Total Knee Arthroplasty: Is It Safe? A Single-Center Study of 4,124 Patients in South Korea

Background@#Although total knee arthroplasty (TKA) is considered an effective treatment for knee osteoarthritis, it carries risks of complications. With a growing number of TKAs performed on older patients, understanding the cause of mortality is crucial to enhance the safety of TKA. This study aimed to identify the major causes of short- and long-term mortality after TKA and report mortality trends for major causes of death. @*Methods@#A total of 4,124 patients who underwent TKA were analyzed. The average age at surgery was 70.7 years. The average follow-up time was 73.5 months. The causes of death were retrospectively collected through Korean Statistical Information Service and classified into 13 subgroups based on the International Classification of Diseases-10 code. The short- and long-term causes of death were identified within the time-to-death intervals of 30, 60, 90, 180, 180 days, and > 180 days. Standard mortality ratios (SMRs) and cumulative incidence of deaths were computed to examine mortality trends after TKA. @*Results@#The short-term mortality rate was 0.07% for 30 days, 0.1% for 60 days, 0.2% for 90 days, and 0.2% for 180 days. Malignant neoplasm and cardiovascular disease were the main short-term causes of death. The long-term (> 180 days) mortality rate was 6.2%. Malignant neoplasm (35%), others (11.7%), and respiratory disease (10.1%) were the major long-term causes of death.Men had a higher cumulative risk of death for respiratory, metabolic, and cardiovascular diseases. Age-adjusted mortality was significantly higher in TKA patients aged 70 years (SMR, 4.3; 95% confidence interval [CI], 3.3–5.4) and between 70 and 79 years (SMR 2.9; 95% CI, 2.5–3.5) than that in the general population. @*Conclusions@#The short-term mortality rate after TKA was low, and most of the causes were unrelated to TKA. The major causes of long-term death were consistent with previous findings. Our findings can be used as counseling data to understand the survival and mortality of TKA patients.

Titanium Alloy Knee Implant Is Associated with Higher Bone Density over Cobalt Chromium:A Prospective Matched-Pair Case-Control Study

Background@#Little is known about the relationship between implant material and periprosthetic bone mineral density (pBMD) in total knee arthroplasty (TKA). The purpose of this study was to investigate the change in pBMD after TKA and to compare pBMD changes between two different implant materials. @*Methods@#A prospective matched-pair case-control study was conducted on 29 patients who underwent bilateral TKAs. The participants were randomly allocated to undergo cemented TKAs with a titanium nitride (TiN)-coated implant on one knee (TiN group) and a cobalt-chromium (CoCr) implant on the other knee (CoCr group). The pBMD was measured using dual-energy X-ray absorptiometry scans before surgery and at 1 and 2 years after surgery. The results were then compared between the two groups. The pBMDs at longer follow-ups (> 2 years) were estimated using simple radiographs (pBMDe). @*Results@#At 2 years after surgery, the pBMD significantly decreased in both groups at medial metaphysis of the tibia and anterior portion of the distal femur (all p < 0.001). The CoCr group showed a larger decrease in pBMD than did the TiN group in the medial and anterior metaphysis of the proximal tibia (p = 0.003 and p = 0.046, respectively). The pBMDe was significantly higher in the TiN group at the anterior portion of the distal femur 7 years after surgery (p = 0.019). @*Conclusions@#The pBMD significantly decreased 2 years after TKA in certain regions regardless of the implant material used. However, the decrease was significantly less in the TiN group in specific regions of the tibia and femur. The TiN implant was beneficial in preserving the periprosthetic bone stock after TKA.

Development of Prediction Model Using Machine-Learning Algorithms for Nonsteroidal Anti-inflammatory Drug-Induced Gastric Ulcer in Osteoarthritis Patients: Retrospective Cohort Study of a Nationwide South Korean Cohort

Background@#Nonsteroidal anti-inflammatory drugs (NSAID) are currently among the most prescribed medications worldwide to relieve pain and reduce inflammation, especially in patients suffering osteoarthritis (OA). However, NSAIDs are known to have adverse effects on the gastrointestinal system. If a gastric ulcer occurs, planned OA treatment needs to be changed, incurring additional treatment costs and causing discomfort for both patients and clinicians. Therefore, it is necessary to create a gastric ulcer prediction model that can reflect the detailed health status of each individual and to use it when making treatment plans. @*Methods@#Using sample cohort data from 2008 to 2013 from the National Health Insurance Service in South Korea, we developed a prediction model for NSAID-induced gastric ulcers using machine-learning algorithms and investigated new risk factors associated with medication and comorbidities. @*Results@#The population of the study consisted of 30,808 patients with OA who were treated with NSAIDs between 2008 and 2013. After a 2-year follow-up, these patients were divided into two groups: without gastric ulcer (n=29,579) and with gastric ulcer (n=1,229). Five machine-learning algorithms were used to develop the prediction model, and a gradient boosting machine (GBM) was selected as the model with the best performance (area under the curve, 0.896; 95% confidence interval, 0.883–0.909). The GBM identified 5 medications (loxoprofen, aceclofenac, talniflumate, meloxicam, and dexibuprofen) and 2 comorbidities (acute upper respiratory tract infection [AURI] and gastroesophageal reflux disease) as important features. AURI did not have a dose-response relationship, so it could not be interpreted as a significant risk factor even though it was initially detected as an important feature and improved the prediction performance. @*Conclusions@#We obtained a prediction model for NSAID-induced gastric ulcers using the GBM method. Since personal prescription period and the severity of comorbidities were considered numerically, individual patients’ risk could be well reflected. The prediction model showed high performance and interpretability, so it is meaningful to both clinicians and NSAID users.

Prognostic Factors of Mid- to Long-term Clinical Outcomes after Arthroscopic Partial Meniscectomy for Medial Meniscal Tears

Background@#Arthroscopic partial meniscectomy (APM) continues to be the popular treatment for meniscal tears, but recent randomized controlled trials have questioned its efficacy. To provide more evidence-based criteria for patient selection, we undertook this study to identify prognostic factors associated with clinical failure after APM for medial meniscus tears. @*Methods@#Medical records of 160 patients followed up for at least 5 years after APM for medial meniscal tears were retrospectively reviewed. Demographic data (age, sex, and body mass index), radiographic variables (Kellgren-Lawrence [K-L] grade and hip-knee-ankle [HKA] angle), and clinical scores (International Knee Documentation Committee score, Tegner activity scale score, Lysholm score, and Knee injury and Osteoarthritis Outcome Score) were recorded. Clinical failure was defined as the need for an additional surgical procedure (arthroscopy, osteotomy, or arthroplasty) or the presence of intolerable pain. Survivorship analysis with clinical failure as an end point was performed using Kaplan-Meier survival curves. Factors related to clinical failure were analyzed using a Cox proportional hazard model. Cutoff values were determined using areas under receiver operating characteristic (ROC) curves. Radiographic progression of osteoarthritis was analyzed using the chi-square test, and serial changes of clinical scores were analyzed using a linear mixed model. @*Results@#Clinical success rates were 95.7% at 5 years, 75.6% at 10 years, and 46.3% at 15 years. Age, HKA angle, and K-L grade (p = 0.01, p = 0.02, and p = 0.04, respectively) were found to be significant risk factors of clinical failure. Cutoff values at 10 years postoperatively as determined by ROC analysis were 50 years for age (sensitivity = 0.778, 1-specificity = 0.589), grade 2 for K-L grade (sensitivity = 0.778, 1-specificity = 0.109), and 5.5° for HKA angle (sensitivity = 0.667, 1-specificity = 0.258). In patients who had clinical success until 10 years after APM, radiological osteoarthritis progressed gradually. However, the clinical scores of patients who achieved clinical success did not decrease significantly over the 10-year follow-up. @*Conclusions@#The poor prognostic factors found to be related to clinical failure after APM for a medial meniscal tear were patient age (≥ 50 years), preoperative K-L grade (≥ grade 2), and preoperative HKA angle (≥ varus 5.5°).

What Has Been Learned in Anterior Cruciate Ligament Reconstruction during the Past 20 Years? / 대한정형외과학회잡지

Considerable progress on anterior cruciate ligament reconstruction surgery has been made over the past 20 years, and the results have improved significantly. An anatomical understanding of the anterior cruciate ligament has also changed, and the surgical technique has also changed accordingly. The double-bundle concept is still valid, but the ribbon-shaped anterior cruciate ligament concept, including direct fiber and indirect fiber, is gradually replacing it. The isometry point theory no longer exists, and various surgical methods, such as single-bundle anatomical reconstruction, double-bundle reconstruction, remnant preservation, and rectangular tunnel technique, are being performed. Regarding the graft, interest in the bone-patellar tendon-bone, patellar tendon, quadriceps tendon, and allogeneic tendon change over time, and this change is ongoing.

Translation and Validation of the Korean Version of the Forgotten Joint Score

Background@#The Forgotten Joint Score (FJS) is a newly developed patient-reported outcome measure designed to evaluate clinical outcome after total knee arthroplasty (TKA). The FJS is known as a sensitive test with a low ceiling effect. It has been recently translated into many languages. However, no study has reported the validity or reliability of a Korean version of the FJS (K-FJS). Thus, the purpose of this study was to address this issue. @*Methods@#According to guidelines for cross-cultural adaptation, translation of the English version of the FJS was performed. After obtaining a license from the original developer, 150 patients who had undergone TKA at more than 1 year to less than 5 years ago completed the K-FJS, visual analog scale, Western Ontario and McMaster Universities Osteoarthritis index (WOMAC), and the 36-Item Short Form (SF-36) health survey. To measure test-retest reliability, the K-FJS was completed twice by telephone survey for 100 patients. Responsiveness was retrospectively calculated based on a survey of 50 patients at 3 months and 1 year after surgery. @*Results@#The K-FJS exhibited an excellent reliability (Cronbach's α, 0.967; intraclass correlation coefficient, 0.958; 95% confidence interval, 0.930–0.974). The ceiling effect of the K-FJS was 8.7% (n = 13), which was lower than the WOMAC's ceiling effect (10%).There was no floor effect. The correlation coefficients with WOMAC and SF-36 (physical function) were 0.708 and 0.682, respectively, indicating good construct validity. However, its correlation with mental health subscale of SF-36 was low (r = 0.143). At 3 to 12 months after TKA, the standardized response mean (SRM) was 0.67, which was lower than the SRM of WOMAC (1.03) obtained in the same period. The K-FJS demonstrated strong measurement properties in terms of good construct validity and reliability. @*Conclusions@#This study suggests that the K-FJS is an excellent instrument that can be used to monitor clinical outcomes after TKA. Using this standardized K-FJS, it would be possible for medical institutions to share more accurate clinical results.

The Key Role of DNA Methylation and Histone Acetylation in Epigenetics of Atherosclerosis

Atherosclerosis, which is the most common chronic disease of the coronary artery, constitutes a vascular pathology induced by inflammation and plaque accumulation within arterial vessel walls. Both DNA methylation and histone modifications are epigenetic changes relevant for atherosclerosis. Recent studies have shown that the DNA methylation and histone modification systems are closely interrelated and mechanically dependent on each other.Herein, we explore the functional linkage between these systems, with a particular emphasis on several recent findings suggesting that histone acetylation can help in targeting DNA methylation and that DNA methylation may control gene expression during atherosclerosis.

Clinical and Radiological Changes after Microfracture of Knee Chondral Lesions in Middle-Aged Asian Patients

BACKGROUND: Although microfracture is widely accepted as an effective treatment option for knee chondral lesions, little is known about the deterioration of clinical outcomes and radiological progression in middle-aged patients. Therefore, this study was conducted to evaluate the clinical and radiological changes after microfracture of knee chondral lesions in middle-aged Asian patients. METHODS: A total of 71 patients were included in the study. They were between the ages of 40 and 60 years and underwent arthroscopic microfracture for localized full-thickness cartilage defects of the knee from January 2000 to September 2015. The recovery status of chondral lesions was assessed by using the magnetic resonance observation of cartilage repair tissue (MOCART) score in postoperative magnetic resonance imaging (MRI). Clinical and radiological results were reviewed, and survival rate with conversion to arthroplasty or osteotomy as an end point was evaluated. RESULTS: The mean age of the patients at surgery was 51.3 ± 4.7 years (range, 40 to 60 years), and the mean follow-up period was 7.2 ± 2.6 years (range, 1.0 to 17.4 years). The MOCART scores of 32 patients at mean postoperative 2.1 years showed three cases (9%) of full recovery, two cases (7%) of hyperplastic recovery, 23 cases (70%) with more than 50% filling, and four cases (14%) with less than 50% filling. Clinical scores improved significantly at 1 year after surgery (p < 0.05); however, the scores deteriorated over time after postoperative 1 year, and the mean values reached preoperative levels at postoperative 10 years. Significant radiological progression of arthritis (Kellgren-Lawrence grade) was observed at 5 years after surgery. Four patients underwent total knee arthroplasty during follow-up. CONCLUSIONS: Most patients showed more than 50% of defect filling at 2 years after surgery on MRI. Clinical results of microfracture of knee chondral lesion showed the best improvement at postoperative 1 year but gradually worsened thereafter until postoperative 10 years. Radiological progression of arthritis was observed from 5 years after surgery.

Incidence of Deep Vein Thrombosis after Major Lower Limb Orthopedic Surgery: Analysis of a Nationwide Claim Registry

PURPOSE: We aimed to evaluate the nationwide incidence and risk factors for symptomatic deep vein thrombosis (DVT) after major lower limb orthopedic surgeries. MATERIALS AND METHODS: The Korean Health Insurance Review and Assessment Service database was used to retrospectively identify International Classification of Disease-10 codes for DVT and operation codes representing hip arthroplasty, knee arthroplasty, and hip fracture surgeries. The age- and gender-adjusted annual incidence of DVT, rates of major lower limb orthopedic surgeries, and the postoperative incidence of DVT according to the surgical procedure were assessed. RESULTS: The age- and gender-adjusted annual incidence of DVT was 70.67 per 100000 persons/year. Compared to patients aged 70 years (p<0.001). Females showed a greater relative risk for DVT than males (1.08; p<0.001). The incidence of postoperative DVT, according to the type of surgery, was significantly greater for knee replacement arthroplasty than for other forms of surgery (p<0.002). The relative risk of postoperative DVT was higher in females in knee replacement arthroplasty (1.47) and hip fracture surgery (2.25) groups, although relatively lower in those who underwent hip replacement arthroplasty (0.97). CONCLUSION: Among major lower limb surgeries, advanced age, female gender, and undergoing a knee replacement arthroplasty were found to be risk factors for developing postoperative DVT. These findings further emphasize the need for orthopedic surgeons to consider the development of DVT after surgery in high-risk patients.

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.

Patient Characteristics and Treatment of Hallux Polydactyly Associated with Varus Deformity / 대한정형외과학회잡지

PURPOSE: To evaluate patient characteristics such as deformity type, associated disease, and family history, and results of treatment of pre-axial polydactyly with hallux varus deformity. MATERIALS AND METHODS: We carried out a retrospective study of 5 patients who presented with preaxial polydactyly with hallux varus deformity, and were treated between 2003 and 2010 at the authors' hospital. Surgeries including extra digit excision, local flap, osteotomy, and interphalangeal joint fusion were performed taking into consideration the deformity types and patient's age. Family history, associated disease, and types of duplication were assessed, and the outcomes of surgery were evaluated with radiographs and appearances of foot. The mean follow-up period was 34 months. RESULTS: All 5 patients had one or more associated anomalies such as congenital anterolateral tibial bowing and polydactyly in three, translocation of chromosome 2 : 13 associated with cryptorchidism in one, pes planovalgus in one, residual poliomyelitis in one, syndactyly of the foot in two, and leg length discrepancy in one patient. There was no family history of hallux polydactyly in any of the cases. All five patients had duplication of the distal phalanx and one of them had a blocked proximal phalanx. The extra digit was completely removed and the varus deformity was corrected in all cases. CONCLUSION: There was a high incidence of associated diseases in patients with hallux polydactyly and varus deformity. Deformity correction could be obtained by surgeries chosen according to the individual deformity type and patient age.