral blood and bone marrow. In the present case, S. epidermidis infection led to acute arrest of hematopoiesis (AAH), also known as aplastic crisis, which is the temporary cessation of red cell production. The development of AAH secondary to S. epidermidis infection is rare and, to the best of our knowledge, this is the first case reported in the literature. The present study increased our knowledge of this rare disease and its characteristics, which will enable physicians to be aware of the development of AAH as a rare complication of S. epidermidis infection.

Decreased extension gap and valgus alignment after implantation of total knee prosthesis in primary varus knees.

It was hypothesised that implantation of a total knee prosthesis may change the size and shape of the joint gap. To test this hypothesis, a tensor device was used which was specifically designed to reproduce the conditions before and after implantation, including attachment of the polyethylene insert trial. This study aimed to compare the joint gaps before and after implantation of a total knee prosthesis using this new tensor device. A total of 259 primary varus knees were included in this study. Knees were exposed using a medial parapatellar approach, and the anterior and posterior cruciate ligaments were resected. After the trial reduction, the intraoperative joint gap kinematics was measured using the tensor device. Implantation of a total knee prosthesis decreased the size of the extension joint gap and made it valgus, but did not influence the size or shape of the flexion joint gap. The present findings suggest that the classical gap technique, which creates equal and rectangular extension and flexion joint gaps in the bone cutting surface, results in an imbalance between the extension and flexion joint gaps after implantation. To achieve equal and rectangular extension and flexion joint gaps after implantation, the prepared extension joint gap should be about 2mm larger than the flexion joint gap and slightly varus before implantation in primary varus knees. Therapeutic study, Level II.

Intraoperative assessment of midflexion laxity in total knee prosthesis

BackgroundSoft-tissue balancing of the knee is fundamental to the success of a total knee arthroplasty (TKA). In posterior-stabilized TKA, there is no stabilizer of the anterior–posterior translation in the midflexion range in which the cam-post mechanism does not engage yet. Therefore, instability in the midflexion range is suspected to occur in posterior-stabilized TKA. The purpose of this study was to measure the joint gap throughout a full range of motion and to analyze the joint gap laxity in the midflexion range after implantation of a mobile-bearing posterior-stabilized total knee prosthesis. MethodsJoint gap kinematics in 259 knees with varus osteoarthritis were measured during TKAs using a tensor device with the same shape of a total knee prosthesis of the same design was used. After the implantation of a mobile-bearing posterior-stabilized prosthesis and the reduction of the patellofemoral joint, the joint gap was measured at 0°, 30°, 60°, 90°, 120°, and 145° of flexion. ResultsThe center size of the joint gap was tight in extension and deep flexion and loose at midflexion ranges, especially at 30° of flexion (p<0.001). The symmetry of the joint gap was varus at 0° and 145° of flexion (p<0.001). ConclusionsOur results showed the joint gap laxity in the midflexion range after the implantation of a mobile-bearing posterior-stabilized prosthesis. Our new tensor device, which can attach the polyethylene insert trial, will provide the important information about the joint gap kinematics after implantation of total knee prostheses. Level of evidenceIV.

The Construction of Three-Dimensional Finite Element Model of TKA Knee

The goal of this study is to construct a three-dimensional (3D) finite element model (FEM) of total knee arthroplasty (TKA) knee including bones, collateral ligaments and total knee prosthesis. Computed tomography (CT) and magnetic resonance imaging (MRI) image data of normal knee joint are imported into MIMICS software. The 3D models of bones and collateral ligaments are respectively reconstructed from CT and MRI image data. Then the reconstructed models are registered and fused together based on external landmarks. The virtual osteotomy and total knee prosthesis implantation are performed to establish the 3D model of TKA knee. Ultimately, A elaborate 3D FEM of TKA knee including anatomical structures and total knee prosthesis is obtained by meshing the 3D model of TKA knee and setting material properties, loading and boundary conditions. The obtained von Mises stress on the polyethlene insert confirms to the clincial mechanical distribution characteristics after TKA. The 3D FEM of TKA knee retains the integrity and accuracy in the anatomical features and provides a foundation for accurate research on the TKA knee biomechanical behaviors.

Uso de enxerto ósseo autólogo associado à osteossíntese de suporte nas falhas ósseas tibiais marginais em prótese total de joelho

OBJECTIVE: To report the initial results from the use of a new technique for fixation of bone grafts in uncontained tibial bone defects in patients undergoing total knee prosthesis implantation. METHODS: Six patients with severe varus deformity of the knee who, after cuts and ligament balancing had been performed, still presented bone deficiencies that reached the edge of the tibial cut and compromised the implant stability, underwent a new fixation technique. RESULTS: Five of the patients had good clinical results, with integration of the graft within 12 weeks. One patient presented clinical complications with wound dehiscence and implant exposure, which evolved to the need for implant removal and knee arthrodesis. CONCLUSION: Support osteosynthesis as a graft fixation method is a viable option for treating tibial bone deficiencies. The proposed technique certainly needs further studies for its validation.

USE OF AUTOLOGOUS BONE GRAFT ASSOCIATED WITH SUPPORT OSTEOSYNTHESIS FOR TIBIAL EDGE BONE LOSSES IN TOTAL KNEE PROSTHESES

Objective: To report the initial results from the use of a new technique for fixation of bone grafts in uncontained tibial bone defects in patients undergoing total knee prosthesis implantation. Methods: Six patients with severe varus deformity of the knee who, after cuts and ligament balancing had been performed, still presented bone deficiencies that reached the edge of the tibial cut and compromised the implant stability, underwent a new fixation technique. Results: Five of the patients had good-clinical results, with integration of the graft within 12 weeks. One patient presented clinical complications with wound dehiscence and implant exposure, which evolved to the need for implant removal and knee arthrodesis. Conclusion: Support osteosynthesis as a graft fixation method is a viable option for treating tibial bone deficiencies. The proposed technique certainly needs further studies for its validation.

Intraoperative Ibandronate Reduced Prosthesis Migration After Implantation of Total Knee Prosthesis

Intraoperative Ibandronate Reduced Prosthesis Migration After Implantation of Total Knee Prosthesis

Experimental Meniscal Allografts in the Rabbit

Pa‰a L., A. Neaas, I. Piperisova, H. Kecova, P. Vi‰Aa, F. Tich˘: Experimental Meniscal Allografts in the Rabbit. Acta Vet. Brno 2005, 74: 87-95. Meniscal injury belongs to most common consequences of stifle trauma in humans. Its treatment usually consists of partial meniscectomy; this procedure, however, predisposes the knee to progression of gonarthrosis and thus increases morbidity and subsequently raises drug consumption. Progression of pathologic changes often leads to implantation of total knee prosthesis. With development of arthroscopy, the number of salvage procedures of injured menisci increased. This method also reduces progression of arthrotic changes. However, not every meniscal lesion is reparable and not every reinserted meniscus will heal. That is why the number of performed meniscectomies is still high. The purpose of this study was to verify on experimental model if transplantation of fresh and frozen medial meniscal allografts into the stifle joints after total meniscectomy reduces progression of gonarthrosis. Progression of arthrotic changes in stifle joints after total meniscectomy was evaluated in three groups of 8 rabbits: group 1: rabbits after total meniscectomy without meniscal transplantation (control); group 2: meniscectomy followed by transplantation of fresh meniscal allograft; group 3: transplantation of deep frozen (-80 °C) meniscal allograft. The results of surgical procedures were evaluated both clinically and radiographically. The quality of allograph incorporation was evaluated both macroscopically and histologically 4 months after the surgery. Severe osteoarthritis developed in rabbits after total meniscectomy. In both groups after meniscal transplantation, allografts healed with well functional stifles and progression of gonarthrosis was reduced comparing to the group of rabbits after meniscectomy alone. The extent of arthrotic changes was smaller after transplantation of frozen allografts than after transplantation of fresh allografts. Histology of stifles with fresh meniscal transplants showed more pronounced perivascular inflammatory infiltration in site of transplant insertion to the joint capsule than in the frozen allografts. Promising results of this study need to be verified in clinical cases. Medial meniscus, allograft, osteoarthritis, stifle joint, knee, rabbit

Paper #185 Computer assisted total knee prosthesis implantation with a non image based system. a prospective, comparative, multicenter study about 821 cases

Paper #185 Computer assisted total knee prosthesis implantation with a non image based system. a prospective, comparative, multicenter study about 821 cases

Total Knee Prosthesis Implantation With a Non-Image-Based Navigation System

Summary A navigation system should improve the quality of a total knee prosthesis implantation in comparison to that obtained with the classic, surgeon-controlled operative technique. The authors implanted 100 total knee prostheses with an infrared navigation system (Orthopilot, Aesculap, Tuttlingen, Germany). The quality of implantation was studied on postoperative long leg coronal and lateral x-rays, and compared with a control group of 100 matched-paired patients operated on with a total knee prostheses implanted using a classic, surgeon-controlled technique. An optimal mechanical femorotibial angle (177–183°) was obtained in 93 cases in the study group and 75 cases in the control group (P <0.05). Similar differences were seen for the coronal and sagittal orientations of both tibial and femoral components. Globally, 67 cases in the study group and 31 cases in the control group were implanted in an optimal manner for all studied criteria (P <0.001). The used navigation system allows significant improvement in the quality of implantation of a total knee prosthesis in comparison to that obtained with classic, surgeon-controlled instrumentation, and long-term outcome might consequently be improved.

Interindividual reproducibility in perioperative rotational alignment of femoral components in knee prosthetic surgery using the transepicondylar axis.

Femoral component malalignment is one of the main causes of persisting anterior knee pain after knee replacement. This study examined interindividual reproducibility in perioperative definition of the transepicondylar axis (TEA) as a reference for measuring the rotational alignment of the femoral component. Eight surgeons experienced in knee prosthetic surgery marked on Thiel-embalmed cadaver specimens the reference points that they would normally use to define the TEA during knee replacement. These were digitized by a video system, and all the spots defined by the surgeon were translated into a reference picture, allowing a digital analysis of the distances between all the spots marked. The maximal distance between the spots that the participants had marked as relevant for the TEA was 13.8 mm at the lateral and 22.3 mm at the medial epicondyle. Projecting all spots marked into one picture resulted in an area of 116 mm2 on the lateral and 102 mm2 on the medial epicondyle. The median range of the fault between two different participants was 6.4 mm on the lateral side (range 13.2 mm) and 9.7 mm on the medial (range 21.6 mm). Because the rotational alignment of the femoral component is extremely relevant for successful implantation of total knee prosthesis, the interindividual discrepancy in defining the TEA as reference is rather high. As this reference line is commonly used, the perioperative variance and the resulting rotational discrepancy of the femoral component must be considered.

Computer-assisted implantation of total knee prostheses: a case-control comparative study with classical instrumentation.

A navigation system should improve the quality of a total knee prosthesis implantation in comparison to that obtained with the classical, surgeon-controlled operative technique. The authors implanted 30 total knee prostheses with an infrared navigation system (Orthopilot, Aesculap, Tuttlingen, Germany). The quality of implantation was studied on postoperative long-leg coronal and lateral X-rays, and compared to a control group of 30 matched-paired total knee prostheses of the same type (Search prosthesis, Aesculap, Tuttlingen, Germany) implanted with a classical, surgeon-controlled technique. An optimal mechanical femorotibial angle (177 to 183 degrees) was obtained in 25 cases in the study group and 21 cases in the control group (p > 0.05). Similar differences were seen for the coronal and sagittal orientations of both tibial and femoral components. Globally, 23 cases in the study group and 8 cases in the control group were implanted in an optimal manner for all studied criteria (p < 0.001). The navigation system used allows a significant improvement in the quality of implantation of a total knee prosthesis in comparison to that obtained with a classical, surgeon-controlled instrumentation, and long-term outcome could consequently be improved.

Computer-assisted implantation of total knee prostheses: A case–control comparative study with classical instrumentation

Computer-assisted implantation of total knee prostheses: A case–control comparative study with classical instrumentation

Computer-Assisted Implantation of Total Knee Prostheses: A Case-Control Comparative Study with Classical Instrumentation

A navigation system should improve the quality of a total knee prosthesis implantation in comparison to that obtained with the classical, surgeon-controlled operative technique. The authors implanted 30 total knee prostheses with an infrared navigation system (Orthopilot®, Aesculap, Tuttlingen, Germany). The quality of implantation was studied on postoperative long-leg coronal and lateral X-rays, and compared to a control group of 30 matched-paired total knee prostheses of the same type (Search® prosthesis, Aesculap, Tuttlingen, Germany) implanted with a classical, surgeon-controlled technique. An optimal mechanical femorotibial angle (177 to 183°) was obtained in 25 cases in the study group and 21 cases in the control group (p > 0.05). Similar differences were seen for the coronal and sagittal orientations of both tibial and femoral components. Globally, 23 cases in the study group and 8 cases in the control group were implanted in an optimal manner for all studied criteria (p < 0.001). The navigation system used allows a significant improvement in the quality of implantation of a total knee prosthesis in comparison to that obtained with a classical, surgeon-controlled instrumentation, and long-term outcome could consequently be improved.

Computerised OrthoPilot system in arthroprosthesis surgery of the knee

The OrthoPilot computerised system assists surgeons in the implantation of total knee prostheses. The technique uses a computer to acquire, in the operating room, data on the anatomical axis of the lower limb where the prosthesis is to be implanted. This is accomplished by infrared transmission diodes which relate information on the size of the femur and on the deepest point of the tibial wear and tear. The software processes the data and provides the surgeon with indications for regulating the incision guides, perpendicular to the mechanical axis, for correcting axial deformities, and for correcting the slope of the prosthetic components. In addition, it gives the size of the femoral component, the height of the tibial incision, the femoral extrarotation and a constant control of the varus-valgus correction and of the pro- and recurvatum of the limb, in both extending and flexing movements.