Proper acetabular cup placement is very important factor for successful clinical results in total hip arthroplasty (THA). Malposition of acetabular cup has been linked to increased rates of dislocation, impingement, pelvic osteolysis, cup migration, leg length discrepancy and polyethylene wear. Recently, some authors reported usefulness of navigation systems to set the acetabular cups with correct position. The purpose of this study is to evaluate the accuracy of acetabular cup placement in THA using computed tomography (CT)-based navigation system. Subjects were 235 hip joints we performed primary THA using CT based navigation system (Stryker® Navigation System, Stryker Corporation, Kalamazoo, MI, USA) from 2008 to 2014 and could assess the implant position by postoperative CT images. Their average age was 65.1 years (range 35–88). In all cases, non-cemented acetabular cups were implanted. TriAD cups (Stryker®) were used in 31 hips, and Tritanium cups (Stryker®) were used in 15 hips, and Trident cups (Stryker®) were used in 189 hips. Registration in this navigation system used surface matching system. We designed cup implantation using preoperative CT images and 3-dimensional (3-D) templates. The planned position of acetabular cup was in principle 40 degrees of inclination and 20 degrees of anteversion. However, we adjusted the better position of the cups according to pelvic tilt and femoral neck anteversion. When we placed acetabular cups, the position, inclination and anteversion, were measured by navigation system. After surgery, the positions of the cups were measured using postoperative CT images, navigation software and 3-D templates. Postoperative position using CT images were adjusted according to preoperative pelvic plane. The discrepancies between intraoperative navigation data and postoperative CT images data were analyzed as accuracy of navigation system in cup placement.Introduction
Material and Methods
Acetabular reconstruction of a total hip arthroplasty (THA) for a case with severe bone loss is most challenging for surgeon. Relatively high rate of failure after the reconstruction surgery have been reported. We have used Kerboull-type acetabular reinforcement devices with morsellised or bulk bone allografts for these cases. The purpose of this study was to examine the midterm results of revision THA using Kerboull-type acetabular reinforcement devices. We retrospectively reviewed 20 hips of revision THA (20 patients) between February 2002 and August 2010. The mean age of the patients at the time of surgery was 67.4 years (range 45–78). All of the cases were female. The mean duration of follow-up was 6.5 years (range 2.1–10.4). The reasons of revision surgeries were aseptic loosening in 10 hips, migration of bipolar hemiarthroplasty in 8 hips, and rheumatoid arthritis in 2 hips. We classified acetabular bone defects according to the American Academy of Orthopaedic Surgeons (AAOS) classification; we found two cases of Type II and eighteen cases of Type III. In terms of bone graft, we performed both bulk and morsellised bone grafts in 6 hips and morsellised bone grafts only in 14 hips. We assessed cup alignment using postoperative computed tomography (CT) and The post-operative and final follow-up radiographs were compared to assess migration of the implant. We measured the following three parameters: the angle of inclination of the acetabular device (Fig. 1); the horizontal migration (Fig. 2a); and vertical migration (Fig. 2b). Substantial migration was defined as a change in the angle of inclination of more than 3 degrees or migration of more than 3 mm. The pre- and postoperative hip functions were evaluated using the Japanese Orthopaedic Association (JOA) hip score.Introduction
Patients and methods
Ankle arthrodesis is a common treatment for destroyed ankle arthrosis with sacrificing the range of motion. On the other hand, total ankle arthroplasty (TAA) is an operation that should develop as a method keeping or improving range of motion (ROM); however, loosening and sinking of the implant have been reported in especially constrained designs of the implant. The concept of FINE TAA is the mobile bearing system (Nakashima Medical Co., Ltd, Okayama Japan) that can reduce stress concentration to implants. The purpose of this study is to evaluate the short-term results of FINE TAA. We performed FINE TAA for osteoarthritis (OA) (2 ankles of 2 patients) and rheumatoid arthritis (RA) (4 ankles of 3 patients). All patients were female. The mean age of the patients was 71.4 years old at the operation. The mean follow-up period was 32.6 (range, 18–55) months. All patients were assessed for Japan Orthopedic Association (JOA) score and ROM in plantar flexion and dorsiflexion at the point of pre-operation and final follow-up. We evaluated radiolucent line, subsidence, and alignment of implants at the latest follow-up.Introduction
Objectives and Methods
While research has been carried out widely for sagital pelvic tilt, research reports for coronal pelvic obliquity are few. The aim of this study is to evaluate changes of the pelvic obliquity before and after total hip arthroplasty. This retrospective study includes 146 cases of hips that were received total hip arthroplasty. There were 20 cases of revision, and 2 cases of re-revision. 17 cases were received bilateral total hip arthroplasty. The standing plain X-ray was used for evaluation of the pelvic obliquity in both before and 1-year after surgery. The correlation of pelvic obliquity was assessed between before and after surgery. 146 cases were classified into 3 groups (A, B, and C) according to the severity of the pelvic obliquity (0º−3º, 3º−6º, and >6º). Among the groups, statistical analysis was evaluated in the leg length discrepancy and the range of motion of the hip (flexion, extension, abduction, adduction, internal and external rotation) before and after surgery with 95% confidence intervals.Introduction
Material and Methods
Continuous epidural anesthesia or femoral nerve block has decreased postoperative pain after total knee arthroplasty to some extent. Although the established efficacy of these pain relief method, some adverse events such as hematoma or muscle weakness are still problematic. Intraoperative local infiltration of analgesia (LIA) has accepted as a promising pain control method after total knee arthroplasty. The safety and efficacy of LIA has been reported, although there are still limited evidence about the effect of LIA on quadriceps function and recovery of range of motion in early post-operative phase. The purpose of this study is to compare the quadriceps function and range of motion after TKA between the LIA with continuous epidural anesthesia and continuous epidural anesthesia alone. Thirty patients with knee osteoarthritis who underwent primary TKA were included in this study. Patients who took anticoagulants were treated continuous epidural anesthesia alone (n=11) and the other patients were treated with LIA with continuous epidural anesthesia (n=19). A single surgeon at our department performed all surgeries. Surgical procedure and rehabilitation process was identical between two groups. Before the implantation, analgesic drugs consisting of 20 ml of 0.75 % ropivacaine and 6.6 mg of dexamethasone were injected into the peri-articular tissues. In each group, fentanyl continuous epidural patient-controlled analgesia (PCA) was also used during 48-h post-operative period. Knee flexion and extension angle were evaluated before surgery, post-op day 3, 7, 10 and 14. The quadriceps function was evaluated by quadriceps peak torque at 30° and 60° flexion using VIODEX. The peak torque was recorded preoperatively, day 14 and 3 month after surgery. The difference between two groups was analyzed by Mann Whitney U-test using Prism 6, a statistical software.Background
Methods
Rotational malalignment of the femoral component still causes patellofemoral complications that result in failures in total knee arthroplasty (TKA). To achieve correct rotational alignment, a couple of anatomical landmarks have been proposed. Theoretically, transepicondylar axis has been demonstrated as a reliable rotational reference line, however, intraoperative identification of the transepicondylar axis is challenging in some cases. Therefore, surgeons usually estimate the transepicondylar axis from posterior condylar axis (PCA) using twist angle determined by the preoperative X-rays and CT. While PCA is the most apparent landmark, radiographs are not able to detect posterior condylar cartilage. In most osteoarthritic knees, the cartilage thickness of the posterior condyle is different between medial and lateral condyles. The purpose of this study is to evaluate the effect of the posterior condylar cartilage on rotational alignment of the femoral component in large number of arthritic patients. Furthermore, we investigated whether the effect of posterior condylar cartilage is different between osteoarthritis (OA) and rheumatoid arthritis (RA). Ninety-nine OA knees and 36 RA knees were included. Detailed information is summarized in Table 1. All cases underwent TKA using navigation system. The institutional review board approved the study protocol and informed consent was obtained from each participants. To evaluate the effect of posterior condylar cartilage, we measured two different condylar twist angle (CTA) using navigation system and intraoperative fluoroscopy-based multi-planner reconstruction (MPR) images obtained by a mobile C-arm. To uniform the SEA in two different measuring systems, we temporary inserted a suture anchors in medial and lateral prominence. The CTA that does not include the posterior condylar cartilage (MPR CTA) is evaluated on MPR images and the CTA that does include the posterior condylar cartilage (Navi. CTA) is calculated by navigation system. The difference between these two angles corresponds to the effect of posterior condylar cartilage on the rotation of the femoral component (Fig. 1). The paired or unpaired t test was used to compare the obtained data. The statistics were performed using GraphPad Prism 6. A P value of 0.05 or less is considered as a significant difference.Objective
Methods
Herniation pits had been considered as a normal variant, a cystic lesion formed by synovial invagination. On the contrary, it was also suggested that herniation pits were one of the diagnostic findings in femoroacetabular impingement (FAI) because of the high prevalence of herniation pits in the FAI patients. To date, the exact etiology is still unknown. The purpose of this study was to evaluate whether there is an association between the presence of herniation pits and morphological indicators of FAI based on computed tomography (CT) examination. We reviewed the CT scans of 245 consecutive subjects (490 hips, age: 21–89 years) who had undergone abdominal and pelvic CT for reasons unrelated to hip symptom from September, 2010 to June, 2011. These subjects were mainly examined for abdominal disorders. We confirmed by the questionnaire survey that there were no subjects who had symptoms of hip joints. We reviewed them for the presence of herniation pits and the morphological abnormalities of the femoral head and acetabulum. Herniation pits were diagnosed when they were located at the anterosuperior femoral head-neck junction with a diameter of more than 3 mm. We measured following four signs as indicators for FAI: α angle, center edge angle (CE angle), acetabular index (AI), and acetabular version. Mann-Whitney U-test was used for statistical analysis.Introduction
Materials and methods
Electron-beam-irradiated Both pure UHMWPE and Vitamin E added (0.3% w/w) resin was used to produce bulk specimens via vacuum direct compression molding at 220°C under 25 MPa for 30 min. Cylindrical pins (3.5 mm diameter, 40 mm length) for ESR measurement were then machined and placed in vacuum packaging. The pins were irradiated at 300 kGy, with half of each test group annealed at 80°C for 24 hours. Free radical measurements were made using a high-sensitive X-band ESR operating at 9.44 GHz. Detection of Vitamin E radicals was performed by comparing the characteristic symmetrical spectrum of oxidized Vitamin E to the spectra observed for the pins using both g-value and linewidth as references. Crosslink density was measured via gel fraction analysis and was performed in accordance with ASTM D2765. Thin sections (20 × 40 mm2, 200 μm) were machined from the bulk specimens, which were then placed in vacuum packaging, irradiated and annealed at the same conditions as those for the ESR measurements. Two of these thin sections were then placed in a stainless-steel cage (200 µm pore diameter) and were immersed in decahydronaphtalene at 200°C for 24 hours. These specimens were then extracted using soxhlet extractor at 100°C for 24 hours and dried in vacuum at 150°C for 12 hours.INTRODUCTION
MATERIALS & METHODS
It have been reported that the wear volume of vitamin E-containing UHMWPE tested with a knee joint simulator was approximately 30% lower than that of virgin UHMWPE at 5 million cycles. However, the wear resistance mechanism of vitamin E-containing UHMWPE has not yet been clarified. The present study examines the effects of the addition of vitamin E on the frictional properties of ultra-high molecular weight polyethylene (UHMWPE) under several different load and serum conditions. Friction tests were carried out using a computer-controlled pin-on-disk friction test apparatus. The UHMWPE pin was mounted vertically at the tip of the leaf spring and linear reciprocating sliding motion for 2,000 cycles with an amplitude of 1 mm and a frequency of 1 Hz, was applied under 3 MPa or 30 MPa loading against Co-28Cr-6Mo alloy disk. The lubricant bath was filled with 5 ml of ultrapure water, fresh serum, post-friction (PF) serum or diluted-PF (DPF) which were kept at a temperature of 37°C. The friction force between the UHMWPE pin and the Co-28Cr-6Mo alloy disk was calculated from the displacement of the leaf spring during the sliding motion. Vitamin E-containing UHMWPE showed a significantly higher friction force than that of virgin UHMWPE in fresh serum lubricant at 30 MPa loading, while there were little differences in either ultrapure water or PF serum or DPF serum. And vitamin E-containing UHMWPE tends to exhibit a lower dynamic friction force within the first few hundred cycles in the case of all serum lubricants at 30 MPa loading. These results suggest that some interaction between the UHMWPE surface and the native conformation proteins was specifically affected by the addition of vitamin E and that some weeping of vitamin E might occur at early stage of sliding. Our results also suggest the importance of the conformational changes of serum proteins for the wear testing.
