In order to restore the neutral limb alignment in total knee arthroplasty (TKA), surgical procedure usually starts with removing osteophytes in varus osteoarthritic knees. However, there are no reports in the literature regarding the exact influence of osteophyte removal on alignment correction. The purpose of this study was to define the influence of osteophyte removal alone on limb alignment correction in the coronal plane in TKA for varus knee. Twenty-eight medial osteoarthritic knees with varus malalignment scheduled for TKA were included in this study. After registration of a navigation system, each knee was tested at maximum extension, and at 30, 40 and 60 degrees of flexion before and after osteophyte removal. External loads of 10 N-m valgus torque at each angle and in both states were applied. Subsequently, the widths of the resected osteophytes were measured.Background
Methods
Upright body posture is maintained with the alignment of the spine, pelvis, and lower extremities, and the muscle strength of the body trunk and lower extremities. Conversely, the posture is known to undergo changes with age, and muscle weakness of lower extremities and the restriction of knee extension in osteoarthritis of the knee (knee OA) have been considered to be associated with loss of natural lumbar lordosis and abnormal posture. As total knee arthroplasty (TKA) is aimed to correct malalignment of lower extremities and limited range of motion of knee, particularly in extension, we hypothesized that TKA positively affects the preoperative abnormal posture. To clarify this, the variation in the alignment of the spine, pelvis, and lower extremities before and after TKA was evaluated in this study. Patients suffering from primary knee OA who were scheduled to receive primary TKA were enrolled in this study. However, patients with arthritis secondary to another etiology, i.e. rheumatoid arthritis, trauma, or previous surgical interventions to the knee, were excluded. Moreover, patients who suffered from hip and ankle OA, cranial nerve diseases, or severe spinal deformity were also excluded. The sagittal vertical axis (SVA), the horizontal distance between the posterosuperior aspect of the S1 endplate surface and a vertical plumb line drawn from the center of the C7 vertebral body, is an important index of sagittal balance of the trunk. Thus, patients were classified into two groups based on the preoperative SVA with preoperative standing lateral digital radiographs: normal (< 40mm) and abnormal (≥ 40mm) groups. The variations in the sagittal alignment of the spine, pelvis and lower extremities were evaluated preoperatively, and at 1 and 3 months postoperatively. This study was approved by an institutional review board, and informed consent for participation was obtained from the patients.Introduction
Patients and methods
The hip hemiarthroplasty in posterior approach is a common surgical procedure at the femoral neck fractures in the elderly patients. However, the postoperative hip precautions to avoid the risk of dislocations are impeditive for early recovery after surgery. We used MIS posterior approach lately known as conjoined tendon preserving posterior (CPP) approach, considering its enhancement of joint stability, and examined the intraoperative and postoperative complications, retrospectively. We performed hip hemiarthroplasty using CPP approach in 30 patients, and hip hemiarthroplasty using conventional posterior approach in 30 patients, and both group using lateral position with the conventional posterior skin incision. The conjoined tendon (periformis, obturator internus, and superior/inferior gemellus tendon) was preserved and the obturator externus tendon was incised in CPP approach without any hip precautions postoperatively. The conjoined tendon was incised in conventional approach using hip abduction pillow postoperatively.Introduction
Methods
A femoral rotational alignment is one of the essential factors, affecting the postoperative knee balance and patellofemoral tracking in total knee arthroplasty (TKA). To obtain an adequate alignment, the femoral component must be implanted parallel to the surgical epicondylar axis (SEA). We have developed “a superimposable Computed Tomography (CT) scan-based template”, in which the SEA is drawn on a distal femoral cross section of the CT image at the assumed bone resection level, to determine the precise SEA. Therefore, the objective of this study was to evaluate the accuracy of the rotational alignment of the femoral component positioned with the superimposed template in TKA. Twenty-six consecutive TKA patients, including 4 females with bilateral TKAs were enrolled. To prepare a template, all knees received CT scans with a 2.5 mm slice thickness preoperatively. Serial three slices of the CT images, in which the medial epicondyle and/or lateral epicondyle were visible, were selected. Then, these images were merged into a single image onto which the SEA was drawn. Thereafter, another serial two CT images, which were taken at approximately 9 mm proximal from the femoral condyles, were also selected, and the earlier drawn SEA was traced onto each of these pictures. These pictures with the SEA were then printed out onto transparent sheets to be used as potential “templates” (Fig. 1-a). In the TKA, the distal femur was resected with the modified measured resection technique. Then, one template, whichever of the two potential templates, was closer to the actual shape, was selected and its SEA was duplicated onto the distal femoral surface (Fig. 1-b). Following that, the distal femur was resected parallel to this SEA. The rotational alignment of the femoral component was evaluated with CT scan postoperatively. For convention, an external rotation of the femoral component from the SEA was given a positive numerical value, and an internal rotation was given a negative numerical value.Introduction
Patients and methods
In order to achieve good clinical results in TKA, soft tissue balance is important. Soft tissue balance is closely related to knee kinematics which affects clinical results. Modified gap balancing technique is one of the standard techniques for posterior stabilized (PS) TKA. On the other hand, appropriate load for the measurement of gap balance has not been established. The purpose of the present study is to measure the mechanical properties of soft tissue structure of knee sleeve in flexion and extension during PS TKA using newly developed balancer. The understanding of the mechanical properties is crucial. In particular if these properties are used as input for surgical procedures, standard technique for many surgeons will be established. Medial compartmental osteoarthrosis (OA) patients (13 female and 7 male) were evaluated. Average age, BMI, and Varus deformity were 72.1 years, 26.9, and 12 degrees, respectively. The newly developed center paddle balancer consists of a built-in spring (Fig. 1). Figure 2 shows the sequence of surgery and measurements. In the surgery, we measured the balance (degrees in Figure 1, A) and distance (mm in Figure 1, B) in extension with a load (Figure 1,C) at transition zone of toe region to linear region. Then, applying the load until flexion gap was the same as that in extension with a patella reduction, we measured the femoral component rotation from the balancer (degrees in Figure 1, A). The anterior and posterior femoral cuts were performed according to measured femoral component rotation which angle is parallel to tibial cut surface.Introduction
Materials and Methods
For restoration of neutral limb alignment in Total Knee Arthroplasty (TKA), we usually start by removing osteophytes in varus osteoarthritic knees. However, we have found no reports in the literature regarding research on the exact influence of osteophyte removal on angle correction. The purpose of this study was to define the influence of osteophyte removal on limb alignment correction in the coronal plane in TKA. Nine patients with varus malalignment that were scheduled for TKA were included in this study. Only patients with degenerative osteoarthritis were considered. After registration of a navigation system, each knee was tested at maximum extension, and 30 and 60 degrees of flexion before and after osteophyte removal. The same examiner applied all external loads of 10 N-m valgus torque at each angle and in both states. Subsequently, the widths of the osteophytes were measured. All data were analyzed statistically using paired t-test and correlation coefficient. A significant difference was determined to be present for P < .05.Introduction
Materials and Methods
Total knee arthroplasty (TKA) is the highly developed procedure for sever osteoarthritic knee, in which there are two major concepts; Cruciate Retaining design (CR) and Posterior Stabilized design (PS). The femoral roll back movement is enforced with the post-cam mechanism in the PS, however, this structure associates with the complications, i.e. wear and dislocation. The CR has been developed to obtain the knee stability with native posterior cruciate ligament (PCL) in TKA. However, the preservation of the PCL can limit knee exposure and increase the technical challenge of surgery. We hypothesized that the knee exposure was easily achieved after the PCL was released, however, the PCL was repaired and the posterior stability was re-established after the TKA with time if it was released subperiostealy. The objective of this study was to evaluate the varying of the posterior stability after the PCL-released CR TKA.Background
Objective
Many factors can influence post-operative kinematics after total knee arthroplasty (TKA). These factors include intraoperative surgical conditions such as ligament release or quantity of bone resection as well as differences in implant design. Release of the medial collateral ligament (MCL) is commonly performed to allow correction of varus knee. Precise biomechanical knowledge of the individual components of the MCL is critical for proper MCL release during TKA. The purpose of this study was to define the influences of the deep medial collateral ligament (dMCL) and the posterior oblique ligament (POL) on valgus and rotatory stability in TKA. This study used six fresh-frozen cadaveric knees with intact cruciate ligaments. All TKA procedures were performed by the same surgeon using CR-TKA with a CT-free navigation system. Each knee was tested at 0°, 20°, 30°, 60°, and 90° of flexion. One sequential sectioning sequence was performed on each knee, beginning with an intact knee (S0), and thereafter femoral arthroplasty only (S1), tibial arthroplasty (S2), release of the dMCL (S3), and finally, release of the POL (S4). The same examiner applied all external load of 10 N-m valgus and a 5 N-m internal and external rotation torque at each flexion angle for the each cutting state. All data were analyzed statistically using one-way ANOVA and we investigated the correlation between the medial gap and the rotation angle. A significant difference was determined to be present for P < .05.Introduction
Materials and Methods
This is a minimum 15 year follow up of a cohort of 58 patients (30 men and 28 women) who underwent 62 non-cemented THR between 1998–2000 (54 unilateral, 4 bilateral), in whom an off-the-shelf “lateral flare” femoral component was implanted. These surgeries were performed by a single surgeon and have been followed continuously by that same surgeon. The mean age at the time of surgery was 60.4 yrs (52–74). There were no exclusions for osteoporosis or type “C” femoral geometry. Although some patients have deceased during these 15 years, there have been no stem failures, revisions or impending stem revisions at the time of follow up or at the time of death in those who have passed. Two patients have undergone revision of their acetabular liner for poly wear. There have been no complaints of thigh pain; and like the results seen in other series employing this stem design, there has been no evidence of bone loss due to stress shielding or subsidence of the femoral component in any of these patients. This mid-term follow up re-affirms the dynamic tension band model of hip biomechanics, upon which the “lateral flare” design is predicated. This model predicts that the proximal lateral femur can experience compression during the gait cycle and as such can be utilized as an additional base of support upon which the femoral component can rest. Rather than relying upon a traditional “press fit” technique to achieve initial implant stability, a technique which is highly dependent upon femoral geometry, bone quality and may risk fracture on implant seating, the “lateral flare” design permits a gentler, safer and more physiologic means of achieving initial implant stability necessary for osseous integration to occur. This alterantive terchnique has been termed a “rest fit”.
Many factors can influence post-operative kinematics after total knee arthroplasty (TKA). These factors include intraoperative surgical conditions such as ligament release or quantity of bone resection as well as differences in implant design. Release of the medial collateral ligament (MCL) is commonly performed to allow correction of varus knee. Precise biomechanical knowledge of the individual components of the MCL is critical for proper MCL release during TKA. The purpose of this study was to define the influences of the deep medial collateral ligament (dMCL) and the posterior oblique ligament (POL) on kinematics in TKA. This study used six fresh-frozen cadaveric knees with intact cruciate ligaments. All TKA procedures were performed by the same surgeon using CR-TKA with a CT-free navigation system. Each knee was tested at 0°, 20°, 30°, 60°, and 90° of flexion. One sequential sectioning sequence was performed on each knee, beginning with femoral arthroplasty only (S1), and thereafter sequentially; medial half tibial resection with spacer (S2), ACL cut (S3), tibial arthroplasty (S4), release of the dMCL (S5), and finally, release of the POL (S6). The same examiner applied all external loads of 10 N-m valgus and 5 N-m internal and external rotation torques at each flexion angle and for each cut state. The AP locations of medial and lateral condyles were determined as the lowest point on each femoral condyle. All data were analyzed statistically using paired t-test. A significant difference was determined to be present for P < .05.Introduction
Materials and Methods
Pulmonary emboli (PE) after total hip and knee arthroplasties is an uncommon event. However, once it happens, it may results in sudden death. Thus, the prophylaxis of venous thromboembolism (VTE), including symptomatic deep vein thrombosis (DVT) and PE, is one of the challenging trials for Orthopaedic surgeons. Many procedures have been developed, e.g. early mobilization, compression stocking, intermittent pneumatic compression (IPC) devices, and anticoagulation agents. However, the most effective treatment for prophylaxis against VTE after the arthroplasties remains undecided. Recently, many low molecular weight heparin (LMWH) agents are developing, and these are strongly effective for anticoagulation. However, these agents sometimes lead to bleeding complications, and result in uncontrolled critical bleeding. We are introducing our protocol with conventional aspirin as VTE prophylaxis after the arithroplasties. All patients prior to the surgeries are evaluated laboratory and duplex venous ultrasonography examinations to exclude thrombophilic or hemophilic conditions, and existence of DVT. Then, the thrombophilic, and also prolonged immobility, obesity, malignant tumors, cardiovascular dysfunction and DVT patients are regarded as high risk for VTE. These are offered a prophylaxis consisting of a removable inferior vena cava (IVC) filter, together with anticoagulant medication. Usually, the filter is removed three months after the surgery. In other patients, the arthroplasties are carried out under the spinal or epidural anesthesia with IPC on both feet. IPC is also applied, except for the periods of ambulation, usually two to three days of hospitalization after surgery. Full weight bearing ambulation with a walker is allowed on post-op day one. Patients receive aspirin (acetylsalicylic acid) 325 mg daily for six weeks starting the night of surgery. Pain is controlled with celecoxib (COX-2 selective nonsteroidal anti-inflammatory drug) 400 mg daily, and oral narcotics for break through pain. Before discharge, usually within three days post surgery, all patients are evaluated DVT by duplex venous ultrasonography. The incidence of blood loss, wound complications, and subcutaneous ecchymosis are recorded.Introduction
Patients and methods
Femoral neck fracture is a common injury in elderly patients. To restore the activity with an acceptable morbidity and to decrease of mortality, surgical procedures are thought to be superior to conservative treatments. Osteosynthesis with internal fixation for nondisplaced type, and hemiarthroplasty or total hip replacement (hip arthroplasties) for displaced type are commonly performed. Cemented arthroplasty has been preferred over non-cemented arthroplasty because of less postoperative pain, better mobility and excellent initial fixation of the implant, especially for osteoporotic and stove-pipe bones. However, pressurizing bone cement may cause cardiorespiratory and vascular complications, and occasionally death, which has been termed as “bone cement implantation syndrome”. To avoid the occurrence of this syndrome, non-cemented implants have been developed. However, most implants with the press fit concepts and flat wedge taper designs have a risk of intraoperative and early postoperative periprosthetic fracture. Recently, we have employed a non-cemented femoral component, which has a lateral expansion to the proximal body as compared to a conventional hip stem. Because of this shape, which is called a “lateral flare”, this stem provides a physiological loading on both the medial and lateral endosteal surfaces of the femur. This is in contrast to conventional hip stem which prioritizes loading on the medial and metaphyseal /dyaphyseal surfaces of the femur. Moreover, the cross section of this stem is trapezoid with the flat posterior surface. This shape provides the stem with rotational stability along the long axis of the femur, and maximizes loading transfer to the posterior aspect of the proximal femur. These mechanical features avoid the need for aggressive impaction of the stem at the time of insertion. It is necessary to only tap gently to achieve the secure initial implant fixation by a “rest fit”. Thus, this technique reduces the risk of fracture. We employed this technique using a non-cemented lateral flare design device for displaced femoral neck fractures since 1996. Surgical procedures were performed with posterior approach under the spinal or epidural anesthesia. Full weight bearing ambulation with a walker was allowed on post-op day one.Introduction
Patients and methods
