Life Expectancy of Patients Undergoing Total Knee Arthroplasty: Comparison With General Population.

BACKGROUND: This study aimed to analyze the life expectancy and cause of death in osteoarthritis (OA) patients who underwent total knee arthroplasty (TKA) and to identify risk factors that affect long-term mortality rate after TKA. METHODS: Among 601 patients, who underwent primary TKA due to OA by a single surgeon from July 2005 to December 2011, we identified patients who died after the operation using data obtained from the National Statistical Office of Korea. We calculated 5-, 10-, and 15-year survival rates of the patients and age-specific standardized mortality ratios (SMRs) compared to general population of South Korea according to the causes of death. We also identified risk factors for death. RESULTS: The 5-year, 10-year, and 15-year survival rates were 94%, 84%, and 75%, respectively. The overall age-specific SMR of the TKA cohort was lower than that of the general population (0.69; P < 0.001). Cause-specific SMRs for circulatory diseases, neoplasms, and digestive diseases after TKA were significantly lower than those of the general population (0.65, 0.58, and 0.16, respectively; all P < 0.05). Male gender, older age, lower body mass index (BMI), anemia, and higher Charlson comorbidity index (CCI) were significant factors associated with higher mortality after TKA. CONCLUSION: TKA is a worthwhile surgery that can improve life expectancy, especially from diseases of the circulatory system, neoplasms, and digestive system, in patients with OA compared to the general population. However, careful follow-up is needed for patients with male gender, older age, lower BMI, anemia, and higher CCI, as these factors may increase long-term mortality risk after TKA. LEVEL OF EVIDENCE: III.

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.

Effect of Total Hip Arthroplasty on Ipsilateral Lower Limb Alignment and Knee Joint Space Width: Minimum 5-Year Follow-up.

BACKGROUND: This study aimed to 1) assess the effect of total hip arthroplasty (THA) on coronal limb alignment, namely, the hip-knee-ankle angle (HKA), 2) identify factors that determine changes in the HKA, and 3) determine whether alignment changes influence the knee joint space width. METHODS: We retrospectively evaluated 266 limbs of patients who underwent THA. Three types of prostheses with neck shaft angles (NSAs) of 132°, 135°, and 138° were used. Several radiographic parameters were measured in the preoperative and final radiographs (at least 5 years after THA). A paired t-test was used to confirm the effect of THA on HKA change. Multiple regression analysis was performed to identify radiographic parameters related to HKA changes following THA and changes in knee joint space width. Subgroup analyses were performed to reveal the effect of NSA change on the HKA change, and the proportion of total knee arthroplasty usage and changes in radiographic parameters between maintained joint space and narrowed joint space groups were compared. RESULTS: The preoperative mean HKA was 1.4° varus and increased to 2.7° varus after THA. This change was related to changes in the NSA, lateral distal femoral angle, and femoral bowing angle. In particular, in the group with a decrease in NSA of > 5°, the preoperative mean HKA was largely changed from 1.4° varus to 4.6° varus after THA. The prostheses with NSA of 132° and 135° also led to greater varus HKA changes than those with an NSA of 138°. Narrowing of the medial knee joint space was related to changes in the varus direction of the HKA, decrease in NSA, increase in femoral offset. CONCLUSION: A large reduction in NSA can lead to considerable varus limb alignment after THA, which can have adverse effects on the medial compartment of the ipsilateral knee.

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.

The limited use of a tourniquet during total knee arthroplasty under a contemporary enhanced recovery protocol has no meaningful benefit: a prospective randomized controlled trial.

PURPOSE: This prospective randomized controlled trial aimed to determine whether the limited use of tourniquets during total knee arthroplasty (TKA) would be more beneficial under the contemporary enhanced recovery after surgery (ERAS) protocol than the conventional use of tourniquets. METHODS: One hundred patients with knee osteoarthritis who underwent primary TKA were randomly assigned to the limited tourniquet (LT, n = 51) and conventional tourniquet (CT, n = 49) groups. Operation time, serial hemoglobin drops, calculated blood loss, transfusion rate, D-dimer levels, and the presence of deep vein thrombosis (DVT) were assessed. In addition, visual analog scale (VAS) scores for pain around the knee and thigh were measured while resting during the day, at night, and during ambulation. Opioid consumption, range of motion, knee circumference, and postoperative complications were also analyzed. Isokinetic muscle strength, knee injury and osteoarthritis outcome scores, and Euro-QoL-5D scores were also assessed before and 3 months after TKA. For statistical analysis, Chi-square and Fisher's exact tests were performed to compare the differences in categorical variables. Continuous variables were compared using an independent t test or Mann‒Whitney U test. RESULTS: The average tourniquet time was 46.7 min in the CT group and 5.4 min in the LT group. Knee pain on the first night after surgery was significantly higher in the CT group (3.2 vs. 4.6, p = 0.033). However, daytime pain in the thigh at 2 weeks and in the knee at 3 months after TKA were higher in the LT group than in the CT group (p = 0.048 and p = 0.036, respectively). The D-dimer level 3 months after TKA was also higher in the LT group than in the CT group (p = 0.028), but there was no difference in DVT incidence between the two groups (n.s.). Additionally, there were no significant differences in the other variables between the groups. CONCLUSIONS: Although the limited use of tourniquets did not increase the operation time, blood loss, or transfusion rate, this study found that the limited use of tourniquets would not provide additional meaningful benefit in reducing pain and early functional restoration after TKA when applying the ERAS protocol. LEVEL OF EVIDENCE: I.

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.

Postoperative rehabilitation using a digital healthcare system in patients with total knee arthroplasty: a randomized controlled trial.

INTRODUCTION: Digital healthcare systems based on augmented reality (AR) show promise for postoperative rehabilitation. We compared the effectiveness of AR-based rehabilitation and conventional rehabilitation after total knee arthroplasty (TKA). MATERIALS AND METHODS: We randomly allocated 56 participants to digital healthcare rehabilitation group (DR group) and conventional rehabilitation group (CR group). Participants in the CR group performed brochure-based home exercises for 12 weeks, whereas those in the DR group performed AR-based home exercises that showed each motion on a monitor and provided real-time feedback. The primary outcome was change in 4-m gait speed. The secondary outcomes were the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) score, health-related quality of life [assessed by the EuroQoL 5-Dimension 5-Level (EQ5D5L) questionnaire], pain [measured using a numeric rating scale (NRS)], Berg Balance Scale (BBS), range of motion (ROM), and muscle strength. Outcomes were measured at baseline (T0) and 3 (T1), 12 (T2), and 24 (T3) weeks after randomization. RESULTS: There was no significant difference in baseline characteristics of participants between two groups, except age and body mass index. No group difference was observed in 4-m gait speed (0.37 ± 0.19 and 0.42 ± 0.28 for the DR and CR groups, respectively; p = 0.438). The generalized estimating equation model revealed no significant group by time interaction regarding for 4-m gait speed, WOMAC, EQ5D5L, NRS, BBS, ROM, and muscle strength score. All outcomes were significantly improved in both groups (p < 0.001). CONCLUSION: The use of a digital healthcare system based on AR improved the functional outcomes, pain, and quality of life of patients after TKA. AR-based rehabilitation may be useful treatment as an alternative to conventional rehabilitation. TRIAL REGISTRATION: ClinicalTrials.gov (identifier: NCT04513353). Registered on August 9, 2020. http://clinicaltrials.gov/ct2/show/NCT04513353 .

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.

Reduction of postoperative nausea and vomiting risk in the second stage during bilateral total knee arthroplasty with a 1-week interval.

PURPOSE: Total knee arthroplasty (TKA) is often performed sequentially on both sides during a single hospital stay. Patients who experience postoperative nausea and vomiting (PONV) after the first operation are concerned about PONV recurrence after the second operation. However, there are few studies regarding the incidence of PONV in staged bilateral TKA with a ≥ 1-week interval. This study aimed to identify the differences in (1) PONV incidence, (2) use of rescue antiemetics, and (3) the amount of opioid consumption between the first and second operations for staged bilateral TKA with a 1-week interval. Based on our anecdotal experience, the hypothesis of this study was that during staged bilateral TKA at a 1-week interval, the PONV incidence and rescue antiemetic requirement after the second operation will be lower than those after the first operation, regardless of opioid consumption. METHODS: Fifty-eight consecutive patients who underwent staged bilateral TKA with a 1-week interval were retrospectively reviewed. All second-stage operations were performed with the same anaesthesia protocol and perioperative patient management protocol as the first-stage operation. PONV incidence was the primary outcome. The requirement for rescue antiemetic drugs and the amount of opioid consumption were secondary outcome variables. The outcome variables were recorded during three postoperative days (Days 0-2) for each stage and were compared between the first and second operations. RESULTS: The incidence rates of nausea and vomiting on Day 0 (p = 0.001 and p = 0.004, respectively) and nausea on Day 1 (p = 0.008) were significantly lower after the second operation. Rescue antiemetic use on Day 0 was significantly lower after the second operation (p = 0.001). The total opioid consumption 72 h after surgery was significantly higher after the second operation (61.76 vs. 34.28 mg, p < 0.001). CONCLUSION: During staged bilateral TKA with a 1-week interval, PONV incidence was lower after the second operation, even with increased opioid consumption. LEVEL OF EVIDENCE: III.

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.

A web-based machine-learning algorithm predicting postoperative acute kidney injury after total knee arthroplasty.

PURPOSE: Acute kidney injury (AKI) is a deleterious complication after total knee arthroplasty (TKA). The purposes of this study were to identify preoperative risk factors and develop a web-based prediction model for postoperative AKI, and assess how AKI affected the progression to ESRD. METHOD: The study included 5757 patients treated in three tertiary teaching hospitals. The model was developed using data on 5302 patients from two hospitals and externally validated in 455 patients from the third hospital. Eighteen preoperative variables were collected and feature selection was performed. A gradient boosting machine (GBM) was used to predict AKI. A tenfold-stratified area under the curve (AUC) served as the metric for internal validation. Calibration was performed via isotonic regression and evaluated using a calibration plot. End-stage renal disease (ESRD) was followed up for an average of 41.7 months. RESULTS: AKI develops in up to 10% of patients undergoing TKA, increasing the risk of progression to ESRD. The ESRD odds ratio of AKI patients (compared to non-AKI patients) was 9.8 (95% confidence interval 4.3-22.4). Six key predictors of postoperative AKI were selected: higher preoperative levels of creatinine in serum, the use of general anesthesia, male sex, a higher ASA class (> 3), use of a renin-angiotensin-aldosterone system inhibitor, and no use of tranexamic acid (all p < 0.001). The predictive performance of our model was good (area under the curve 0.78 [95% CI 0.74-0.81] in the developmental cohort and improved in the external validation cohort (0.89). Our model can be accessed at https://safetka.net . CONCLUSIONS: A web-based predictive model for AKI after TKA was developed using a machine-learning algorithm featuring six preoperative variables. The model is simple and has been validated to improve both short- and long-term prognoses of TKA patients. Postoperative AKI may lead to ESRD, which surgeons should strive to avoid. LEVEL OF EVIDENCE: Diagnostic level II.

Long-Term Wear-Related Complications of Cross-Linked Versus Conventional Polyethylene After Total Hip Arthroplasty: A Meta-Analysis.

BACKGROUND: Highly cross-linked polyethylene (HXLPE) liners have been developed to address the wear-related problems associated with conventional polyethylene (CPE) such as osteolysis or aseptic loosening in total hip arthroplasty (THA). In this systematic meta-analysis, we compared the long-term efficacy in preventing radiological osteolysis and revision surgery between HXLPE and CPE. METHODS: We included 14 studies that compared HXLPE and CPE reporting the incidence of wear-related complications with a minimum follow-up of 10 years. We investigated 5 wear-related complications: osteolysis, excessive wear, linear wear rate, revision surgery due to wear, and progress of osteolysis/aseptic loosening. We conducted a pair-wise meta-analysis to estimate odds ratio (OR) and a proportional meta-analysis to estimate the incidence of each complication. RESULTS: Among 1,175 THAs, 220 osteolysis and 78 wear-related revisions were detected. The use of HXLPE reduced the risk of overall osteolysis (OR 0.30; P = .001), excessive wear (OR 0.10; P < .001), linear wear rate (weighted mean difference 0.09; P < .001), the risk of overall wear-related revisions (OR 0.06; P < .001), and revisions due to aseptic loosening (OR 0.23; P = .015). As per the proportional meta-analysis, the pooled prevalence of osteolysis, excessive wear, and the overall wear-related revision rate were 14%, 8%, and 3% in HXLPE and 25%, 33%, and 20% in CPE, respectively. CONCLUSION: The current evidence shows that HXLPE dramatically reduced the rate of osteolysis and wear-related revision surgery. However, as polyethylene wear and osteolysis still lead to revision surgery, ongoing clinical and retrieval studies are required to analyze long-term outcomes.

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.

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.

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.

Aggravation of Ankle Varus Incongruency Following Total Knee Replacement Correcting ≥10° of Genu Varum Deformity: A Radiographic Assessment.

BACKGROUND: This study aimed to investigate the change in ankle varus incongruencies following total knee replacement (TKR) in patients with preoperative genu varum deformity of ≥10°. METHODS: The study cohort was composed of patients who underwent TKR in a single institution for knee osteoarthritis with preoperative genu varum deformity of ≥10° and concomitant varus ankle incongruencies. Eight radiographic measurements were evaluated preoperatively and postoperatively: mechanical tibiofemoral angle, mechanical lateral distal femoral angle, medial proximal tibial angle, lateral distal tibial angle, tibial plafond inclination, talar inclination, tibiotalar tilt angle (TTTA), and tibia-mechanical axis angle. Of these, TTTA represented the quantitative degree of ankle joint incongruency. RESULTS: A total of 110 patients (male = 2; female = 108) were included in the analysis. The mean patient age was 68.9 (standard deviation [SD] 7.2) years at the time of TKR. All radiographic measurements showed significant changes postoperatively, representing the appropriate correction of genu varum deformity and restoration of the mechanical axis. Nineteen patients (17.3%) showed postoperative decrease in TTTA, 2 (1.8%) remained the same, and 89 (80.9%) showed increase. Overall, mean preoperative and postoperative TTTA were 3.3° (SD 2.2°) and 4.7° (SD 2.9°), respectively (P < .001), representing the aggravation of varus ankle incongruencies. CONCLUSION: Varus ankle incongruencies showed aggravation following TKR despite correction of genu varum deformity and restoration of the mechanical axis. This could be an important cause of postoperative increase or development of ankle pain following TKR. Therefore, patients with preoperative varus ankle incongruencies need to be warned of possible aggravation of ankle symptoms and be evaluated before TKR. LEVEL OF EVIDENCE: Prognostic level III.

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.