Patient-Reported Outcomes following Single- and Multiple-Radius Total Knee Replacement: A Randomized, Controlled Trial

Although single-radius (SR) designs of total knee replacement (TKR) have theoretical benefits, the clinical advantage conferred by such designs is unknown. The aim of this randomized, controlled study was to compare the short-term clinical outcomes of the two design rationales. A total of 105 knees were randomized to receive either a single radius (Scorpio, Stryker; SR Group) or multiple radius (AGC, Zimmer Biomet; MR group) TKR. Patient-reported outcomes (Oxford Knee Score [OKS] and Knee Society Score [KSS]) were collected at 6 weeks, 6 months, and 1 year following surgery. No knees were revised. There was no difference in primary outcomes: OKS was 39.5 (95% confidence interval [CI]: 36.9–42.1) in the SR group and 38.1 (95% CI: 36.0–40.3) in the MR group (p = 0.40). KSS was 168.4 (95% CI: 159.8–177.0) in the SR group; 159.5 (95% CI 150.5–168.5) in the MR group (p = 0.16). There was a small but statistically significant difference in the degree of change of the objective subscale of the KSS, favoring the SR design (p = 0.04), but this is of uncertain clinical relevance. The reported benefits of SR designs do not provide demonstrable functional advantages in the short term

Effect of Void Network on CMB Anisotropy

We study the effect of a void network on the CMB anisotropy in the Einstein-de Sitter background using Thompson &Vishniac's model. We consider comprehensively the Sacks-Wolfe effect, the Rees-Sciama effect and the gravitational lensing effect. Our analysis includes the model of primordial voids existing at recombination, which is realized in some inflationary models associated with a first-order phase transition. If there exist primordial voids whose comoving radius is larger than $\sim10h^{-1}$Mpc at recombination, not only the Sachs-Wolfe effect but also the Rees-Sciama effect is appreciable even for multipoles l\lsim1000 of the anisotropy spectrum. The gravitational lensing effect, on the other hand, slightly smoothes the primary anisotropy; quantitatively, our results for the void model are similar to the previous results for a CDM model. All the effects, together, would give some constraints on the configuration or origin of voids with high-resolution data of the CMB anisotropy.Comment: 23 pages, latex, 12 eps figures, some calculations and discussions are added, to appear in ApJ 510 (1999

Comparison of outcomes after UKA in patients with and without chondrocalcinosis: a matched cohort study

Purpose: Chondrocalcinosis can be associated with an inflammatory arthritis and aggressive joint destruction. There is uncertainty as to whether chondrocalcinosis represents a contraindication to unicompartmental knee arthroplasty (UKA). This study reports the outcome of a consecutive series of patients with chondrocalcinosis and medial compartment osteoarthritis treated with UKA matched to controls. Methods: Between 1998 and 2008, 88 patients with radiological chondrocalcinosis (R-CCK) and 67 patients with histological chondrocalcinosis (H-CCK) were treated for end-stage medial compartment arthritis with Oxford UKA. One-to-two matching was performed to controls, treated with UKA, but without evidence of chondrocalcinosis. Functional outcome and implant survival were assessed in each group. Results: The mean follow-up was 10 years. The mean Oxford Knee Score (OKS) at final follow-up was 43, 41 and 41 in H-CCK, R-CCK and control groups (change from baseline OKS was 21, 18 and 15, respectively). The change was significantly higher in H-CCK than in control but was not significantly different in R-CCK. Ten-year survival was 96 % in R-CCK, 86 % in H-CCK and 98 % in controls. Although the survival in H-CCK was significantly worse than in control, only one failure was due to disease progression. Conclusion: The presence of R-CCK does not influence functional outcome or survival following UKA. Pre-operative radiological evidence of CCK should not be considered to be a contraindication to UKA. H-CCK is associated with significantly improved clinical outcomes but also a higher revision rate compared with controls. Level of evidence: Case control study, Level III

Implant materials and prosthetic joint infection: the battle with the biofilm

Prosthetic joint infection (PJI) is associated with poor clinical outcomes and is expensive to treat.Although uncommon overall (affecting between 0.5% and 2.2% of cases), PJI is one of the most commonly encountered complications of joint replacement and its incidence is increasing, putting a significant burden on healthcare systems.Once established, PJI is extremely difficult to eradicate as bacteria exist in biofilms which protect them from antibiotics and the host immune response.Improved understanding of the microbial pathology in PJI has generated potential new treatment strategies for prevention and eradication of biofilm associated infection including modification of implant surfaces to prevent adhesion of bacteria.Much research is currently ongoing looking at different implant surface coatings and modifications, and although most of this work has not translated into clinical medicine there has been some early clinical success. Cite this article: EFORT Open Rev 2019;4:633-639. DOI: 10.1302/2058-5241.4.180095

Unicompartmental knee arthroplasty: is the glass half full or half empty?

There is a large amount of evidence available about the relative merits of unicompartmental and total knee arthroplasty (UKA and TKA). Based on the same evidence, different people draw different conclusions and as a result, there is great variability in the usage of UKA. The revision rate of UKA is much higher than TKA and so some surgeons conclude that UKA should not be performed. Other surgeons believe that the main reason for the high revision rate is that UKA is easy to revise and, therefore, the threshold for revision is low. They also believe that UKA has many advantages over TKA such as a faster recovery, lower morbidity and mortality and better function. They therefore conclude that UKA should be undertaken whenever appropriate. The solution to this argument is to minimise the revision rate of UKA, thereby addressing the main disadvantage of UKA. The evidence suggests that this will be achieved if surgeons use UKA for at least 20% of their knee arthroplasties and use implants that are appropriate for these broad indications

The revision partial knee classification system: understanding the causative pathology and magnitude of further surgery following partial knee arthroplasty.

AIMS: Joint registries classify all further arthroplasty procedures to a knee with an existing partial arthroplasty as revision surgery, regardless of the actual procedure performed. Relatively minor procedures, including bearing exchanges, are classified in the same way as major operations requiring augments and stems. A new classification system is proposed to acknowledge and describe the detail of these procedures, which has implications for risk, recovery, and health economics. METHODS: Classification categories were proposed by a surgical consensus group, then ranked by patients, according to perceived invasiveness and implications for recovery. In round one, 26 revision cases were classified by the consensus group. Results were tested for inter-rater reliability. In round two, four additional cases were added for clarity. Round three repeated the survey one month later, subject to inter- and intrarater reliability testing. In round four, five additional expert partial knee arthroplasty surgeons were asked to classify the 30 cases according to the proposed revision partial knee classification (RPKC) system. RESULTS: Four classes were proposed: PR1, where no bone-implant interfaces are affected; PR2, where surgery does not include conversion to total knee arthroplasty, for example, a second partial arthroplasty to a native compartment; PR3, when a standard primary total knee prosthesis is used; and PR4 when revision components are necessary. Round one resulted in 92% inter-rater agreement (Kendall's W 0.97; p < 0.005), rising to 93% in round two (Kendall's W 0.98; p < 0.001). Round three demonstrated 97% agreement (Kendall's W 0.98; p < 0.001), with high intra-rater reliability (interclass correlation coefficient (ICC) 0.99; 95% confidence interval 0.98 to 0.99). Round four resulted in 80% agreement (Kendall's W 0.92; p < 0.001). CONCLUSION: The RPKC system accounts for all procedures which may be appropriate following partial knee arthroplasty. It has been shown to be reliable, repeatable and pragmatic. The implications for patient care and health economics are discussed. Cite this article: Bone Jt Open 2021;2(8):638-645

Pathogenesis and treatment options for hemophilic synovitis

INTRODUCTION: Hemophilia is characterized by recurrent bleeding episodes, most commonly in the knees, elbows and ankles. Repeated hemarthroses lead to synovial hypertrophy and a vicious cycle of chronic synovitis arises, leading to destruction of the joint. AREAS COVERED: This article covers the pathogenesis of chronic hemophilic synovitis and its treatment by means of different types of synovectomy. EXPERT OPINION: Both radiosynovectomy (RS) and arthroscopic synovectomy considerably improve the frequency of bleeding episodes. RS is the best option for patients with synovitis unresponsive to a three-month trial of hematological prophylaxis. If the bleeding is refractory to three successive episodes of RS at six monthly intervals, arthroscopic synovectomy is indicated. Open synovectomy should be reserved for adults with elbow synovitis requiring radial head removal and synovectomy in the same surgical session. RS is effective and safe, and particularly helpful in patients with inhibitors as they are at greatest risk of bleeding episodes and have the highest risk of complications of surgery

Platelet-Rich Plasma in the Treatment of Patellar Tendinopathy: A Systematic Review

BACKGROUND: Patellar tendinopathy (PT) is a major cause of morbidity in both high-level and recreational athletes. Whilst there is good evidence for the effectiveness of eccentric exercise regimens in its treatment, a large proportion of patients have disease which is refractory to such treatments. This has led to the development of novel techniques including platelet-rich plasma (PRP) injection, which aims to stimulate a normal healing response within the abnormal patellar tendon. However, little evidence exists at present to support its use. PURPOSE:The aim of this systematic review was to determine the safety and effectiveness of PRP in the treatment of PT, and to quantify its effectiveness relative to other therapies for PT. STUDY DESIGN: Systematic review. METHODS: A systematic review was conducted in accordance with the PRISMA guidelines. A literature review was conducted of the Medline, EMBASE and Cochrane databases, as well as trial registries. Both single-arm and comparative studies were included. The outcomes of interest were pain (as measured by visual-analogue or other, comparable scoring systems), functional scores and return to sport. Study quality and risk of bias were assessed using the MINORS score (for non-randomised studies) and the Cochrane risk of bias tool. RESULTS: Eleven studies fitted the inclusion criteria. Of these, two were randomised, controlled trials (RCTs), and one was a prospective, non-randomised cohort study. The remainder were single-arm case series. All noncomparative studies demonstrated a significant improvement in pain and function following PRP injection. Complications and adverse outcomes were rare. The results of the comparative studies were inconsistent and superiority of PRP over control treatments could not be conclusively demonstrated. CONCLUSION: PRP is a safe and promising therapy in the treatment of recalcitrant PT. However, its superiority over other treatments such as physiotherapy remains unproven. Further RCTs are required to determine the relative effectiveness of the many available treatments for PT, and to determine the subgroups of patients who stand to gain the most from the use of these therapies

The Cosmological Constant

This is a review of the physics and cosmology of the cosmological constant. Focusing on recent developments, I present a pedagogical overview of cosmology in the presence of a cosmological constant, observational constraints on its magnitude, and the physics of a small (and potentially nonzero) vacuum energy.Comment: 50 pages. Submitted to Living Reviews in Relativity (http://www.livingreviews.org/), December 199

Strong interface-induced spin-orbit coupling in graphene on WS2

Interfacial interactions allow the electronic properties of graphene to be modified, as recently demonstrated by the appearance of satellite Dirac cones in the band structure of graphene on hexagonal boron nitride (hBN) substrates. Ongoing research strives to explore interfacial interactions in a broader class of materials in order to engineer targeted electronic properties. Here we show that at an interface with a tungsten disulfide (WS2) substrate, the strength of the spin-orbit interaction (SOI) in graphene is very strongly enhanced. The induced SOI leads to a pronounced low-temperature weak anti-localization (WAL) effect, from which we determine the spin-relaxation time. We find that spin-relaxation time in graphene is two-to-three orders of magnitude smaller on WS2 than on SiO2 or hBN, and that it is comparable to the intervalley scattering time. To interpret our findings we have performed first-principle electronic structure calculations, which both confirm that carriers in graphene-on-WS2 experience a strong SOI and allow us to extract a spin-dependent low-energy effective Hamiltonian. Our analysis further shows that the use of WS2 substrates opens a possible new route to access topological states of matter in graphene-based systems.Comment: Originally submitted version in compliance with editorial guidelines. Final version with expanded discussion of the relation between theory and experiments to be published in Nature Communication