Hirotaka Iguchi

Application of full-scale three-dimensional models in patients with rheumatoid cervical spine.

Full-scale three-dimensional (3D) models offer a useful tool in preoperative planning, allowing full-scale stereoscopic recognition from any direction and distance with tactile feedback. Although skills and implants have progressed with various innovations, rheumatoid cervical spine surgery remains challenging. No previous studies have documented the usefulness of full-scale 3D models in this complicated situation. The present study assessed the utility of full-scale 3D models in rheumatoid cervical spine surgery. Polyurethane or plaster 3D models of 15 full-sized occipitocervical or upper cervical spines were fabricated using rapid prototyping (stereolithography) techniques from 1-mm slices of individual CT data. A comfortable alignment for patients was reproduced from CT data obtained with the patient in a comfortable occipitocervical position. Usefulness of these models was analyzed. Using models as a template, appropriate shape of the plate-rod construct could be created in advance. No troublesome Halo-vests were needed for preoperative adjustment of occipitocervical angle. No patients complained of dysphasia following surgery. Screw entry points and trajectories were simultaneously determined with full-scale dimensions and perspective, proving particularly valuable in cases involving high-riding vertebral artery. Full-scale stereoscopic recognition has never been achieved with any existing imaging modalities. Full-scale 3D models thus appear useful and applicable to all complicated spinal surgeries. The combination of computer-assisted navigation systems and full-scale 3D models appears likely to provide much better surgical results.

Arthroscopic Synovectomy of the Metacarpophalangeal and Proximal Interphalangeal Joints

Few reports about clinical experience in arthroscopy of finger joints exist. Furthermore, little attention has been given to arthroscopic synovectomy of rheumatoid fingers. Herein, we describe our experience with arthroscopic synovectomy of metacarpophalangeal (MCP) and proximal interphalangeal (PIP) joints in patients with rheumatoid arthritis. Arthroscopic synovectomy was performed in 45 finger joints (18 MCP joints, 26 PIP joints, and 1 interphalangeal thumb joint) of 23 patients with rheumatoid arthritis. All procedures were performed on an outpatient basis under regional anesthesia. The diameter of the arthroscope for small joints was 1.5 mm, and a mini shaver system with a 2.5-mm cutter was used for synovectomy. We developed new portals for PIP joints that were established on the dorsolateral aspect at a position more lateral than previously reported portals. Intraarticular structures of finger joints were well visualized, and magnified observation of the articular cartilage and synovial membrane was possible. Because insertion of the instruments into the palmar cavity was not possible without causing damage to the articular surfaces, synovectomy of the palmar capsule could not be performed. However, arthroscopic synovectomy of the dorsal capsule under visual control could be safely performed using the 2-portal technique. None of the patients experienced postprocedural complications. Swelling of each joint disappeared after the procedure and did not return in many cases for a long period. Furthermore, no joints required reoperation. We conclude that arthroscopy of MCP and PIP joints is useful not only for the assessment of articular cartilage and synovium but also for synovectomy in rheumatoid arthritis.

Morphometric analysis of the peroneal tubercle using a three-dimensional computed tomography model

BACKGROUND The peroneal tubercle is a small bony ridge located on the lateral wall on the calcaneus immediately inferior to the lateral malleolus and separates the peroneus brevis and peroneus longus tendons. The size and configuration of the peroneal tubercle has been implicated in the pathogenesis of peroneal tendon tears and tenosynovitis and is the increasing object of clinical interest. However, the morphology of the tubercle is difficult to assess with precision. METHODS We utilized a new method to evaluate the three-dimensional (3D) geometry of 46 calcanei from 34 consecutive patients; average patient age was 48.0 years who underwent lower extremity computed tomography (CT) for clinical treatment of non-peroneal tubercle-related conditions. The 3D geometries of calcanei were reconstructed by using the computer software to calculate the surface 3D models. To measure the size of the peroneal tubercle, we virtually excised it from the 3D calcaneus model and made a precise measurement of the height. RESULTS Peroneal tubercles with measured heights of 1mm or more were detected in 65% of the feet, with an average tubercle height of 2.59mm. Peroneal tubercles were larger and more frequent in middle-aged or older than younger patients.

Clinical Results of NCU Ceramic Total Knee Arthroplasty

During the period from 1989 to 1993, Nagoya City University (NCU) ceramic total knee arthroplasty was performed in 89 knees of 60 patients and followed-up for more than 1 year. The diagnoses were osteoarthritis in 50 knees and rheumatoid arthritis in 39 knees. Overall clinical results were almost the same as those of metal components. Although not extremely important clinically, a radiological subsidence of components of more than 1 mm was observed in 3 tibial components and one patellar component out of nine cementless knees. In recent studies, bone ingrowth around alumina ceramic implants was considered to be quite similar to that of metal implants. For this reason, cement use is recommended for the fixation of ceramic implants. Complications associated with ceramic implants were observed in two knees. One was the intraoperative breakage of a tibial tray and the other was a postoperative breakage of a tibial tray without trauma. After the experience of these complications, which may be characteristic of ceramics, we concluded that alumina ceramics were not an appropriate material for the tibial tray and decided to change the material to titanium alloy.

Paper 254: Blocking Myostatin with Suramin Can Enhance Muscle Healing

Objectives: Muscle injuries are very common musculoskeletal problems in sports medicine. Although current therapies such as RICE (rest, ice, compression, and elevation) are the norm for treatment, complete functional recovery is hindered by the development of scar tissue formation. Myostatin, a negative regulator of muscle growth, has been shown to stimulate fibrosis in skeletal muscle.1 Thus, we have focused the current study on the prevention of scar tissue through the down-regulation of myostatin by suramin, an anti-fibrotic agent which is already approved by Food and Drug Administration (FDA). Using an animal (murine) model of muscle contusion, we examined, 1) whether suramin can block the effect of myostatin and promote myogenic differentiation of myoblast cells in vitro and 2) whether suramin treatment enhances muscle regeneration and reduce fibrosis by down-regulating myostatin expression in vivo. Methods & Materials: In vitro: Myoblast cells were cultured with low-serum medium containing different concentrations of myostatin (0 and 1 g/ml) and suramin (0, 1, and 25 g/ml) to induce myogenic differentiation. In vivo: The muscle contusion was made on the tibialis anterior (TA) muscle of each mouse. Two weeks after injury, different concentrations of suramin (0 and 2.5 mg) were injected intramuscularly (n 20 mice/ group). At different time points (0.5, 1, 2, 10, and 14 days after injection), mice were sacrificed and cryosections of TA muscle were analyzed histologically. Results: In vitro: Myostatin treatment significantly inhibited the myogenic differentiation of myoblasts. However, suramin treatment significantly blocked myostatin’s effects and moreover suramin treatment stimulated the fusion of myoblasts in a dose-dependent manner in the presence of myostatin. In vivo: Suramin (2.5 mg) injection demonstrated a significant increase in the number of regenerating myofibers and reduction of fibrotic area when compared with the control group (0 mg). Furthermore, suramin injection effectively inhibited the expression of myostatin in the injured muscle. Conclusion: Suramin improved skeletal muscle healing by enhancing regeneration and reducing fibrosis after contusion injury. Furthermore, a decrease the expression of myostatin in injured muscle treated with suramin may reveal a possible mechanism by which suramin improves skeletal muscle healing after injury. Our findings may contribute to the development of progressive therapies for muscle injury. Acknowledgements: The authors are grateful for technical assistance from Maria Branca, Jessica Tebbets, Aiping Lu. Funding support was provided by Department of Defense (W81XWH-06-1-0406 awarded to Dr. Johnny Huard, Ph.D.), the William F. and Jean W. Donaldson Chair at the Children’s Hospital of Pittsburgh, and the Henry J. Mankin Endowed Chair in Orthopaedic Surgery at the University of Pittsburgh. Paper 255: The Influence of Locally Applied Platelet Derived Growth Factor on Free Tendon Graft Remodeling After Anterior Cruciate Ligament Reconstruction in Athletes FERNANDO RADICE, MD, CHILE, PRE-

Preoperative Simulation System for the ZCHW Custom Hip Prosthesis and Its Usage Through the Internet

The ZCHW custom hip prosthesis has been developed at the Department of Biomedical Engineering, University College of London, by Peter S. Walker and colleagues since 1988. About 3000 cases have been performed under the name of CAD- CAM Hip in the U.K., with very good results. We have been joining in the project since 1990, and 19 cases have been done since 1995 when the Japanese Ministry of Health and Welfare issued permission for it usage. A 3-D preoperative simulation system was developed to determine if there were problems, and the system was refined so as to be able to use it over the Internet. In this article, the results of these cases and the utility of the preoperative simulation system are presented.

A Finite Element Analysis for the Dysplastic Hip: About Rotational Acetabular Osteotomy

Acetabular dysplasia is the major cause of osteoarthritis (OA) of the hip in Japan. Pre- or early stages of osteoarthritic cases due to dysplastic hip underwent rotational acetabular osteotomy (RAO) at Nagoya City University Hospital. A two-dimensional finite element model was employed to reveal the effects of RAO. The dynamic characteristics revealed by finite element analysis showed that the center of gravity of the stress on the loaded articular cartilage had shifted medially and that the average of the stress had decreased postoperatively.