Anterior approach total hip arthroplasty (AA-THA) has a steep learning curve, with higher complication rates in initial cases. Proper surgical case selection during the learning curve can reduce early risk. This study aims to identify patient and radiographic factors associated with AA-THA difficulty using Machine Learning (ML).

Consecutive primary AA-THA patients from two centres, operated by two expert surgeons, were enrolled (excluding patients with prior hip surgery and first 100 cases per surgeon). K- means prototype clustering – an unsupervised ML algorithm – was used with two variables - operative duration and surgical complications within 6 weeks - to cluster operations into difficult or standard groups.

Radiographic measurements (neck shaft angle, offset, LCEA, inter-teardrop distance, Tonnis grade) were measured by two independent observers. These factors, alongside patient factors (BMI, age, sex, laterality) were employed in a multivariate logistic regression analysis and used for k-means clustering. Significant continuous variables were investigated for predictive accuracy using Receiver Operator Characteristics (ROC).

Out of 328 THAs analyzed, 130 (40%) were classified as difficult and 198 (60%) as standard. Difficult group had a mean operative time of 106mins (range 99–116) with 2 complications, while standard group had a mean operative time of 77mins (range 69–86) with 0 complications. Decreasing inter-teardrop distance (odds ratio [OR] 0.97, 95% confidence interval [CI] 0.95–0.99, p = 0.03) and right-sided operations (OR 1.73, 95% CI 1.10–2.72, p = 0.02) were associated with operative difficulty. However, ROC analysis showed poor predictive accuracy for these factors alone, with area under the curve of 0.56. Inter-observer reliability was reported as excellent (ICC >0.7).

Right-sided hips (for right-hand dominant surgeons) and decreasing inter-teardrop distance were associated with case difficulty in AA-THA. These data could guide case selection during the learning phase. A larger dataset with more complications may reveal further factors.

Prosthetic joint infection (PJI) is a serious complication following joint replacement. Antiseptic solutions are often used for intraoperative wound irrigation particularly in cases of revision for PJI. Antiseptic irrigation is intended to eradicate residual bacteria which may be either free floating or in residual biofilm although there is no clear clinical efficacy for its use. Also, reviewing the scientific literature there is discordance in in vitro results where some studies questions antiseptic efficacy whilst others suggest that even at low concentration antiseptic agents are effective at eradicating bacterial biofilms.

The aim of this in vitro study was to establish the efficacy of undiluted antiseptic agents at eradication of a typical PJI forming biofilm and determine the importance of an antiseptic neutralisation step in this assessment.

Mature Staphylococcus epidermidis biofilms grown on TiAl6V4 discs were submerged in chlorohexidine (CHL) gluconate 4%, povidone-iodine (PI) 10% or phosphate-buffered saline (PBS) control solution. The discs were then rinsed, the biofilm bacteria suspended in solution using sonication and vortexing, and the viable count (CFU/ml) of the bacterial suspensions determined. The rinse/suspension solution was either (a) PBS or (b) Dey-Engley neutralization broth (NB).

When PBS was used to rinse/suspend the biofilm a highly significant, 7.5 and 4.1, mean log reduction in biofilm vitality was observed from the control, for CHL 4% and PI 10%, respectively. However, when NB was the rinse/suspension solution the apparent antiseptic biofilm eradication efficacy was replaced with a statistically significant but clinically irrelevant less the one log-reduction in biofilm vitality.

Clinical antiseptic agents are ineffective at eradicating S. epidermidis biofilm in an in vitro PJI model and absence of a neutralisation step gives the false impression of efficacy. Antiseptics alone are an ineffective treatment for biofilm related PJI and no substitute for meticulous debridement.

Prosthetic joint infection (PJI) is an important cause of arthroplasty failure. There is no method to disclose the presence or map the distribution of the in vivo biofilm on infected arthroplasty despite the recognition that such a tool would aid intraoperative decision making and improve novel implant design. The aim of this study was to test the efficacy of four dyes to disclose bacterial biofilm in an in vitro setting.

Four dyes with known affinity to bacterial biofilm were assessed to determine their efficacy to disclose biofilms in an in vitro model of PJI. Three dyes (Methylene Blue, Indocyanine Green and Rose Bengal) have established clinical utility and the other, Thioflavin T, is known to fluoresce in the presence of amyloid a known biofilm constituent. The efficacy of the dyes to discriminate between biofilms of different mass and vitality (high, low or the non-inoculated control) was determined after three minutes exposure of the biofilm to the dyes by calculating the amount of dye bound to the biofilm via sonication and spectrophotometry, quantification of the dye through standardised photographic imaging of the stained biofilm and the calculation of inter-observer agreement. Each experiment was performed in triplicate for each dye and repeated three times.

For each of the disclosure dyes assessed there was significant difference demonstrated between the amount of dye bound to the high and low mass biofilms (p<0.05) as well as in the amount of dye quantified in photographic and fluorescent image assessment between biofilms of differing mass (p<0.01). There was excellent agreement between three observers, for each disclosure dye, in determining the biofilm mass of each stained disc (Kappa>0.91).

This study demonstrates the efficacy of biofilm disclosure dyes in an in vitro PJI model which could one day be used to disclose and map the clinical biofilm in vivo.

Current evidence suggests that superior surgical team performance is linked to fewer intra-operative errors, reductions in mortality and even improved patient outcomes. Virtual reality has demonstrated excellent efficacy in training surgeons and scrub nurses individually, however its impact on training teams is currently unknown. This study aimed to assess if training together (scrub nurse and surgeon) in an innovative multiplayer virtual reality program was superior to single player training for novices learning anterior approach total hip arthroplasty (AA-THA).

40 participants (20 novice surgeons (CT1-ST3 level) and 20 novice scrub nurses) were enrolled in this study and randomised to individual or team virtual reality training. Individually-trained participants played with virtual avatar counterparts, whilst teams trained live in pairs (surgeon and scrub nurse). Both groups underwent 5 VR training sessions over 6 weeks. Subsequently, they underwent a real-life assessment in which they performed AA-THA on a high-fidelity model with real equipment in a simulated operating theatre. Teams performed together and individually-trained participants were randomly paired up with a solo player of the opposite role. Videos of the assessment were marked by two blinded expert assessors. The primary outcome was team performance as graded by the validated NOTECHs II score. Secondary outcomes were procedure time and number of technical errors from an expert pre-defined protocol.

Teams outperformed individually-trained participants for non-technical skills in the real-world assessment (NOTECHS-II score 50.3 ± 6.04 vs 43.90 ± 5.90, p=0.0275). They completed the assessment 28.1% faster (31.22 minutes ±2.02 vs 43.43 ±2.71, p=0.01), and made close to half the number of technical errors when compared to the individual group (12.9 ± 8.3 vs 25.6 ± 6.1, p=0.001).

Multiplayer, team training appears to lead to faster surgery with fewer technical errors and the development of superior non-technical skills.

Evidence supporting the use of virtual reality (VR) training in orthopaedic procedures is rapidly growing. However, the impact of the timing of delivery of this training is yet to be tested. We aimed to investigate whether spaced VR training is more effective than massed VR training.

24 medical students with no hip arthroplasty experience were randomised to learning the direct anterior approach total hip arthroplasty using the same VR simulation, training either once-weekly or once-daily for four sessions. Participants underwent a baseline physical world assessment on a saw bone pelvis. The VR program recorded procedural errors, time, assistive prompts required and hand path length across four sessions. The VR and physical world assessments were repeated at one-week, one-month, and 3 months after the last training session.

Baseline characteristics between the groups were comparable (p > 0.05). The daily group demonstrated faster skills acquisition, reducing the median ± IQR number of procedural errors from 68 ± 67.05 (session one) to 7 ± 9.75 (session four), compared to the weekly group's improvement from 63 ± 27 (session one) to 13 ± 15.75 (session four), p < 0.001. The weekly group error count plateaued remaining at 14 ± 6.75 at one-week, 16.50 ± 16.25 at one-month and 26.45 ± 22 at 3-months, p < 0.05. However, the daily group showed poorer retention with error counts rising to 16 ± 12.25 at one-week, 17.50 ± 23 at one-month and 41.45 ± 26 at 3-months, p<0.01. A similar effect was noted for the number of assistive prompts required, procedural time and hand path length. In the real-world assessment, both groups significantly improved their acetabular component positioning accuracy, and these improvements were equally maintained (p<0.01).

Daily VR training facilitates faster skills acquisition; however weekly practice has superior skills retention.

Abstract

Abstract

Abstract

Interbody fusion aims to treat painful disc disease by demobilising the spinal segment through the use of an interbody fusion device (IFD). Diminished contact area at the endplate interface raises the risk of device subsidence, particularly in osteoporosis patients. The aim of the study was to ascertain whether vertebral body (VB) cement augmentation would reduce IFD subsidence following dynamic loading. Twenty-four human two-vertebra motion segments (T6–T11) were implanted with an IFD and distributed into three groups; a control with no cement augmentation; a second with PMMA augmentation; and a third group with calcium phosphate (CP) cement augmentation. Dynamic cyclic compression was applied at 1Hz for 24 hours in a specimen specific manner. Subsidence magnitude was calculated from pre and post-test micro-CT scans. The inferior VB analysis showed significantly increased subsidence in the control group (5.0±3.7mm) over both PMMA (1.6±1.5mm, p=.034) and CP (1.0±1.1mm, p=.010) cohorts. Subsidence in the superior VB to the index level showed no significant differences (control 1.6±3.0mm, PMMA 2.1±1.5mm, CP 2.2±1.2mm, p=.811). In the control group, the majority of subsidence occurred in the lower VB with the upper VB displaying little or no subsidence, which reflects the weaker nature of the superior endplate. Subsidence was significantly reduced in the lower VB when both levels were reinforced regardless of cement type. Both PMMA and CP cement augmentation significantly affected IFD subsidence by increasing VB strength within the motion segment, indicating that this may be a useful method for widening indications for surgical interventions in osteoporotic patients.

INTRODUCTION

Over 85% of patients with multiple myeloma (MM) have bone disease, mostly affecting thoraco-lumbar vertebrae. Vertebral fractures can lead to pain and large spinal deformities requiring application of vertebroplasty (PVP). PVP could be enhanced by use of Coblation technique to remove lesions from compromised MM vertebrae prior to cement injection (C-PVP).