Total Hip Replacement for the Treatment of End Stage Arthritis of the Hip: A Systematic Review and Meta-Analysis

Background

Evolvements in the design, fixation methods, size, and bearing surface of implants for total hip replacement (THR) have led to a variety of options for healthcare professionals to consider. The need to determine the most optimal combinations of THR implant is warranted. This systematic review evaluated the clinical effectiveness of different types of THR used for the treatment of end stage arthritis of the hip.

Methods

A comprehensive literature search was undertaken in major health databases. Randomised controlled trials (RCTs) and systematic reviews published from 2008 onwards comparing different types of primary THR in patients with end stage arthritis of the hip were included.

Results

Fourteen RCTs and five systematic reviews were included. Patients experienced significant post-THR improvements in Harris Hip scores, but this did not differ between impact types. There was a reduced risk of implant dislocation after receiving a larger femoral head size (36 mm vs. 28 mm; RR = 0.17, 95% CI: 0.04, 0.78) or cemented cup (vs. cementless cup; pooled odds ratio: 0.34, 95% CI: 0.13, 0.89). Recipients of cross-linked vs. conventional polyethylene cup liners experienced reduced femoral head penetration and revision. There was no impact of femoral stem fixation and cup shell design on implant survival rates. Evidence on mortality and complications (aseptic loosening, femoral fracture) was inconclusive.

Conclusions

The majority of evidence was inconclusive due to poor reporting, missing data, or uncertainty in treatment estimates. The findings warrant cautious interpretation given the risk of bias (blinding, attrition), methodological limitations (small sample size, low event counts, short follow-up), and poor reporting. Long-term pragmatic RCTs are needed to allow for more definitive conclusions. Authors are encouraged to specify the minimal clinically important difference and power calculation for their primary outcome(s) as well CONSORT, PRISMA and STROBE guidelines to ensure better reporting and more reliable production and assessment of evidence.     

Noncatalytic assembly of ribonuclease III with double-stranded RNA

Ribonuclease III (RNase III) represents a family of double-stranded RNA (dsRNA) endonucleases. The simplest bacterial enzyme contains an endonuclease domain (endoND) and a dsRNA binding domain (dsRBD). RNase III can affect RNA structure and gene expression in either of two ways: as a dsRNA-processing enzyme that cleaves dsRNA, or as a dsRNA binding protein that binds but does not cleave dsRNA. We previously determined the endoND structure of Aquifex aeolicus RNase III (Aa-RNase III) and modeled a catalytic complex of full-length Aa-RNase III with dsRNA. Here, we present the crystal structure of Aa-RNase III in complex with dsRNA, revealing a noncatalytic assembly. The major differences between the two functional forms of RNase III.dsRNA are the conformation of the protein and the orientation and location of dsRNA. The flexibility of a 7 residue linker between the endoND and dsRBD enables the transition between these two forms.     

Transposition studies of mini-Mu plasmids constructed from the chemically synthesized ends of bacteriophage Mu

We describe below the chemical synthesis of the right and left ends of bacteriophage Mu and characterize the activity of these synthetic ends in mini-Mu transposition. Mini-Mu plasmids were constructed which carry the synthetic Mu ends together with the Mu A and B genes under control of the bacteriophage λ p_L promoter. Derepression of p_L leads to a high frequency of mini-Mu transposition (5.6 × 10⁻²) which is dependent on the presence of the Mu ends and the Mu A and B proteins. Five deletion mutants in the Mu ends were tested in the mini-Mu transposition system and their effects on transposition are described.     

Molecular basis for triclosan activity involves a flipping loop in the active site

The crystal structure of the Escherichia coli enoyl reductase-NAD+-triclosan complex has been determined at 2.5 A resolution. The Ile192-Ser198 loop is either disordered or in an open conformation in the previously reported structures of the enzyme. This loop adopts a closed conformation in our structure, forming van der Waals interactions with the inhibitor and hydrogen bonds with the bound NAD+ cofactor. The opening and closing of this flipping loop is likely an important factor in substrate or ligand recognition. The closed conformation of the loop appears to be a critical feature for the enhanced binding potency of triclosan, and a key component in future structure-based inhibitor design.     

Disco-ordinate expression of the Escherichia coli gal operon after prophage lambda induction.

EcoRI endonuclease crystallizes in space group C2 with unit cell parameters $\text{a = 209}\text{A}\text{?}\text{, b = 129}\text{A}\text{?}\text{, c = 50}\text{A}\text{?}\text{and}\text{β = 98.4 °}$. Four 29,000 molecular weight subunits per asymmetric unit would give a reasonable V_m value of 2.87 ų/dalton. EcoRI endonuclease is the first protein which recognizes a specific sequence of bases in DNA to be crystallized in a form suitable for high resolution structure analysis.