In total knee arthroplasty, polyethylene wear has been a major cause of revision surgery. However, it is sometimes difficult to determine the time of revision surgery in elderly people due to their concomitant diseases. Therefore, the brace for measuring polyethylene wear under computed tomography was developed. The brace works by strapping a femoral component tightly to a polyethylene insert by applying compression force between the sole of the foot and the thigh. Holes of 1, 2, 5, 10 mm in diameter and 0.1, 0.2, 0.5 and 1 mm in depth were created in the posteromedial part of polyethylene inserts. The inserts were provided from Teijin-nakashima Co. ltd. (Jodo, Okayama, Japan). The Hi-tech knee artificial joint (Teijin-nakashima Co. ltd.) was applied to a cadaveric knee and CT images of the knee were taken with a combination of insets with varying diameters and depths holes, using Aquilion ONE (Toshiba Medical Systems Corporation, Ohtawara, Japan). The finding conditions were as follows, Voltage; 120V, Current; 5A, slice thickness; 0.5 mm helical. The patient, who received total knee arthroplasty over 15 years ago, wore the brace and was examined using computed tomography. Afterward, the patient received revision surgery to replace the worn insert into new one. The removed insert was measured with a three-dimensional measuring machine (Cyclon, Mitsutoyo Co. ltd., Kawasaki, Japan). At a 1.0 mm depth, all holes could be detected. At a 0.5 mm depth, holes of 2, 5, 10 mm in diameter could be detected. At a 0.1∼0.2 mm depth, there was no hole detected. After revision surgery, a three-dimensional measuring machine revealed a 1.8 mm thickness of the insert on the medial side. The CT reconstruction image showed a1.84 mm thickness similar to the virtually measured figure.Methods
Results
The superior analgesic effects of minodronate compared with other bisphosphonates has been previously reported. However, to our knowledge, there are no studies analyzing the analgesic effects of bisphosphonates on chronic pain. The purpose of the present study was to evaluate the analgesic effects of minodronate (MIN), alendronate (ALN), and pregabalin (PRG) on chronic pain caused by chronic constriction injury (CCI) of the sciatic nerve. Four-week-old female Wister rats underwent ovariectomy. At 8 weeks old, the left sciatic nerve was ligated to induce the chronic pain model (CCI side), and sham surgery was performed on the right posterior limb as a CCI control (control side). The rats were divided into the following four groups: 1) MIN group, administered with minodronate (0.15 mg/kg/week) (n = 10); 2) ALN group, administered with alendronate (0.15 mg/kg/week) (n = 10); 3) PRG group, administered with pregabalin (10 mg/kg) (n = 9); and 4) Control group, administered with vehicle (n = 10). Treatments were administered subcutaneously every week for 2 weeks immediately after CCI. To quantify the sensitivity to a tactile stimulus, paw withdrawal in response to a tactile stimulus was measured using von Frey filaments at 0, 1, and 2 weeks after CCI. Von Frey filaments were applied to the plantar surface of the hindpaws for 3 s, and this was repeated three times. Paw withdrawal in response to the stimulus was evaluated by scoring as follows: 0, no response; 1, a slow and/ or slight response to the stimulus; 2, a quick withdrawal response; 3, an intense withdrawal response away from the stimulus. The mean value of the score was adopted as the pain score. After evaluating the response, bilateral femurs were harvested for bone mineral density (BMD) measurements. The pain score of the CCI side was significantly higher than that of the sham side in all groups (p < 0.05) at each time point. The pain score for the MIN group, but not the ALN group, of the CCI side was significantly lower (p = 0.05) at 0 and 1 week after CCI. Total femoral BMD of the CCI side was significantly lower in the PRG and Control groups than those of the MIN and ALN groups (p < 0.05). No significant difference was identified for BMD between the MIN and ALN groups. Minodronate showed a significant analgesic effect on chronic pain and suppressed osteoporotic changes caused by CCI.
In total knee arthroplalsties, there are risks of revision surgeries because of aseptic loosening, polyethylene wear, and metal component breakage. The data such as model, type, size, and manufacturing companies are required at the time of revision surgeries. However, it is sometimes difficult to acquire such data due to patient's change of address and the elimination and consolidation of hospitals in the long-term. Therefore, we try to use the Radio Frequency IDentification (RFID) in the total knee joint system. The FerVID family (Fujitsu Co. Ltd., Tokyo, Japan) was prepared as the RFID tag. It was radio-resistant below the dose of 50kGy, which allowed gamma sterilization. The RFID tags were embedded into the anterior side of GUR 1050 UHMWPE inserts and 0.3wt% vitamin E blended UHMWPE. The UHMWPE inserts were manufactured by thecompression molding method at the maximum temperature of 220°C and the maximum compressive force of 245kgf/cm2. The manufactured inserts were implanted in fresh cadaveric knees. The tibial base plate was made of Ti6Al4V. The femoral components were made of Co-Cr-Mo or Ti-6Al-4V. Communication Performance was measured with the interrogator (DOTR-920 MHz-band, Tohoku Systems Support Co. Ltd., Miyagi, Japan). The transmission output was up to 1W. Received Signal Strength Indicator (RSSI) was measured 500 times at 15 mm away from the surface of skin in the extension and 90° flexion of the knee (Fig1).Introduction
Materials and methods
The bioactive polyetheretherketone (PEEK) was fabricated by the combination of PEEK and CaO-SiO2 particles, which formed hydroxyapatite on its surfaces in simulated body fluid and showed good mechanical propeties. The study revealed osteoblast-like cell proliferation and gene expression on the bioactive PEEK. Peek and bioactive PEEK discs (24 mm in diameter and 2 mm in thickness) were prepared. Bioactive PEEk was produced by the combination of 80 vol% Peek powder and 20 vol% CaO-SiO2 particles (30CaO · 70SiO2). Discs were sterilized with ethylene oxide gas. The study was approved by the ethics committee in Chiba University. Human osteoblast-like cells were used in the study. The cells at passage 3–5 were used in the experiments. 2 × 105cells /disc were culture at 37°C in a humidified atmosphere with 5% CO2, and the media was replaced every 3 days. At days 3, 7, 21, the culture media, cells and discs were collected respectively. Cell attachment assay was performed. Cells were seeded at a density of 4 × 105 cells /well and incubated for 2 hours at 37 C in a humidified atmosphere with 5% CO2. The cells on the discs were evaluated by DNA content. The real-time PCR was performed with regard to type I collagen (COLI), osteocalcin (OC), osteonectin (ON), osteopontin (OPN), and GAPDH. The alkaline phosphatase activity (ALP) was measeured at 3, 7, and 21 days, which samples as used in the DNA-content assay. Alizalin Red Staining was performed at day 21 to quantify calcification deposits in discs. Results were analyzed using Student's The content of DNA showed similar increases on PEEK and bioactive PEEK in the course of day 3, 7, 21. The cell attachment of bioactive PEEK was two times larger than that of PEEK. Real-time PCR results of human osteoblast-like cells cultured on PEEK and bioactive PEEK discs were shown in Fig. 1. There were no significant differences between cells on PEEK and bioactive PEEK with respect to COL I and ON mRNA expression. However, human osteoblast-like cells on bioactive PEEK presented higher expression of OPN and OCN mRNA at day 21. No significant differences were found in ALP activity of both discs. Calcification deposits were observed only on bioactive PEEK at day 21Materials and Methods
Results
Many TKA instruments were developed in these days. Distal femoral cutting guide using intra-medullary system were divided into two methods, from anterior or medial. Many companies employed anterior cutting guide, however these guides have a disadvantage of wide skin and quadriceps incision. Only Zimmer provided medial cut guide which performed short skin and quadriceps incision. However, reference point (medial femoral condyle) will be a risk of imprecise cutting for a medial condyle defect cases. We tried L-shaped new distal femoral cutting guide, reference point will be both femoral condyle and cutting from antero-medial side. The purpose of this study was to prove usefulness of the new guide. Twenty-nine knees were employed in this study. All knees were treated with Optetrak knee system (Exactec). Surgical methods were as follows, mid line skin incision, short para-patellar deep incision, no patellar resurfacing, PS type implant and cement fixation were employed. 13 knees were used original anterior cutting guide (O group) and 16 knees were used new antero-medial cut guide (N group). Study items were length of skin incision, length of Quadriceps incision, surgical time, JOA score, and component tilting angles (implant position were compared to femoral axis with AP and lateral view of roentgenograms).Purpose
Materials and Methods
ROBODOC is a well known tool for a computer assisted arthroplasty. However, the incision tends to enlarge with the system because of the restriction of range of motion. We have developed the robot system for minimally invasive arthroplasty. This report shows the accuracy of our system composed of original planning software, navigation and bone cutting robot. We took the DICOM data of cadaver knees from computed tomography. The data were transferred to the workstation for planning. Matching points for registration and cutting planes were determined on the planning software. Cutting tool was the 6th robot which was able to recognize the locations of its apex and the cadaver knee with navigation system. We made five planes for TKA and two planes for UKA on femur. Then we made one plane on tibia. We evaluated the accuracy by measurement the location of cutting plane under navigation system and by CT data. The registration errors of femur and tibia were less than 1.0mm about cadaver knees. The errors of cutting planes were 1.3 mm about the distal end of femur and 0.5 mm about the proximal end of tibia. The accuracies of the angles of cutting planes were 1.9 degrees and 0.8 degrees compared to the mechanical axis. The errors of anterior and posterior plane of femur were increased compared to the distal plane. It was because the accuracy of registration were correct in axial direction but was not satisfied in rotational direction. The error was considered by the location of points which decided the rotation alignment. We will make effort to minimize the errors of registration and put it into practical use as soon as possible.
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.
