An accelerometer-based portable navigation system (KneeAlign2, OrthAlign Inc., Aliso Viejo, CA) is expected to improve mechanical axis and component alignment compared to conventional instrumentation in total knee arthroplasty (TKA). However, past reports have evaluated its accuracy using only radiographic measurements. The purpose of this study was to analyze the accuracy of the KneeAlign2 system with radiography and more detailed three-dimensional (3D) CT. We targeted 22 patients (24 knees) with severe osteoarthritis who underwent primary TKA using the KneeAlign2 system. Cemented, fixed-bearing, cruciate-retaining prostheses were implanted in all patients. We used postoperative standing-position full-length radiographic evaluation of the lower limbs to measure the hip-knee-ankle angle (HKA), frontal femoral component angle (FFC), and frontal tibial component angle (FTC). However, lower limb rotation and knee flexion could affect radiographic measurement of HKA and the component positioning angle. We used 3D bone models reconstructed from pre- and postoperative CT images to precisely analyze the 3D component positioning. For a 3D matching bone model made from these models, a 2D projection of the pre- and postoperative component positioning planes was made, and the projection angle was measured as angle error compared to the preoperative planned position (Figure 1). Average surgery time and total blood loss on postoperative day 7 were also recorded.INTRODUCTION
METHODS
Dysplastic hip has not only deficiency of acetabulum but also femoral deformity. Therefore, selection of stem is important in cementless THA for dysplasia. Especially using of short stem should be challenge for deformed femur. We studied clinical performance and radiological findings after THA with triple tapered short stem (Optimys hip) for dysplastic hip. From May 2013, we performed cementless THA for osteoarthritis with dysplasia. Seventy-one hips of 67 patients were examined including four males and 63 females. Age at surgery was from 36 to 88 years old (61.7 in average). Surgical approach was used modified Watson-Jones in all hips. Clinical evaluation was used modified Harris hip score (MHSS), incidence of complications and thig pain. Radiological findings were evaluated according Engh's classification and grade of stress shielding. Follow-up period was minimum one year and was 21.3 months in average.Introduction
Materials and method
Patient matched instrumentation (PMI) have been proposed the accuracy of bone cuts through custom cutting blocks and provide the proper alignment of total knee arthroplasty (TKA). On the other hand, there are some reports that the introduction of PMI for guiding bone cuts could increase the incidence of malalignment in primary TKA. Recent comparisons between patient-specific cutting guides and quantitative assessments of postoperative alignment have revealed the presence of outliers with respect to coronal alignment. The purpose of this study was to assess the implanted component alignment post-operatively between one type of MRI based PMI (Visionaire; Smith & Nephew, Inc, Memphis, Tenn) and conventional surgical instrumentation (CI) using radiographs and CT scan. 32 knees in 32 patients (25 women) with medial type knee osteoarthritis were underwent cruciate retaining TKA between September 2013 and May 2015, and were included in this study. Preoperative MRI scanning of the hip, knee, and ankle was performed for PMI group (n=12) and CT scanning was performed for CI group (n=20) 6 weeks before surgery according to a standard scanning protocol to determine the surgical epicondylar axis (SEA). Postoperatively, we compared operation time, blood loss, and mechanical alignment of two groups. Post-surgical mechanical alignments such as hip-knee-ankle angle (HKA), frontal femoral component angle (FFC), and frontal tibial component angle (FTC) were determined using long leg radiographs (Fig. 1). CT scans were used to assess the condylar twist angle (CTA) made by SEA and posterior condylar axis (Fig. 2). Each measurement was performed by two, blinded independent observers, and interclass correlation for each measurement was calculated. A student's two-tailed t test was used to compare the two cohorts, with statistical significance set at a p-value of <0.05.Introduction
Methods
Fixation patterns of cementless stem were known as proximal or distal part. Distal fixation was seen in fully porous coated stem and stress shielding of the proximal femur was indicative. These phenomena did not lower the clinical results, but technical difficulties were more and more in revision surgery because of infection or dislocation. There was lot of reports that alendronate was effective for treatment of osteoporosis by induction of apoptosis in osteoclasts. We can expect alendronate to modify the bone quality around the stem after cementless THA. We studied prospectively that quantitative computed tomography (QCT) measured bone mineral density around the stem between alendronate group and control. We tried to clarify that stress shielding after cementless THA can be prevented by use of alendronate or not.Introduction
Objectives
The aim of this study was to report a 3 year follow up of vitamin E add polyethylene in total knee arthroplasty. UHMWPE powder (GUR1050) was mixed with 0.3% of vitamin E before consolidation by direct compression molding. The vitamin E added UHMWPE was applied to the articular surface and patella in 65 patients (mean age, 69.6 years). Joint fluid concentrations of tocopherol and matrix metalloproteinase 9 were measured in vitamin E added UHMWPE cases one year after surgery, and were compared to those of conventional UHMWPE cases and osteoarthritis patients. Concentrations of α-tocopherol and γ-tocopherol were measured by using HPLC with ultraviolet-visible wavelength detection. Concentrations of matrix metalloproteinase 9 were detected by using enzyme immunoassay. The Average Knee Society score were 91.7(clinical) and 76.7(functional). There were three failures (1 supracondylar fracture, and 2 skin necrosis). The average concentrations of α-tocopherol were 281.8μg/dL (10 cases) in the vitamin E group, 371.8μg/dL (15 cases) in the conventional group, and 317.8μg/dL (46 cases) in the osteoarthritis group. There were no significant differences among three groups. The average concentrations of γ-tocopherol were 43.4μg/dL in the vitamin E group, 52.3μg/dL in the conventional group, and 49.8μg/dL in the osteoarthritis group. There were no significant differences among three groups. The average concentrations of matrix metalloproteinase 9 were 83.2 ng/mL in the vitamin E group, 78.4 ng/mL in the conventional group, and 17.4 ng/mL in the osteoarthritis group. There was no significant difference between the vitamin E group and the conventional group. However, The matrix metalloproteinase 9 concentrations of the osteoarthritis group were significantly lower than others. No cases exhibited measurable polyethylene wear or osteolysis and also no abnormal values relating to vitamin E on joint fluid examinations. At three year follow-up, vitamin E added polyethylene demonstrated the safe use for the human body.
Combined multi-detector row CT (MD-CT) pulmonary angiography (CTPA) and lower extremity venography (CTV) is an effective method for detection of pulmonary embolism (PE) and deep vein thrombosis (DVT). However, the usefulness of this method after total knee arthroplasty (TKA) has not been reported. The aim of this study is to evaluate our screening program in the management of thromboembolism. Over a 1.5-year period, 30 patients with primary TKA were examined using an MD-CT (Lightspeed ultra 16.GE) before and 7th day after operation. 25 seconds after intravenous administration of 320ml of contrast material, CTPA was performed with 1.25-mm collimation and CTV from the iliac crest to the ankles was done with 0.625-mm collimation 165 seconds after contrastmaterial injection. The mean age of the patients was 72.2 (53–80). Twenty patients had osteoarthritis, nine had rheumatoid arthritis and one osteonecrosis. All patients were received 4 weeks of warfarin therapy and prophylaxis. PE was observed in A1+2, A3, A6, A9, A10 area. PE was most frequently detected in A10 area of pulmonary artery (6/30). While, DVT was detected in only popliteal vein (6/30). The incidence of PE was 30% (9/30)and DVT 20% (6/30). Both PE and DVT were observed in 3 patients, the incidence was 10% (3/30). Combined CTPA and CTV is a safe and accurate diagnotic method for detecting PE and DVT after TKA, and the ability to directly visualize emboli of this system is effective as therapeutic tool.
