Influence of strength and balance ability on functional performance in the involved and uninvolved sides after anterior cruciate ligament reconstruction.

BACKGROUND: The restoration and management of the uninvolved side have been emphasized to prevent a second anterior cruciate ligament (ACL) injury and to ensure that athletes return to sports after ACL reconstruction. OBJECTIVE: To determine the factors influencing the single leg hop test (SLHT) and single leg vertical jump test (SLVJT) at 1 year postoperatively after ACL reconstruction in both the involved and uninvolved sides. METHODS: Ninety-four patients who underwent ACL reconstruction were assessed at 1 year postoperatively. Multiple regression models included eight independent variables with two dependent variables (SLHT and SLVJT.), each on the involved and uninvolved side. RESULTS: On the involved side, the Y balance test (YBT), extensor peak torque per body weight (PT/BW), Biodex balance system anteroposterior index (BBS-API), and sex accounted for 53.9% of the variance in SLHT (P= 0.002), and extensor PT/BW and YBT accounted for 26.3% of the variance in SLVJT (P= 0.027). On the uninvolved side, YBT, sex, age, BBS-API, and flexor PT/BW accounted for 47.0% of the variance in SLHT (P= 0.046), and flexor PT/BW, YBT, and age accounted for 44.9% of the variance in SLVJT (P= 0.002). CONCLUSION: Knee extensor strength on the involved side and flexor strength on the uninvolved side influence the two functional performance tests. The YBT was an important factor in the two functional performance tests in both sides. Anteroposterior stability was the only factor that influenced the SLHT bilaterally.

Rehabilitation after Repair of Medial Meniscus Posterior Root Tears: A Systematic Review of the Literature.

Background: There is no consensus established on postoperative rehabilitation after medial meniscus posterior root tear (MMPRT) repair, including when and how physicians can apply range of motion (ROM) exercise, weight-bearing (WB), brace use, and return to sports (RTS). The purpose of this study was to systematically review the literature on postoperative rehabilitation characteristics of MMPRT repair regarding ROM, WB, brace use, and RTS. Methods: A literature search was performed using the Medline/PubMed, Cochrane Central Register of Controlled Trials, and Embase databases. The inclusion criteria were English language, human clinical studies, and studies describing rehabilitation protocols after MMPRT repair such as ROM, WB, brace use, and RTS. Abstracts, case reports, cohort studies, controlled laboratory studies, human cadaveric or animal studies, systematic reviews, and meta-analyses were excluded. Results: Thirteen studies were included. Of the 12 ROM studies, ROM was started immediately within 1 or 2 days after operation in 6 studies and after 2 to 3 weeks of knee immobilization in the rest. Of the 13 WB studies, partial weight-bearing was initiated 1 to 4 weeks after operation in 8 studies and 6 weeks in the rest. Of the 9 brace studies, patients were immobilized by a splint for 2 weeks in 3 studies, and in the rest, a brace with full extension was applied for 3 to 6 weeks after several days of splint application. Of the 7 RTS studies, RTS was allowed at 6 months in 6 studies and 5 to 7 months in 1 study. Conclusions: This systematic review revealed conservative rehabilitation protocols were more widely adapted as ROM and WB were restricted at certain degrees during postoperative periods in most protocols analyzed. However, it is impossible to identify a consensus on rehabilitation protocols as the protocols analyzed in this review were distinct each other and heterogeneous. In the future, a well-designed comparative study among different rehabilitation protocols is essential to establish a consensus.

Does a Lower Limb Balance Test after Anterior Cruciate Ligament Reconstruction Have a Significant Correlation with Postoperative Clinical Score, Stability, and Functional Performance Test?

Background: Lower limb balance ability is reduced after anterior cruciate ligament reconstruction (ACLR). However, the recovery of balance based on functional test scores after ACLR is not known because the correlation between balance and clinical scores remains unclear. We aimed to analyze the correlation between lower limb balance assessed by functional test and clinical knee test scores after ACLR. Methods: We evaluated lower limb balance using the anterior-posterior stability index (APSI) of the Biodex Balance System (BBS). Patients underwent clinical tests to evaluate the knee, including the Tegner activity score, International Knee Documentation Committee (IKDC) subjective score, Lysholm score, and KT-2000 arthrometer measurement, hamstring per quadriceps muscle strength ratio at 60°/sec (HQ ratio), and functional performance tests (single-leg hop and single-leg vertical jump tests) 1 year after ACLR. We used a paired t-test to compare continuous preoperative and postoperative variables and Pearson's correlation coefficient to determine the relationship between BBS-APSI and clinical scores. Results: Forty-eight patients (35 men and 13 women; mean age, 28.9 ± 8.3 years) were included. The follow-up period and BBS-APSI were 12.4 ± 2.0 months and 0.9 ± 0.4, respectively. Tegner activity score, IKDC subjective score, Lysholm score, and KT-2000 arthrometer measurement improved significantly postoperatively (p < 0.001). BBS-APSI was correlated with the Tegner activity score (r = -0.335, p = 0.020), IKDC subjective score (r = -0.301, p = 0.037), Lysholm score (r = -0.323, p = 0.025), single-leg hop test results (r = -0.300, p = 0.038), and single-leg vertical jump test results (r = -0.336, p = 0.019). There was no correlation between KT-2000 arthrometer measurement and HQ ratio. Conclusions: BBS-APSI was correlated with functional performance test scores after ACLR, rendering the BBS-APSI as a useful assessment tool to evaluate postoperative functional recovery. Continuously improving balance after ACLR could be useful for functional recovery after surgery.

Changes in Bone Marrow Lesions Following Root Repair Surgery Using Modified Mason-Allen Stitches in Medial Meniscus Posterior Root Tears.

Root repair can prevent osteoarthritis (OA) by restoring hoop tension in medial meniscus posterior root tears (MMPRTs). This study aims to investigate bone marrow edema (BME) lesions known to be associated with OA following MMPRTs. Methods: Thirty patients with transtibial pull-out repair were recruited. Subchondral BME lesions were evaluated using magnetic resonance imaging (MRI) at 1-year follow-ups. Participants were categorized into three groups: no change of BME lesions (group one), improved BME lesions (group two) and worsened BME lesions (group three). Clinical scores and radiological outcomes, specifically Kellgren-Lawrence grade, medial joint space width and cartilage grade and meniscal extrusion were evaluated and compared between groups. Results: After surgery, twenty-three patients with no BME, three patients with BME lesions on the medial femoral condyle, one patient with BME lesions on the medial tibia plateau and three patients with BME lesions on both were investigated. A total of 20 patients in group one (66.7%) showed no change in BME lesions. In group two, seven patients (23.3%) presented with improved BME lesions. Only three patients (10%) showed worsened BME lesions (group three). Moreover, Lysholm scores and the rate of progression of cartilage grades were significantly worse in group three patients. Meniscal extrusion was significantly reduced in group two, whereas extrusion was significantly progressed in group three. Conclusion: Patients with worsened BME lesions showed less favorable outcomes than other patients. A decrease in meniscal extrusion can have a positive effect on BME lesions after root repair.

An Increasing Trend in the Number of Anterior Cruciate Ligament Reconstruction in Korea: A Nationwide Epidemiologic Study.

Background: Most epidemiologic studies of anterior cruciate ligament reconstruction (ACLR) to date have been conducted in Western populations, whereas no studies have been conducted in Asian populations. In this study, the incidence and trend of ACLR in Korea were investigated through an epidemiological big data analysis. Methods: The data were collected by the Health Insurance Review and Assessment Service from 2008 to 2016 in Korea. Patient records with the coding of cruciate ligament reconstruction were allocated, and ACLR patients were further refined by medical diagnosis coding. The total number and incidence of ACLR procedures per 100,000 person-years were investigated and more detailed analysis was conducted according to sex and age. Furthermore, concomitant surgical procedures performed during ACLR were investigated. Results: The total number and incidence of ACLR procedures rose from 10,248 and 21.8 to 14,500 and 29.1 between 2008 and 2016, respectively. The incidence of ACLR procedures increased by 33.5% over this 9-year period. Over this period, the total number and incidence increased from 8,543 and 36.4 to 11,534 and 46.4, respectively, in males and from 1,705 and 7.2 to 2,966 and 11.9, respectively, in females. ACLR was performed more frequently in males than in females; however, the increase rate was higher in females than males. ACLR was performed most frequently in patients in their 20s, followed by patients in their 30s, 40s, and 10s. The most frequent concomitant procedures performed during ACLR were meniscectomy (13.6% in 2008 and 9.8% in 2016) and meniscal repair (5.8% in 2008 and 8.8% in 2016). Conclusions: The incidence of ACLR consistently rose between 2008 and 2016 in Korea. The current study will enhance our understanding of the epidemiology of ACLR, which is needed to devise cost-effective preventive measures.

Correlation Between Y-Balance Test and Balance, Functional Performance, and Outcome Measures in Patients Following ACL Reconstruction.

BACKGROUND: The Y-Balance test (YBT) is commonly used to evaluate balance after anterior cruciate ligament reconstruction (ACLR). However, several studies have also used it as a functional performance test (FPT). PURPOSE: This study aimed to examine the relationship between YBT scores and measures of knee joint laxity, static balance, knee flexor and extensor torque and strength ratio, and FPTs. STUDY DESIGN: Retrospective cohort study. METHODS: Fifty-nine patients who underwent ACLR using hamstring autografts were retrospectively analyzed. The Pearson correlation coefficient was used to determine the strength of the association between scores on the YBT and selected outcomes including laxity measured via the KT-2000 arthrometer, static balance measured via the Biodex Balance System, isokinetic muscle torque and hamstring-to-quadriceps (HQ) ratio, and performance on the single leg hop test and the single leg vertical jump test. RESULTS: Forty-six men and 13 women were included. The mean age and follow-up period were 29.6 ± 9.6 years and 12.4 ± 2.1 months, respectively. The KT-2000 arthrometer measures, Biodex Balance System scores, and HQ ratio measurements were not significantly correlated with the YBT scores. All YBT scores, except the YBT-anterior score, correlated with the isokinetic extensor and flexor torques (r-values: 0.271-0.520). All the YBT scores had significant weak to moderate correlations with the single leg hop test and single leg vertical jump test scores: YBT-anterior (r = 0.303, r = 0.258), YBT-posteromedial (r = 0.475, r = 0.412), YBT-posterolateral (r = 0.525, r = 0.377), and YBT-composite (r = 0.520, r = 0.412). CONCLUSION: Post-ACLR YBT scores correlated with functional performance and muscle strength, but not with static balance, joint laxity, and HQ ratios. The YBT scores as a measure of balance are related to improved functional performance and isokinetic torque measures. LEVEL OF EVIDENCE: 3.

An increasing trend of posterior cruciate ligament reconstruction in South Korea: epidemiologic analysis using Korean National Health Insurance System Database.

BACKGROUND: The posterior cruciate ligament is crucial for posterior stability of the knee joint, and, as well as anterior cruciate ligament reconstruction, posterior cruciate ligament reconstruction (PCLR) has attracted interest in orthopedic literature. A few studies have investigated epidemiologic data of PCLR in Western countries. However, there has been no report on the epidemiological pattern of PCLR in the Asian population, including South Korea. Therefore, this study investigated the incidence and trends of PCLR in South Korea using the Korean National Health Insurance (NHI) System Database. METHODS: The data was collected by the Korean Health Insurance Review and Assessment Service (HIRA) from 2008 to 2016 in South Korea. Patients with a record of cruciate ligament reconstruction and PCLR were allocated from the database. An analysis of the total number and incidence per 100,000 people/year of PCLR procedures and other epidemiologic parameters was conducted according to sex and age. RESULTS: The incidence of PCLR procedures rose from 2.3 to 2.6 per 100,000 people (from 1101 to 1299 total cases; 13% increase) between 2008 and 2016: from 3.8 to 4.0 (from 901 to 1000) in males, and from 0.8 to 1.2 (from 200 to 299) in females. PCLR was performed more frequently in males than in females, however, the rate of increase was higher in females than males. The incidence of PCLR over 9  years was highest in patients in their 20s, followed by patients in their 40s and 30s. CONCLUSION: The incidence of PCLR procedures increased by 13% over 9 years in South Korea. PCLR was performed approximately three times more in men than in women. The incidence of PCLR was highest in patients in their 20s, followed by those in their 40s. The current study will enhance our understanding of the epidemiology of PCLR. STUDY DESIGN: Descriptive Epidemiology Study.

Efficacy of GCWB106 (Chrysanthemum zawadskii var. latilobum extract) in osteoarthritis of the knee: A 12-week randomized, double-blind, placebo-controlled study.

BACKGROUND: GreenCross Wellbeing Corporation (GCWB) 106 is a food item based on Chrysanthemum zawadskii var. latilobum extract. It has an inhibitory effect on joint inflammation. OBJECTIVE: This study investigated the efficacy and safety of GCWB106 for osteoarthritis (OA) of the knee joint. METHODS: Overall, 121 participants with mild OA were recruited and randomly divided into two groups. One group received GCWB106 for 12 weeks and the other group received placebo for 12 weeks. Outcomes were evaluated using the Korean-Western Ontario and McMaster Universities Index (K-WOMAC), visual analog scale, Korean Short Form Health Survey 36 score, and laboratory test results. RESULTS: After 12 weeks of study treatment, the GCWB106 group exhibited a significant improvement compared with the placebo group in overall K-WOMAC score (P = .042) and K-WOMAC physical function score (P = .015). The GCWB106 group showed significant improvement in the visual analog scale pain score (P < .001) compared with the placebo group after 6 weeks and 12 weeks; no adverse drug reactions or serious adverse events were reported in either group. CONCLUSION: GCWB106 can safely reduce pain and improve knee function with therapeutic effects in OA of the knee joint. LEVEL OF EVIDENCE: Randomized, double-blind, placebo-controlled clinical study, Level I.

Preoperative varus alignment and postoperative meniscus extrusion are the main long-term predictive factors of clinical failure of meniscal root repair.

PURPOSE: No studies have been conducted to determine long-term predictors of clinical failure after surgical root repair. This study identified long-term prognostic factors of clinical failure after pull-out repair of medial meniscus posterior root tears (MMPRTs) at a minimum of 10 year follow-up. METHODS: A total of 37 patients who underwent MMPRT pull-out repair and had been observed for more than 10 years were recruited for this study. The mean follow-up period was 125.9 ± 21.2 months. Clinical failure of the procedures was defined as conversion to total knee arthroplasty (TKA). Participants were categorized into two groups: non-failure and failure groups. Various factors, including demographic features and radiologic findings, were analyzed and compared between the two groups. Meniscus extrusion was assessed at coronal magnetic resonance imaging preoperatively and 1 year postoperatively. Independent risk factors were determined by univariate analysis and logistic regression analysis. To determine the cut-off value for risk factors, the receiver-operating characteristic curve analysis was performed. RESULTS: In total, eight patients (22%) were converted to TKA during the follow-up period. With univariate analysis, statistically significant differences between two groups were observed in mechanical varus alignment (P = 0.018), rate of the number of patient with more meniscal extrusion values after surgery (P = 0.024), and the difference between the preoperative and 1-year postoperative value of meniscus extrusion (mm) (P = 0.010). In a logistic analysis, OR of mechanical varus alignment and differences in meniscus extrusion value before and 1 year after surgery was 1.5 (P = 0.048) and 3.7 (P = 0.034). The cut-off values of mechanical varus alignment and differences in meniscus extrusion values were 5 degrees and 0.7 mm. CONCLUSION: Clinically, preoperative varus alignment and increased meniscal extrusion after surgery were found to be predictive for a clinical failure after meniscal root repair in a long-term perspective. Thus, these negative prognostic factors should be taken into consideration for performing root repair in MMPRTs. LEVEL OF EVIDENCE: Level III.

An increasing trend of the number of meniscus allograft transplantation in Korea.

PURPOSE: Meniscus allograft transplantation (MAT) can be performed to treat symptomatic patients with meniscus-deficient knees. However, the current epidemiologic status of MAT is unknown in many countries, including Korea. This study aimed to investigate the national trends of MAT in Korea which covers MAT procedures by the Korean national health insurance system. METHODS: Information from the national database was acquired through the Korean Health Insurance Review and Assessment Service (HIRA) from 2010 to 2017. All patients encoded as MAT were included. The total number of MATs and their incidence per 100,000 persons were determined, and the results were stratified by age and sex. RESULTS: The total number of MATs and their incidence per 100,000 persons per year were 369 and 0.77, respectively, in 2010, which increased to 826 and 1.72, respectively, in 2017. The number of MATs increased by 124% over 8 years. The peaks for the total number of MATs and their incidence were seen in patients in their 20 s in 2010, but in 2017, the peaks were observed in patients who were in their 40 s. MAT was performed more frequently in males (61%) than in females (39%) over the study period. CONCLUSION: The total number of MATs and their incidence had increased by 124% between 2010 and 2017. The peak treatment age range for MAT changed from 20 years of age in 2010 to 40 years of age in 2017, and MAT was performed more frequently in males than in females. LEVEL OF EVIDENCE: IV.

Root Repair Versus Partial Meniscectomy for Medial Meniscus Posterior Root Tears: Comparison of Long-term Survivorship and Clinical Outcomes at Minimum 10-Year Follow-up.

BACKGROUND: The importance of repair in medial meniscus posterior root tears (MMPRTs) has been increasingly recognized because it restores hoop tension. However, no study has compared the long-term outcomes between meniscectomy and repair. HYPOTHESIS: Survivorship and clinical outcomes of repair would be better than those of meniscectomy after long-term follow-up. STUDY DESIGN: Cohort study; Level of evidence, 3. METHODS: Between 2005 and 2009, patients with MMPRTs who had been followed up for at least 10 years after partial meniscectomy (n = 18) or pullout repair (n = 37) were recruited. Clinical assessments, including the Lysholm score and International Knee Documentation Committee (IKDC) subjective score, were evaluated preoperatively and at the final follow-up. The final results in each group were compared with the preoperative results, and the final results of the groups were compared. Clinical failure was defined as conversion to total knee arthroplasty (TKA), and the final clinical scores were assessed just before TKA. Kaplan-Meier survival analysis was used to investigate the survival rates of surgical procedures. RESULTS: Mean ± SD follow-up period was 101.4 ± 45.9 and 125.9 ± 21.2 months in the meniscectomy and repair groups, respectively (P = .140). The mean Lysholm and IKDC scores, respectively, in the meniscectomy group were 50.8 ± 7.7 and 37.6 ± 7.0 preoperatively and 58.2 ± 22.1 and 44.4 ± 19.0 postoperatively (P = .124; P = .240). In the repair group, the mean Lysholm score and IKDC score, respectively, significantly increased from 52.3 ± 10.9 and 41.0 ± 9.6 preoperatively to 77.1 ± 24.0 and 63.7 ± 20.6 postoperatively (P < .001; P < .001). The final Lysholm and IKDC scores in the repair group were significantly better than those in the meniscectomy group (P = .004; P = .003). In cases of clinical failure, 10 patients (56%) in the meniscectomy group and 8 patients (22%) in the repair group converted to TKA in the follow-up period (P = .016). According to Kaplan-Meier analysis, the 10-year survival rates for the meniscectomy and repair groups were 44.4% and 79.6%, respectively (P = .004). CONCLUSION: In MMPRTs, root repair was superior to partial meniscectomy in terms of clinical results for at least 10 years of follow-up. From a long-term perspective, repair with restoration of hoop tension is more effective management than meniscectomy.

National Trends of Meniscectomy and Meniscus Repair in Korea.

BACKGROUND: Meniscus surgeries are frequently performed in orthopaedics. However, their current status is not well known in many countries, including Korea. This study aimed to investigate the national trends of meniscus surgery in Korea. METHODS: Information from the national database was acquired through the Korean Health Insurance Review and Assessment Service from 2010 to 2017. All cases coded as meniscectomy or meniscus repair were included. The total number and incidence of cases of meniscus surgery per 100,000 persons were determined, and the results were stratified by age and gender. The meniscus repair ratio for the total number of meniscus surgeries was evaluated. RESULTS: The total number and incidence of meniscectomy cases were 65,752 and 137, respectively, in 2010, which increased to 74,088 and 154, respectively, in 2017. The number of meniscectomies increased by 12.67% in 8 years. The total number and incidence of meniscus repair cases were 9,055 and 18, respectively, in 2010, which increased to 14,947 and 31 in 2017. The number of meniscus repairs increased by 65.04%. The meniscus repair ratio was 12.1% in 2010, which increased to 16.8% in 2017. The highest peak was noted for patients who underwent meniscus surgeries in their 50s and 60s. Meniscectomy was performed more frequently in women (57%) than in men (43%), whereas repair was performed more frequently in men (54%) than in women (46%) over the study period. CONCLUSION: The total number and incidence of meniscus surgeries increased from 2010 to 2017; the number and incidence of meniscus repair procedures increased more rapidly than those of meniscectomy, with the peak treatment age for both surgeries being in the 50s and 60s. The current study will contribute to understanding the epidemiology of meniscus surgery, its prevention, and cost-saving measures in Korea.

The International Knee Documentation Committee Score Indicates Midterm Patient Satisfaction with Outcomes after Meniscal Allograft Transplantation.

BACKGROUND: This study aimed to identify the factors associated with patient satisfaction with the outcome of meniscal allograft transplantation (MAT). MATERIALS AND METHODS: Patients treated with MAT from March 2006 to May 2009 were asked to complete a five-point Likert scale regarding satisfaction with the outcome of MAT, in addition to the following subjective outcome evaluation forms: the International Knee Documentation Committee (IKDC) subjective forms, Knee Society Score knee and function forms, and Lysholm Knee Scoring Scale. We collected radiologic data using X-ray and magnetic resonance imaging and assessed isokinetic muscle strength test using the Biodex System 3. We investigated whether these parameters were significantly associated with patient satisfaction. Statistical analysis was computed using univariate and multivariable logistic regression. RESULTS: Among the 130 patients who underwent MAT, 49 participated in the interview and were included in this study. The mean followup period was 50.4 months. Mean patient age was 40 (±9) years; 33 were male and 16 were female (33%). The lateral meniscus was transplanted in 13 (27%) patients, while the medial meniscus was involved in 36 (73%) patients. On univariate analysis, sex and isokinetic extension strength deficit at 60° and 180° as well as the IKDC, Knee Society, and Lysholm scores showed significant association with patient satisfaction regarding the outcome. On multivariable logistic regression, only the IKDC score showed a significant association, with P = 0.04. CONCLUSIONS: The study results support the importance of patient-reported subjective outcomes in terms of patient satisfaction following a surgical procedure. Regarding MAT, the IKDC outcome score reflects patient satisfaction. LEVEL OF EVIDENCE: Level III.

Pullout fixation for medial meniscus posterior root tears: clinical results were not age-dependent, but osteoarthritis progressed.

PURPOSE: This study investigated the outcomes of pullout fixation for medial meniscus posterior root tears (MMPRTs) in patients ≤ 60 years old versus patients > 60 years old. It was hypothesized that older patients would demonstrate results comparable with those of younger patients. METHODS: Patients with pullout fixation who were followed-up for more than 5 years were included. Patients were categorized into two groups based on age (group A, ≤ 60 years; group B, > 60 years). The Lysholm score, Kellgren-Lawrence (K-L, 0/1/2/3/4) grade, and medial joint space width were evaluated retrospectively. Preoperative results were compared with the final results in each group, which were compared between groups. RESULTS: Twenty-five patients in group A (mean age, 54.7 ± 3.8 years) and 22 patients in group B (mean age, 65.6 ± 4.4 years) were recruited. The mean follow-up duration was 70.9 months. The Lysholm score (group A, 53.0 ± 9.1 to 86.0 ± 12.1, P < 0.001; group B, 51.1 ± 7.1 to 82.9 ± 9.7, P < 0.001) improved significantly. However, the joint space width (group A, 4.7 ± 1.1 to 3.9 ± 1.1 mm, P < 0.001; group B, 4.7 ± 0.9 to 3.8 ± 0.9 mm, P < 0.001) and K-L grade (group A, 3/17/5/0/0 to 0/7/11/7/0, P < 0.001; group B, 2/14/6/0/0 to 0/3/14/5/0, P < 0.001) worsened significantly. No significant differences between groups were observed in final outcomes, including Lysholm score (n.s.), K-L grade (n.s.), and joint space narrowing (n.s.). No case with operation failure that require total knee arthroplasty was not observed. CONCLUSION: MMPRT fixation did not prevent the progression of arthrosis completely. However, clinical outcomes were not age-dependent. Thus, age may not be a critical factor to consider when applying fixation. LEVEL OF EVIDENCE: Retrospective case-control study; Level of evidence, IV.

Rivaroxaban and Acetylsalicylic Acid for Prevention of Venous Thromboembolism Following Total Knee Arthroplasty in Korean Patients.

PURPOSE: To investigate the incidence of venous thromboembolism (VTE) after total knee arthroplasty (TKA) with chemoprophylaxis using acetylsalicylic acid (AA) or rivaroxaban in Korean patients. MATERIALS AND METHODS: Between May 2011 and November 2013, 268 TKA patients (330 cases) were randomly allocated to 3 groups (group A: subcutaneous injection of 5,000 IU low-molecular-weight heparin for 2 days followed by oral administration of 100 mg AA for 5 days; group X7: oral administration of 10mg rivaroxaban for 7 days; and group X10: oral administration of 10 mg rivaroxaban for 10 days). Multidetector-row computed tomography (MDCT) was performed at 10 days and 3 months postoperatively to evaluate VTE changes. RESULTS: The VTE incidence was 38.2%, 20.0%, and 10.0% in groups A, X7, and X10, respectively (p＜0.001). Pulmonary embolism (PE) was identified in 19.1%, 10.0%, and 2.7% in groups A, X7, and X10, respectively (p＜0.001). Proximal or symptomatic deep vein thrombosis (DVT) occurred primarily in group A, but the incidence was not significantly different among groups. On follow-up MDCT, PE was resolved completely with treatment in 29/30 (96.7%), and so was asymptomatic distal DVT in 24/27 (88.8%) without treatment. CONCLUSIONS: Rivaroxaban had a lower incidence of overall VTE than AA, but no difference was observed in symptomatic VTE. The 10-day course of rivaroxaban had a lower incidence of overall VTE than the 7-day course.

Corrigendum to: Effects of salmon DNA fraction in vitro and in a monosodium iodoacetate-induced osteoarthritis rat model.

[This corrects the article on p. 163 in vol. 22, PMID: 29520169.].

Effects of salmon DNA fraction in vitro and in a monosodium iodoacetate-induced osteoarthritis rat model.

PRF001 is a fragmented DNA polymer extracted from the testes of salmon. The purpose of this study was to assess the anti-inflammatory effect of PRF001 in vitro as well as the protective effect of PRF001 intake against arthritis in a rat model. In vitro, cell survival and inflammatory markers after H2O2 treatment to induce cell damage were investigated in CHON-001 cells treated with different concentrations of PRF001. In vivo, osteoarthritis was induced by intra-articular injection of monosodium iodoacetate (MIA) into the knee joints of rats. After consumption of PRF001 (10, 50, or 100 mg/kg) for 4 weeks, inflammatory mediators and cytokines in articular cartilage were investigated. In vitro, the levels of inflammatory markers, IL-1ß, TNF-α, COX-2, iNOS, and PGE2, were significantly suppressed by PRF001 treatment. In vivo, the inflammatory mediators and cytokines, IL-1ß, p-Erk1/2, NF-κB, TNF-α, COX-2, and PGE2, as well as MMP3 and MMP7, which have catabolic activity in chondrocytes, were decreased in the MIA-induced osteoarthritic rats following intake of PRF001. Histological analysis revealed that PRF001 had a protective effect on the articular cartilage. Altogether, these results demonstrated that the anti-inflammatory property of PRF001 contributes to its protective effects in osteoarthritis through deregulating IL-1ß, TNF-α, and subsequent signals, such as p-Erk1/2, NF-κB, COX-2, PGE2, and MMPs.

Comparison of Tibiofemoral Contact Mechanics After Various Transtibial and All-Inside Fixation Techniques for Medial Meniscus Posterior Root Radial Tears in a Porcine Model.

PURPOSE: To compare tibiofemoral contact mechanics after fixation for medial meniscus posterior root radial tears (MMPRTs). METHODS: Seven fresh knees from mature pigs were used. Each knee was tested under 5 conditions: normal knee, MMPRT, pullout fixation with simple sutures, fixation with modified Mason-Allen sutures, and all-inside fixation using Fastfix 360. The peak contact pressure and contact surface area were evaluated using a capacitive sensor positioned between the meniscus and tibial plateau, under a 1,000-N compression force, at different flexion angles (0°, 30°, 60°, and 90°). RESULTS: The peak contact pressure was significantly higher in MMPRTs than in normal knees (P = .018). Although the peak contact pressure decreased significantly after fixation at all flexion angles (P = .031), it never recovered to the values noted in the normal meniscus. No difference was observed among fixation groups (P = .054). The contact surface area was significantly lower in MMPRTs than in the normal meniscus (P = .018) and increased significantly after fixation at all flexion angles (P = .018) but did not recover to within normal limits. For all flexion angles except 60°, the contact surface area was significantly higher for fixation with Mason-Allen sutures than for fixation with simple sutures or all-inside fixation (P = .027). At 90° of flexion, the contact surface area was significantly better for fixation with simple sutures than for all-inside fixation (P = .031). CONCLUSIONS: The peak contact pressure and contact surface area improved significantly after fixation, regardless of the fixation method, but did not recover to the levels noted in the normal meniscus after any type of fixation. Among the fixation methods evaluated in this time 0 study, fixation using modified Mason-Allen sutures provided a superior contact surface area compared with that noted after fixation using simple sutures or all-inside fixation, except at 60° of flexion. However, this study had insufficient power to accurately detect the differences between the outcomes of various fixation methods. CLINICAL RELEVANCE: Our results in a porcine model suggest that fixation can restore tibiofemoral contact mechanics in MMPRT and that fixation with a locking mechanism leads to superior biomechanical properties.

Survivorship Analysis and Clinical Outcomes of Transtibial Pullout Repair for Medial Meniscus Posterior Root Tears: A 5- to 10-Year Follow-up Study.

PURPOSE: This study investigated the clinical outcomes and mid- to long-term survival rates in patients undergoing transtibial pullout repair of medial meniscus posterior root tears (MMPRTs) after a minimum follow-up of 5 years. METHODS: Between 2005 and 2011, patients with MMPRTs who had been followed for at least 5 years after undergoing transtibial pullout repair were recruited. Participants were identified using medical records and information in a prospectively collected database. Clinical outcomes were assessed based on a comparison of patient preoperative Lysholm scores and their scores at the final follow-up. A Kaplan-Meier survival analysis was used to investigate the survival rates of repair procedures. Clinical failures were defined as cases requiring conversion to total knee arthroplasty (TKA) or having final Lysholm score <65 or less than their preoperative scores. RESULTS: Overall, 91 patients (mean age, 58.7 ± 9.7 years) were included: the mean follow-up duration was 84.8 ± 13.8 months. Among these patients, the mean Lysholm score improved significantly from 51.8 ± 7.9 preoperatively to 83.0 ± 11.1 at the final follow-up (P < .001). Overall, 4 patients failed due to conversion to TKA (n = 1) or having final Lysholm scores <65 or less than the preoperative scores (n = 3). The overall Kaplan-Meier probabilities of survival after repair were 99% at 5 years, 98% at 6 years, 95% at 7 years, and 92% at 8 years. CONCLUSIONS: Among patients with MMPRTs, transtibial pullout repair demonstrated a high clinical survival rate and the patients demonstrated clinical improvement, based on mid- and long-term follow-up examinations. LEVEL OF EVIDENCE: Level IV, retrospective uncontrolled case series.