Alignment changes after open-wedge high tibial osteotomy result in offloading in the patellofemoral joint: a SPECT/CT analysis.

PURPOSE: The patellofemoral (PF) joint may be adversely affected by medial open-wedge high tibial osteotomy (OWHTO). This study aimed to evaluate the PF compartmental changes using combined single-photon emission computed tomography (SPECT) and conventional computed tomography (CT) after OWHTO to provide clinical guidance regarding the PF joint pressure and force. METHODS: Patients with medial osteoarthritis and varus malalignment > 5° were treated using OWHTO. Patients with a minimum 2-year follow-up were included in the study. The patellar positions were evaluated based on the radiographic parameters. The changes in chondral lesions during second-look arthroscopic examination were evaluated, and the PF joint arthritis grade was recorded on patellar Merchant radiographs using Kellgren-Lawrence classification. The PF compartmental changes according to SPECT/CT analysis after OWHTO were evaluated in all patients. The scintigraphic uptake was graded on four scales. Patients were divided into improved and unimproved groups according to the PF compartmental grade using the SPECT/CT uptake grading system. RESULTS: At a mean follow-up period of 47.0 months (range 25-74 months), the mean mechanical femorotibial angle changed significantly from varus 6.3° (range 5-12°) to valgus 2.6° (range 0-8°); p < 0.001) postoperatively. The radiological parameters presenting patellar positions, including the tibial slope, patellar convergence angle, and lateral tilt angle, did not change significantly between the preoperative values and the 2-year follow-up values. The mean patellar height significantly decreased (0.07 ± 0.14, p = 0.001 according to the Blackburn-Peel index and 0.32 ± 0.23, p < 0.001 using the modified Insall-Salvati ratio). The average tibial tubercle to trochlear groove (TT-TG) distance significantly decreased from 14.1 to 12.2 mm (p < 0.001). The Q angle also significantly decreased from 9.8o to 7.7o (p = 0.008). Chondral lesions of the patella and trochlear groove revealed significant deterioration; at 2 years after OWHTO, the arthritic grades of the PF joints worsened significantly, as determined by radiography (p = 0.007). Scintigraphic uptake in the PF joint was significantly lower (from 2 to 1) at 2 years postoperatively compared to that immediately after the index operation (p < 0.001). Only 4 of 56 (7.1%) patients showed increased uptake. Comparison between the improved and unimproved groups according to scintigraphic uptake changes revealed that the changes in the cartilage status on the patellar undersurface and TT-TG distance were the most significant predictive factors of increased scintigraphic uptake in the PF joint after OWHTO. CONCLUSION: Alignment correction by OWHTO result in PF compartment offloading and should be considered when identifying the surgical indications for OWHTO. LEVEL OF EVIDENCE: Therapeutic, Level IV.

Early medial reconstruction combined with severely injured medial collateral ligaments can decrease residual medial laxity in anterior cruciate ligament reconstruction.

INTRODUCTION: This study aimed to describe an anatomic medial knee reconstruction technique for combined anterior cruciate ligament (ACL) and grade III medial collateral ligament (MCL) injuries and to assess knee function and stability restoration in patients who underwent primary MCL reconstruction compared with primary repair. METHODS: A total of 105 patients who had undergone anatomic ACL reconstruction between 2008 and 2017 were enrolled in this retrospective study and divided into two groups according to concomitant MCL ruptures. Group A included patients with isolated ACL ruptures without MCL injuries. Group B included patients with both ACL and MCL injuries, and it was subdivided into three groups according to the severity of the MCL injury and treatment modality: B-1, grade I or II MCL injury treated conservatively; B-2: grade III MCL injury treated by primary MCL repair; and B-3: grade III MCL injury treated by primary reconstruction. Knee stability was measured via Telos valgus radiography at 6-month and 2-year postoperative. The Lysholm score, Tegner activity level, Likert scales (satisfaction), and return to previous sports were evaluated at 2-year postoperative. RESULTS: At 6-month postoperative, there was no significant difference in medial laxity between the B-2 and B-3 groups. However, at 2-year postoperative, medial laxity were significantly higher both at 30° of flexion (5.2° versus 2.2°, p = 0.020) and at full extension (3.4° versus 1.1°, p < 0.001) in patients in B-2 group compared to those in B-3 group. There were no statistically significant differences between the two groups with respect to Lysholm scores, Tegner activity levels, Likert scales (satisfaction), and returning to previous sports at the 2-year follow-up. CONCLUSION: Primary medial reconstruction combined with severely injured MCL in ACL reconstruction may decrease residual medial laxity more than primary repair. LEVEL OF EVIDENCE: Retrospective observational study, IV.

Machine-learning algorithm that can improve the diagnostic accuracy of septic arthritis of the knee.

PURPOSE: Prompt diagnosis and treatment of septic arthritis of the knee is crucial. Nevertheless, the quality of evidence for the diagnosis of septic arthritis is low. In this study, the authors developed a machine learning-based diagnostic algorithm for septic arthritis of the native knee using clinical data in an emergency department and validated its diagnostic accuracy. METHODS: Patients (n = 326) who underwent synovial fluid analysis at the emergency department for suspected septic arthritis of the knee were enrolled. Septic arthritis was diagnosed in 164 of the patients (50.3%) using modified Newman criteria. Clinical characteristics of septic and inflammatory arthritis were compared. Area under the receiver-operating characteristic (ROC) curve (AUC) statistics was applied to evaluate the efficacy of each variable for the diagnosis of septic arthritis. The dataset was divided into independent training and test sets (comprising 80% and 20%, respectively, of the data). Supervised machine-learning techniques (random forest and eXtreme Gradient Boosting: XGBoost) were applied to develop a diagnostic model using the training dataset. The test dataset was subsequently used to validate the developed model. The ROC curves of the machine-learning model and each variable were compared. RESULTS: Synovial white blood cell (WBC) count was significantly higher in septic arthritis than in inflammatory arthritis in the multivariate analysis (P = 0.001). In the ROC comparison analysis, synovial WBC count yielded a significantly higher AUC than all other single variables (P = 0.002). The diagnostic model using the XGBoost algorithm yielded a higher AUC (0.831, 95% confidence interval 0.751-0.923) than synovial WBC count (0.740, 95% confidence interval 0.684-0.791; P = 0.033). The developed algorithm was deployed as a free access web-based application ( www.septicknee.com ). CONCLUSION: The diagnosis of septic arthritis of the knee might be improved using a machine learning-based prediction model. LEVEL OF EVIDENCE: Diagnostic study Level III (Case-control study).

Patellar fractures in elderly patients: a multicenter computed tomography-based analysis.

INTRODUCTION: This study aimed to demonstrate the characteristics of patellar fractures and evaluate clinical outcomes in elderly patients. PATIENTS AND METHODS: Medical records of patients aged ≥ 60 years who presented with patellar fractures were retrospectively reviewed from an institutionally approved multicenter (five institutions) orthopedic database. Patient characteristics and fracture patterns were identified, and the clinical outcomes were investigated. We compared differences according to the injury mechanism (low- vs. high-energy). RESULTS: A total of 202 patients [mean age, 69.4 years (range, 60-88 years); male, 89, female, 113] were included in this study. The mean follow-up period was 14.8 months (range 6-58 months), and 75% of the fractures were from low-energy injuries. According to the AO /OTA classification, the most common type was type C (136 cases, 67.3%; 33 cases, C1; 23, C2; and 80, C3), followed by type A (39 cases), type B (26 cases), and unclassified (1 case). The unclassified case was an intra-articular marginal impaction without cortical breakage. Computed tomography (CT) revealed that of the cases, 66.8% had an inferior pole involvement; 80.7%, a comminuted fragment; and 10.4%, an impacted fracture. A total of 166 fractures (82.2%) were treated surgically. The mean union time and range of motion were 13.1 weeks and 123.8° (range 30-150°), respectively. The Lysholm score was 82.1 ± 12.0, with 65.7% of the cases having excellent or good function. The complication rate was 12.4% (24 cases), including ten, four, two, and five cases of infection, fixation failure, nonunion, malunion, and pin migration, respectively. The reoperation rate was 26.4%. CONCLUSION: Patellar fractures in the elderly were mostly from low-energy injuries, and types C3 and A1 were the most common. CT images demonstrated high rates of an inferior pole involvement and comminution. The complication and reoperation rates were relatively high.

Is lower tourniquet pressure during total knee arthroplasty effective? A prospective randomized controlled trial.

BACKGROUND: Higher tourniquet pressures may be associated with an increased risk of complications. We aimed to determine (1) whether a lower tourniquet pressure [systolic blood pressure (SBP) + 120 mmHg] is as effective as conventional tourniquet pressure (SBP + 150 mmHg) in providing a bloodless surgical field and decreasing blood loss, and (2) whether lowering the tourniquet pressure decreases tourniquet-related complications compared to conventional inflation pressure. METHODS: One hundred and sixty knees in 124 patients undergoing total knee arthroplasty (TKA) were randomly allocated to either conventional (n = 80) or lower inflation pressure group (n = 80). The quality of the initial surgical field and occurrence of intraoperative blood oozing, hemoglobin drop, drained volume and calculated blood loss were assessed as efficacy variables. Safety outcome variables included post-operative pain, tourniquet site skin problems (ecchymosis, bullae, skin necrosis), and other tourniquet-related complications such as nerve palsy, venous thromboembolism, and delayed rehabilitation. RESULTS: A comparable bloodless surgical field was successfully provided in both groups (100% vs. 99%, p = 1.000). One case in the conventional pressure group and two cases in the lower pressure group showed intraoperative blood oozing (p = 1.000), which was successfully controlled after an increase of 30 mmHg in the tourniquet inflation pressure. There was no difference in the hemoglobin drop, drained volume, and calculated blood loss. The two groups did not differ in any safety outcomes such as post-operative pain, thigh complications, and other tourniquet related complications. CONCLUSION: This study demonstrates that a tourniquet inflation pressure of 120 mmHg above the SBP is effective method during TKA. TRIAL REGISTRATION: The trial was with ClinicalTrials.gov ( NCT01993758 ) on November 25, 2013.

What is the Ideal Route of Administration of Tranexamic Acid in TKA? A Randomized Controlled Trial.

BACKGROUND: TKA commonly involves substantial blood loss and tranexamic acid has been used to reduce blood loss after TKA. Numerous clinical trials have documented the efficacy and safety of intravenous (IV) or intraarticular (IA) use of tranexamic acid. Combined administration of tranexamic acid also has been suggested; however, there is no consensus regarding the ideal route of tranexamic acid administration. QUESTIONS/PURPOSES: (1) To compare the efficacy of tranexamic acid in terms of total blood loss and the allogeneic transfusion rate among three routes of administration: IV alone, IA alone, and combined IV and IA. (2) To compare these regimens in terms of venous thromboembolism (VTE) and the frequency of wound complications. METHODS: In total, 376 patients undergoing TKA between March 2014 and March 2015 were randomized to four groups by the route of tranexamic acid administration: IV only, IA only, low-dose combined (IV + IA injection of 1 g), and high-dose combined (IV + IA injection of 2 g). The calculated total blood loss, allogeneic transfusion rate, decrease in hemoglobin, the frequency of symptomatic deep vein thrombosis and pulmonary embolism, wound complications, and periprosthetic joint infection were compared among the groups. Total blood loss was calculated using estimated total body blood volume and hemoglobin loss. The decision regarding when to transfuse was determined based on preset criteria. RESULTS: The high- and low-dose combined groups and the IA-only group had lower total blood loss (564 ± 242 mL, 642 ± 242 mL, and 633 ± 205 mL, respectively) than the IV-only group (764 ± 217 mL; mean differences = 199 mL [95% CI, 116-283 mL], p < 0.001; 121 mL [95% CI, 38-205 mL], p = 0.001; 131 mL [95% CI, 47-214 mL], p < 0.001); no differences were found among the other three groups. No patients in any study group received an allogeneic transfusion. One patient in the IV-only group had a symptomatic pulmonary embolism develop, but no other symptomatic VTE events occurred in any group. In addition, no differences were observed in wound complications, such as superficial wound necrosis (one patient in the IV-only and the high-dose combined group, respectively) and oozing (IV-only, IA-only, low-dose combined, high-dose combined = 3%, 4%, 4%, and 7%; p = 0.572) between the groups. No patients had a periprosthetic joint infection. CONCLUSION: IA tranexamic acid administration further reduces blood loss after TKA in comparison to IV use alone; no additional effect in further reducing blood loss was found in combination with IV tranexamic acid. Appropriately powered studies are needed to confirm the safety of this route of administration as the preferred route of administration in TKA. LEVEL OF EVIDENCE: Level I, therapeutic study.

After early release of tourniquet in total knee arthroplasty, should it be reinflated or kept deflated? A randomized trial.

PURPOSE: This study was undertaken to determine the efficacy of reinflation of the tourniquet after its early release in TKA compared to early release alone, in terms of surgical field visualization and operative time. We also questioned whether tourniquet reinflation after its early release is safe, with respect to post-operative blood loss, post-operative pain and other tourniquet-related complications. METHODS: Two hundred and six patients undergoing TKA were randomly allocated to either the early release (deflation) group (n = 105) or reinflation after early release (reinflation) group (n = 101). Efficacy was measured in terms of surgical field visualization, specifically the number of wound clearances, and operative time. Safety outcomes were drained volume, decline in haemoglobin on post-operative days 2 and 5, the frequency of transfusion, knee and thigh pain visual analog scale, local wound complications, tourniquet site complications and other complications, including infection, deep vein thrombosis and pulmonary embolism. RESULTS: Surgical field visualization was better in the reinflation group; however, the operative time did not differ between the two groups. There were no differences between the two groups in post-operative blood loss, decline in haemoglobin on days 2 and 5, transfusion rate, pain level, local complications and other complications. CONCLUSION: Reinflation of tourniquet is a safe alternative to its early release after deflation in that it improves surgical field visualization during TKA. LEVEL OF EVIDENCE: Therapeutic study, Level I.

The use of navigation in medial opening wedge high tibial osteotomy can improve tibial slope maintenance and reduce radiation exposure.

PURPOSES: We sought to determine the usefulness and the disadvantages of the navigation in medial opening wedge high tibial osteotomy (MOWHTO) compared to the conventional technique, in terms of target coronal alignment achievement, tibial slope maintenance, radiation exposure and operative time. METHODS: We retrospectively compared 40 knees treated with navigated MOWHTO by one surgeon with 20 knees treated with conventional MOWHTO by another surgeon. Screw length of the plate was predetermined using validated simple algorithms only in the navigation group to facilitate the operation. The acceptable range of the postoperative coronal alignment was defined as 2°-6° of the mechanical tibiofemoral angle (mTFA) and 55%-70% of the weight loading line coordinate (WLL). The proportion of the coronal alignment outlier, posterior tibial slope change, fluoroscopy time and operative time were compared. RESULTS: The coronal alignment outliers were fewer in the navigation group, but the differences were not significant (mTFA outlier 18% vs. 30%, p = 0.326; WLL outlier 20% vs. 30%, p = 0.519). Tibial slope was maintained in the navigation group (+0.3°, p = 0.732), whereas increased in the conventional group (+3°, p < 0.001). The fluoroscopy time was shorter in the navigation group (10.4 seconds vs. 24.8 seconds, p < 0.001). The operative time was comparable in both groups (41.3 minutes vs. 39.2 minutes, p = 0.232). CONCLUSIONS: The use of navigation can improve tibial slope maintenance and reduce radiation exposure in MOWHTO, without considerable extension of operative time by optimising the surgical technique. LEVEL OF EVIDENCE: Level III, retrospective comparative study.

Do glycemic markers predict occurrence of complications after total knee arthroplasty in patients with diabetes?

BACKGROUND: Patients with diabetes have increased risk of infections and wound complications after total knee arthroplasty (TKA). Glycemic markers identifying patients at risk for complications after TKA have not yet been elucidated. QUESTIONS/PURPOSES: We aimed to determine the correlations among four commonly used glycemic markers and to identify the glycemic markers most strongly associated with the occurrence of surgical site infections and postoperative wound complications in patients with diabetes mellitus after undergoing TKA. METHODS: Our retrospective study included 462 patients with diabetes, who underwent a total of 714 TKAs. Blood levels of glycemic markers, including preoperative fasting blood glucose (FBG), postprandial glucose (PPG2), glycated hemoglobin (HbA1c), and levels obtained from random glucose testing on postoperative days 2, 5, and 14, were collected on all patients as part of a medical clearance program and an established clinical pathway for patients with diabetes at our center. Complete followup was available on 93% (462 of 495) of the patients. Correlations among markers were assessed. Associations between the markers and patient development of complications were analyzed using multivariate regression analyses of relevant cutoff values. We considered any of the following as complications potentially related to diabetes, and these were considered study endpoints: surgical site infection (superficial and deep) and wound complications (drainage, hemarthrosis, skin necrosis, and dehiscence). During the period of study, there were no fixed criteria applied to what levels of glycemic control patients with diabetes needed to achieve before undergoing arthroplasty, and there were wide ranges in the levels of all glycemic markers; for example, whereas the mean HbA1c level was 7%, the range was 5% to 11.3%. RESULTS: There were positive correlations among the levels of the four glycemic markers; the strongest correlation was found between the preoperative HbA1c and PPG2 levels (R = 0.502, p < 0.001). After controlling for potential confounding variables using multivariate analysis, the HbA1c cutoff level of 8 (odds ratio [OR], 6.1; 95% confidence interval [CI], 1.6-23.4; p = 0.008) and FBG 200 mg/dL or higher (OR, 9.2; 95% CI, 2.2-38.2; p = 0.038) were associated with superficial surgical site infection after TKA. CONCLUSIONS: In general, there is a positive correlation among the various available glycemic markers among patients with diabetes undergoing TKA, and patients undergoing surgery with HbA1c ≥ 8 and/or FBG ≥ 200 mg/dL were associated with superficial surgical site infection. These findings should be considered in patient selection and preoperative counseling for patients with diabetes undergoing TKA. LEVEL OF EVIDENCE: Level III, prognostic study.

Clinical Performance of the 1st American Academy of Orthopaedic Surgeons Clinical Guideline on Prevention of Symptomatic Pulmonary Embolism after Total Knee Arthroplasty in Korean Patients.

We sought to document the clinical performance of the 1st American Academy of Orthopaedic Surgeons (AAOS) guideline on the prevention of symptomatic pulmonary embolism (PE) after total knee arthroplasty (TKA) in Korean patients, in terms of the proportions of the each risk-stratified group, efficacy and safety. Consecutive 328 patients underwent TKA were preoperatively assessed for the risks of PE and bleeding and categorized into 4 groups: 1) standard risk, 2) high risk for PE, 3) high risk for bleeding, and 4) high risks both for PE and bleeding. One of three options was administered according to the groups (aspirin in group 1 or 4; enoxaparin and following aspirin in group 2; antithrombotic stocking in group 3). Incidences of symptomatic deep vein thrombosis (DVT) and PE, and major or minor bleeding complications were evaluated. Majority of the patients (86%) were assessed to be with standard risks both for PE and bleeding. No patient experienced symptomatic DVT or PE and major bleeding. Eleven percent of the patients discontinued chemoprophylaxis because of bleeding-related wound complication. In conclusion, the 1st AAOS guideline functions successfully in Korean patients undergoing TKA in terms of prevention of symptomatic DVT and PE while avoiding major bleeding complications.

Prevalence and predictors of post-operative coronal alignment outliers and their association with the functional outcomes in navigated total knee arthroplasty.

We aimed to determine the prevalence and predictors for being an outlier after navigated TKA and asked whether navigated TKAs with perfect coronal alignment have better functional outcomes than those without it. Alignment was measured in 124 patients (191 knees) with navigated TKAs who were available for 1year functional outcome assessment. The outcomes were compared among the 3 subgroups divided by the deviation of mechanical axis from neutral (0°): the perfect, 0° or within 1°; the acceptable, 1°-3°; and the outlier, beyond 3°. The prevalence of outliers was 20.4%, and the severity of preoperative varus deformity was the strongest predictor. Accuracy of coronal alignment in radiographs did not correlate consistently with functional outcomes.

Tryptophanyl tRNA synthetase is an alternative synovial biomarker for diagnosis of septic arthritis in knee joint.

BACKGROUND: To evaluate the diagnostic characteristics of tryptophanyl tRNA synthetase (WRS) for the diagnosis of septic arthritis of the knee joint and to determine whether it is a reliable and sensitive synovial biomarker for discriminating septic arthritis from other types of arthritis. METHODS: Patients joint effusions for which septic arthritis was suspected were prospectively recruited between January 2019 and September 2020. A total of 9 patients had septic arthritis, 6 had acute gout attack, 1 had an acute flare of chronic rheumatic arthritis, and 46 had pseudogout or reactive arthropathy. Traditional inflammatory markers were measured, and their diagnostic abilities were compared. Neutrophil count, C-reactive protein (CRP) level, WRS, and human neutrophil α-defensin levels were assessed in the synovial fluids. Demographic parameters and biomarkers with a P < 0.05 in differentiating septic from nonseptic arthritis were included in a multivariable model. A multivariable logistic regression with a stepwise selection was performed to build the final combined model. Receiver operating characteristic curves were used to establish optimal thresholds for the diagnosis of septic arthritis of the knee joint, and the area under the curve was calculated to determine the overall accuracy of these tests compared with patients with nonseptic inflammatory arthritis. RESULTS: Patients with septic arthritis were more likely to display higher serum WBC and CRP levels, synovial neutrophil counts, and levels of two synovial biomarkers, including WRS and α-defensin. WRS showed the highest specificity (87.5%) and sensitivity (83.3%) with α-defensin among the three synovial biomarkers. CONCLUSIONS: Synovial fluid WRS is a relevant biomarker in discriminating septic arthritis from other inflammatory arthritis and should be tested in an independent cohort. LEVEL OF EVIDENCE: prospective observational study, III.

Must bilaterality be considered in statistical analyses of total knee arthroplasty?

BACKGROUND: In studies of TKA, treating each knee as an independent case in patients with bilateral TKAs can lead to errors, because patients with bilateral and unilateral TKAs may achieve different levels of function and because the assumption of statistical independence is violated. QUESTIONS/PURPOSES: We determined whether (1) patients undergoing bilateral TKAs have different demographics and preoperative and postoperative function from those undergoing unilateral TKAs, and (2) means, SEs, and p values change substantially based on how the two cases of bilateral TKAs are treated in statistical analyses. METHODS: We retrospectively compared 513 patients undergoing unilateral TKAs and 602 patients undergoing bilateral TKAs regarding demographics (age, gender, BMI), preoperative and 1-year postoperative function (motion arc, American Knee Society score, patellofemoral score, WOMAC(TM), SF-36). Each case of a bilateral TKA was treated as independent in the reference analyses. Then changes of mean, SEs, and p values were compared with those of the reference method when three other methods of analysis were used: using mean values of both knees, randomly selecting one side, and using a generalized estimating equation. RESULTS: Patients undergoing bilateral TKAs had higher female predominance (95% versus 90%) and BMI (27.4 versus 26.1 kg/m(2)) than those undergoing unilateral TKAs. Although patients undergoing bilateral TKAs had worse preoperative function, they achieved comparable function at 1 year. The mean values did not differ considerably depending on the four methods. The SEs and p values of the reference method were generally the smallest, but the differences appeared negligible. CONCLUSIONS: Our analyses suggest bilaterality can be ignored in the analysis of TKA, since postoperative function is comparable between unilateral and bilateral TKAs and the theoretical errors in statistical analysis had little effect on the results.

Three-column subdivision for isolated posterolateral tibial plateau fractures and perspective surgical approaches.

BACKGROUND: This study aimed (1) to introduce a computed tomography (CT)-based classification of the posterolateral compartment of the tibial plateau based on the fibula and to propose the individualized surgical approaches for each zone; and (2) to determine the surgical approach based on the classification, that would achieve a safe and effective reduction and could improve postoperative clinical outcomes. METHODS: Eighteen cases of tibia plateau fracture involving the isolated posterolateral compartment in a single institution were retrospectively analyzed. The posterolateral compartment of the tibial plateau was segmented into three zones based on the fibular position and an individualized surgical approach was proposed for each zone. In anterior Zone I, surgical treatment was performed using an extended anterolateral approach and the patient was placed in the supine position; in middle Zone II, using the transfibular approach in the supine position; in posterior Zone III, using the posteromedial approach in the prone position. RESULTS: In all cases, anatomical articular reduction (intra-articular step off in CT images <2 mm) was achieved and maintained for the follow up period. The average mechanical medial proximal tibial angle was increased from 87.6° before surgery to 88.2° in the immediate postoperative period (P = 0.060), and maintained for the follow up period (mean 89.9° at 1-year follow up). At the 1-year follow up, the knee range of motion averaged 140° and the Lysholm knee function score was 95.0 points. CONCLUSION: An individualized surgical approach and fixation according to three-zone subdivision for isolated posterolateral tibial plateau fractures provided an effective and safe method to treat posterolateral tibial plateau fractures.

Change of joint-line convergence angle should be considered for accurate alignment correction in high tibial osteotomy.

BACKGROUND: The alignment correction after high tibial osteotomy (HTO) is made both by bony correction and soft-tissue correction around the knee. Change of the joint-line convergence angle (JLCA) represents the soft-tissue correction after HTO, which is the angle made by a tangential line between the femoral condyles and the tibial plateau. We described the patterns of JLCA change and related factors after HTO and investigated the appropriate preoperative planning method. METHODS: Eighty patients who underwent HTO between 2013 and 2016 were included for this retrospective study. Standing, whole-limb radiograph, supine knee anteroposterior (AP) and lateral were measured on the preoperative and postoperative radiographs. The patterns of JLCA changes and related factors were analyzed. RESULTS: JLCA decreased by a mean of 0.9° ± 1.2° (P < 0.001) after HTO. Sixteen patients (20%, group II) showed a greater JLCA decrease ≥ 2°, while 64 (80%, group I) patients remained in a narrow range of JLCA change < 2°. Group II showed more varus deformity (varus 8.1° vs. varus 4.7° in the mechanical femorotibial angle, P < 0.001), greater JLCA on standing (4.9° vs. 2.1°, P < 0.001), and the difference of JLCA in the standing and supine positions (2.8° vs. 0.7°, P < 0.001) preoperatively compared to group I. The risk of a greater JLCA decrease ≥ 2° was associated with greater preoperative JLCA in the standing position and the difference between the JLCA in the standing and supine positions. Postoperative JLCA correlated better with preoperative JLCA in the supine position than those in the standing position. A preoperative JLCA ≥ 4° or the difference of preoperative JLCA in the standing and supine positions ≥ 1.7° was the cut-off value to predict a large JLCA decrease ≥ 2° after HTO in the receiver operating characteristic (ROC) curve analysis. CONCLUSIONS: Surgeons should consider the effect of the JLCA change during the preoperative planning and intraoperative procedure to avoid unintended overcorrection.

Relationship of Bone Mineral Density and Knee Osteoarthritis (Kellgren-Lawrence Grade): Fifth Korea National Health and Nutrition Examination Survey.

BACKGROUND: Osteoarthritis (OA) and osteoporosis (OP) are the 2 most common bone disorders associated with aging. We can simply assume that older patients have a higher incidence of OA and OP with more severity. Although several papers have conducted studies on the relationship between OA and OP, none of them has demonstrated a conclusive link. In this study, we used radiological knee OA and bone mineral density (BMD; T-score of the total hip and lumbar spine) to analyze the incidence of OA and OP in a large population. We aimed to determine the relationship between OA and OP and investigate the associated risk factors. METHODS: This cross-sectional study used data extracted from the 2010-2012 Korea National Health and Nutrition Examination Survey. We evaluated a total of 4,250 participants aged ≥ 50 years who underwent knee radiography and dual-energy X-ray absorptiometry and their laboratory results. The relationship between radiological knee OA and BMD was assessed. The generalized linear model was used to evaluate the relationship between BMD and Kellgren-Lawrence (KL) grade. RESULTS: The higher KL grade was associated with older age, higher body mass index (BMI), female sex, and lower hemoglobin level (p < 0.001). No significant association was found between OA and the following variables: white blood cell, platelet, total cholesterol, vitamin D, alkaline phosphatase, parathyroid hormone, hypertension, diabetes, asthma, dyslipidemia, smoking status, alcohol consumption, and regular exercise (p > 0.05). After adjusting for confounding factors (age, BMI, diabetes, hypertension, smoking, and alcohol consumption), the average T-scores of total hip and lumbar spine were the highest in the mild OA group with KL grade 2 (-0.22 ± 1.08 and -0.89 ± 1.46, respectively, p < 0.001). The average T-scores of the total hip and lumbar spine significantly decreased as OA progressed from moderate (KL grade 3; -0.49 ± 1.05 and -1.33 ± 1.38, respectively, p < 0.001) to severe (KL grade 4; -0.73 ± 1.13 and -1.74 ± 1.75, respectively, p < 0.001). T-scores of the moderate-to-severe OA group were significantly lower than those of the non-OA group (KL grades 0 and 1, p < 0.001). CONCLUSIONS: Compared with the non-OA group, BMD (T-scores of the total hip and lumbar spine) was higher in the mild OA group and lower in the moderate-to-severe OA group.

Application of Three-Dimensional Computed Tomography Improved the Interrater Reliability of the AO/OTA Classification Decision in a Patellar Fracture.

We investigated whether interrater reliabilities of the AO/OTA classification of patellar fracture change with the imaging modalities applied, including plain radiography and two- and three-dimensional (2-D and 3-D) computed tomography (CT). Seven orthopedic specialists and four orthopedic residents completed a survey of 50 patellar fractures to classify the fractures according to the AO/OTA classification for patellar fractures. Initially, the survey was conducted using plain radiography only, then with 2-D CT introduced three weeks later and 3-D CT introduced six weeks later. Fleiss' Kappa coefficients were calculated to determine interrater reliability. The overall interrater reliability of the AO/OTA classifications was 0.40 (95% CI, 0.38-0.42) with plain radiography only and 0.43 (95% CI, 0.41-0.45) with the addition of 2-D CT. With the addition of 3-D CT, the reliability was significantly improved to 0.54 (95% CI, 0.52-0.56). In specialists, interrater reliability of the classifications was moderate with all three imaging modalities. With the use of 3-D CT, interrater reliability of the classification was 0.53 (95% CI, 0.50-0.56), which was significantly higher than that with the use of 2-D CT (κ = 0.45; 95% CI, 0.42-0.48). In residents, interrater reliability of the classification was 0.30 (95% CI, 0.24-0.36) with plain radiography. The reliability improved to 0.49 (95% CI, 0.43-0.56) with the addition of 2-D CT, which was significantly higher than that with plain radiography only. The use of 3-D CT imaging improved interrater reliability of the classification. Therefore, surgeons, especially residents, may benefit from using 3-D CT imaging for classifying and planning the treatment of patellar fractures.

The risk of concomitant injuries of the contralateral side in valgus injured knee by lateral bumper impact - "Windswept injury mechanism".

PURPOSE: Valgus injury of high energy of the lateral bumper impact can lead blows to the inside of the knee that push the knee outwards or indirect injury where a varus force is applied to the contralateral knee, which injury pattern named as "Windswept injury mechanism" in this study. The objective of this study was to establish injury pattern in the contralateral side knee on the basis of this pattern recognition to enhance a diagnosis of interrelated osseous and soft-tissue injuries. METHODS: Sixteen patients by "Windswept injury mechanism" were identified, who visited a level 1 trauma center between Jan 2007 and Dec 2016. We first evaluated the osseous and soft tissue injuries at primary impacted site by valgus force after checking MRI. Thereby, assessed the contralateral knee which structures were injured. To find any correlation between both knees in ligament injuries, patients were divided into two groups according to coincided anterior cruciate ligament (ACL) rupture. RESULTS: By the "Windswept injury mechanism", MCL total rupture was observed in all primary knees, and the major ligament injuries also were coincided on the contralateral knee. In primary knee, either ACL or PCL was ruptured in all cases. 9 patients (56%) had combined ACL rupture with MCL injury, 12 patients (75%) of combined PCL injury, and 5 patients (31%) had combined injury of both ACL and PCL. In contralateral knee, lateral collateral ligament injury was observed in 69%. 7 patients (44%) was combined with ACL injury, 7 patients (44%) with combined PCL injury, 4 patients (25%) with combined both ACL and PCL injury. In comparison of two groups, significantly higher risk of ACL injury in the contralateral knee was identified when coincided ACL and MCL injury in primary knee (p = 0.003). CONCLUSION: The specific mechanism-based injury pattern of "Windswept injury mechanism" was the first to identify the mechanism that showed concomitant major ligament injuries in the contralateral knee and to develop validated the higher risk of ACL injury in the contralateral knee when combined ACL and MCL injuries in primary knee, which improving diagnosis of potentially subtle and easily missed knee injuries.

Factors affecting stability after medial opening wedge high tibial osteotomy using locking plate: A cadaveric study.

OBJECTIVES: To investigate the effect of screw length, lateral hinge fracture, and gap filling on stability after medial opening wedge high tibial osteotomy (MOW HTO) using a locking plate. METHODS: Forty tibiae from fresh-frozen cadavers were randomly allocated into five groups. Group A was bicortically fixated, while Group B and Group C were unicortically fixated: 90% and 55% of drilled tunnel length, respectively. Group D was fixated using 90% length screws with a fractured lateral hinge. Group E was fixated using 90% length screws with gap filling using a bone substitute. Operated tibiae were tested under axial compressive load using a material testing machine. The medial gap changes under the serial axial load of 100-600 N and ultimate failure load were measured. RESULTS: Group D showed the biggest medial gap change and lowest failure load, while Group E presented the smallest gap change and highest failure load. The medial gap changes tended to increase with shorter screw length, but the difference was not significant between Groups A, B, and C. Group C and Group D showed greater medial gap change and lower failure load compared with Group E, while not differing from Group A and Group B. CONCLUSIONS: Unicortical fixation in proximal screw holes of a locking plate was not inferior to bicortical fixation regarding axial stability in MOW HTO, although proximal screws that are too short should be avoided. Lateral hinge fracture decreased, while gap filling with bone substitute increased axial stability.

Navigated versus Conventional Technique in High Tibial Osteotomy: A Meta-Analysis Focusing on Weight Bearing Effect.

PURPOSE: We aimed to determine whether navigated opening wedge high tibial osteotomy (HTO) is superior to the conventional technique in terms of accuracy of the coronal and sagittal alignment correction, functional outcome, and operative time. METHODS: Studies comparing navigated and conventional HTO were included in this meta-analysis. We compared the incidence of radiological outliers in coronal alignment and tibial slope maintenance, mean differences in functional outcome scales, and operative time. Subgroup analyses were performed on coronal alignment accuracy based on the intraoperative method of alignment confirmation: fluoroscopy vs. gap measurement method. RESULTS: Twelve studies were included: there were 434 knees in the navigated HTO studies and 405 knees in the conventional HTO studies. The risk of outlier was lower in navigated HTO than in conventional HTO; however, the difference was not significant when navigated HTO was compared with conventional HTO performed using the gap measurement method. Tibial slope maintenance was comparable or better in navigated HTO. No difference was found in the American Knee Society function and Lysholm scores. Navigated HTO necessitated a longer operative time of approximately 10 minutes. CONCLUSIONS: The use of navigation in HTO can improve accuracy in both coronal and sagittal alignments, but its clinical benefit is unclear.