Cartiva interpositional arthroplasty versus arthrodesis in the treatment of Hallux rigidus: A retrospective comparative study with mean 2 year follow up.

BACKGROUND: Hallux rigidus is a common condition characterised by first metatarsophalangeal joint (MTPJ) degeneration, pain and limited range of motion (ROM). The gold standard surgical treatment is arthrodesis, providing good pain relief, but sacrifices ROM. The Cartiva synthetic cartilage implant (SCI) has been utilised as an interpositional arthroplasty, aiming to reduce pain whilst preserving range of motion. Current evidence for Cartiva SCI is limited. The aim was to evaluate the clinical outcomes of Cartiva SCI compared to arthrodesis undertaken in our centre. METHODS: A retrospective cohort study was conducted, enrolling all adult patients who underwent primary first MTPJ SCI arthroplasty or arthrodesis for the treatment hallux rigidus. The primary outcome was a validated patient-reported outcome measure (PROM), the Manchester-Oxford Foot Questionnaire (MOXFQ). Secondary outcomes included EQ-5D, complication rates, VAS Pain and FAAM (ADL). RESULTS: Between 2017 and 2020 there were 33 cases divided into two groups (17 Cartiva SCI, 16 arthrodesis, mean age 59.0 ± 9.9 years) with a mean follow up of 2.3 years. There was no statistically significant difference in any of the MOXFQ, EQ-5D, VAS Pain or FAAM (ADL) outcome scores between the Arthrodesis and SCI groups (p > 0.05). The mean MOXFQ Index score was 7.2 ± 6.4 for the SCI group and 3.9 ± 5.8 for the Arthrodesis group at final follow up (p = 0.15). Although complications were high in both groups, the overall hallux reoperation rate was 29.4 % in the SCI cohort and 0.0 % for arthrodesis. CONCLUSION: This retrospective comparative study found no significant superiority of Cartiva SCI over arthrodesis in terms of PROMs. Due to the higher rate of further surgical intervention in the SCI cohort, we recommend arthrodesis as the preferred surgical option for hallux rigidus. LEVEL OF EVIDENCE: III.

Tourniquet use in ankle arthroscopy: A systematic review.

BACKGROUND: Ankle arthroscopy is commonly performed using a thigh tourniquet and is thought to improve visibility and reduce operative time. However, the current evidence is unclear as to whether the use of a tourniquet provides these benefits. The aim of this study was to investigate whether there is any clinical benefit of using a tourniquet in ankle arthroscopy. METHODS: A systematic review following PRISMA guidelines was undertaken. All clinical studies published in Medline, Embase, PubMed and the Cochrane Library Database from inception until January 2023 reporting on the use of a tourniquet in ankle arthroscopy were included. RESULTS: 180 studies were identified of which 3 (164 patients) met the inclusion criteria. All studies showed no statistically significant difference in mean surgical time and complication rate between the tourniquet and non-tourniquet groups. Overall, the quality of the evidence was moderate to poor without data in favour or against the routine use of tourniquets in ankle arthroscopy. CONCLUSION: The current literature suggests that there are no significant differences in mean surgical time and complication rate between the tourniquet and non-tourniquet groups.

The intra-muscular course and distribution of the anterior interosseous nerve within pronator quadratus: An anatomical study.

Background: The anterior interosseous nerve (AIN) is a terminal motor branch of the median nerve innervating the following three muscles from proximal to distal: Flexor pollicis longus (FPL), the radial half of flexor digitorum profundus (FDP), and the pronator quadratus (PQ). The aim of this study was to define the course of the AIN within the PQ to aid surgeons performing distal radial procedures. Methods: Ten embalmed cadaveric forearms were dissected to identify the path of the AIN within PQ. An en-bloc excision of the PQ with its supplying AIN and vasculature was performed to identify a safe zone where PQ can be elevated without damaging AIN. A scoping literature search was performed to identify other studies reporting the path of AIN through PQ. Results: The mean distance from the radial border of the radius perpendicular to the point at which the AIN enters the PQ was 22.3 mm (range 21-24 mm). The mean distance from the distal wrist crease to the AIN entering PQ was 74.3 mm (range 59-84 mm). The mean number of nerve branches to PQ was 5.2 (range 3-8). In all specimens, the AIN was found to lie on the radial side of the anterior interosseous artery (AIA). Conclusions: The AIN courses on the deep surface of the PQ in a longitudinal proximal to distal direction. A 'safe zone' was identified within 20 mm of the radial border of the distal radius, which may be utilised by surgeons in a muscle-splitting approach to the distal radius.

Aseptic lymphocytic vasculitis-associated lesion in a well-fixed total knee arthroplasty: a case report.

Adverse reactions to metal debris in relation to metal-on-metal hip arthroplasty has been heavily discussed in the literature. In contrast, few cases have been reported in the context of total knee arthroplasty. A 77-year-old woman presented with a painful total knee arthroplasty. At the time of revision surgery, intra-articular cream-coloured fluid and material was found in association with a well-fixed prosthesis. Synovial and capsular samples were obtained for histological assessment and a diagnosis of aseptic lymphocytic vasculitis associated lesion was confirmed. The patient went on to have an uncomplicated recovery following a two-stage revision to a constrained knee prosthesis.

Diffusion of radiotracers in normal and ischemic brain slices.

Diffusion in the extracellular space (ECS) is important in physiologic and pathologic brain processes but remains poorly understood. To learn more about factors influencing tissue diffusion and the role of diffusion in solute-tissue interactions, particularly during cerebral ischemia, we have studied the kinetics of several radiotracers in control and hypoxic 450-microm hippocampal slices and in 1,050-microm thick slices that model the ischemic penumbra. Kinetics were analyzed by nonlinear least squares methods using models that combine extracellular diffusion with tissue compartments in series or in parallel. Studies with 14C-polyethylene glycol confirmed prior measurements of extracellular volume and that ECS shrinks during ischemia. Separating diffusion from transport also revealed large amounts of 45Ca that bind to or enter brain as well as demonstrating a small, irreversibly bound compartment during ischemia. The rapidity of 3H2O entry into cells made it impossible for us to distinguish intracellular from extracellular diffusion. The diffusion-compartment analysis of 3-O-methylglucose data appears to indicate that 5 mmol/L glucose is inadequate to support glycolysis fully in thick slices. Unexpectedly, the diffusion coefficient for all four tracers rose in thick slices compared with thin slices, suggesting that ECS becomes less tortuous in the penumbra.

Restoring adenine nucleotides in a brain slice model of cerebral reperfusion.

Tissue adenine nucleotides are depleted during cerebral ischemia, impeding recovery after reperfusion. Although prior studies have attempted to prevent the initial loss of adenylates, the present study tests the hypothesis that stimulating synthesis of adenine nucleotides, through either adenosine kinase or adenine phosphoribosyltransferase, would result in significant cerebroprotection. To study the effects on neurons and glia directly while avoiding the influence of the cerebral vasculature, hippocampal brain slices were used for the model of transient ischemia with reperfusion. The standard brain slice insult of brief exposure to anoxia with aglycemia was modified based on studies which showed that a 30-minute exposure to air with 1 mmol/L glucose produced a stable, moderate reduction in ATP during the insult and that, 2 hours after return to normal conditions, there was moderate depletion of tissue adenine nucleotides and histologic injury. Treatments with 1 mmol/L adenosine, AMP, or adenine were equivalent in partially restoring adenine nucleotides. Despite this, only adenosine afforded histologic protection, suggesting a protective role for adenosine receptors. There also was evidence for metabolic cycling among adenine nucleotides, nucleosides, and purines. Adenosine may exert direct cerebroprotective effects on neural tissue as well as indirect effects through the cerebral vasculature.

Effects of K+, pH and glutamate on 45Ca kinetics in hippocampal brain slices.

Altered calcium homeostasis is likely to play a pathogenetic role in cerebral ischemia. In order to further understand which factors associated with ischemia contribute to disturbances of calcium metabolism, the influence of 3 isolated insults, 8 mM K+, pH 6.1 and 1 mM glutamate, on total tissue calcium were studied by analysis of steady-state kinetics of 45Ca in 500 microns hippocampal brain slices. 45Ca kinetics were analyzed with 2 bi-exponential models by non-linear least-squares analysis. Tissue wet weight/protein was measured simultaneously. Each experimental condition produced a unique tissue response. Raising K+ had no effect on tissue water but increased the rate of uptake of Ca2+ into the larger, rapidly equilibrating tissue Ca2+ space. Acidosis reduced tissue water and the amount of Ca2+ in the slowly equilibrating compartment due to enhanced efflux from that space. Glutamate increased tissue water in a time-dependent manner and increased the influx and amount of Ca2+ in the slowly equilibrating space. Combined insults revealed minimal interaction between K+ and acidosis or glutamate, but glutamate with acidosis worsened tissue injury. We discuss the relationship of this technique to other methods for studying tissue calcium and the significance of the observations regarding ischemia.

Sterol synthesis: studies of the metabolism of 14 alpha-methyl-5 alpha-cholest-7-en-3 beta-ol.

[3 alpha-3H]14 alpha-Methyl-5 alpha-cholest-7-en-3 beta-ol has been prepared by chemical synthesis. The metabolism of this compound has been studied in the 10,000 g supernatant fraction of liver homogenates of female rats. Efficient conversion to cholesterol was observed. Other labeled compounds recovered after incubation of [3 alpha-3H]14 alpha-methyl-5 alpha-cholest-7-en-3 beta-ol with the enzyme preparations include the unreacted substrate, 5 alpha-cholesta-7,14-dien-3 beta-ol, 5 alpha-cholesta-8,14-dien-3 beta-ol, cholesta-5,7-dien-3 beta-ol, 5 alpha-cholest-8(14)-en-3 beta-ol, 5 alpha-cholest-8-en-3 beta-ol, and 5 alpha-cholest-7-en-3 beta-ol. In addition, significant amounts of incubated radioactivity were recovered in steryl esters. The steroidal components of these esters were found to contain labeled 14 alpha-methyl-5 alpha-cholest-7-en-3 beta-ol, 5 alpha-cholesta-8,14-dien-3 beta-ol, 5 alpha-cholesta-7,14-dien-3 beta-ol, 5 alpha-cholest-8-en-3 beta-ol, 5 alpha-cholest-7-en-3 beta-ol, and cholesterol.

Replication of the Moloney murine sarcoma-leukemia virus in XC cells.

The XC rat cell line was found to support the replication of a strain of the Moloney murine sarcoma-leukemia virus. In growth curve experiments cytopathology was paralleled by the production of murine sarcoma virus and leukemia virus progeny having the biologic, antigenic, and biophysical properties of the infecting virus.