UNASSIGNED: Studies of clinical outcomes that compare the Medial Pivot design (MP) with the Posterior-Stabilized design (PS) were controversial. The meta-analysis was performed to summarize existing evidence, aiming to determine whether MP was superior to PS prosthesis.
UNASSIGNED: Search strategies followed the recommendations of the Cochrane collaboration. Electronic searches such as PubMed, Embase, Web of Science, and Cochrane were systematically searched for publications concerning medical pivot and posterior stabilized prosthesis from the inception date to April 2021. Authors also manually checked and retrieved a reference list of included publications for potential studies, which the electronic searches had not found. Two investigators independently searched, screened, and reviewed the full text of the article. Disagreements generated throughout the process were resolved by consensus, and if divergences remain, they were arbitrated by a third author. Subsequently, patients were divided into the MP and PS groups.
UNASSIGNED: This study included 18 articles, comprising a total of 2614 patients with a similar baseline. The results showed the PS group had a higher risk of the patellar clunk or crepitus. However, the theoretical advantages of MP prosthesis could not translate to the difference in knee function, clinical complications, revision rate and satisfaction. Similarly, the shape and mechanism of prostheses could not affect the implant position and postoperative alignment.
UNASSIGNED: The MP prosthesis can reduce the patellar clunk or crepitus rate. However, choices between the MP and PS prosthesis would not affect knee function, clinical complications, revision rate, patient satisfaction, implant position, and postoperative alignment.

Previous studies have demonstrated equivalent survivorship of modular metal-backed tibial (MBT) and all-polyethylene tibial (APT) components. The purpose of this study is to compare the utilization and outcomes of APT and MBT components in a large US database.
The American Joint Replacement Registry was queried to identify all patients undergoing primary total knee arthroplasty (TKA) during the study period from 2012 to 2019. These patients were divided into cohorts based on tibial component (APT or MBT). Cohort demographics including gender, hospital size, hospital teaching status, region, age, and Charlson Comorbidity Index were reported with descriptive statistics. Overall reoperation rates and revisions for infection, aseptic loosening, periprosthetic fracture, manipulation under anesthesia, and revision for other reasons were identified using International Classification of Diseases, Ninth Revision and Current Procedural Terminology codes and compared across APT and MBT cohorts. Kaplan-Meir survival analysis was performed based on reason for reoperation for APT and MBT.
During the study period, 703,007 TKAs were reported with 97.8% utilizing MBT and 2.2% utilizing APT components. Despite the introduction of alternative payment models during the study period, the utilization of APT decreased from 5.8% in 2012 to 1.7% in 2019. The survival of APT and MBT TKAs were similar across the study period: 98.1% vs 98.6% at 8 years. The rate of reoperation for all-causes was higher for APT compared to MBT (1.36% vs 1.00%; odds ratio 1.52).
Despite their paucity of use and lower cost APT remained within a 0.4% margin of survivorship when compared to MBT implants for up to 8 years.
Level III, retrospective.

UNASSIGNED: Knee instability is considered one of the most frequent cause of failure after primary total knee arthroplasty (TKA). In order to address intraoperative instability, varus-valgus constrained knee implants (VVC) are increasingly utilized in primary TKA. Despite an increased risk of mechanical failure, short to mid-term results seem to be encouraging, but long-term results are still lacking.
UNASSIGNED: A systematic review of prospective and retrospective studies that reported clinical outcomes of patients with VVC systems in primary TKAs between 1990 and 2020 was performed.
UNASSIGNED: In all, 28 articles met our inclusion criteria. A total of 2798 VVC implants were used in primary TKA. The all-cause revision-free survivorship was 95.2% at a mean follow-up of 7 years. Infection and aseptic loosening were the most common reasons for reoperation with an incidence of 1.8% and 1.7%, respectively. Overall complication rate was 9.6%, the most common complications were knee stiffness and infection with an incidence of 2.8% and 2.5%, respectively.
UNASSIGNED: VVC implants in primary TKA are associated with improved functional outcomes and good mid-term survivorship, comparable to lower level of constraint implants. Non-modular stemless seem to be reliable implants at mid-term follow-up. However, given the lack data coming from long-term studies, VVC implants should be used cautiously in primary TKA.

BACKGROUND: One of the rare complications of primary total knee arthroplasty is intra-operative fracture. Intra-operative fracture during revision knee arthroplasty has been well-documented but there is limited literature on fractures occurring during primary knee arthroplasty. We conducted a systematic review of the literature to compare and contrast the various studies to clearly define the predisposing factors, incidence, and characteristics of the fracture itself and to arrive at a consensus on the management and prevention of intra-operative fractures during primary knee arthroplasty.
METHODS: The PubMed/Medline, Cochrane, Scopus and Embase databases were searched using keywords \"intra-operative fracture\", \"distal femoral fracture\", \"tibial fracture\", \"patella fracture\" and \"primary total knee arthroplasty\". A total of 158 articles were retrieved and after further filtration and exclusion processing, 10 articles that evaluated intra-operative fractures in primary total knee arthroplasty were included for the review.
RESULTS: The reported incidence of intra-operative fractures varied from 0.2% to 4.4%. A higher incidence in female patients with a male to female ratio of 0.4 was reported. Posterior stabilized (PS) total knee arthroplasty was associated with higher risk of intra-operative femoral fractures by many authors in this review. Timing of occurrence and location of the intra-operative fractures can vary widely, with femoral fractures occurring more commonly during bone preparation, trialing and impaction of the final implant and tibial fractures occurring during preparation for the tibial keel and impaction of the tibial component.
CONCLUSIONS: Intra-operative fractures during primary total knee arthroplasty are rare with higher risk associated with osteoporosis, rheumatoid arthritis, advanced age, female gender, chronic steroid use, metabolic bone disorders, PS type of femoral implant and difficult surgical exposure of the knee joint due to severe deformities. A plethora of management options have been utilized according to surgeon preference. Standard principles of fracture fixation and arthroplasty principles should be followed to achieve stable internal fixation and any unstable fracture site should be bypassed with the utilization of stemmed components. Satisfactory radiographic and functional outcome can be expected with appropriate treatment.

(1) Background: We have updated knowledge of the psychometric qualities of patient-reported outcome measures and, for the first time, systematically reviewed and compared the psychometric qualities of physical tests for patients with knee osteoarthritis who are undergoing total knee arthroplasty. This work was conducted to facilitate the choice of the most appropriate instruments to use in studies and clinical practice. (2) Methods: A search of medical databases up to December 2019 identified the studies and thus the instruments used. The quality of the measurement properties was assessed by the Bot et al. criteria. (3) Results: We identified 20 studies involving 25 instruments. Half of the instruments were questionnaires (n = 13). Among the condition-specific instruments, the Oxford knee score, Knee injury and Osteoarthritis Outcomes Score, and the Western Ontario and McMaster Universities Osteoarthritis index had the highest overall scores. Concerning generic tools, the Medical Outcomes Study Short-Form 36 (SF-36) or SF-12 obtained the highest overall score. For patient-specific tools, the Hospital Anxiety and Depression Scale ranked the highest. Some physical tests seemed robust in psychometric properties: 6-min Walk Test, five times Sit-To-Stand test, Timed Up and Go test strength testing of knee flexor/extensor by isometric or isokinetic dynamometer and Pressure Pain Threshold. (4) Conclusion: To make stronger recommendations, key areas such as reproducibility, responsiveness to clinical change, and minimal important change still need more rigorous evaluations. Some promising physical tests (e.g., actimetry) lack validation and require rigorous studies to be used as a core set of outcomes in future studies.

OBJECTIVE: Vancomycin powder (VP) has been used to prevent periprosthetic joint infection (PJI). However, studies investigating the efficacy of VP to prevent infection in primary total knee arthroplasty (TKA) are very rare. The purpose of this study was to investigate the efficacy of VP application to prevent PJI in TKA.
METHODS: Between 2012 and 2016, 976 consecutive patients who underwent primary TKA were included in the present study. Patients were divided into two groups. There were 474 patients (48.6%) in the VP group and 502 patients in the control group (51.4%). Except for VP, all procedures were the same in both groups. In the VP group, 2 g of VP was poured into the joint just before the fascia was closed. Average follow-up was 53.2 months (24-84 months).
RESULTS: Infection was found in 4 (0.84%) of 474 patients in the VP group and 5 (0.99%) of 502 patients in the control group. There was no statistically significant difference between groups in terms of infection rates (p = 0.535). Staphylococcus aureus was found in 2 patients in the VP group. Two patients had S. aureus and 1 patient had Pseudomonas aeruginosa in the control group. There was no statistically significant difference between groups in terms of demographic parameters (p > 0.05).
CONCLUSIONS: Intrawound VP administration doesn\'t change the infection rates in primary TKA. The VP administration for preventing PJI is not recommended in primary TKA.
METHODS: III.

Despite technological advances in operative technique and component materials, the total knee arthroplasty (TKA) revision burden, in the United States, has remained static for the past decade. In light of an anticipated exponential increase in annual surgical volume, it is important to thoroughly understand contemporary challenges associated with technologically driven TKA. This descriptive literature review harvested 69 relevant publications to extrapolate patient trends, benefits, costs, and complications associated with computer-assisted surgery, patient specific instrumentation, and intra-operative sensors. Due to additional charges, a steep learning curve, and questionable cost-effectiveness, widespread use of these systems has been limited. Intra-operative sensors are a relatively recent development, and have been shown to improve both soft-tissue balance and overall functional outcomes at a relatively low price and without disrupting operative workflow. The introduction of new technology into the operating suite should be considered carefully, especially with respect to combined clinically efficacy and cost.