To investigate the tibiofemoral rotational profiles during surgery in navigated posterior-stabilized (PS) total knee arthroplasty (TKA) and investigated the effect on postoperative maximum flexion angles. At first, twenty-five consecutive subjects (24 women and 1 man; age: mean, 77 years; range, 58–85 years) with varus osteoarthritis treated with navigated PS TKA (Triathlon, Stryker, Mahwah, NJ) were enrolled in this study. Kinematic parameters, including the tibiofemoral rotational angles from maximum extension to maximum flexion, were recorded thrice before and after PCL resections, and after implantation. The effect of PCL resection and component implantation on tibiofemoral rotational kinematics was statistically evaluated. Then, the effect of tibiofemoral rotational alignment changes on the postoperative maximum angles were retrospectively examined with 96 subjects (84 women, 12 men; average age, 76 years; age range, 56–88 years) who underwent primary TKA.Purpose
Materials and Methods
It is generally accepted that the cement mantle surrounding the femoral component of a cemented total hip arthroplasty (THA) should be complete without any defects, and of at least 2 mm in thickness. Radiographic evaluation is the basis for assessment of the cement mantle. The adequacy of radiographic interpretation is subject to debate. Poor interobserver and intraobserver reproducibility of radiographic cement mantle assessment has been reported. In this study, 3D template software was used that allow anatomical measurements and analysis of three-dimensional digital femura geometry based on CT scans. The purpose of this study is to analyze the three-dimensional cement mantle thickness of cemented hip stem. 52 hips that underwent THA with Exeter stem (Stryker Orthopaedics, Mahwah, NJ) were enrolled in this study. All surgeries were performed by a single surgeon. There were 49 hips in 49 women and 3 hips in 3 men. The average age at surgery was 73 years (range, 60–88 years). The etiology of the hip lesions were osteoarthrosis in 49, rheumatoid arthritis in 3, and osteonecrosis of the femoral head in 1. For preoperative and postoperative evaluation, a CT scan of the pelvis and knee joint was obtained and was transferred to 3D template software (Zed hip, Lexi, Tokyo, Japan). We evaluated the alignment for stem anteversion/valgus/anterior tilt angles and the contact of the cortical bone with the cement mantle was evaluated.Purpose
Materials and Methods
Increased long-term survival of TKA is becoming more important. Several studies have confirmed that optimal positioning and alignment of prosthetic components is crucial for the best long-term results. Therefore, the purpose of the current study was to compare the postoperative alignment and sizing of femoral prosthesis among patients performed by 3 different navigation systems. Twenty patients who underwent primary TKA (E. motion; B. Braun Aesculap, Tuttlingen, Germany) using a CT-free navigation system (OrthoPilot v 4.2) by modified gap technique were enrolled in this study. The results of this study group were retrospectively compared with those in a control group of 20 matched-paired posterior stabilized TKAs (Triathlon;Stryker; Mahwah, NJ, USA) which were using another CT-free navigation system (Stryker Navigation System) by measured technique and 20 matched-paired posterior stabilized TKAs (Press-fit Condylar prosthesis; DePuy, Tokyo, Japan) using CT-based navigation system (VectorVision) by measured technique. Several parameters were evaluated for each patient using Athena Knee (Softcube Co, Ltd. Osaka, Japan), 3-D image-matching software. The coronal component angles and sagittal component angles were measured in relation to mechanical axis (MA). In addition, axial femoral component angle was measured in relation to surgical epicondylar axis (SEA) and axial tibial component angle was measured in relation to Akagi line.Introduction
Methods
The axis of the fibula in the sagittal plane are known as a landmark for the extramedullary guide in order to minimize posterior tibial slope measurement error in the conventional total knee arthroplasty (TKA). However, there are few anatomic studies about them. We also wondered if the fibula in the coronal plane could be reliable landmark for the alignment of the tibia. This study was conducted to confirm whether the fibula is reliable landmark in coronal and sagittal plane. We evaluated 60 osteoarthritic knees after TKA using Athena Knee (SoftCube Co, Ltd, Osaka, Japan) 3-D image-matching software. Angle between the axis of the fibula (FA) and the mechanical axis (MA) in the coronal and sagittal plane were measured.Background:
Methods:
Appropriate intraoperative soft tissue balancing is recognized to be essential in total knee arthroplasty (TKA). However, it has been rarely reported whether intraoperative soft tissue balance reflects postoperative outcomes. In this study, we therefore assessed the relationship between the intra-operative soft tissue balance measurements and the post-operative stress radiographs at a minimum 1-year follow-up in cruciate-retaining (CR) TKA, and further analyzed the postoperative clinical outcome. The subjects were 25 patients diagnosed with osteoarthritis with varus deformity and underwent primary TKA. The mean age at surgery was 72.0 ± 7.5 years (range, 47–84 years). The Surgeries were performed with the tibia first gap technique using CR-TKA (e motion, B. Braun Aesculap) and the image-free navigation system (Orthopilot). We intraoperatively measured varus ligament balance (°, varus angle; VA) and joint component gap (mm, center gap; CG) at 10° and 90° knee flexion guided by the navigation system, with the patella reduced. At a minimum 1-year follow-up, post-operative coronal laxity at extension was assessed by varus and valgus stress radiographs of the knees with 1.5 kgf using a Telos SE arthrometer (Fa Telos) and that at flexion was assessed by epicondylar view radiographs of the knees with a 1.5-kg weight at the ankle. After calculating postoperative VA and CG from measurements of radiographs, measurements and preoperative and postoperative clinical outcome, such as Knee Society Clinical Rating System (Knee score; KSS, Functional score; KSFS) and postoperative knee flexion, were analyzed statistically using linear regression models and Pearson's correlation coefficient.Introduction
Methods
In cruciate-retaining total knee arthroplasty (TKA), among many factors influencing post-operative outcome, increasing the tibial slope has been considered as one of the beneficial factors to gain deep flexion because of leading more consistent femoral rollback and avoiding direct impingement of the insert against the posterior femur. In contrast, whether increasing the tibial slope is useful or not is controversial in posterior-stabilized (PS) TKA, Under such recognition, accurate soft tissue balancing is also essential surgical intervention for acquisition of successful postoperative outcomes in TKA. In order to permit soft tissue balancing under more physiological conditions during TKAs, we developed an offset type tensor to obtain soft tissue balancing throughout the range of motion with reduced patello-femoral(PF) and aligned tibiofemoral joints and have reported the relationship between intra-operative soft tissue balance and flexion angles. In this study, we therefore assessed the relationship between intra-operative soft tissue balance assessed using the tensor and the tibial slope in PS TKA. Thirty patients aged with a mean 72.6 years were operated PS TKA(NexGen LPS-Flex, Zimmer, Inc. Warsaw, IN) for the varus type osteoarthritis. Following each bony resection and soft tissue release using measure resection technique, the tensor was fixed to the proximal tibia and femoral trial prosthesis was fitted. Assessment of the joint component gap (mm) and the ligament balance in varus (°)was carried out at 0, 10, 45, 90and 135degrees of knee flexion. The joint distraction force was set at 40lbs. Joint component gap change values during 10-0°,45-0°, 90-0°, 135-0° flexion angle were also calculated. The tibial slopes were measured by postoperative lateral radiograph. The correlation between the tibial slope and values of soft tissue balance were assessed using linear regression analysis.Introductions
Materials and methods
Accurate soft tissue balancing has been recognized as important as alignment of bony cut in total knee arthroplasty (TKA). In addition, using a tensor for TKA that is designed to facilitate soft tissue balance measurements throughout the range of motion with a reduced patello-femoral (PF) joint and femoral component in place, PF joint condition (everted or reduced) has been proved to have a significant effect for intra-operative soft tissue balance. On the other hand, effect of patellar height on intra-operative soft tissue balance has not been well addressed. Therefore, in the present study, we investigated the effect of patellar height by comparing intra-operative soft tissue balance of patella higher subjects (Insall-Salvati index>1) and patella lower subjects (Insall-Salvati indexâ‰/1). The subjects were 30 consecutive patients (2 men, 28 women), who underwent primary PS TKA (NexGen LPS-flex PS: Zimmer, Warsaw, IN, USA) between May 2003 and December 2006. All cases were osteoarthritis with varus deformity. Preoperative Insall-Salvati index (ISI) was measured and patients were divided into two groups; the patella higher group (ISIï1/4ž1: 18 knees average ISI was 1.12) and the patella lower group (ISIâ‰/1; 12 knees average ISI was 0.94). Component gap and ligament balance (varus angle) were measured using offset-type tensor with 40lb distraction force after osteotomy with the PF joint reduced and femoral trial in place at 0, 10, 45, 90, 135 degrees of knee flexion. Data of two groups were compared using unpaired t test.Introduction
Materials and methods
