Presoaking hamstring autograft with vancomycin does not jeopardize its biomechanical properties, including graft elongation, after cyclic loading.

PURPOSE: Presoaking the graft with vancomycin before implantation has been shown to reduce the risk of postoperative infection after anterior cruciate ligament reconstruction (ACLR). However, the effects of presoaking on the graft biomechanical properties remain unclear. This study aimed to determine whether presoaking the graft with vancomycin affects the graft biomechanical properties and length after cyclic loading. METHODS: Ten paired (20 specimens) gracilis and semitendinous tendons were harvested from fresh-frozen human cadaveric specimens. Two tendons were folded in half to make four strands, and the grafts were randomized into the vancomycin and control groups. The graft was exposed to the antibiotic solution for 15 min (5 mg/mL) and prepared by mixing 1 g of vancomycin with 200 mL of normal saline (NaCl 0.9%). The control group was soaked in normal saline for 15 min. The prepared grafts were attached to the actuator of a dynamic tensile-testing machine. All grafts were tested with 3000 cycles of cyclic loading followed by a pull-to-failure. The cyclic loading protocol consisted of position and load control blocks to simulate the graft in vivo in the postoperative phase after ACLR. RESULTS: Presoaking in vancomycin did not jeopardize the biomechanical properties of the graft. In addition, presoaking with vancomycin did not elongate the grafts. No significant differences were found in the mean Young's modulus and the mean total elongation of the graft of the specimen between the vancomycin group and the control group. CONCLUSION: Presoaking the graft with vancomycin jeopardized neither its biomechanical properties nor elongation even after cyclic loading in this in vitro study. It is suggested that vancomycin presoaking could be considered a safe and effective preventive measure for postoperative infections after ACLR. LEVEL OF EVIDENCE: Not applicable.

Assessment of a novel deep learning-based software developed for automatic feature extraction and grading of radiographic knee osteoarthritis.

BACKGROUND: The Kellgren-Lawrence (KL) grading system is the most widely used method to classify the severity of osteoarthritis (OA) of the knee. However, due to ambiguity of terminology, the KL system showed inferior inter- and intra-observer reliability. For a more reliable evaluation, we recently developed novel deep learning (DL) software known as MediAI-OA to extract each radiographic feature of knee OA and to grade OA severity based on the KL system. METHODS: This research used data from the Osteoarthritis Initiative for training and validation of MediAI-OA. 44,193 radiographs and 810 radiographs were set as the training data and used as validation data, respectively. This AI model was developed to automatically quantify the degree of joint space narrowing (JSN) of medial and lateral tibiofemoral joint, to automatically detect osteophytes in four regions (medial distal femur, lateral distal femur, medial proximal tibia and lateral proximal tibia) of the knee joint, to classify the KL grade, and present the results of these three OA features together. The model was tested by using 400 test datasets, and the results were compared to the ground truth. The accuracy of the JSN quantification and osteophyte detection was evaluated. The KL grade classification performance was evaluated by precision, recall, F1 score, accuracy, and Cohen's kappa coefficient. In addition, we defined KL grade 2 or higher as clinically significant OA, and accuracy of OA diagnosis were obtained. RESULTS: The mean squared error of JSN rate quantification was 0.067 and average osteophyte detection accuracy of the MediAI-OA was 0.84. The accuracy of KL grading was 0.83, and the kappa coefficient between the AI model and ground truth was 0.768, which demonstrated substantial consistency. The OA diagnosis accuracy of this software was 0.92. CONCLUSIONS: The novel DL software known as MediAI-OA demonstrated satisfactory performance comparable to that of experienced orthopedic surgeons and radiologists for analyzing features of knee OA, KL grading and OA diagnosis. Therefore, reliable KL grading can be performed and the burden of the radiologist can be reduced by using MediAI-OA.

Medial Meniscus Posterior Root Repair Restores Contact Pressure and Contact Area to Its Native State Even After Opening-Wedge High Tibial Osteotomy: A Cadaveric Biomechanical Study.

PURPOSE: To elucidate the effect of medial meniscus posterior root (MMPR) repair during opening-wedge high tibial osteotomy (OWHTO) in terms of contact pressure (CP) and contact area (CA). METHODS: Nine fresh-frozen human cadaveric knee specimens were included. Each specimen was tested under 9 conditions comprising 3 different degrees of correction during OWHTO (neutral, 5° of valgus, and 10° of valgus) and 3 different types of MMPR conditions (intact, torn, and repaired). The prepared specimens were attached to a customized tibiofemoral jig in a fully extended state. The CP and CA generated by a tibiofemoral axial load of 650 N was recorded using the Tekscan sensor's pressure mapping software. Statistical analysis was performed using a repeated measures analysis of variance. RESULTS: The increased CP and decreased CA in torn MMPR was decreased and increased, respectively, to the intact MMPR after repairing, irrespective of whether OWHTO was performed. The mean CP at a correction angle of 5° of valgus was 0.4067 ± 0.0768 MPa for intact MMPR, which increased to 0.7340 ± 0.1593 MPa for the torn MMPR and decreased to 0.3614 ± 0.0639 MPa for the repaired MMPR. In addition, the proportion of decrease in CP and increase in CA after MMPR repair was constant, compared with the torn MMPR, irrespective of the degree of correction during OWHTO. CONCLUSIONS: MMPR repair decreases CP and increases CA, irrespective of whether OWHTO is performed. The biomechanical advantage of repairing torn MMPR is maintained, regardless of the degree of correction during OWHTO. CLINICAL RELEVANCE: Both OWHTO and MMPR repair are known to protect the medial compartment of the knee. However, there are concerns in performing 2 procedures simultaneously. Results of our study showed that concurrent repair of the MMPR during OWHTO is useful for protecting the medial compartment of the knee with respect to tibiofemoral contact biomechanics.

Repair of medial meniscus posterior root tear is effective for root healing and cartilage regeneration in opening wedge high tibial osteotomy.

PURPOSE: This study aimed to determine whether the repair of a medial meniscus posterior root tear (MMPRT) is effective for MMPRT healing, cartilage regeneration, and clinical outcomes in opening wedge high tibial osteotomy (OWHTO). METHODS: This retrospective study included 80 patients who underwent OWHTO and subsequent second-look arthroscopy. The patients were divided into OWHTO-with-MMPRT-repair (n = 40) and OWHTO alone (n = 40) groups, and the healing rates (complete/partial/failure) were compared. Each group was further divided into over- and under-corrected subgroups to compare healing rates. The International Cartilage Repair Society (ICRS) grade, cartilage defect size, Koshino stage, ICRS cartilage repair assessment score of the medial femoral condyle (MFC), and International Knee Documentation Committee (IKDC) scores between the OWHTO-with-MMPRT-repair and OWHTO alone groups were compared according to whether microfracture was performed on the MFC. RESULTS: The overall healing rate of the MMPRT was higher in the OWHTO-with-MMPRT-repair group than that in the OWHTO alone group (P < 0.001). In addition, in the subgroup analysis, no difference in the MMPRT healing rate between the over-correction and under-correction groups when MMPRT repair was performed (n.s). In contrast, without MMPRT repair, the healing rate was lower in the under-correction group than that in the over-correction group (P = 0.03). Cartilage regeneration of the OWHTO-with-MMPRT-repair group was superior to that of the OWHTO alone group (P < 0.05). The IKDC subjective scores of the OWHTO-with-MMPRT-repair and OWHTO alone groups were 34.5 and 33.1 before surgery (n.s) and 50 and 47.2 at one year after surgery, respectively (n.s). These differences between the two groups for cartilage regeneration and IKDC subjective scores showed the same pattern regardless of microfractures. CONCLUSIONS: MMPRT repair during OWHTO might improve MMPRT healing, even with under-correction, and cartilage regeneration of MFC, regardless of microfracture. However, OWHTO with MMPRT repair might not improve short-term clinical outcomes compared to OWHTO alone. Further randomized clinical trials are necessary. LEVEL OF EVIDENCE: III, Retrospective cohort study.

Delayed normalization of C-Reactive protein and erythrocyte sedimentation rate was not associated with inferior clinical outcomes after total knee arthroplasty.

BACKGROUND: The purpose of this study aimed to identify the proportion of patients with delayed normalization of C-reactive protein (CRP) and Erythrocyte sedimentation rate (ESR) after TKA, to determine postoperative thresholds predictive of prolonged elevation. Further, we aimed to determine if the clinical outcomes of patients with prolonged elevation were inferior to those without prolonged elevation. METHODS: The records of 211 unilateral and 320 bilateral TKA were reviewed. Patients were divided into the normal and elevation group based on CRP and ESR levels at 6 weeks and 3 months. The temporal pattern of CRP and ESR change in both groups was compared, and thresholds predictive of elevation at 6 weeks and 3 months were identified. Further, the Western Ontario and McMaster Universities Osteoarthritis (WOMAC) index and Tegner activity scale of both groups at 6 months, 1 year, and 2 years after TKA were compared. RESULTS: The proportion of patients with elevated CRP and ESR at 6 weeks and 3 months was CRP: 24.2%, 10%, ESR: 51.6%, 29.9% in unilateral and CRP: 31.5%, 10.6%, ESR: 58.1%, 42.7% in bilateral TKA. The thresholds for elevation at 6 weeks and 3 months were 9.5 mg/dL, 11.4 mg/dL (CRP at 6 weeks) and 81.5 mm/h, 74.5 mm/h (ESR at 3 months). There was no difference in the WOMAC score and Tegner activity scale between both groups. CONCLUSIONS: CRP and ESR are often elevated for a prolonged period even in the absence of infection after TKA. Such cases show distinct temporal patterns, which are predictable, and do not appear to have a significant effect on clinical outcome.

Presence of Night Pain, Neuropathic Pain, or Depressive Disorder Does Not Adversely Affect Outcomes After Total Knee Arthroplasty: A Prospective Cohort Study.

BACKGROUND: A considerable proportion of patients warranting total knee arthroplasty (TKA) have night pain, neuropathic pain, and/or depressive disorder, which may not be resolved by TKA. This prospective, longitudinal cohort study aimed to document the prevalence of night pain, neuropathic pain, and depressive disorder in patients with advanced knee osteoarthritis undergoing TKA and to determine whether the specific coexisting pain and/or disorder at the time of TKA adversely affected postoperative outcomes. METHODS: In this study, 148 patients undergoing TKA were longitudinally evaluated. The presence of night pain, neuropathic pain (determined using Douleur Neuropathique 4 [DN4]) and depressive disorder (determined using the Patient Health Questionnaire-9 [PHQ-9]) was determined before and 6 weeks, 3 months and 1 year after TKA. In addition, Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) and EuroQol-5 Dimension (EQ-5D) scores were assessed before and 1 year after TKA. Potential associations of night pain, neuropathic pain, and/or depressive disorder with pre- and postoperative WOMAC and EQ-5D scores were examined in subgroup analyses. RESULTS: Preoperatively, 72% (n = 106) of patients reported night pain, and the prevalences of neuropathic pain and depressive disorder were 15% and 17%, respectively. Preoperatively, compared with patients without night pain, those with night pain had significantly poorer preoperative WOMAC scores, but no significant difference was seen between groups 1 year after TKA. Preoperatively, the WOMAC, EQ-5D, and EQ-5D health scores of patients with neuropathic pain were not significantly different from those of patients without neuropathic pain, and there was no difference in clinical outcome scores 1 year after TKA between these groups. Preoperatively, the patients with depressive disorder showed significantly poorer preoperative WOMAC, EQ-5D, and EQ-5D health scores than those without depressive disorder, but no significant differences in scores were observed 1 year after TKA between these groups. CONCLUSION: This study revealed a considerable prevalence of night pain, neuropathic pain, and depressive disorder in patients undergoing TKA and that patients with these specific conditions reported poorer functional and quality of life scores preoperatively. However, such adverse effects disappeared after TKA. Our study findings suggest that TKA can provide satisfactory outcomes for patients with these specific conditions.

Effect of distance between the feet on knee joint line orientation after total knee arthroplasty in standing full-limb radiographs.

PURPOSE: Although knee joint line orientation (KJLO) after total knee arthroplasty (TKA) has been emphasized as an important factor that can affect postoperative knee kinematics, the effect of foot position on KJLO has not been fully understood. This study aimed to (1) identify the anatomical and positional factors that determine KJLO after TKA, and (2) determine the effect of foot position on KJLO after TKA. The hypothesis of this study was that the post-TKA KJLO would change depending on the distance between the feet, as well as the coronal implant positions. METHODS: A total of 92 radiographs from 46 patients who underwent TKA were retrospectively reviewed. Two postoperative standing full-limb anteroposterior radiographs taken with the feet in different positions (with both feet in contact with each other or shoulder width apart) from each patient were evaluated. The correlation between KJLO after TKA and possible anatomical and positional factors, including leg length, lateral distal femoral angle (LDFA), medial proximal tibial angle (MPTA), ankle joint line orientation (AJLO), mechanical tibiofemoral angle (mTFA), and distance between the feet, were analyzed, and the KJLO equation was computed using multiple linear regression. KJLO was also compared among different combinations of valgus or varus alignment of the femoral and tibial components. RESULTS: LDFA, MPTA, AJLO, and distance between the feet were identified as determinants of KJLO after TKA, and the distance between the feet was strongly correlated with KJLO. Based on the KJLO equation (KJLO [°] = 107.548 - 0.441 × LDFA [°] - 0.832 × MPTA [°] + 0.093 × AJLO [°] + 0.037 × ITD [mm]), KJLO changes by 3.7° per 100 mm of distance between the feet. The KJLO of patients with valgus femoral and varus tibial components was more parallel to the ground than those with other combinations. CONCLUSION: KJLO after TKA was strongly affected by the distance between the feet when taking full-limb radiography, and the KJLO changed by 3.7° per 100 mm of distance between the feet. To assess the KJLO after TKA reproducibly, standardization of the distance between the feet is necessary. LEVEL OF EVIDENCE: IV.

Asymmetric transepicondylar axis between varus and valgus osteoarthritic knees in windswept deformity can be predicted by hip-knee-ankle angle difference.

PURPOSE: Studies regarding the best strategy to determine appropriate femoral component rotation during bilateral total knee arthroplasty (TKA) in wind swept deformities (WSD) are very limited. The purpose of this study was (1) to evaluate whether femoral rotational profiles differ between varus and valgus osteoarthritic knees in WSD and (2) to analyze the correlation between femoral rotational profiles and coronal radiologic parameters. METHODS: A total of 40 patients who were diagnosed with bilateral knee osteoarthritis with WSD between January 2010 and December 2020 at a single institution were retrospectively reviewed. On axial computed tomography scans, femoral rotational profile parameters such as the clinical transepicondylar axis (cTEA) and anterior-posterior (AP) axis were compared between valgus and varus osteoarthritic knees. In standing full-limb AP radiographs, coronal radiographic parameters including hip-knee-ankle angle (HKA), valgus correction angle (VCA), lateral distal femoral angle (LDFA), medial proximal tibial angle (MPTA), and joint line convergence angle (JLCA) were measured in both knees. The correlation between the varus-valgus cTEA difference, and differences in coronal radiologic parameters was analyzed. RESULTS: In valgus osteoarthritic knees, cTEA was significantly increased compared to varus osteoarthritic knees by 1.5° (valgus: 7.65° ± 1.82°, varus: 6.15° ± 1.58°, p < 0.001). All coronal radiologic parameters, including HKA, LDFA, MPTA, JLCA, and VCA, were significantly different between valgus and varus knees. In correlation analysis, the varus-valgus cTEA difference was significantly correlated with LDFA (r = 0.365, p = 0.021), MPTA (r = 0.442, p = 0.004), and HKA differences (r = 0.693, p < 0.001), with the HKA difference showing the strongest correlation with the cTEA difference. CONCLUSION: In bilateral knee osteoarthritis with WSD, valgus knees showed significantly increased cTEA compared to varus knees, and the cTEA difference positively correlated with the HKA difference between valgus and varus knees. To determine the optimal femoral component rotation during TKA in WSD, assessment of cTEA with pre-operative CT scans or careful intra-operative measurement is recommended, especially in patients with large HKA difference. LEVEL OF EVIDENCE: III, Retrospective cohort study.

Prevalence and Characteristics of Onychomycosis in Patients with Knee Osteoarthritis: A Single-centre Prospective Cross-sectional Study.

Knee disorders that compromise patients' lower leg movements and self-care may put these patients at greater risk of onychomycosis. However, little is known about the prevalence of onychomycosis in patients with knee diseases. This study evaluated the prevalence and characteristics of onychomycosis in patients with knee osteoarthritis. A total of 520 consecutive patients with symptomatic knee osteoarthritis who visited the Department of Orthopedics for a potential knee surgery were evaluated for onychomycosis by PCR-based reverse blot hybridization assay. Of the 520 patients, 308 (59.2%) were diagnosed with onychomycosis. Age (p = 0.004), male sex (p = 0.015), and being barefooted (p = 0.031) were statistically significant risk factors for onychomycosis. Knee disease severity, based on Kellgren-Lawrence grade, was associated with severity of onychomycosis. The impairment of physical function and self-care caused by knee disorders may increase the prevalence of onychomycosis in these patients.

Current Trends and Projected Burden of Primary and Revision Total Knee Arthroplasty in Korea Between 2010 and 2030.

BACKGROUND: This study aimed to (1) document the total knee arthroplasty (TKA) use in Korea from 2010 to 2018, (2) evaluate whether rapid increase in TKA use has been maintained, and (3) estimate the projected TKA burden to 2030 based on the current use. METHODS: Using the Health Insurance Review and Assessment Korean database, procedural rate, growth rate, and revision burden of primary and revision TKAs in Korea between 2010 and 2018 were analyzed. TKA procedural numbers were also stratified by age and gender. Then, the projected TKA burden to 2030 including procedural number and medical costs were estimated using linear and quasi-Poisson regression models, respectively. RESULTS: Between 2010 and 2018, procedural rate of primary and revision TKAs has increased by 35% and 68%, respectively. More than 85% of primary and revision TKAs were performed on female patients, and the subgroup of patients aged ≥80 years showed a marked increase in primary and revision TKA use. According to the projection model, the number of primary and revision TKAs is predicted to increase between 53% and 91%, and between 75% and 155%, respectively, by 2030. CONCLUSION: Between 2010 and 2018, the procedural rates of primary and revision TKAs in Korea increased gradually by 35% and 68%, respectively, and previously observed striking growth rate has markedly slowed. Nevertheless, compared to 2018, the burdens of primary and revision TKAs are projected to increase up to 91% and 155%, respectively, by 2030. LEVEL OF EVIDENCE: Therapeutic Level III.

Effects of Intravenous Dexamethasone on Glycemic Control in Patients With Type 2 Diabetes Mellitus After Total Knee Arthroplasty.

BACKGROUND: We sought to determine whether administrations of intravenous (IV) dexamethasone jeopardize blood glycemic control, increase rates of postoperative complications, and diabetic medication change after TKA. METHODS: This retrospective study included 427 patients with DM who underwent TKA. Patients were divided into two groups according to the use of IV dexamethasone (Dexa and No Dexa). For the Dexa, IV dexamethasone (5mg) was administered twice (surgery day, postoperative day 1). Blood glucose level until postoperative day 5, whether the mean blood glucose level was ≥200 mg/dL or not, the rate of a diabetic medication change, and postoperative complications (surgical site infection, delayed wound healing) were analyzed. RESULTS: The adverse effects of IV dexamethasone on glycemic control were limited to the day of injection. The mean blood glucose level was 168.8 mg/dL and 204.4 mg/dL on operation day and 193.0 mg/dL and 210.5 mg/dL on postoperative day 1 in the No Dexa and the Dexa, respectively. High preoperative glycated hemoglobin (HbA1c) levels, but not IV dexamethasone administration, increased the risk of postoperative blood glucose level ≥200 mg/dL (odds ratio [OR], 2.810) and diabetic medication change (OR, 3.635, P < .001). A preoperative HbA1c level of >7.05% was associated with the risk of diabetic medication change. There was increase of postoperative complications (OR, 0.693, P = .552). CONCLUSIONS: IV dexamethasone have transient effects on increasing the blood glucose level after TKA in patients with DM. However, patients with a preoperative HbA1c level of ≥7.05% may need to change their diabetic medication after TKA, regardless of IV dexamethasone administration.

Bone Mineral Density Around the Knee Joint: Correlation With Central Bone Mineral Density and Associated Factors.

INTRODUCTION: The aims of this study were to (1) assess the bone mineral density (BMD) around the knee joint, (2) determine the correlation between central and knee BMDs, and (3) investigate the factors associated with BMD around the knee joint in patients with knee osteoarthritis (OA). METHODOLOGY: This cross-sectional study included 122 patients who underwent total knee arthroplasty. Central and knee dual-energy X-ray absorptiometry was performed preoperatively. BMD at 6 regions of interest (ROIs) around the knee joint were measured, and their correlations with central BMD were determined using Spearman's correlation analysis. Lower limb alignment, severity of OA, body mass index (BMI), preoperative functional and pain scores were assessed to elucidate the factors associated with knee BMD using linear regression analysis. RESULTS: Around the knee joint, BMD was the lowest at the distal femoral metaphysis and lateral tibial condyle. Knee BMD was significantly correlated with central BMD. However, the correlation coefficients varied by the ROI. Additionally, multivariate analysis revealed different associations with respect to the regions around the knee joint. Varus alignment of the lower limb was associated with increased BMD of the medial condyles and decreased BMD of lateral condyles. High grade OA was a protective factor; it was associated with increased BMD at the lateral condyles of the femur and tibia. Higher BMI was an independent protective factor in all ROIs around the knee joint except the lateral femoral condyles. Lower functional level was not associated with decreased BMD, whereas a higher pain score was significantly associated with lower BMD at the proximal tibial metaphysis. CONCLUSIONS: Knee BMD was significantly correlated with central BMD. However, the correlations varied with the regions around the knee joint probably due to their independent association with the alignment of the lower limb, severity of OA, BMI, and preoperative pain level.

Microfractures Versus a Porcine-Derived Collagen-Augmented Chondrogenesis Technique for Treating Knee Cartilage Defects: A Multicenter Randomized Controlled Trial.

PURPOSE: The purpose of this study was to evaluate the clinical efficacy and safety of treating patients with a cartilage defect of the knee with microfractures and porcine-derived collagen-augmented chondrogenesis technique (C-ACT). METHODS: One hundred participants were randomly assigned to the control group (n = 48, microfracture) or the investigational group (n = 52, C-ACT). Clinical and magnetic resonance imaging (MRI) outcomes were assessed 12 and 24 months postoperatively for efficacy and adverse events. Magnetic Resonance Observation of Cartilage Repair Tissue (MOCART) assessment was used to analyze cartilage tissue repair. MRI outcomes for 50% defect filling and repaired tissue/reference cartilage (RT/RC) ratio were quantified using T2 mapping. Clinical outcomes were assessed using the visual analogue scale (VAS) for pain and 20% improvement, minimal clinically important difference (MCID), and patient acceptable symptom state for Knee Injury and Osteoarthritis Outcome Score (KOOS) and the International Knee Documentation Committee score. RESULTS: MOCART scores in the investigation group showed improved defect repair and filling (P = .0201), integration with the border zone (P = .0062), and effusion (P = .0079). MRI outcomes showed that the odds ratio (OR) for ≥50% defect filling at 12 months was statistically higher in the investigation group (OR 3.984, P = .0377). Moreover, the likelihood of the RT/RC OR becoming ≥1 was significantly higher (OR 11.37, P = .0126) in the investigation group. At 24 months postoperatively, the OR for the VAS 20% improvement rate was significantly higher in the investigational group (OR 2.808, P = .047). Twenty-three patients (52.3%) in the control group and 35 (77.8%) in the investigation group demonstrated more than the MCID of KOOS pain from baseline to 1 year postoperatively, with a significant difference between groups (P = .0116). CONCLUSION: In this multicenter randomized trial, the addition of C-ACT resulted in better filling of cartilage defect of the knee joint. LEVEL OF EVIDENCE: Level Ⅰ, Multicenter Randomized Controlled Trial.

Anterior-stabilized TKA is inferior to posterior-stabilized TKA in terms of postoperative posterior stability and knee flexion in osteoarthritic knees: a prospective randomized controlled trial with bilateral TKA.

PURPOSE: To determine whether knee stability, range of motion (ROM) and clinical scores differ between anterior-stabilized (AS) and posterior-stabilized (PS) total knee arthroplasty (TKA). METHODS: This prospective randomized controlled trial included 34 patients with severe bilateral knee osteoarthritis who underwent bilateral TKA between June 2010 and July 2011 using AS and PS designs of a single-implant system. AS TKA with ultracongruent inserts was performed in one knee and PS TKA with a cam-post mechanism was performed in the other knee in each patient. Clinical and radiological data from a mean follow-up period of 5 years, including ROM, clinical scores, peak knee torque determined by isokinetic test, knee joint laxity determined by Telos stress views, tourniquet time and subjects' preference were analyzed. RESULTS: The mean postoperative knee flexion angle did not differ between groups until 1 year. Beginning 2 years postoperatively, the knee flexion angle decreased slightly in the AS group and was smaller than that in the PS group (p = 0.004). The mean Knee Society knee score was higher in the PS group than in the AS group after 2 years. The quadriceps strength did not differ between groups. The mean posterior laxity after TKA was 6-8 mm greater in the AS group than in the PS group. No radiological loosening was observed in either group. More subjects preferred PS knees to AS knees. However, this difference was not significant. CONCLUSION: AS primary TKA was inferior to PS TKA in terms of posterior knee stability, postoperative knee flexion and clinical scores after 2 years. LEVEL OF EVIDENCE: Therapeutic study, Level 1.

Postoperative Intravenous Iron Supplementation Does Not Improve Hemoglobin Level and Transfusion Rate Following Staged Bilateral Total Knee Arthroplasty.

BACKGROUND: We determined whether postoperative intravenous (IV) iron supplementation could reduce transfusion rate in patients undergoing staged bilateral total knee arthroplasty (TKA). Furthermore, we examined whether hemoglobin (Hb) levels and iron profile differed between patients with and without postoperative IV iron supplementation. METHODS: This retrospective, comparative cohort study included 126 patients who underwent primary staged bilateral TKA during a single hospitalization. The second TKA was performed at a week's interval. Group iron (n = 65) received IV iron immediately after each surgery, while patients in group no-iron (n = 61) received no iron after surgery. Transfusion rate, change in Hb levels, and iron profile including serum iron, ferritin, total iron binding capacity, and transferrin saturation were evaluated preoperatively; on postoperative days 1, 2, and 4 after the first TKA; and postoperative days 1, 2, 4, and 7, 6 weeks, and 3 months after the second TKA. RESULTS: There were no significant differences in Hb levels and transfusion rate following staged bilateral TKA between patients with and without postoperative IV iron supplementation although serum iron profiles were improved in patients with IV iron supplementation. CONCLUSION: Postoperative IV iron supplementation immediately after acute blood loss caused by TKA was not effective in improving the transfusion rate. Therefore, surgeons should use protocols other than postoperative IV iron supplementation for reducing the transfusion rate in patients undergoing staged bilateral TKA in a single hospitalization. LEVEL OF EVIDENCE: III.

Development and validation of a prediction model for knee joint line orientation after high tibial osteotomy.

BACKGROUND: Maintenance of optimal knee joint line orientation (KJLO) is important after high tibial osteotomy (HTO). No tools, however, are currently available that could predict the value of postoperative KJLO before surgery. First, this study sought to determine the effects of various preoperative anatomical alignment parameters to postoperative KJLO. Based upon these analyses, we aimed to devise an equation that predicts the value of postoperative KJLO. METHODS: A total of 14 radiographic parameters were measured in preoperative and postoperative full-limb standing anteroposterior radiographs on 50 patients who underwent open-wedge HTO. The parameters were analysed using multivariable linear regression to predict KJLO after HTO. External validation of the equation was done with 20 patients who underwent HTO at another institution. RESULTS: After HTO, KJLO increased from - 0.8° to 2.9° (P < 0.001). Based on the multivariable linear regression analysis, an equation was derived that can estimate postoperative KJLO after HTO; postoperative KJLO(°) = 1.029 + 0.560 × preoperative KJLO(°) + 0.310 × preoperative tibia plateau inclination(°) + 0.463 × aimed correction angle(°). The adjusted coefficients of determination value for this equation was 0.721. The equation also showed good calibration and predictability in external validation with predicted squared correlation coefficient of 0.867. CONCLUSIONS: This study analysed the effects of preoperative anatomical alignment parameters on the postoperative KJLO. An equation which predicts postoperative KJLO with preoperative anatomical alignment factors was devised and validated. This equation would help in selecting optimal patients for HTO and in selecting the optimal target correction angle in HTO.

Does unicompartmental knee arthroplasty have worse outcomes in spontaneous osteonecrosis of the knee than in medial compartment osteoarthritis? A systematic review and meta-analysis.

INTRODUCTION: The role of unicompartmental knee arthroplasty (UKA) in spontaneous osteonecrosis of the knee (SONK) remains controversial, even though SONK involves only one compartment of the knee joint. We aimed to compare the survival rate and clinical outcomes of UKA in SONK and medial compartment osteoarthritis (MOA) via a meta-analysis of previous studies. MATERIALS AND METHODS: MEDLINE, Embase, and Cochrane Library were searched up to January 2018 with keywords related to SONK and knee arthroplasty. Studies were selected with predetermined inclusion criteria: (1) medial UKA as the primary procedure, (2) reporting implant survival or clinical outcomes of osteonecrosis and osteoarthritis, and (3) follow-up period > 1 year. Quality assessment was performed using the risk of bias assessment tool for non-randomized studies. A random-effects model was used to estimate the pooled relative risk (RR) and standardized mean difference. RESULTS: The incidence of UKA revision for any reason was significantly higher in SONK than in MOA group (pooled RR = 1.83, p = 0.009). However, the risk of revision due to aseptic loosening was not significantly different between the groups. Moreover, when stratified by the study quality, high-quality studies showed similar risk of overall revision in SONK and MOA (p = 0.71). Subgroup analysis revealed no significant difference in failure between SONK and MOA after cemented mobile and fixed bearing UKA. Results of uncemented UKA were reported only in one study, which showed higher failure of SONK compared to MOA. Clinical outcomes after UKA were similar between SONK and MOA (p = 0.66). CONCLUSIONS: Cemented UKA has similar survival and clinical outcomes in SONK and MOA. Prospective studies designed specifically to compare the UKA outcomes in SONK and MOA are necessary.

Two-stage approach to total knee arthroplasty using colistin-loaded articulating cement spacer for vancomycin-resistant Pseudomonas aeruginosa infection in an arthritic knee.

BACKGROUND: A two-stage approach to total knee arthroplasty (TKA) using an antibiotic-impregnated articulating cement spacer is an option for an infected arthritic knee. Vancomycin combined with broad-spectrum antibiotics can be used to make an antibiotic-impregnated articulating cement spacer. Causative organisms are sometimes not confirmed before surgery. Joint infections of multidrug-resistant organisms are increasing. Therefore, routine combinations of antibiotics may not be effective. METHODS AND RESULTS: We present a case of a patient who developed vancomycin-resistant Pseudomonas aeruginosa infection in an arthritic knee. A 71-year-old man was initially diagnosed with pyogenic arthritis caused by Staphylococcus aureus. He underwent arthroscopic debridement elsewhere. However, the infection persisted. He was referred to our hospital, and we performed a two-stage TKA using a vancomycin-based antibiotic-impregnated articulating cement spacer. Vancomycin-resistant P. aeruginosa was identified after surgery. Intravenous colistin was added. However, this failed, either because vancomycin was not effective against P. aeruginosa, or because insufficient systemic colistin due to colistin-induced acute kidney injury. Therefore, debridement was repeated, and colistin-loaded cement spacer was inserted. The spacer delivered high concentrations of colistin to the infected joint with decreased systemic effects. Thus, less systemic colistin was used. The infection was controlled without recurrent acute kidney injury. One year after surgery, conversion to TKA was successfully performed. CONCLUSION: A two-stage approach to TKA using a colistin-loaded articulating cement spacer can be used for an arthritic knee infected by vancomycin-resistant P. aeruginosa. Furthermore, local administration of colistin using a cement spacer can reduce the systemic side effects of colistin.

Revision surgery for failed anterior cruciate ligament reconstruction with extension deficiency.

BACKGROUND: Some patients with recurrent symptomatic instability after primary anterior cruciate ligament (ACL) reconstruction have an extension deficiency (ED). This study (a) compared preoperative clinical conditions between the ED and non-ED groups undergoing revision ACL reconstruction, (b) documented clinical and arthroscopic findings in ACL-reconstructed patients with reinstability and ED, and (c) determined whether the ED could be resolved and whether the clinical results of revision surgery differed between the ED and non-ED groups. METHODS: This study included 58 patients who underwent revision ACL reconstruction. Patients were divided into the ED and non-ED groups. Preoperatively, the demographics and clinical conditions of the two groups were compared. Intraoperatively, the pathological structures that related to ED were documented. After surgery, the degree of postoperative ED and functional outcomes were compared between the two groups at 2-year follow-up. RESULTS: The International Knee Documentation Committee subjective score and SF-36 physical component summary scores were worse in the ED group than the non-ED group preoperatively (54 vs 48 [P = 0.014]; 42 vs 39 [P = 0.031], respectively). Intraoperatively, the ED group showed significantly more frequent graft malposition (50% vs 5%), anvil osteophytes (44% vs 0%), and scarring around posterior intercondylar notch (100% vs 0%). However, there was no difference in the degree of postoperative ED and functional outcome between the two groups at follow-up. CONCLUSIONS: ED in patients with recurrent instability after primary ACL reconstruction could be treated with good clinical result by addressing the pathological conditions causing ED in addition to ACL re-reconstruction.

Incidence of deep vein thrombosis before and after total knee arthroplasty without pharmacologic prophylaxis: a 128-row multidetector CT indirect venography study.

BACKGROUND: We sought to document the incidences of deep vein thrombosis (DVT) before and after total knee arthroplasty (TKA). In addition, we aimed to explor whether routine preoperative DVT evaluation was useful to establish DVT treatment strategies after TKA. Finally, we wanted to evaluate whether the incidences of DVT differed between patients undergoing unilateral and staged bilateral TKA within the same hospitalization period. METHODS: The retrospective study included 153 consecutive patients (253 knees) with osteoarthritis who underwent primary TKA. After surgery, mechanical compression devices (only) were used for DVT prophylaxis. DVT status before and after TKA was determined via 128-row, multidetector, computed tomography/indirect venography. RESULTS: Overall, the preoperative DVT incidence was 2.6% per patient and 1.6% per knee. All preoperative DVTs were distal in nature and asymptomatic. After TKA, newly developed thrombi were evident in various calf veins, without propagation of any pre-existing thrombi. Postoperatively, the overall incidences of DVT were 69.9% per patient and 58.5% per knee. The DVT incidences were 66% per patient and 69.8% per knee in the unilateral TKA group. In contrast, the incidences were 72% per patient and 55.5% per knee in the staged bilateral TKA group. There was one case of symptomatic distal (unilateral TKA; 0.65% per patient and 0.4% per knee) and proximal DVT (bilateral TKA; 0.65% per patient and 0.4% per knee), respectively. CONCLUSIONS: The incidence of symptomatic DVT was low in Asian patients treated with mechanical compression devices alone, although substantial portion of patients had DVT after surgery. Routine preoperative DVT evaluation is probably not necessary; preoperative DVT was rare and of limited clinical relevance. Furthermore, staged bilateral TKA during a single period of hospitalization does not increase the incidence of DVT.