INTRODUCTION

Combining novel diverse population-based software with a clinically-demonstrated implant design is redefining total hip arthroplasty. This contemporary stem design utilized a large patient database of high-resolution CT bone scans in order to determine the appropriate femoral head centers and neck lengths to assist in the recreation of natural head offset, designed to restore biomechanics. There are limited studies evaluating how radiographic software utilizing reference template bone can reconstruct patient composition in a model. The purpose of this study was to examine whether the application of a modern analytics system utilizing 3D modeling technology in the development of a primary stem was successful in restoring patient biomechanics, specifically with regards to femoral offset (FO) and leg length discrepancy (LLD).

“Simulation”, “deliberate practice”, “rehearsal” have been used to describe safe acquisition and practice of skills before patient contact. Simulation resources are being introduced as a General Medical Council mandate. Individual simulators have shown multi-level evidence but there is no guidance to form a simulation curriculum. We devised a pilot arthroscopy course based on a 4-stage model. Stage 1: session covering anatomy, equipment, and skills required; Stage 2: practice on low fidelity simulators (Arthroscopic Skills Acquisition Tools (ASATs), ArthroBox, Synthetic Knee); Stage 3: practice on high fidelity simulators (Cadaveric Knee, Virtual Reality); Stage 4: assessment on performance intra-operatively. This study sought feedback on Stages 1–3 with the aim that the feedback will help identify how trainees wish to use simulators.

Five arthroscopic simulators were used in this one-day pilot course. Prior to commencing, participants were asked which simulator they felt would help them the most. Feedback on each stage, and individual simulator (Likert scale), and how trainees would like to be trained was prospectively collected.

Seven orthopaedic juniors took part. All felt the high-fidelity simulators will be the most useful. All stages were ranked with equal importance, whilst cadaveric, plastic, VR, Arthrobox and lastly ASATs ranked in order of realism respectively. For cadaveric arthroscopy trainees wished the trainers to be there all the time (6/7), whilst for VR all trainees wanted their trainers part of the time.

We have shown that junior trainees value a structured method of skills acquisition and have identified that high fidelity simulation requires trainers to be present to provide relevant feedback. Such feedback mechanisms need to be incorporated in any curriculum so that simulation tools are not seen as a standalone training method.

Compartment syndrome (CS) is a unique form of skeletal muscle ischaemia. N-acetyl cysteine (NAC) is an anti-oxidant in clinical use, with beneficial microcirculatory effects.

Sprague-Dawley rats (n=6/group) were randomised into Control, CS and CS pre-treated with NAC (0.5g/kg i.p. 1 hr prior to induction) groups. In a post-treatment group NAC was administered upon muscle decompression. Cremasteric muscle was placed in a pressure chamber in which pressure was maintained at diastolic minus 10 mm Hg for 3 hours inducing CS, muscle was then returned to the abdominal cavity. At 24 hours and 7 days post-CS contractile function was assessed by electrical stimulation. Myeloperoxidase (MPO) activity was assessed at 24-hours.

CS injury reduced twitch (50.4±7.7 vs 108.5±11.5, p<0.001; 28.1±5.5 vs. 154.7±14.1, p<0.01) and tetanic contraction (225.7±21.6 vs 455.3±23.3, p<0.001; 59.7±12.1 vs 362.9±37.2, p<0.01) compared with control at 24 hrs and 7 days respectively. NAC pre-treatment reduced CS injury at 24 hours, preserving twitch (134.3±10.4, p<0.01 vs CS) and tetanic (408.3±34.3, p<0.01 vs CS) contraction. NAC administration reduced neutrophil infiltration (MPO) at 24 hours (24.6±5.4 vs 24.6±5.4, p<0.01). NAC protection was maintained at 7 days, preserving twitch (118.2±22.9 vs 28.1±5.5, p<0.01) and tetanic contraction (256.3±37 vs 59.7±12.1, p<0.01). Administration of NAC at decompression also preserved muscle twitch (402.4±52; p<0.01 versus CS) and tetanic (402.4±52; p<0.01 versus CS) contraction, reducing neutrophil infiltration (24.6±5.4 units/g; p<0.01).

These data demonstrate NAC provided effective protection to skeletal muscle from CS induced injury when given as a pre- or post-decompression treatment.

Objective

To compare the ability of a new composite bio-absorbable screw and two conventional metal screws to maintain fixation of scaphoid waist-fractures under dynamic loading conditions.