The aim of this study was to assess the impact of Covid-19 measures on the rate of surgical site infections (SSI) and subsequent readmissions in orthopaedic patients.

Retrospective, observational study in a level 1 major trauma center comparing rates of SSI in orthopaedic patients who underwent surgery prior to the Covid-19 lockdown versus that of patients who underwent surgery during the lockdown period. A total of 1151 patients were identified using electronic clinical records over two different time periods; 3 months pre Covid-19 lockdown (n=680) and 3 months during the Covid-19 lockdown (n=470). Patients were followed up for 1 year following their initial procedure. Primary outcome was readmission for SSI. Secondary outcomes were treatment received and requirement for further surgeries.

The most commonly performed procedures were arthroplasty and manipulation under anaesthesia with 119 in lockdown vs 101 non-lockdown (p=0.001). The readmission rate was higher in the lockdown group with 61 (13%) vs 44 (6.5%) in the non-lockdown group (p <0.001). However, the majority were due to other surgical complications such as dislocations. Interestingly, the SSI rates were very similar with 24 (5%) in lockdown vs 28 (4%) in non-lockdown (p=0.472). Twenty patients (4.2%) required a secondary procedure for their SSI in the lockdown group vs 24 (3.5%) in non-lockdown (p=0.381). Mortality rate was similar at 44 (9.3%) in lockdown vs 61 (9.0%; p=0.836).

Whilst Covid-19 precautions were associated with higher readmission rates, there was no significant difference in rate of SSI between the two groups.

The angle of acetabular inclination is an important measurement in total hip replacement (THR) procedures. Determining the acetabular component orientation intra-operatively remains a challenge. An increasing number of innovators have described techniques and devices to achieve it. This paper describes a mechanical inclinometer design to measure intra-operative acetabular cup inclination. Then, the mechanical device is tested to determine its accuracy. The aim was to design an inclinometer to measure inclination without existing instrumentation modification. The device was designed to meet the following criteria: 1. measure inclination with acceptable accuracy (+/− 5o); 2. easy to use intra-operatively (handling & visualization); 3. adaptable and useable with majority of instrumentation kits without modification; 4. sterilizable by all methods; 5. robust/reusable.

The prototype device was drafted by computer aided design (CAD) software. Then a prototype was constructed using a 3D printer to establish the final format. The final device was CNC machined from SAE 304 stainless steel. The design uses an eccentrically weighted flywheel mounted on two W16002-2RS ball bearings pressed into symmetrical housing components. The weighted wheel is engraved with calibrated markings relative to its mass centre. Device functioning is dependent on gravity maintaining the weighted wheel in a fixed orientation while the housing can adapt to the calibration allowing for determining the corresponding measurement. The prototype device accuracy was compared to a digital device. A digital protractor was used to create an angle. The mechanical inclinometer (user blinded to digital reading) was used to determine the angle and compared to the digital reading.

The accuracy of the device compared to the standard freehand technique was assessed using a saw bone pelvis fixed in a lateral decubitus position. 18 surgeons (6 expert, 6 intermediate, 6 novice) were asked to place an uncemented acetabular cup in a saw bone pelvis to a target of 40 degrees. First freehand then using the inclinometer. The inclination was determined using a custom-built inertial measurement unit with the user blinded to the result. Comparison between the mechanical and digital devices showed that the mechanical device had an average error of −0.2, a standard deviation of 1.5, and range −3.3 to 2.6. The average root mean square error was 1.1 with a standard deviation of 0.9. Comparison of the inclinometer to the freehand technique showed that with the freehand component placement 50% of the surgeons were outside the acceptable range of 35–45 degrees. The use of the inclinometer resulted all participants to achieve placement within the acceptable range. It was noted that expert surgeons were more accurate at achieving the target inclination when compared to less experienced surgeons.

This work demonstrates that the design and initial testing of a mechanical inclinometer is suitable for use in determining the acetabular cup inclination in THR. Experimental testing showed that the device is accurate to within acceptable limits and reliably improved the accuracy of uncemented cup implantation in all surgeons.

Background

Outcomes for patients with acute illnesses may be affected by the day of the week they present to hospital. Policy makers state this ‘weekend effect’ to be the main reason for pursuing a change in consultant weekend working patterns. However, it is uncertain whether such a phenomenon exists for elective orthopaedic surgery. This study investigated whether a ‘weekend effect’ contributed to adverse outcomes in patients undergoing elective hip and knee replacements.

Outcomes for patients with acute illnesses may be affected by the day of the week they present to hospital. Policy makers state this ‘weekend effect’ to be the main reason for pursuing a change in consultant weekend working patterns. However, it is uncertain whether such a phenomenon exists for elective orthopaedic surgery.

This study investigated whether a ‘weekend effect’ contributed to adverse outcomes in patients undergoing elective hip and knee replacements.

Retrospectively collected data was obtained from our institutions electronic patient records. Using univariate analysis, we examined potential risk factors including; Age, Sex, ASA Grade, Comorbidities, as well as the day of the week, hospital admission and surgery occurred. Subsequent multivariate analyses identified covariate- adjusted risk factors, associated with prolonged hospital stays. 30-day mortality data was assessed according to the day of the week surgery was performed.

892 patients underwent arthroplasty surgery from 01/09/2014 till the 31/08/2015. 457 patients had a total hip and 435 had a total knee replacement. 814 patients (91.3%) underwent surgery during the week, while 78 (8.7%) had surgery on a Saturday. There was no difference in the average Length of Stay (LOS) between groups (5.0, 2.6 versus 5.0, 3.4, p=0.95), and weekend surgery was not associated with a LOS greater than 4 days. The two variables found to be associated with a prolonged LOS were; increasing age (RR) 1.02 (95% CI: 1.01–1.03, p<0.001) and an ASA score of 2, (RR) 1.6 (95% CI: 1.15 − 2.20, p=0.005). There was one death in a patient who was ASA III, and who underwent surgery on a Monday.

There is no ‘weekend effect’ for elective orthopaedic surgery. Changes in consultant weekend working patterns are unlikely to have any effect on mortality or LOS for elective orthopaedic patients.