Regaining the walking ability is one of the main purposes of total knee arthroplasty (TKA). Improving the activities of daily living is a key of patient satisfaction after TKA. However, some patients do not gain enough improvement of ADL as they preoperatively expected, and thus are not satisfied with the surgery. The purpose of this study is to clarify the relationship between preoperative and postoperative physical functional status and whether preoperative scoring can predict the postoperative walking ability. Consecutive 136 patients who underwent total knee arthroplasty for osteoarthritis were prospectively assessed. The average age (±SD) was 74±7.7 and 74% of the patients was female. Berg Balance Scale (BBS) was assessed preoperatively and one year after the surgery. The time needed for 10m walking, muscle power for knee extension and flexion, visual analog scale (VAS) for pain in walking, and necessity of canes in walking were also assessed at one year after the surgery. Multivariate correlation analysis was performed for each parameter. Speaman rank correlation coefficient revealed that preoperative BBS was significantly correlated with the time needed for 10m walking (ρ=0.66, p<0.001). Logistic regression analysis also revealed that preoperative BBS is also correlated with the necessity for canes in walking one year after the surgery. The cut-off value of preoperative BBS for the necessity of canes in walking by ROC curve analysis was 48 points with 79% in sensitivity and 80% in specificity. The muscle powers were also weakly correlated with the walking ability at one year after the surgery, but VAS for pain was not. The study indicated that preoperative physical balance could predict the ability of walking one year after TKA regardless of the reduction of pain. It is suggested that surgery should be recommended before the physical balance function deteriorates to achieve the better walking ability after the TKA
High tibial osteotomy (HTO) is a useful treatment option for osteoarthritis of the knee. Closing-wedge HTO (CW-HTO) had been mostly performed previously, but the difficulties of surgical procedure when total knee arthroplasty (TKA) conversion is needed are sometimes pointed out because of the severe deformity in proximal tibia. Recently, opening-wedge HTO (OW-HTO) is becoming more popular, but the difference of the two surgical techniques about the influence on proximal tibia deformity and difficulties in TKA conversion are not fully understood. The purpose of this study was to compare the influence of two surgical techniques with CW-HTO and OW-HTO on the tibial bone deformity using computer simulation and to assess the difficulties when TKA conversion should be required in the future. In forty knees with medial osteoarthritis, the 3D bone models were created from the series of 1 mm slices two-dimensional contours using the 3D reconstruction algorithm. The 3-D imaging software (Mimics, materialize NV, Leuven, Belgium) was applied and simulated surgical procedure of each CW-HTO and OW-HTO were performed on the same knee models. In CWHTO, insertion level was set 2cm below the medial joint line [Fig.1]. While in OW-HTO, that was set 3.5cm below the medial joint line and passed obliquely towards the tip of the fibular head [Fig.2]. The correction angle was determined so that the postoperative tibiofemoral angle would be 170 degrees. The distance between the center of resection surface and anatomical axis, and the angle of anatomical axis and mechanical axis were measured in each procedure. Secondly, a simulated TKA conversion was operated on the each tibial bone models after HTO [Fig.3]. The distance between the nearest points of tibial implant and lateral cortical bone was assessed as the index of the bone-implant interference.«Purpose»
«Methods»
Adjusting the joint gap length to be equal in both extension and flexion is an important issue in total knee arthroplasty (TKA). Tight flexion gaps occur sometimes, particularly with the cruciate-retaining (CR) type of TKA, and it impede knee flexion. In posterior stabilizing (PS) TKA, because sacrificing the PCL increases the flexion gap, the issue of gap balancing with PS-TKA is usually focused on decreasing the enlarged flexion gap to be equal to the extension gap. It is generally known that posterior tibial slope would affect the flexion gap, however, the extent to which changes in the tibial slope angle directly affect the flexion gap remains unclear. This study aimed to clarify the influence of tibial slope changes on the flexion gap in CR- or PS-TKA. The flexion gap was measured using a tensor device with the femoral trail component in 20 cases each of CR- and PS-TKA. A wedge plate with a 5° inclination was placed on the tibial cut surface by switching its front–back direction to increase or decrease the tibial slope by 5°. The flexion gap in changing the tibial slope was compared to that of the neutral slope measured with a flat plate that had the same thickness of the wedge plate center.Background
Methods
Controversy still exists as to whether total knee arthroplasty (TKA) provides reproducible knee kinematics during activities. In this study, we evaluated the A total of twenty four knees in nineteen patients following cruciate-retaining (CR) or posterior-stabilized (PS) TKA were randomly included in the study. The twenty-four knees included 22 female knees and 2 male knees in patients aged 73 years. The pre-operative diagnosis was osteoarthritis in 22 knees and rheumatoid arthritis in 2 knees. The average follow-up period after surgery was 29 months, and average post-operative knee extension/flexion angle was 2°/121°. The average knee score was 93 and the average functional score was 77. Continuous sagittal radiological images were obtained during stair-climbing for each patient using a large flat panel detector. Anteroposterior (AP) tibiofemoral position, implant flexion, and axial rotation angles were determined in three dimensions using a 3D-to-2D model-to-image registration technique. In CR TKA, the minimum distances between the femoral trochlea and the intercondylar eminence of the tibial insert were measured using a CAD software program. In PS TKA, the minimum distances between the femoral cam and the posterior aspect of the tibial post and between the femoral trochlea and the anterior aspect of the tibial post were measured.Introduction
Patients and Methods
Using the tibial extramedullary guide needs meticulous attention to accurately align the tray in total knee arthroplasty (TKA). We previously reported the risk for varus tray alignment if the anteroposterior (AP) axis of the ankle was used for the rotational direction of the guide. The purpose of our study was to determine whether aligning the rotational direction of the guide to the AP axis of the proximal tibia reduced the incidence of varus tray alignment when compared to aligning the rotational direction of the guide to the AP axis of the ankle.Introduction
Materials and Methods
Radiographs and computed tomography (CT) images are used for the preoperative planning in total knee arthroplasty (TKA), however, these two-dimensional (2D) measurements are affected easily by limb position and scanning direction relative to three-dimensional (3D) bone model analyses. The purpose of our study was to compare these measurements to evaluate the factors affecting the difference. A total of 75 osteoarthritis knees before primary TKA were assessed. The full-length weight-bearing anteroposterior radiograph and CT slices were used for the 2D measurement. Three-dimensional measurement used 3D bone model reconstructed from the CT data and the coordinate system as the previous reports (Figure 1). We measured FVA (femoral valgus angle), CRA (the angle between the posterior condylar line <PC-L> and the clinical epicondylar axis <CEA>), and SRA (the angle between the PC-L and the surgical epicondylar axis <SEA>). Intra- and inter-observer reliabilities were assessed by intraclass correlation coefficients (ICC), and the differences between the 2D and the 3D measurements (Differences) were evaluated. In addition, we evaluated whether preoperative factors (preoperative extension angle, HKA, BMI and CT scanning direction) affected the differences between the 3D and the 2D measurements. Computer simulation was used to examine the influences of CT scanning direction.Introduction
Patients and Methods
