There is debate in the literature whether rotating hinge knee (RHK) or constrained condylar knee (CCK) prostheses lead to better clinical outcomes and survival rates in patients undergoing revision total knee arthroplasty (RTKA). The purpose of this meta-analysis is to compare the survivorship and clinical outcomes of RHK and CCK prostheses. In this meta-analysis, we reviewed studies that evaluated pain and function scores, range of motion (ROM), complications, and survival rates in patients treated with RHK or CCK with short-term (<5 years) or midterm (5-10 years) follow-up. The survivorship was considered as the time to additional surgical intervention such as removal or revision of the components. A total of 12 studies (one randomized study and 11 non-randomized studies) met the inclusion criteria and were analyzed in detail. The proportion of the knees in which short-term (<5 years) survival rates (RHK, 83/95; CCK, 111/148; odds ratio [OR] 0.52; 95% CI, 0.24-1.11; P = 0.09) and midterm (5-10 years) survival rates (RHK, 104/128; CCK, 196/234; OR 1.05; 95% CI, 0.56-1.97; P = 0.88) were evaluated did not differ significantly between RHK and CCK prostheses. In addition, there were no significant differences in ROM (95% CI: -0.40 to 9.93; P = 0.07) and complication rates (95% CI: 0.66 to 2.49; P = 0.46). In contrast, CCK groups reported significantly better pain score (95% CI: 0.50 to 2.73; P = 0.005) and function score (95% CI: 0.01 to 2.00; P = 0.05) than RHK groups. This meta-analysis revealed that 87.4% of RHK and 75.0% of CCK prostheses survive at short-term (<5 years), while 81.3% of RHK and 83.8% of CCK prostheses survive at midterm (5-10 years). The differences in standardized mean pain and function scores we detected were likely to be imperceptible to patients and almost certainly below the minimum clinically important level, despite a significant difference in both groups. Based on the findings of the current meta-analysis, RHK prostheses continue to be an option in complex RTKA with reasonable midterm survivorship.

This study was performed to compare the clinical outcomes of unicompartmental knee arthroplasty (UKA) revised to total knee arthroplasty (TKA) versus primary TKA.

Background and purpose - Up to 20% of patients are dissatisfied after total knee arthroplasty (TKA), mainly because of pain and restricted physical function. We developed a prediction model for 6-month knee range of motion, knee pain, and walking limitations in patients undergoing TKA surgery. Patients and methods - We performed a prospective cohort study of 4,026 patients who underwent elective, primary TKA between July 2013 and July 2017. Candidate predictors included demographic, clinical, psychosocial, and preoperative outcome measures. The outcomes of interest were (i) knee extension and flexion range of motion, (ii) knee pain rated on a 5-point ordinal scale, and (iii) self-reported maximum walk time at 6 months post TKA. For each outcome, we fitted a multivariable proportional odds regression model with bootstrap internal validation. Results - At 6 months post TKA, around 5% to 20% of patients had a flexion contracture ³ 10°, range of motion < 90°, moderate to severe knee pain, or a maximum walk time £ 15 minutes. The model c-indices (the probabilities to correctly discriminate between 2 patients with different levels of follow-up TKA outcomes) when evaluating these patients were 0.71, 0.79, 0.65, and 0.76, respectively. Each postoperative outcome was strongly influenced by the same outcome measure obtained preoperatively (all p-values < 0.001). Additional statistically significant predictors were age, sex, race, education level, diabetes mellitus, preoperative use of gait aids, contralateral knee pain, and psychological distress (all p-values < 0.001). Interpretation - We have developed models to predict, for individual patients, their likely post-TKA levels of knee extension and flexion range of motion, knee pain, and walking limitations. After external validation, they can potentially be used preoperatively to identify at-risk patients and to help patients set more realistic expectations about surgical outcomes.

Virtual representations of the knee joint can provide clinicians, scientists, and engineers the tools to explore mechanical functions of the knee and its tissue structures in health and disease. Modeling and simulation approaches such as finite element analysis also provide the possibility to understand the influence of surgical procedures and implants on joint stresses and tissue deformations. A large number of knee joint models are described in the biomechanics literature. However, freely accessible, customizable, and easy-to-use models are scarce. Availability of such models can accelerate clinical translation of simulations, where labor-intensive reproduction of model development steps can be avoided. Interested parties can immediately utilize readily available models for scientific discovery and clinical care. Motivated by this gap, this study aims to describe an open source and freely available finite element representation of the tibiofemoral joint, namely Open Knee, which includes the detailed anatomical representation of the joint's major tissue structures and their nonlinear mechanical properties and interactions. Three use cases illustrate customization potential of the model, its predictive capacity, and its scientific and clinical utility: prediction of joint movements during passive flexion, examining the role of meniscectomy on contact mechanics and joint movements, and understanding anterior cruciate ligament mechanics. A summary of scientific and clinically directed studies conducted by other investigators are also provided. The utilization of this open source model by groups other than its developers emphasizes the premise of model sharing as an accelerator of simulation-based medicine. Finally, the imminent need to develop next-generation knee models is noted. These are anticipated to incorporate individualized anatomy and tissue properties supported by specimen-specific joint mechanics data for evaluation, all acquired in vitro from varying age groups and pathological states.

Osteoarthritis (OA) is a common degenerative musculoskeletal disease highly prevalent in aging societies worldwide. Traditionally, knee OA is diagnosed using conventional radiography. However, structural changes of articular cartilage or menisci cannot be directly evaluated using this method. On the other hand, ultrasound is a promising tool able to provide direct information on soft tissue degeneration. The aim of our study was to systematically determine the site-specific diagnostic performance of semi-quantitative ultrasound grading of knee femoral articular cartilage, osteophytes and meniscal extrusion, and of radiographic assessment of joint space narrowing and osteophytes, using MRI as a reference standard. Eighty asymptomatic and 79 symptomatic subjects with mean age of 57.7 years were included in the study. Ultrasound performed best in the assessment of femoral medial and lateral osteophytes, and medial meniscal extrusion. In comparison to radiography, ultrasound performed better or at least equally well in identification of tibio-femoral osteophytes, medial meniscal extrusion and medial femoral cartilage morphological degeneration. Ultrasound provides relevant additional diagnostic information on tissue-specific morphological changes not depicted by conventional radiography. Consequently, the use of ultrasound as a complementary imaging tool along with radiography may enable more accurate and cost-effective diagnostics of knee osteoarthritis at the primary healthcare level.

No abstract available

This research examines knee osteoarthritis (OA), a prevalent orthopedic disease marked by cartilage degeneration and chronic synovitis, leading to pain, restricted mobility, and eventual loss of knee function. Notably, patellofemoral osteoarthritis constitutes a significant proportion of knee OA cases. Our study aims to assess the impact of knee arthroscopic debridement coupled with peripatellar denervation on restoring knee function in OA patients and analyze the risk factors affecting treatment outcomes. By doing so, we hope to contribute to the informed selection of clinical treatment plans, addressing a disease that, if untreated, significantly impairs patients' quality of life.

The change in hip-knee-ankle (HKA) angle after total knee arthroplasty (TKA) may cause an adjustment in hindfoot alignment (HFA). However, the relationship between the changes in HKA angle and HFA is still not well studied. This study aimed to investigate the association between HKA angle and hindfoot alignment changes after TKA for varus knee osteoarthritis.

Since the optimal surgery for isolated medial knee osteoarthritis (OA) is unclear, this study aimed at comparing the effectiveness of unicondylar knee replacement (UKR) with total knee replacement (TKR) for simple medial knee OA.

The study of localized immune-related factors has proven beneficial for a variety of conditions, and one area of interest in the field of orthopaedics is the impact of implants and localized infections on immune response. Several cytokines have shown increased systemic concentrations (in serum/plasma) in response to implants and infection, but tissue-level cytokines have not been investigated as thoroughly.

Due to the significant role of rotational properties for normal knee function, this study aimed to investigate transverse plane kinematics and kinetics in total knee arthroplasty and unicondylar knee arthroplasty patients during activities of daily living compared to a healthy control group, including stair ascent and descent. The study participants consisted of a total knee arthroplasty group including posterior cruciate retaining and posterior stabilized designs as well as a unicondylar knee arthroplasty group and a healthy control group. Three-dimensional kinematics and kinetics were captured using a Vicon system and two Kistler force plates embedded in the floor and another two in a staircase. Inverse dynamics of the lower limbs was computed in Anybody™ Modeling System. Transverse plane joint angles and joint moments were analyzed utilizing the statistical non-parametric mapping approach, considering the entire curve shape for statistical analysis. The patients with total knee arthroplasty exhibited significantly reduced knee internal rotation of the operated knee compared to the control group and the patients' unimpaired limb, especially during the stair climbing tasks. Both unicondylar and total knee arthroplasty patients were found to have similar reduced internal rotation motion time series in stair descent. In conclusion, potential kinematic and kinetic benefits of unicondylar knee arthroplasty over total knee arthroplasty could not be proven in the current study. Aside from the usually mentioned reasons inducing constrained knee internal rotation in total knee arthroplasty patients, future studies should investigate to what extent co-contraction may contribute to this functional impairment in patients after knee arthroplasty surgery.

Current methods for assessing knee osteoarthritis (OA) do not provide comprehensive information to make robust and accurate outcome predictions. Deep learning (DL) risk assessment models were developed to predict the progression of knee OA to total knee replacement (TKR) over a 108-month follow-up period using baseline knee MRI. Participants of our retrospective study consisted of 353 case-control pairs of subjects from the Osteoarthritis Initiative with and without TKR over a 108-month follow-up period matched according to age, sex, ethnicity, and body mass index. A traditional risk assessment model was created to predict TKR using baseline clinical risk factors. DL models were created to predict TKR using baseline knee radiographs and MRI. All DL models had significantly higher (p < 0.001) AUCs than the traditional model. The MRI and radiograph ensemble model and MRI ensemble model (where TKR risk predicted by several contrast-specific DL models were averaged to get the ensemble TKR risk prediction) had the highest AUCs of 0.90 (80% sensitivity and 85% specificity) and 0.89 (79% sensitivity and 86% specificity), respectively, which were significantly higher (p < 0.05) than the AUCs of the radiograph and multiple MRI models (where the DL models were trained to predict TKR risk using single contrast or 2 contrasts together as input). DL models using baseline MRI had a higher diagnostic performance for predicting TKR than a traditional model using baseline clinical risk factors and a DL model using baseline knee radiographs.

This meta-analysis compared the gait patterns of unicompartmental knee arthroplasty (UKA) patients and total knee arthroplasty (TKA) patients during level walking by evaluating the kinetics, kinematics, and spatiotemporal parameters. Studies were included in the meta-analysis if they assessed the vertical ground reaction force (GRF), joint moment at stance, flexion at initial contact, flexion at swing, overall range of motion (ROM), coronal knee angle at stance, walking speed, cadence, and stride length in UKA patients or TKA patients. Seven non-randomized studies met the criteria for inclusion in this meta-analysis. UKA patients and TKA patients were similar in terms of vertical GRF (95% CI: -0.36 to 0.20; P = 0.60), joint moment (95% CI: -0.55 to 0.63; P = 0.90), kinematic outcomes (95% CI: -0.72 to 1.02; P = 0.74), walking speed (95% CI: -0.27 to 0.81; P = 0.32), and cadence (95% CI: -0.14 to 0.68; P = 0.20). In contrast, the stride length (95% CI: 0.01 to 0.80; P = 0.04) differed significantly between groups. Subgroup analyses revealed that the pooled data were similar between the groups: 1st maximum (heel strike), -0.18 BW (P = 0.53); 1st minimum (mid-stance), -0.43 BW (P = 0.08); and 2nd maximum (toe off), -0.03 BW (P = 0.87). On gait analysis, there were no significant differences in vertical GRF, joint moment at stance, overall kinematics, walking speed, or cadence between UKA patients and TKA patients during level walking. However, the TKA group had significantly shorter stride length than UKA patients. Although the comparison was inconclusive in determining which types of knee arthroplasty offered the closest approximation to normal gait, we consider it important to provide better rehabilitation programs to reduce the abnormal stride length in TKA patients compared to UKA patients.

Background and Objectives: Clinically, it is beneficial to determine the knee osteoarthritis (OA) subtype that responds well to conservative treatments. Therefore, this study aimed to determine the differences between varus and valgus arthritic knees in the response to conservative treatment. We hypothesized that valgus arthritic knees would respond better to conservative treatment than varus arthritic knees. Materials and Methods: Medical records of 834 patients who received knee OA treatment were retrospectively reviewed. Patients with Kellgren-Lawrence grades III and IV were divided into two groups according to knee alignment (varus arthritic knee, hip-knee-ankle angle [HKA] > 0° or valgus arthritic knee, HKA < 0°). The Kaplan-Meier curve with total knee arthroplasty (TKA) as an endpoint was used to compare the survival probability between varus and valgus arthritic knees at one, two, three, four, and five years after the first visit. A receiver operating characteristic (ROC) curve was used to compare the HKA thresholds for TKA between varus and valgus arthritic knees. Results: Valgus arthritic knees responded better to conservative treatment than varus arthritic knees. With TKA as an endpoint, the survival probabilities for varus and valgus arthritic knees were 24.2% and 61.4%, respectively, at the 5-year follow-up (p < 0.001). The thresholds of HKA for varus and valgus arthritic knees for TKA were 4.9° and -8.1°, respectively (varus: area under the ROC curve [AUC] = 0.704, 95% confidence interval [CI] 0.666-0.741, p < 0.001, sensitivity = 0.870, specificity = 0.524; valgus: AUC = 0.753, 95% CI 0.693-0.807, p < 0.001, sensitivity = 0.753, specificity = 0.786). Conclusions: Conservative treatment is more effective for valgus than for varus arthritic knees. This should be considered when explaining the prognosis of conservative treatment for knees with varus and valgus arthritis.

Unicompartmental knee osteoarthritis (UKOA) is the early stage of knee joint degeneration, which is characterized by unicompartmental degeneration and mostly occurs in medial compartment. Pain and limited motion are main symptoms, which affect patients' life quality. Periarticular knee osteotomy (PKO) for lower extremity alignment correction is an effective treatment for UKOA with abnormal alignment, which could relieve pain and improve joint function by adjusting lower extremity alignment. At present, no clinical guidelines are available for the treatment of UKOA by PKO for lower extremity alignment correction. Experts from the Clinical New Technology Application Committee of the Chinese Hospital Association, Joint Surgery Study Group of the Chinese Orthopaedic Association of the Chinese Medical Association, and Osteoarthritis Study Group of the Chinese Association of Orthopaedic Surgeons of the Chinese Medical Doctor Association formulated these guidelines. The Grading of Recommendations Assessment, Development, and Evaluation (GRADE) grading system and the Reporting Items for Practice Guidelines in Healthcare (RIGHT) were adopted to select 25 most concerning questions. Finally, 25 recommendations were formulated through evidence retrieval, evidence quality evaluation, and the determination of directions and strength of recommendations. Recommendation items 1-5 are indications and contraindications for PKO for lower extremity alignment correction, items 6-21 are surgical methods and principles, item 22 describes 3D printing corrective osteotomy technique, and items 23-25 address the perioperative period, follow-up management, and other content. These guidelines are designed to improve the normalization and standardization of KOA treatment by PKO for lower extremity alignment correction.

The aim of this study was to compare robotic arm-assisted bi-unicompartmental knee arthroplasty (bi-UKA) with conventional mechanically aligned total knee arthroplasty (TKA) in order to determine the changes in the anatomy of the knee and alignment of the lower limb following surgery.

The purpose of this study is to review the current literature on knee joint biomechanical gait data analysis for knee pathology classification. The review is prefaced by a presentation of the prerequisite knee joint biomechanics background and a description of biomechanical gait pattern recognition as a diagnostic tool. It is postfaced by discussions that highlight the current research findings and future directions.

Knee osteoarthritis is a common musculoskeletal condition in elderly individuals. This survey was conducted with the aim to identify the problems of this group of patients for compilation of healthcare programs targeted at determining the outcome of osteoarthritis before and 3 months after knee arthroplasty.

The primary aim of this study was to describe a baseline comparison of early knee-specific functional outcomes following revision total knee arthroplasty (TKA) using metaphyseal sleeves with a matched cohort of patients undergoing primary TKA. The secondary aim was to compare incidence of complications and length of stay (LOS) between the two groups.

The aim of the present study was to evaluate the effect of patellar denervation (PD) in preventing anterior knee pain (AKP) and improving knee function after total knee arthroplasty (TKA) without patellar resurfacing, and to help surgeons decide whether or not to use PD in TKA.