Venous Thromboembolism Following Hip and Knee Replacement Arthroplasty in Korea: A Nationwide Study Based on Claims Registry

The aim of this study was to examine the incidence and trends of clinically relevant venous thromboembolism (VTE) including deep vein thrombosis (DVT) and pulmonary embolism (PE) after hip and knee replacement arthroplasty (HKRA) in Korea. Between January 1 and December 31, 2010, 22,127 hip replacement arthroplasty (HRA) patients and 52,882 knee replacement arthroplasty (KRA) patients were enrolled in the analysis using the administrative claims database of the Health Insurance Review and Assessment Service (HIRA). All available parameters including procedure history and clinically relevant VTE during the 90 days after HKRA were identified based on diagnostic and electronic data interchange (EDI) codes. The overall incidence of VTE, DVT, and PE during the 90 days was 3.9% (n=853), 2.7% (n=597), and 1.5% (n=327) after HRA, while the incidence was 3.8% (n=1,990), 3.2% (n=1,699), and 0.7% (n=355) after KRA. The incidence of VTE after HKRA was significantly higher in patients who had previous VTE history (odds ratio [OR], 10.8 after HRA, OR, 8.5 after KRA), chronic heart failure (2.1, 1.3), arrhythmia (1.8, 1.7), and atrial fibrillation (3.4, 2.1) than in patients who did not. The VTE incidence in patients with chemoprophylaxis was higher than that in patients without chemoprophylaxis. The incidence of VTEs revealed in this retrospective review was not low compared with the results of the studies targeting other Asian or Caucasian populations. It may warrant routine prevention including employment of chemoprophylaxis. However, the limitation of the reviewed data mandates large scale prospective investigation to affirm this observation.

The Epidemiology and National Trends of Bearing Surface Usage in Primary Total Hip Arthroplasty in Korea

BACKGROUND: We analyzed the data for primary total hip arthroplasty (THA) in the Korean nationwide database to assess (1) the epidemiology and national trends of bearing surface usage in THAs and (2) the prevalence of each type of bearing surface according to age, gender, hospital type, primary payer, and hospital procedure volume. METHODS: A total of 30,881 THAs were analyzed using the Korean Health Insurance Review and Assessment Service database for 2007 through 2011. Bearing surfaces were sub-grouped according to device code for national health insurance claims and consisted of ceramic-on-ceramic (CoC), metal-on-polyethylene (MoP), ceramic-on-polyethylene (CoP), and metal-on-metal (MoM). The prevalence of each type of bearing surface was calculated and stratified by age, gender, hospital type, primary payer, and procedure volume of each hospital. RESULTS: CoC was the most frequently used bearing surface (76.7%), followed by MoP (11.9%), CoP (7.3%), and MoM (4.1%). The proportion of THAs using a CoC bearing surface increased steadily from 71.6% in 2007 to 81.4% in 2011, whereas the proportions using CoP, MoP, and MoM bearing surfaces decreased. The order of prevalence was identical to that in the general population regardless of age, gender, hospital type, primary payer, and hospital procedure volume. CONCLUSIONS: The trends and epidemiology of bearing surface usage in THAs in Korea are different from those in other countries, and the CoC bearing surface is the most prevalent articulation. In future, the results of a large-scale study using nationwide data of THAs involving a CoC bearing surface will be reported in Korea.

Lateral Closing Wedge Osteotomy of Tibia for Degenerative Arthritis / 대한정형외과학회잡지

Proximal tibial osteotomy is an effective, well-established treatment for unicompartmental arthritic knee with varus or valgus deformity. Four basic types are commonly described: lateral closing wedge osteotomy, medial open wedge osteotomy, dome osteotomy, and medial opening hemicallotasis. The objective of this procedure is to realign the weight-bearing axis through the knee by redistributing the forces of weight to the less involved compartment of the knee. With thorough preoperative planning and careful selection of patients, optimal outcome can be expected with preservation of the patient's joint. In this article, we reviewed selection of patients, surgical planning, surgical technique, complications, pre- and post-operative change in mechanics, and long term surgical outcome of closing wedge osteotomy. Optimal outcome is expected in patients with young age (younger than 60), stable knee, medially confined osteoarthritis, and good range of motion. According to the literature, average 10-year survival rate is expected to be 60% to 90%. Closing wedge osteotomy allows for rapid bone healing, early weight bearing, rehabilitation, and low rates of correction loss. Surgeons should keep in mind that optimal indication, preoperative planning, and use of safe operative technique are essential to achievement of best results.

Outcomes of the Different Types of Total Knee Arthroplasty with the Identical Femoral Geometry

PURPOSE: There are controversies around the role of the posterior cruciate ligament and the effect of design modifications for high flexion in total knee arthroplasty (TKA). So, we compared the clinical outcomes of the cruciate retaining (CR), posterior stabilized (PS), and high flexion posterior stabilized (F-PS) designs in TKA with identical femoral geometry. MATERIALS AND METHODS: One hundred seventy nine knees with 3 different types of prostheses after a minimum 5-year follow-up were enrolled in this retrospective study: 45 with CR, 40 with PS and 94 with F-PS. The mean ages of these groups were 65.7, 67.2, and 67.5, and the mean durations of follow-up were 8.1, 8.0, and 6.8 years, respectively. We compared the range of motion, functional outcomes, and radiographic measurements at the 2-year follow-up and last follow-up. RESULTS: The maximal flexion angle was significantly lower in the CR group than the F-PS group at the 2-year follow-up. However, there was no significant difference at the last follow-up. Functional outcomes and survival rate of the three groups were similar at the last follow-up. CONCLUSIONS: Three different types of TKAs (CR, PS and F-PS) with identical femoral geometry showed similar mid-term outcomes with regard to the range of motion, functional outcomes and survival rate.

Anatomical Assessment of the Distal Femur and Tibia for Optimal Femoral Rotational Alignment in Total Knee Arthroplasty

PURPOSE: This study aimed 1) to identify the rotational axis of the femur that provides a balanced 90degrees flexion space in TKA, 2) to assess the changes in the flexion space in deep flexion, and 3) to assess the changes in rotational alignment, with using the posterior condylar axis (PCA) as a guide, and as the changes are related to asymmetric cartilage erosion of the posterior condyle. MATERIALS AND METHODS: The axial MR images of the distal femur in knee extension and the coronal images of the distal femur and the entire tibia at 90 and 130degrees were examined in 40 healthy adults. RESULTS: The clinical transepicondylar axis (TEA) provides a balanced 90degrees flexion space on average. The balanced flexion space in 90degrees became an asymmetrical space with relative narrowing of the medial side in 130degrees. Every 1 mm of asymmetrical cartilage erosion between the posterior condyles changed the femoral rotation by approximately 1degrees when using the PCA as a guide. CONCLUSION: This study suggests that the clinical TEA is the rotational reference that provides a balanced flexion space. When using the PCA as a rotational reference, a surgeon should consider the potential change in the rotational angle that is caused by asymmetrical cartilage erosion.

Rotational Alignment of the Femoral Components in Total Knee Arthroplasty: A Modified Gap Technique Using Manual Distraction

PURPOSE: This study was undertaken to introduce a modified gap technique using manual distraction for achieving proper rotational alignment of the femoral components in total knee arthroplasty (TKA) and we compared the accuracy of the rotational alignment of the femoral components in TKAs when using a navigation system with that of another conventional technique. MATERIALS AND METHODS: We randomly used three different methods and implants (group 1: 3degrees external rotation from the posterior condylar axis method, group 2: a modified gap technique using manual distraction and group 3: a navigation system, Orthopilot(R)) in 92 patients. We measured the posterior condylar angles (PCA: the angle between the posterior condylar line and the transepicondylar axis) on computed tomography before and after surgery. RESULTS: The analysis showed no significant differences of the demographic data (age, height, weight, body mass index) and of the mean PCAs for the rotational alignment of the femoral components between the three groups (preoperative PCA: 5.45degrees vs. 5.34degrees vs. 5.24degrees, respectively; postoperative PCA: 1.91degrees vs. 1.17degrees vs. 1.37degrees, respectively, p>0.05). However, the conventional 3degrees external rotation method showed a higher frequency of outliers (p=0.028). CONCLUSION: The modified gap technique using manual distraction showed a higher accuracy of the femoral rotational alignment compared with that of the 3degrees external rotation method by reducing the outliers, and the modified gap technique using manual distraction showed similar results compared with those of the navigation method.

Rigid Stepped Plate (RSP) for the Internal Fixation of the High Tibial Osteotomy / 대한정형외과연구학회지

PURPOSE: To compare the fixation power of the newly devised RSP (rigid stepped plate) with the L-plate by mechanical study and to prove the efficacy of the RSP. MATERIALS AND METHODS: Lateral closing wedge proximal tibial osteotomy was performed on the 10-monthsold porcine tibiae, which were fixed by 15 L-plates and 15 RSP's. Each group of 5 pairs of the specimen were applied to the Instron apparatus and loaded by compression, valgus, and varus bending. The fixation power was compared by the stiffness of each construct. RESULTS: Specimen fixed by the RSP's showed larger stiffness than those fixed by the L-plate. Even though the difference was not statistically significant in compression (p=0.465), it was statistically significant in valgus (p=0.047) and varus (p=0.009) bending. CONCLUSION: The RSP can be applied with minimal skin incision, will provide firm initial fixation to the osteotomy site, and seems to enable early range of motion exercise. It will improve the outcome of proximal tibial osteotomy by preventing excessive soft tissue dissection and complications resulting from long-term immobilization of the knee joint.

Short Term Clinical Results of Anatomical Reconstruction in the Posterolateral Corner of the Knee using Achilles Tendon Allograft / 대한정형외과학회잡지

PURPOSE: The purpose of this study was to evaluate the short term clinical results of the new anatomical reconstruction including 3 major posterolateral structures of the knee using a split Achilles allograft. MATERIALS AND METHODS: Eleven knees with posterolateral rotary instability underwent new anatomical posterolateral reconstruction between January 2002 and June 2003. The clinical results were assessed using the Lysholm score and Tegner activity level scales and physical examinations including posterolateral drawer test, dial tests at 30 and 90 degrees of knee flexion, varus stress tests at 0 and 30 degrees of knee flexion. RESULTS: Follow-up averaged 26 months (range, 12 to 29 months). The mean preoperative Lysholm score was 38.6 and at the time of latest follow-up, the mean score was improved to 72.5. The mean preoperative Tegner activity level was improved from 1.6 points to 3.3. Ten out of 11 patients showed negative conversion of the posterolateral drawer test and varus stress test at 30 degrees of flexion postoperatively. All patients, who showed positive signs on the external rotation-dial test at 30 degrees of knee flexion preoperatively, improved postoperatively. In eight patients, preoperative positive signs of varus stress tests at 0 degrees of knee flexion and the external rotation-dial test at 90 degrees of knee flexion disappeared postoperatively. CONCLUSION: This study suggests that the new anatomical reconstruction of posterolateral corner of knee is a reliable method providing excellent stability and satisfactory short term clinical results.

Anatomical Assessment of Distal Femur for Optimal Femoral Component Rotational Alignment in TKA / 대한정형외과학회잡지

PURPOSE: We evaluated the relationship among the various rotational reference axes of femoral component in TKA, and the potential change in rotational alignment when a posterior condylar axis (PCA) was used as a reference for different cartilage erosions between the medial and lateral posterior femoral condyles. MATERIALS AND METHODS: The study subjects included twenty male and twenty female volunteers. Axial MR image of the distal femur were used to measure the angles among the clinical transepicondylar axis (cTEA), surgical transepicondylar axis (sTEA), the PCA, and the AP axis. We then evaluated the difference in the amount of rotation between a normal and osteoarthritic model when the PCA was used as a rotational reference. RESULTS: The mean angle between cTEA and PCA was 5.4 degrees, and it was significantly greater in the female (6.5 degrees) than in the male group (4.3 degrees). The cTEA demonstrated a perpendicular relationship with the AP axis in both groups. The average angles between cTEA and sTEA were 3.2 degrees in the male group and 3.8 degrees in the female group. When we assumed complete erosion of the cartilage on the medial posterior condyle with preservation on the lateral side, the angles between the cTEA and PCA decreased by an average of 1.9 degrees in both groups. CONCLUSION: This study suggests that the two transepicondylar axes, which demonstrated greater than 3 degrees in angle-difference, should be defined clearly in scientific reports and in their application as rotational references in TKA. Some significant gender differences in the rotational profile were noted. When the PCA is used as a rotational reference, potential errors caused by the different amounts of cartilage erosion between the medial and lateral posterior condyles should be considered.