Date: 2009-10-30 Session: Symposium: Arthroplasty: High Performance Knee Time: 0800-0930 Room: Hall A1 Abstract number: 22773 CAOS KNEE ARTHROPLASTY Kang-Il KIM Kyung Hee University East-West Neo Medical Center, Seoul (KOREA) Recently, in order to enhance the accuracy of total knee arthroplasty (TKA) and to obtain better results, computer assisted surgery (CAS) has been developed and used. Examples of CAS-TKA include CT-based/ image-free computer-assisted navigation systems and operations using a surgical robot and many studies with clinical results on these are being published. Furthermore, In the presence of extra-articular deformity, TKA is difficult to perform because of altered anatomical axis and landmarks. TKA using a CAS system is associated with greater accuracy of component position, higher frequency of normal limb alignment and fewer radiographic outliers and it also has been reported to be effective especially in patients with extra-articular deformity. The navigation systems offer intraoperative information that let the surgeon manage the intervention and perform TKA with anticipated favorable results. The current navigation systems help us in placement of the cutting jigs. The first surgical robot for total joint arthroplasty was developed in 1986. Since then, several models of robot have been developed and tested. To date, few clinical and research studies have been published. Regardless of the joint involved, surgical procedures for successful robot-assisted TKA can be divided into several distinct stages. These include preoperative planning, calibration of the robot, surgical exposure, fixing a bone to the robot, registration, milling, and implantation. To perform a successful TKA using a robot, all of these stages should be completed effectually. Although we cannot present our clinical data in its entirety, most of the surgeries we performed proceeded uneventfully. However, even when the surgery was well planned, we sometimes encountered unexpected obstacles during the robotic surgery. From minor problems to more serious ones, the impacts of these obstacles on the surgery were variable. Moreover soft tissue balancing cannot be done with a robot, meticulous surgical experience is mandatory to finish successful TKA. Date: 2009-10-30 Session: Symposium: Arthroplasty: High Performance Knee Time: 0800-0930 Room: Hall A1 Abstract number: 22721 BICOMPARTMENTAL KNEE ARTHROPLASTY Alfred TRIA Robert Wood Johnson Medical School, Somerset, New Jersey (UNITED STATES) The presentation will review the early results of bicompartmental knee arthroplasty using a single piece femoral component for both a medial unicondylar and patellofemoral replacement. 40 patients with 42 knees underwent the replacement. They were chosen by history, physical examination, and x-rays. 38 patients were available for the 2 year follow up. There were 15 males and 23 females. Average age was 70 years (range 49-89). Average BMI was 30 (range 21-42). Average preoperative range of motion was 122 degrees and postoperative was 120. Knee Society score improved from 49 to 84 and the function score improved from 57 to 81. 3 patients have global knee pain and two have been revised to a TKA. One tibial tray has fractured and one has settled anteriorly. 10 patients have persistent anterior knee pain and one patient underwent a lateral release for patellar subluxation. 5 of the original 42 knees have either been revised or are pending revision (12 %) and 10 knees have persistent anterior knee pain (25 %). The surgical technique may need to be improved but the author cannot recommend the prosthesis for general use at the present time. Date: 2009-10-30 Session: Symposium: Arthroplasty: High Performance Knee Time: 0800-0930 Room: Hall A1 Abstract number: 22744 HIGH FLEXION KNEE: CLINICAL OUTCOME AT 5- TO 6-YEAR FOLLOW UP Aree TANAVALEE Department of Orthopaedics, Faculty of Medicine, Bangkok (THAILAND) PURPOSE: To evaluate the outcome TKA with the use of NexGen-Flex Legacy Posterior Stabilized (LPS) at 5- to 6-year follow up. MATERIAL AND METHOD: A consecutive series of 165 patients (189 knees) who underwent TKA using the NexGen-Flex LPS prosthesis were evaluated. Selection criteria included arc of motion >120°, <20°of deformity in corona l plane, <15° of flexion contracture, and <30 of BMI. At a minimum 5-year FU, clinical results, functional outcomes and maximum knee flexion were assessed. The percentage of knees that were able to kneel, sit in Thai polite style and sit cross-legged was evaluated. Preoperatively, patients were divided into 2 groups; A: able to do heel to buttock bending, and B: unable to do. RESULTS: The mean FU was 64 months and 156 patients [group A: 51 patients (60 knees)]; [group B: 105 patients (118 knees)] were evaluated. There were no statistical differences in patient’s age (70.5 and 69.8 yrs), preoperative knee deformity (4.7° and 5.1° of anatomical varus), BMI (25.7 and 26.4), preoperative KS clinical score (37.7 and 37.1), preoperative function score (31.5 and 30.9), postoperative KS clinical score (96.5 and 96.0) and postoperative function score (87.9 and 87.7). The average maximum flexion was significantly decreased from 146.2° to 135.0° in group A (p, 0.012). On the other hand, it was increased from 133.7° to 134.7° in group B without statistical significance. No significant difference between groups for kneeling (15.1% and 14.8%), sitting in Thai polite style (37.7% and 36.5%) and sitting cross-legged (42.1% and 42.5%). There was no early loosening related to implant. CONCLUSION: The NexGen-Flex LPS prosthesis provided favorable clinical outcomes at 5- to 6-year FU. However, it did not improve knee flexion when preoperative flexion was >120°. Furthermore, it decreased knee flexion when preoperative heel to buttock flexion was possible. Date: 2009-10-30 Session: Arthroplasty - Hip Time: 1030-1200 Room: Hall A1 Abstract number: 22776 THE ROLE OF CERAMIC TOTAL HIP REPLACEMENT IN THE MANAGEMENT OF HIP ARTHRITIS IN THE YOUNG ADULT James P. WADDELL ARTOF, Toronto/Ontario (CANADA) Hip arthritis in young adults causes significant disability. The use of hard bearing surfaces has provided an opportunity to use hip arthroplasty as a treatment for hip arthritis in the young adult as an alternative to osteotomy or arthrodesis. Metal-on-metal bearing surfaces have enjoyed considerable success both as conventional hip. Concerns have been raised regarding metal-metal arthroplasty with systemic increases in serum metal ion levels and specific local allergic reactions to metal wear debris resulting in significant soft tissue damage around the hip. Furthermore resurfacing appears to have a restricted role in many young patients as it may be contra- indicated in women of child bearing age, in patients with avascular necrosis and has a limited ability to correct significant deformity. Therefore many young adults have conditions that make them questionable candidates for resurfacing arthroplasty. The role of ceramic in total hip arthroplasty has evolved over the last 30years. Because of the hardness of ceramic and the ability to bring ceramic surfaces to a high polish wear rates of ceramic-on-polyethylene have been recognized as being superior to wear rates of conventional cobalt- chrome-on-polyethylene. The unfortunate experience of using zirconia-on-polyethylene led to an unwillingness to support the ceramic- on-polyethylene but with the advent of improved ceramic bearing surfaces and highly cross-linked polyethylene this will once again be a popular option for young patients with hip arthritis. Ceramic/ceramic articulation remains popular because a very low wear rate and excellent durability. Improved fracture toughness in the blended alumina/zirconia ceramic components will allow for an increased variety of head and liner options. We will detail our experiences with zirconia-on-polyethylene, alumina-on-polyethylene and alumina-alumina during this presentation. Date: 2009-10-30 Session: Arthroplasty - Hip Time: 1030-1200 Room: Hall A1 Abstract number: 21828 THIRD-GENERATION CERAMIC-ON-CERAMIC BEARINGS IN REVISION TOTAL HIP ARTHROPLASTY Jun-Dong CHANG Hangang Sacred Heart Hospital, Hallym University, Seoul (KOREA) PURPOSE: With an increase of revision total hip arthroplasty (THA), the choice of bearing surface becomes more important. Wear debris by conventional metal-on-polyethylene articulations may cause extensive osteolysis, especially in young patients. The purpose of the study is to evaluate the outcomes after revision THA with use of third generation ceramic-on-ceramic bearing. MATERIALS AND METHODS: We analyzed the clinical and radiographic outcomes after revision THA using third-generation ceramic-on-ceramic bearing (Biolox Forte; CeramTec, Plochingen, Germany) in 42 hips (37 patients; 17 men and 20 women). Their mean age was 48.8 years (32 - 59 years), and their mean weight was 61.5 ± 5.8 kg (50 - 72 kg) and BMI was 23.8. The mean duration of follow-up monitoring was 5.4 years (3.2-8.0 years). RESULTS: At final follow-up evaluation after revision, the average Harris Hip Score was 91.3. There were no revised hips during follow-up period. In 6 hips (14.3%), minor complications were observed: 3 heterotopic ossifications, 2 dislocations, and 1 infection. There were no hips with radiolucent lines, vertical or horizontal acetabular cup migration or osteolysis during the follow- up period. In 21 hips with bone graft, incorporation of bone graft was observed radiographically at final follow-up examination. There were no re-revised cases. CONCLUSION: