Venous Thromboembolism (VTE) prophylaxis is an essential part of orthopaedic surgeries in preventing life-threatening thromboembolic events such as Deep Vein Thrombosis (DVT) and Pulmonary Embolism (PE). Orthopaedic surgery has the highest incidence rate of thromboembolic events as compared to any other surgical specialities, making it an essential component in managing any orthopaedic case. At Queen's Medical Centre (QMC), a major trauma centre in the United Kingdom (UK), sees up to 750 NOF fracture cases annually, making it one of the busiest trauma and orthopaedic centres in the UK. Our study aims to evaluate how VTE Prophylaxis is conducted in a UK Major Trauma Centre for NOF and pelvic fragility fractures and how human factors can improve its efficacy.

The Nottingham University Hospitals (NUH) Trust has implemented new guidelines from August 2019 that patients with fragility fractures such as NOF and pelvic fractures are prescribed with 28 days VTE prophylaxis with Enoxaparin, or their own anti-coagulants if risk of thrombosis exceed the risk of bleeding. This is an adaptation from the trust to align their guidelines closer to the NICE 2018 guidelines. We will be evaluating the initial compliance of VTE Prophylaxis, identify and utilise human factors, then re-analyse the department after implementing interventions on the same batch of junior doctors working in the department. Data of 100 patients with fragility fractures were collected, 50 consecutive patients in the pre-intervention window during August 2019 and 50 in the post-intervention window during November 2019.

The pre-intervention data had 43 NOF and 7 Pelvic fractures. Our study showed that 93% of NOF fracture and 100% of pelvic fracture received the correct course of VTE prophylaxis. The data was presented at the local department junior doctor academic session. Three simple human factor interventions were implemented over the course of September and October: Education to the trauma and orthopaedic department on the new guideline, extended VTE labels on drug charts for patients with fragility fractures, VTE reminder labels at doctors' stations. Another 50 consecutive patients' data were collected during November 2019. Data shows that 97.8% of NOF (p>0.05) and 60% of pelvic fracture (p>0.05) received the correct course of VTE prophylaxis

Our data has shown an increase in correct VTE prescription for NOF fracture patients, which is the main bulk of our fragility fracture patients whilst we see a drop in pelvic fracture patients. Due to the limited time frame of four months where junior doctors in the UK rotate between specialities, we are only able to collect data during the first month, implement interventions between datasets and collect data on the final month of the four-month rotation. A future bigger study might provide a more significant result on the department. We believe that the key to achieving 100% VTE prophylaxis in the T&O department is optimising human factors, educating junior doctors, who are not orthopaedic trained, with sufficient information of the guidelines, and evidence of the risk and benefits of providing prolonged VTE prophylaxis for orthopaedic patients.

In conclusion, we found that QMC, a major trauma centre with high patient volume and turnover, has a high level of compliance with VTE prophylaxis for fragility fractures and it is imperative that utilising human factors will inch the department closer to its goal of 100% VTE compliance.

Introduction

Clear operative oncological margins are the main target in malignant bone tumour resections. Novel techniques like patient specific instruments (PSIs) are becoming more popular in orthopaedic oncology surgeries and arthroplasty in general with studies suggesting improved accuracy and reduced operating time using PSIs compared to conventional techniques and computer assisted surgery. Improved accuracy would allow preservation of more natural bone of patients with smaller tumour margin.

Novel low-cost technology improving accuracy of surgical cuts, would facilitate highly delicate surgeries such as Joint Preserving Surgery (JPS) that improves quality of life for patients by preserving the tibial plateau and muscle attachments around the knee whilst removing bone tumours with adequate tumour margins. There are no universal guidelines on PSI designs and there are no studies showing how specific design of PSIs would affect accuracy of the surgical cuts.

We hypothesised if an increased depth of the cutting slot guide for sawblades on the PSI would improve accuracy of cuts.

The aim of this project is to test the parameters of Patient Specific Instruments (PSIs) and measuring accuracy of surgical cuts using sawblades with different depths of PSI cutting guide slot.

Clear operative oncological margins are the main target in malignant bone tumour resections. Novel techniques like patient specific instruments (PSIs) are becoming more popular in orthopaedic oncology surgeries and arthroplasty in general with studies suggesting improved accuracy and reduced operating time using PSIs compared to conventional techniques and computer assisted surgery. Improved accuracy would allow preservation of more natural bone of patients with smaller tumour margin. Novel low-cost technology improving accuracy of surgical cuts, would facilitate highly delicate surgeries such as Joint Preserving Surgery (JPS) that improves quality of life for patients by preserving the tibial plateau and muscle attachments around the knee whilst removing bone tumours with adequate tumour margins. There are no universal guidelines on PSI designs and there are no studies showing how specific design of PSIs would affect accuracy of the surgical cuts. We hypothesised if an increased depth of the cutting slot guide for sawblades on the PSI would improve accuracy of cuts.

A pilot drybone experiment was set up, testing 3 different designs of a PSI with changing cutting slot depth, simulating removal of a tumour on the proximal tibia. A handheld 3D scanner (Artec Spider, Luxembourg) was used to scan tibia drybones and Computer Aided Design (CAD) software was used to simulate osteosarcoma position and plan intentioned cuts. PSI were designed accordingly to allow sufficient tumour. The only change for the 3 designs is the cutting slot depth (10mm, 15mm & 20mm). 7 orthopaedic surgeons were recruited to participate and perform JPS on the drybones using each design 2 times. Each fragment was then scanned with the 3D scanner and were then matched onto the reference tibia with customized software to calculate how each cut (inferior-superior-vertical) deviated from plan in millimetres and degrees. In order to tackle PSI placement error, a dedicated 3D-printed mould was used.

Comparing actual cuts to planned cuts, changing the height of the cutting slot guide on the designed PSI did not deviate accuracy enough to interfere with a tumour resection margin set to maximum 10mm. We have obtained very accurate cuts with the mean deviations(error) for the 3 different designs were: [10mm slot: 0.76 ± 0.52mm, 2.37 ± 1.26°], [15 mm slot: 0.43 ± 0.40 mm, 1.89 ± 1.04°] and [20 mm: 0.74 ± 0.65 mm, 2.40 ± 1.78°] respectively, with no significant difference between mean error for each design overall, but the inferior cuts deviation in mm did show to be more precise with 15 mm cutting slot (p<0.05).

Simulating a cut to resect an osteosarcoma, none of the proposed designs introduced error that would interfere with the tumour margin set. Though 15mm showed increased precision on only one parameter, we concluded that 10mm cutting slot would be sufficient for the accuracy needed for this specific surgical intervention. Future work would include comparing PSI slot depth with position of knee implants after arthroplasty, and how optimisation of other design parameters of PSIs can continue to improve accuracy of orthopaedic surgery and allow increase of bone and joint preservation.