Three-year clinical and radiological results of a cruciate-retaining type of the knee prosthesis with anatomical geometry developed in Japan.

BACKGROUND: The FINE total knee was developed in Japan and clinical use began in 2001. It has unique design features, including an oblique 3o femorotibial joint line that reproduces anatomical geometry. Although 20 years have passed since the FINE knee was clinically used for the first time in Japan, a formal clinical evaluation including patient-reported and radiographic outcomes has not been undertaken. METHODS: A total of 175 consecutive primary cruciate-retaining (CR)-FINE total knee arthroplasties (TKAs) at our hospital between February 2015 and March 2017 were included in this study. Three years postoperatively, range of motion (ROM), Knee Society Score (KSS), Knee Injury and Osteoarthritis Outcome Score (KOOS) and Forgotten Joint Score (FJS) were recorded and compared with preoperative scores. Radiographic analyses including mechanical alignment, component alignment, and incidence of radiolucent lines also were undertaken based on the radiographs 3 years postoperatively. RESULTS: One-hundred twenty-two knees (70%) were available for 3-year follow-up data using KOOS, except for the sports subscale. Postoperative KOOS-symptom, -pain and -ADL were > 85 points, but KOOS-sports, -QOL and FJS were less satisfactory. ROM, KSS and all the subscales of KOOS were significantly improved compared with preoperative scores. Postoperative mean FJS was 66 and was significantly correlated with all the subscales of KOOS, but not with postoperative ROM. Radiolucent lines ≧1 mm wide were detected in five knees (4.1%). There were no major complications needing revision surgeries. CONCLUSIONS: Patient-reported outcomes (PROs) for symptoms, pain and ADL after the CR-FINE TKA were generally improved, but those for sports, QOL and FJS were improved less. The incidence of radiolucent lines was rare but detected around the femoral components. With the mid- to long-term follow-up, improvements of surgical technique will be necessary to achieve better PROs from patients receiving the FINE knee.

Predicting clinical outcomes after total knee arthroplasty from preoperative radiographic factors of the knee osteoarthritis.

BACKGROUND: Total knee arthroplasty (TKA) is the major surgical treatment for end-stage osteoarthritis (OA). Despite its effectiveness, there are about 20% of patients who are dissatisfied with the outcome. Predicting the surgical outcome preoperatively could be beneficial in order to guide clinical decisions. METHODS: One-hundred and ten knees of 110 consecutive patients who underwent TKAs for varus knees resulting from OA were included in this study. Preoperative varus deformities were evaluated by femorotibial angle (FTA), medial proximal tibial angle (MPTA) and lateral distal femoral angle (LDFA), and classified as a severe varus (SV) or a mild varus (MV) group. The osteophyte score (OS), which we developed originally, was also calculated based on the size of the osteophytes and classified as groups with more or less osteophytes. We compared preoperative and 1-year postoperative range of motion, the Knee Society Score, and Japanese Knee injury Osteoarthritis Outcome Score (KOOS) between SV and MV groups (varus defined by FTA, MPTA, or LDFA), in each group with more or less osteophytes. RESULTS: When varus deformities were defined by FTA, regardless of OS, postoperative KOOS subscales and/or the improvement rates were significantly higher in the SV group than in the MV group. When varus defined by MPTA, regardless of OS, there were no significant differences in postoperative KOOS subscales between groups. However, when varus defined by LDFA, scores for pain, activities of daily living (ADL), and quality of life (QOL) on postoperative KOOS and/or the improvement rates were significantly higher in the SV group than in the MV group only in patients with less osteophytes. No significant differences were found between groups in patients with more osteophytes. CONCLUSIONS: We classified OA types by radiographic measurements of femur and tibia in combination with OS. Postoperative patient-reported outcomes were better in patients with SV knees but were poor in patients with knees with MV deformity and less osteophytes.

Effect of biological agents on synovial tissues from patients with rheumatoid arthritis.

Objectives: To compare the inflammation of synovium before and after biological agents in the patients with rheumatoid arthritis (RA) and to investigate the association between synovial histopathology and disease activity.Methods: Synovial tissues were obtained during operations from 34 patients before and after treatment with biological agents. The synovial tissue was evaluated using hematoxylin and eosin staining. Synovial histopathology was evaluated by Rooney score.Results: The Rooney score was also significantly decreased after treatment with biological agents in all items (p < .001). After the treatment with biological agents, Moderate disease activity group had significantly higher scores of focal aggregates of lymphocytes (p = .02), diffuse infiltrates of lymphocytes (p = .019), and the Rooney total scores (p = .002) than remission and low disease activity groups.Conclusion: Our results demonstrated that biological agents significantly decreased the RA synovial inflammation and synovial histopathology in sublining layer reflected disease activity.

Motion type and knee articular conformity influenced mid-flexion stability of a single radius knee prosthesis.

PURPOSE: Single radius knee implants were introduced to reduce the level of paradoxical anterior femoral translation (AFT) during mid-flexion after total knee arthroplasty. Findings from clinical and experiment studies are inconsistent, which may be due to the different loading conditions and articular conformities of the knee implants studied. The aim of this study is to analyze how variations in these two factors affect the mid-flexion stability of a single radius knee prosthesis. METHODS: Six daily activities (walking, stair ascent, stair descent, sit-to-stand, pivot turn and crossover turn), and three articular conformity ratios (low, moderate and high) were considered. The resulting AFTs from the 18 finite element models were analyzed. RESULTS: For low conformity knees, the worst case activity (the greatest AFT) was sit-to-stand with an AFT of 6.2 mm, while for the moderate conformity the worst case was crossover turn and pivot turn. For high conformity, all activities produced a relatively small AFT ranging from 0 mm to 1.8 mm, which more closely resembles natural knee motion. In addition, no AFT was recorded during stair ascent for all three conformities (low, moderate, high). CONCLUSIONS: This study demonstrated that the amount of AFT is highly dependent on the activity being undertaken and the articular conformity of the knee prosthesis, and the worst case activity depends on the knee conformity. The clinical relevance of this study is that it offers valuable information towards the design of improved knee prostheses and selection of knee implants for clinical use. LEVEL OF EVIDENCE: II.

A comparative study of flat surface design and medial pivot design in posterior cruciate-retaining total knee arthroplasty: a matched pair cohort study of two years.

BACKGROUND: Component design is one of the contributory factors affecting the postoperative flexion angle. The purpose of this study was to compare short-term outcomes of flat surface and medial pivot designs in posterior cruciate-retaining (CR) total knee arthroplasty (TKA). METHODS: A retrospective, case-control, and observational cohort study consisted of matched-pairs of the flat surface design (Hi-Tech Knee II) and the medial pivot design (FINE Knee) in CR-TKA with a two-year follow-up period. RESULTS: Hi-Tech Knee II and FINE knee groups each included 7 males and 38 females. Surgical time was significantly shorter in the FINE Knee group than in the Hi-Tech Knee II group (104.8 min versus 154.9 min, p = 0.001). Estimated total blood loss was significantly lower in the FINE Knee group than in the Hi-Tech Knee II group (654 ml versus 1158 ml, p = 0.001). The postoperative flexion angle was significantly better in the FINE Knee group than in the Hi-Tech Knee II group (119.3 degrees versus 112.5 degrees), and was positively correlated with the preoperative flexion angle. Postoperative Knee Society scores were significantly better in the FINE Knee group than in the Hi-Tech Knee II group (93.0 points versus 85.0 points, p = 0.001), especially for postoperative pain relief (46.0 points versus 39.0 points out of 50, p = 0.001). Complications were not observed in either group over a two-year follow-up period. CONCLUSION: The short-term outcome of the medial pivot design used in CR-TKA was more favorable than the flat surface design, especially for surgical time, estimated total blood loss, postoperative flexion angle, and knee pain.

Does use of a biologic agent increase the incidence of postoperative infection in surgery for rheumatoid arthritis after total joint arthroplasty?

OBJECTIVES: The goal of the study was to examine the influence of biological agents on postoperative infections such as surgical site infection (SSI) and late infection in patients with rheumatoid arthritis after total joint arthroplasty at our hospital between January 2006 and December 2011. METHODS: The patients were divided into groups with (Bio group, 267 joints) and without (Non-Bio group, 300 joints) treatment with biological agents. We examined the incidence of postoperative infection in Bio group and Non-Bio group. Multivariate logistic regression analysis was performed to identify the risk factor of postoperative infection. RESULTS: The incidences of superficial and deep SSI were 0.37% and 1.0%, respectively, in the Bio group, and 0.67% and 0%, respectively, in the Non-Bio group, with no significant difference between the two groups. The incidences of late infection were 1.0% and 0% in the Bio and Non-Bio groups, respectively, again with no significant difference between the groups. Multivariate logistic regression analysis revealed the following values for the surgery of the foot and ankle region [P = 0.001, odds ratio (OR) = 19.27; 95% confidence interval (CI) 4.67-79.45]. The use of biological agents was not a risk factor for postoperative infection. CONCLUSIONS: These results suggest that the use of biological agents does not significantly increase the incidences of SSI and late infection after orthopedic surgery in patients with rheumatoid arthritis after total joint arthroplasty.

Analysis of perioperative clinical features and complications after orthopaedic surgery in rheumatoid arthritis patients treated with tocilizumab in a real-world setting: results from the multicentre TOcilizumab in Perioperative Period (TOPP) study.

OBJECTIVE: To evaluate perioperative changes in rheumatoid arthritis (RA) patients treated with tocilizumab. METHODS: We collected RA cases with tocilizumab and orthopaedic surgery from 1999 to 2010. Incidences of postoperative infections, delayed wound healing, and RA symptom flare-ups were extracted from the data for comparison with patients without these postoperative events. We also evaluated the changes in C-reactive protein (CRP) and body temperature in patients without postoperative complications with normal CRP before surgery, i.e., patients without postoperative events in whom the tocilizumab level was maintained, for each duration to discontinuation before surgery. RESULTS: A total of 161 cases (n = 122) were collected. The patients had mean age of 56.9 years, and mean disease duration of 12.8 years at operation. Joint replacement surgery was performed in 89 cases. Three patients had postoperative infections (two superficial and one organ/space surgical-site infection), 20 had delayed wound healing, and 36 had RA symptom flare-ups. Delayed wound healing occurred most commonly in patients who underwent spinal surgery (P = 0.0061, versus patients without delayed wound healing). CRP levels were high when tocilizumab was restarted in patients with RA symptom flare-ups (P = 0.0010, versus patients without RA symptom flare-ups). Increased postoperative CRP was observed in patients without postoperative events when the duration from final tocilizumab infusion to surgery was long. The changes in body temperature showed a similar trend to CRP. CONCLUSIONS: Although it has been demonstrated that infection rates in patients treated with tocilizumab are by no means high, incidence of delayed wound healing was significantly higher in cases with surgical interventions such as foot and spinal surgeries. Many patients treated with tocilizumab remained in a normal range of CRP even during the perioperative period. For prevention of perioperative complications, observation of postoperative conditions and surgical wounds, and subjective symptoms of patients are considered important.

The impact of postoperative inclination of the joint line on clinical outcomes in total knee arthroplasty using a prosthesis with anatomical geometry.

The goal of this study was to investigate the impact of postoperative inclination of the joint line on clinical results after total knee arthroplasty (TKA) using a prosthesis with anatomical geometry. This study included 145 primary cruciate-retaining type of knee prosthesis with anatomical geometry. Three years postoperatively, clinical outcomes including the patient-reported outcomes (PROs) were recorded. Limb alignment was evaluated by the hip-knee-ankle (HKA) axis and inclination of the joint line was assessed by the joint line orientation angle (JLOA). Knees were divided into two groups according to the HKA: in-range (- 3 to 3°) and outlier group (< - 3° or > 3°) or the JLOA: in-range (2-4°) and outlier group (< 2° or > 4°), and clinical outcomes were compared between the groups. Postoperative Knee Society Function Score (KS-FS) was significantly higher in the HKA in-range group than the outlier group (p = 0.01). The Knee Society Knee Score and all subscales of the Knee injury Osteoarthritis Outcome Score were comparable between the groups. A multivariate analysis revealed a significant association between age at operation and postoperative KS-FS > of 80 points. Neither HKA in-range nor JLOA in-range were associated with the higher knee function. In conclusion, TKA-postoperative inclination of the joint line was not relevant to the short-term PROs. Treatment strategies that attempt to make joint line inclination in order to improve postoperative PROs should be avoided, and alignment goals such as kinematic alignment should be considered carefully.

Incidence of venous thromboembolism after spine surgery.

BACKGROUND: The incidence of venous thromboembolism (VTE) has varied among studies of patients undergoing elective spine surgery. This may be because of differences in prophylaxis for VTE and differences in methods of observation. Furthermore, some studies have reported symptomatic deep vein thrombosis (DVT) or pulmonary thromboembolism (PE), whereas others have included asymptomatic DVT or PE, making comparisons difficult. Therefore, the objective of this study was to determine the incidence of symptomatic and asymptomatic PE in patients undergoing elective spine surgery and to evaluate therapeutic methods for these conditions. METHODS: The subjects were 1975 patients who underwent spine surgery in our hospital from 1990 to 2011. Patients treated from January 1990 to November 1996 (n = 541, Group A) did not receive prophylaxis whereas those treated from January 2000 to February 2011 (n = 1,434, Group B) used a foot pump during and after surgery and subsequently wore elastic stockings. All subjects in Group A began ambulation ≥2 weeks after surgery whereas those in Group B began to walk earlier-within 3 days for patients who underwent decompression and within 1 week for those treated with fusion. From June 2010 to February 2011, contrast-enhanced computed tomography (CT) was performed 1 week after surgery for 100 patients to evaluate the presence of DVT and PE. Since March 2004, D-dimer was measured 1 week after surgery and patients with a level ≥10 µg/mL were followed up. RESULTS: The incidence of symptomatic PE was significantly higher in Group A than in Group B (8/541, 1.5% vs. 3/1,434, 0.2%). In 3 patients in Group B, PE developed within 1 week postoperatively and D-dimer values at onset were ≤10 µg/mL. In the 100 cases examined by contrast-enhanced computed tomography (CT), asymptomatic PE and VTE were detected in 18 and 19%, respectively. The D-dimer level 1 week after surgery was ≥10 µg/mL in 105 of 841 patients; however, none of these patients had clinically symptomatic VTE for at least 3 months postoperatively. CONCLUSIONS: Mechanical prophylaxis and early ambulation may be effective in reducing the incidence of symptomatic PE after spine surgery. Asymptomatic PE developed in 18% of patients who received mechanical prophylaxis, but the incidence of symptomatic PE was only 0.2%. Prompt diagnosis and treatment are required for patients who develop symptomatic PE.

Perioperative complications in elective surgery in patients with rheumatoid arthritis treated with biologics.

We retrospectively investigated the influence of biological agents on delayed wound healing and the occurrence of postoperative surgical site infection (SSI) in patients after surgery for rheumatoid arthritis. The patients were divided into two groups-those with and without treatment with biological agents (276 and 278 joints, respectively)-and adverse events (delay in wound healing and SSI) were investigated. Wound healing was delayed in 11.4% of total knee arthroplasty (TKA) operations, 16.7% of total ankle arthroplasty operations, and 9.7% of foot surgeries in the treatment group, and in 5.5% of TKA operations, 12.5% of total elbow arthroplasty operations, and 5.7% of foot surgeries in the non-treatment group. The difference in the incidence of delayed wound healing between the two groups was not statistically significant. In the treatment group, postoperative superficial and deep infection developed in one and two joints, respectively. In the non-treatment group, superficial infection developed in one joint. There was no statistically significant difference between the two groups. These findings suggest that the use of biological agents may not affect the incidence of postoperative adverse events related to wound healing and SSI.

Assessment of influences of posterior rotation of the tibial condyles on the Insall-Salvati ratio.

The positional relationship between patellar and femoral articular surfaces may vary according to the degree of posterior rotation of the tibial condyle, which may influence the patellar configuration. We hypothesized that the configuration of the patella has a rhomboid transformation similar to that of the tibial condyle. This cohort study included 313 patients with knee pain who underwent lateral-view knee digital radiography. The length of the long axis, short axis of the patella, and patellar tendon length of the patellofemoral joint were measured. The patella axis ratio (length of long/short axis) as patellar configuration and Insall-Salvati ratio were calculated. Correlations between the configuration of the tibial condyle and the three length parameters and the Insall-Salvati ratio were assessed. Posterior rotation and the rhomboid transformation of the tibial condyle were positively correlated with the length of the long axis of the patella and negatively correlated with the Insall-Salvati ratio. The more the tibial articular surface shifted posteriorly due to posterior rotation and rhomboid transformation of the tibial condyle, the longer the long axis of the patella was, and the smaller the Insall-Salvati ratio was. The long axis of the patella became longer due to rhomboid transformation, similar to the tibial condyle.

Lateral shift of the femoral condyle after total knee arthroplasty: simulation using 2D-templates of the medial pivot design on knee radiographs of young Japanese patients.

BACKGROUND: Total knee arthroplasty (TKA) is an established surgical treatment for advanced knee osteoarthritis by which patients can expect improvement of knee pain and function. Although many surgeons have investigated limb alignment after TKA, changes in coronal positional relation between the femur and tibia are not known well. METHODS: Radiographs of 105 knees of young Japanese patients between 20 and 49 years-old (60 men and 45 women) without osteoarthritic changes who received arthroscopic surgeries at our hospital were used in this study. Using 2D-templates of the medial pivot design (the FINE total knee), we simulated TKA on a SYNAPSE-PACS software. First, the femoral component was placed in normal knee alignment and then was merged to the medial concave of the insert where the tibial component was placed in neutral alignment. The length of the mediolateral shift of the femoral component was measured as an estimate of lateral shift of the femoral condyle, of which association with radiographic parameters including the femorotibial angle (FTA), lateral distal femoral angle (LDFA), and medial proximal tibial angle (MPTA) was analyzed. Subjects were classified into three groups according to the femoral component size that was chosen in simulation of TKA, and the lateral shift of the femoral condyle was compared between groups. RESULTS: The estimated mean lateral shift of the femoral condyle was 5.99 ± 1.98 mm and was greater in males than females (p < 0.05). Also, it was most highly correlated with the medial proximal tibial angle (MPTA) (r = - 0.553, p < 0.01). A group receiving larger component sizes significantly shifted more laterally compared with a group receiving smaller component sizes (p < 0.01). CONCLUSIONS: These results suggest that the coronal positional relation between the femur and tibia is altered and subsequent ligament imbalance may occur after mechanically aligned TKA using the medial pivot design.

Adiponectin stimulates prostaglandin E(2) production in rheumatoid arthritis synovial fibroblasts.

OBJECTIVE: Adipokines may influence inflammatory and/or immune responses. This study was undertaken to examine whether adiponectin affects the production of prostaglandin E(2) (PGE(2)) by rheumatoid arthritis synovial fibroblasts (RASFs). METHODS: Synovial tissue was obtained from patients with RA who were undergoing joint replacement surgery. Fibroblast-like cells from the third or fourth passage were used as RASFs. Expression of adiponectin receptor messenger RNA (mRNA) and protein was detected. PGE(2) (converted from arachidonic acid) was measured by enzyme-linked immunosorbent assay (ELISA). Expression of mRNA and protein for cyclooxygenase 2 (COX-2) and membrane-associated PGE synthase 1 (mPGES-1), key enzymes involved in PGE(2) synthesis, was detected in RASFs. The effects of RNA interference (RNAi) targeting the adiponectin receptor genes and the receptor signal inhibitors were examined. The influence of adiponectin on NF-kappaB activation in RASFs was measured with an ELISA kit. RESULTS: Adiponectin receptors were detected in RASFs. Adiponectin increased both COX-2 and mPGES-1 mRNA and protein expression by RASFs in a time- and concentration-dependent manner. PGE(2) production by RASFs was also increased by the addition of adiponectin, and this increase was inhibited by RNAi for the adiponectin receptor gene, or coincubation with the receptor signal inhibitors. Enhancement of NF-kappaB activation by adiponectin as well as by interleukin-1beta was observed in RASFs. CONCLUSION: Our findings indicate that adiponectin induces COX-2 and mPGES-1 expression, resulting in the enhancement of PGE(2) production by RASFs. Thus, adiponectin may play a role in the pathogenesis of synovitis in RA patients.

Analysis of the kinematics of total knee prostheses with a medial pivot design.

Analysis of the kinematics of the FINE Total Knee System (Nakashima Medical, Okayama, Japan) revealed that the medial condyle is fixed and the lateral condyle shows lateral posterior movement and tibial internal rotation. Analysis of the kinematics of the ADVANCE Total Knee System (Wright Medical Technology, Arlington, Tenn) revealed that the medial condyle is fixed and the lateral condyle shows anterior movement in the early stage, changing thereafter to posterior movement. With regard to rotation, initial external rotation subsequently changes to internal rotation. Analysis of the kinematics of the ADVANTIM Total Knee System (Wright Medical Technology) revealed that the bicondyle shows posterior movement, subsequently changing to anterior and posterior movements. Thus, unlike the FINE or ADVANCE Total Knee Systems, the ADVANTIM Total Knee System shows internal rotation.

Risk of postoperative complications in rheumatoid arthritis relevant to treatment with biologic agents: a report from the Committee on Arthritis of the Japanese Orthopaedic Association.

PURPOSE: Since biologic agents were introduced to treat rheumatoid arthritis (RA) in 2003, the number of orthopedic surgical procedures under treatment with biologic agents has been increasing in Japan. However, whether biologic agents cause an increase in the prevalence of postoperative complications is as yet unknown. The Committee on Arthritis of the Japanese Orthopedic Association investigated the prevalence of postoperative complications in patients with RA in teaching hospitals in Japan. METHODS: Between January 2004 and November 2008, surveillance forms about medications and surgical procedures in patients with RA were sent to 2,019 teaching hospitals. Data were analyzed by the Rheumatoid Arthritis Committee. RESULTS: Biologic agents were administered to RA patients in 632 of 1,245 hospitals (50.8%); 430 of the 1,245 hospitals (34.5%) used surgical intervention under treatment with biologic agents. The number of surgical procedures under treatment with biologic agents was 3,468, and the prevalence of infection was 1.3% (46 cases). The prevalence of infection was 1.0% (567 procedures) in 56,339 procedures under treatment with nonbiologic disease-modifying anti-rheumatic drugs. There were no significant differences between biological and nonbiological treatment groups with respect to the prevalence of infection. In the joint arthroplasty group, the number of procedures under biological and nonbiological treatment was 1,626 and 29,903, and the prevalence of infection was 2.1% (34 procedures) and 1.0% (298 procedures), respectively. There was a significant difference between groups. The odds ratio was 2.12 (95% confidence interval 1.48-3.03, P < 0.0001). CONCLUSION: The chance of having biological treatment with joint arthroplasty was more than twofold greater in patients with surgical-site infections compared with those treated with nonbiologic agents. Caution is required for surgical procedure, perioperative course, and obtaining consent for joint arthroplasty for patients with RA undergoing surgery under biological agents.

Recent trends in orthopedic surgery performed in Japan for rheumatoid arthritis.

The aim of this report was to review the use of orthopedic surgeries performed to manage rheumatoid arthritis (RA). Our review of studies published in English indicates that there has been a decrease in RA-associated surgeries in Western countries. Improvements in medical treatment may partly explain the reduction in numbers of orthopedic joint surgeries, which also suggests a worldwide trend toward improved long-term outcomes. However, the results of our multicenter study in Japan indicate that the number of RA-associated operations has not decreased, and that the numbers of operations performed annually have been relatively stable from 1998 to 2008. Although there definitely has been a decline in the numbers of synovectomy surgeries, the numbers of operations on the upper limbs and foot arthroplasties have increased. With the trend toward milder disease because of improved medical treatment, we speculate that RA patients may want and need better function for the activities of daily living. The combination of medical treatment and surgical intervention is thought to improve outcomes in RA patients who will develop joint destruction. Additional studies, including analyses of RA databases containing long-term data on a variety of surgical interventions, are needed.

Acupuncture needle-associated prosthetic knee infection after total knee arthroplasty.

The case of a patient who previously had permanent acupuncture needles placed in the knee joint and had been doing well, with no evidence of infection, but who eventually underwent a revision total knee arthroplasty due to acupuncture needle-associated prosthetic infection is presented. The microorganism responsible for the infection was Enterococcus faecalis, a bacterium which rarely causes infection following arthroplasty. This case should be highlighted to increase the awareness of healthcare providers to acupuncture-associated subclinical infection that may be exacerbated by surgical manipulation.

The posterior tibial slope is mainly created by the posterior rotation of the tibial condyles.

PURPOSE: Constitutional varus in the coronal plane is formed based on the Hueter-Volkmann's law. The varus deformity occurs at the proximal metaphysis of the tibia and the tibial condyle rotates medially. In the sagittal plane, we hypothesized that the posterior slope angle of the tibial articular surface may also occur at the proximal metaphysis and the tibial condyle rotates posteriorly. The purpose of this study was to verify the hypothesis. METHODS: A total of 208 patients who underwent TKA had lateral view proximal tibia digital radiograph on which seven parameters were analyzed. The posterior slope angle of the tibial articular surface relative to the anterior wall of the tibial condyle and that relative to the anterior cortex of the tibial shaft were assessed. Correlation between the position of the tibial condyle and the posterior slope angle of the articular surface were assessed. RESULTS: The proximal tibial condyle itself did not have a posterior slope in the 86.5% of the participants. Posterior rotation of the tibial condyle created posterior slope of the tibial articular surface relative to the anterior cortex of the tibial shaft. The more tibial condyle was posteriorly rotated, the more the tibial articular surface shifted posteriorly. CONCLUSION: Study findings showed that the posterior tibial slope occurs at the proximal metaphysis of the tibia, and the tibial condyle rotates posteriorly. The posterior tibial slope involves the posterior shift of the tibial articular surface. The posterior tibial slope is mainly created by the posterior rotation of the tibial condyle.

Proximal tibia vara involves the medial shift of the tibial articular surface.

PURPOSE: According to the concept of the constitutional varus, the tibial articular surface (TAS) has varus inclination. On the other hand, it has been reported that proximal tibia vara involved medial shift of the TAS. However, it has not been assessed whether varus inclination of the TAS has a correlation with the medial shift. We investigated whether varus inclination of the TAS has a correlation with the medial shift. If there is a correlation between two parameters, the influence of the medial shift of the TAS on the value of the hip-knee-ankle (HKA) angle and the femorotibial angle should be considered. METHODS: A total of 112 patients who underwent total knee arthroplasty had anteroposterior view tibia digital radiograph on which five parameters were analyzed. Varus angle of the TAS, the distance between the mechanical axis and the anatomical axis on the articular surface, and the width of the articular surface were measured. RESULTS: The more the proximal tibia had varus deformity, the more the TAS shift medially would be. Therefore, the mechanical axis does not match the anatomical axis. Because the HKA angle was assessed based on the concept that the mechanical and anatomical axes match on the tibia, this angle may not express the true alignment of the lower extremity in knees with proximal tibia vara. CONCLUSION: In varus knees, the proximal tibia has a medial shift of the TAS that may influence the value of the HKA angle.

Adiponectin stimulates IL-8 production by rheumatoid synovial fibroblasts.

The adipokines are linked not only to metabolic regulation, but also to immune responses. Adiponectin, but not leptin or resistin induced interleukin-8 production from rheumatoid synovial fibroblasts (RSF). The culture supernatant of RSF treated with adiponectin induced chemotaxis, although adiponectin itself had no such effect. Addition of antibody against adiponectin, and inhibition of adiponectin receptor gene decreased adiponectin-induced IL-8 production. Nuclear translocation of nuclear factor-kappa B was increased by adiponectin. The induction of interleukin-8 was inhibited by mitogen-activated protein kinase inhibitors. These findings suggest that adiponectin contributes to the pathogenesis of rheumatoid arthritis.