Temporal patterns of commonly used clinical outcome scales during a 5-year period after total knee arthroplasty.

Background: It is not established beyond doubt whether improvements in functional outcome after total knee arthroplasty (TKA) are maintained in the long term. We therefore investigated the temporal patterns of functional outcome [using range of motion (ROM), American Knee Society (AKS) score, Western Ontario and McMaster Universities Arthritis Index (WOMAC) score, and 36-Item Short Form Health Survey (SF-36) score] over a 5-year period after uncomplicated TKA, and whether these patterns differed by implant type and patient age.

Materials And Methods: This prospective study evaluated 138 patients who underwent unilateral TKA with either a mobile-bearing (MB) or fixed-bearing (FB) posterior-stabilized prosthesis.

Early Clinical Outcomes of a New Posteriorly Stabilized Total Knee Arthroplasty Prosthesis: Comparisons with Two Established Prostheses.

Purpose: We sought to determine whether early clinical performance of new posterior stabilized (PS) knee system, the Vega-PS (Aesculap), is better than that of two established total knee arthroplasty (TKA) prostheses, the E.motion-PS (Aesculap) and the Genesis II (Smith & Nephew) in terms of functional outcomes, patient satisfaction, and incidence of adverse events.

Materials And Methods: We compared the clinical outcomes of 206 consecutive TKAs using Vega-PS with those of 205 TKAs using E.

Crosscultural Adaptation and Validation of the Korean Version of the New Knee Society Knee Scoring System.

Background: The 2011 Knee Society Score (2011 KS Score) is used to characterize the expectations, symptoms, physical activity, and satisfaction of patients who undergo TKA and is widely used to assess the outcome of TKA. However, it has not been adapted or validated for use in Korea.

Questions/purposes: We developed a Korean version of the 2011 KS Score and evaluated the (1) test-retest reliability, (2) convergent validity, and (3) responsiveness of the Korean version.

Active Flexion in Weight Bearing Better Correlates with Functional Outcomes of Total Knee Arthroplasty than Passive Flexion.

Purpose: Correlations between maximum flexion and functional outcomes in total knee arthroplasty (TKA) patients are reportedly weak. We investigated whether there are differences between passive maximum flexion in nonweight bearing and other types of maximum flexion and whether the type of maximum flexion correlates with functional outcomes.

Materials And Methods: A total of 210 patients (359 knees) underwent preoperative evaluation and postoperative follow-up evaluations (6, 12, and 24 months) for the assessment of clinical outcomes including maximum knee flexion.

Can Serum Albumin Level and Total Lymphocyte Count be Surrogates for Malnutrition to Predict Wound Complications After Total Knee Arthroplasty?

Background: Although the serum albumin level and total lymphocyte count (TLC) have been reported as valid and reliable markers for defining malnutrition, their cutoff levels and predictive values for wound complications in patients undergoing total knee arthroplasty (TKA) remain questionable.

Methods: A total of 3169 TKAs performed between April 2003 and December 2013 were retrospectively reviewed. We determined the prevalence of malnutrition on applying different definitions, with various cutoff values of serum albumin and TLC and analyzed the variations in outcome.

Why Patients Do Not Participate in Sports Activities After Total Knee Arthroplasty.

Background: It is important to identify the reasons or factors preventing patients from participating in sports activities after total knee arthroplasty (TKA) to improve patient satisfaction and general health that can be gained from regular sports activities.

Purpose: To determine the reasons for lack of participation in regular sports activities after TKA as perceived by patients and to identify specific factors involved.

Study Design: Case series; Level of evidence, 4.

Analysis of Longitudinal Outcome Data with Missing Values in Total Knee Arthroplasty.

We sought to determine the influence of missing data on the statistical results, and to determine which statistical method is most appropriate for the analysis of longitudinal outcome data of TKA with missing values among repeated measures ANOVA, generalized estimating equation (GEE) and mixed effects model repeated measures (MMRM). Data sets with missing values were generated with different proportion of missing data, sample size and missing-data generation mechanism. Each data set was analyzed with three statistical methods.

Functional Outcomes of a New Mobile-Bearing Ultra-Congruent TKA System: Comparison With the Posterior Stabilized System.

We determined whether a new mobile-bearing ultra-congruent (UC) TKA system provides better functional outcomes than an established posterior-stabilized (PS) prosthesis. The functional outcomes (motion arc, AKS scores, WOMAC Index, and SForm-36 scores evaluated at 1 and 2 years postoperatively), satisfaction and incidences of adverse events were compared between the knees implanted with mobile-bearing UC prosthesis (n=103) and the mobile-bearing PS prosthesis (n=99). At 2 years, mobile-bearing UC TKAs showed similar functional outcomes and satisfaction, but smaller motion arc compared to mobile-bearing PS TKAs (126° vs.

Clinical Implications of Femoral Anthropometrical Features for Total Knee Arthroplasty in Koreans.

Anthropometric features of Asians femora and their clinical relevance with regard to TKA are not rigorously investigated. We attempted to determine how well current prostheses accommodate femoral anthropometric features of Koreans and whether the presence of condylar or trochlear overhang or underhang adversely affects functional outcomes. We hypothesized that current prostheses do not accommodate Korean female femora well, and that overhang or underhang would adversely affect outcomes.

Patients still wish for key improvements after total knee arthroplasty.

Purpose: Our goals were to rigorously document and explore the interrelationships of various parameters in the aftermath of total knee arthroplasty (TKA), including patient characteristics, clinical scores, satisfaction levels, and patient-perceived improvements.

Materials And Methods: A questionnaire addressing sociodemographic factors, levels of satisfaction, and "wished-for" improvements was administered to 180 patients at least 1 year post primary TKA. Both satisfaction levels and wished-for improvements were assessed through nine paired parameters.

Prevalence of osteoporosis in female patients with advanced knee osteoarthritis undergoing total knee arthroplasty.

This study sought to demonstrate bone mineral density (BMD) conditions in elderly female patients with knee osteoarthritis (OA) undergoing total knee arthroplasty (TKA). In addition, we sought to determine whether their BMD conditions differ from those of community-based females without knee OA. Finally we sought to determine whether clinical statuses are related to BMD in the knee OA patients.

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°.

Activity levels and participation in physical activities by Korean patients following total knee arthroplasty.

Background: The objectives of this study were to describe changes in physical activity profiles of Korean patients after TKA and to determine whether the postoperative physical activity level is influenced by patient socio-demographic factors and postoperative functional outcomes. We also sought to determine whether regular postoperative physical activity is associated with greater patient satisfaction after TKA.

Methods: This observational study included 369 patients.

Coexisting lumbar spondylosis in patients undergoing TKA: how common and how serious?

Background: Information on the coexistence of lumbar spondylosis and its influence on overall levels of pain and function in patients with advanced knee osteoarthritis (OA) undergoing total knee arthroplasty (TKA) would be valuable for patient consultation and management.

Questions/purposes: The purposes of this study were to document the prevalence and severity of coexisting lumbar spondylosis in patients with advanced knee OA undergoing TKA and to determine whether the coexisting lumbar spondylosis at the time of TKA adversely affects clinical scores in affected patients before and 2 years after TKA.

Methods: Radiographic lumbar spine degeneration and lumbar spine symptoms including lower back pain, radiating pain at rest, and radiating pain with activity were assessed in 225 patients undergoing TKA.

The patterns of limb length, height, weight and body mass index changes after total knee arthroplasty.

The objective of this retrospective review of 466 patients was to document changes in limb length, leg length discrepancy (LLD), height, weight, and body mass index (BMI) 1 year after TKA and the patterns of height, weight, and BMI during 5 years. To determine change patterns over 5 years, the data of 291 patients were analyzed and compared with those of age and gender-matched normal subjects. Limb length, height, and weight increased, BMI remained unchanged, and LLD decreased 1 year after TKA.

Clinical value of tranexamic acid in unilateral and simultaneous bilateral TKAs under a contemporary blood-saving protocol: a randomized controlled trial.

Purpose: Despite the documented blood-saving effects of tranexamic acid (TNA) in total knee arthroplasty (TKA), the question whether clinical values of TNA are identical in unilateral and bilateral TKAs remains unclear. This study was undertaken to determine the clinical values of TNA in unilateral and simultaneous bilateral TKAs under a contemporary blood-saving protocol in terms of efficacy (total blood loss and transfusion rate) and safety (the incidences of symptomatic deep vein thrombosis and pulmonary embolism).

Methods: One hundred and eighty unilateral and 146 bilateral TKA patients were randomized into TNA group or control group.

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).

Incidence, predictors, and effects of residual flexion contracture on clinical outcomes of total knee arthroplasty.

Patients who present with large flexion contracture (FC) but have well maintained maximum flexion tend to have a flexion-extension gap mismatch, which can cause residual FC or flexion instability after TKA. We routinely use posterior-stabilized implants, perform soft tissue balancing and additional distal femur resection, and determine the polyethylene insert thickness based on flexion-extension gap difference to avoid postoperative FC and flexion instability. We retrospectively reviewed 911 TKAs performed with this protocol to determine the incidence, predictors and effects of postoperative FC on clinical outcomes.

Use of simple algorithms to predict screw length facilitates navigation-controlled medial opening-wedge osteotomy using the TomoFix HTO system.

This study was performed to establish simple algorithms to predict proper screw lengths for the 4 proximal holes of TomoFix plates (Synthes GmbH; Solothurn, Switzerland) based on radiographic mediolateral (ML) and anteroposterior (AP) dimensions of the proximal tibia and to determine how well these algorithms function for navigation-controlled medial opening-wedge high tibial osteotomy (HTO) using TomoFix. Experimental HTO surgery was performed in proximal tibial models manufactured for 30 patients undergoing HTO to determine the longest screw lengths for the 4 proximal holes of TomoFix plates. Eight algorithms were created for the 4 proximal screws by investigating the relationships between measured screw lengths and radiographic dimensions and were used for 30 navigation-controlled medial opening-wedge HTOs.

Femoral lateral bowing and varus condylar orientation are prevalent and affect axial alignment of TKA in Koreans.

Background: Coronal alignment is considered key to the function and longevity of a TKA. However, most studies do not consider femoral and tibial anatomical features such as lateral femoral bowing and the effects of these features and subsequent alignment on function after TKA are unclear.

Questions/purposes: We therefore determined (1) the prevalence of lateral femoral bowing, varus femoral condylar orientation, and severe tibia plateau inclination in female Koreans undergoing TKA; (2) whether postoperative alignments are affected by these anatomical features and improved by the use of navigation; and (3) whether postoperative coronal alignments are associated with function.

Use of reduced-dose periarticular injection for pain management in simultaneous bilateral total knee arthroplasty.

We investigated the safety and efficacy of the bilateral periarticular multimodal drug injection (PMDI) at a reduced dosage in patients undergoing simultaneous bilateral total knee arthroplasty (SBTKA). In total, 45 patients undergoing SBTKA received 65 mL PMDI in each knee (reduced-dose group). The incidence of drug-related adverse effects and wound complications were evaluated.

Does periarticular injection have additional pain relieving effects during contemporary multimodal pain control protocols for TKA?: A randomised, controlled study.

Although the analgesic effects of periarticular multimodal drug injection (PMDI) after TKA have been well documented, there is little information about additional pain relieving effects of PMDI incorporated to contemporary multimodal pain control protocols which have been proved to provide excellent analgesia. We performed a parallel-group, randomised, controlled study to determine whether PMDI provides additional clinical benefits on contemporary multimodal analgesic protocols including preemptive analgesics, continuous femoral nerve block, and IV-PCA. Eighty-seven patients were randomized to a PMDI group (n=45) or to a No-PMDI group (n=42).

Novel approach to reducing discrepancies in radiographic and navigational limb alignments in computer-assisted TKA.

This study was conducted (1) to document discrepancies between preoperative and postoperative radiographic measurements and postregistration and postimplantation intraoperative navigational measurements of coronal limb alignments, and (2) to identify predictors of discrepancies between radiographic and navigational measures. In addition, we propose the use of a novel radiographic measuring method, and we demonstrate that this method reduces discrepancies. For 107 total knee arthroplasties performed using a navigation system, coronal alignment were assessed using preoperative and postoperative whole limb radiographs using the standard and novel radiographic methods.

The radiographic predictors of symptom severity in advanced knee osteoarthritis with varus deformity.

Information concerning the abilities of radiographic parameters to predict the symptoms of advanced osteoarthritis (OA) of the knee would be valuable, because plain knee radiographs are used as one of the primary tools for the selection of treatment modalities. We aimed to identify the radiographic predictors of symptom severity in patients with varus knee OA advanced enough to warrant total knee arthroplasty (TKA). In 341 knees with primary varus OA warranting TKA, pertinent radiographic features of the medial and lateral tibiofemoral joint (TFJ), and the patellofemoral joint (PFJ) were assessed separately and scored.