30-day outcome after orthopaedic surgery in patients assessed as negative for COVID-19 at the time of surgery during the peak of the pandemic

Introduction

In December 2019 an outbreak of coronavirus disease 2019 (COVID-19) caused by a novel coronavirus, severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) was recognized in Wuhan, China.¹ Over the following 3 months the virus spread globally and on 11 March 2020 was declared a pandemic by the World Health Organization (WHO). In the UK, due to the increase in reported cases and the impending demand on NHS critical care pathways, all elective surgery in the NHS ceased on 15 April 2020.² Emergency and urgent surgical cases continued as local resources allowed.

Emerging data on the outcomes of surgery in patients who are screened as SARS-CoV-2 positive in the seven days prior to surgery has reported a 30 day mortality rate of 21.2%, with 30 day mortality rates of up to 40% in those who develop respiratory complications.^3,4 In particular, in adjusted analyses, male sex, age 70 years or greater, American Society of Anesthesiologists⁵ grade 3 or greater, major surgery and emergency surgery have been identified as presenting the highest risk of mortality.⁴

As the UK is now past the peak of COVID-19, the UK government has asked hospitals to attempt to return to elective surgery.⁶ This should be undertaken in hospitals using clinical pathways where patients are screened for COVID-19 prior to undertaking surgery and risk is reduced by operating on patients who are believed to be at lower risk of COVID-19 complications.^7,8 However, as yet there is no published data on the outcome of patients who are believed to be COVID-19 negative following preoperative screening. This lack of data adversely affects shared decision making for patients and clinical teams, where the decision to undergo surgery depends on the balance between benefit and risk.^9,10 If elective surgery is to be restarted, there is a critical need for short-term outcome data of patients who are believed to be COVID-19 negative at the time of surgery to help develop safe patient pathways and provide data to inform shared decision making for elective surgery when COVID-19 remains in circulation.

The aim of this study is to report the 30 day COVID-19 related morbidity and mortality of patients assessed as COVID-19 negative through screening who underwent emergency or urgent surgery in the NHS during the peak of the COVID-19 pandemic.

Methods

A retrospective, single centre, observational cohort study of all patients undergoing orthopaedic surgery under general or regional anaesthetic between 17 March 2020 and 3 May 2020 was performed. Outcomes were stratified by British Orthopaedic Association (BOA) COVID-19 Patient Risk Assessment Tool.⁷ Patients considered COVID-19 positive at the time of surgery, based on nasopharyngeal swab positive for SARS-CoV-2 viral RNA or symptoms suggestive of COVID-19 in the absence of a negative nasopharyngeal swab result at the time of surgery, were excluded from the analysis. The study was approved by the local audit committee.

Participants

The Nuffield Orthopaedic Centre (NOC) is a tertiary referral centre providing services for all orthopaedic specialties including treatment of sarcoma. Trauma, excluding peri-prosthetic and malignant pathological fractures who are treated at the NOC, are managed under the care of the Trauma Unit based at the John Radcliffe Hospital. The NOC stands on a separate site to other NHS hospitals. It also provides rheumatology, sports medicine, and clinical genetics services but does not have any general medical or respiratory wards. Following the WHO declaring COVID-19 a pandemic on 11 March 2020, all non-cancer elective activity stopped at our trust on 17 March 2020. During the study period we continued to run surgical lists for patients who required emergency or urgent orthopaedic surgery requiring general or spinal anaesthesia and these patients form our study group.

There were three routes of admission to the NOC for emergency or urgent orthopaedic surgical care: emergency admission, planned urgent admission or transfer from another centre or MDT admission via the tumour service, or bone infection service (Figure 1). Emergency admissions from the on-call emergency patient pathway had direct admission to the NOC. Planned admissions were patients, already on treatment pathways, who were admitted to the NOC for urgent surgery. Tumour service cases were discussed at MDT with this service continuing in line with national guidance following NHS guidelines. The local peak of COVID-19, as assessed by the number of inpatients at our trust, occurred during the first half of April 2020 (Figure 2).

Fig. 1

Study flow.

Fig. 2

Local inpatient caseload across our trust during study period (grey).

Results

Discussion

In a cohort of 96 patients assessed as negative for COVID-19 at the time of surgery who underwent 100 emergency or urgent orthopaedic procedures during the COVID-19 pandemic 9.4% (nine patients) were found to be SARS-CoV-2 positive by nasopharyngeal swab by 30 days after operation. The overall 30-day mortality rate across the whole cohort of patients during this period was 3%. Of those testing positive for SARS-CoV-2 66% (six patients) developed significant COVID-19 related complications and there was a 33% (three patients) 30 day mortality rate. The COVID-19 related morbidity and mortality was 2.9% and 0% respectively in British Orthopaedic Association COVID-19 Patient Risk Assessment low and medium risk patients and 14.8% and 11.1% in high and very high risk patients.

The emerging data indicate that SARS-CoV-2 infection at the time of surgery is associated with a high mortality.^3,4 Furthermore, there is some data that infection during the postoperative period, (within 30 days of surgery) carries a similar risk of mortality, with rates of up to 25% reported.⁴ Our data have confirmed that while overall the mortality across our cohort was low, in those that were diagnosed as SARS-CoV-2 positive within 30 days of surgery it was 33%. The relevance of this is that when considering the risk versus benefit of operative intervention, in addition to considering a patient’s SARS-CoV-2 status at base line, it also important to consider a patients risk of acquiring symptomatic SARS-COV-2 during their postoperative recovery, as this may also present a significant risk to life.

There are very few studies to date that report the results of surgery performed in patients screened and considered COVID-19 negative prior to surgery. The focus of other studies has been on the outcomes of patients who are COVID-19 positive at the time of surgery where mortality rates of 21% have been previously reported.^3,4 In our study we identified a transition rate from SARS-CoV-2 negative to positive following surgery of 9.4% within 30 days, with around half of cases being detected as an inpatient and half as a outpatient. This data is consistent with data reported by the COVIDSurg collaborative, where over half of inpatient COVID-19 diagnosis were postoperative.⁴ While our hospital does not have any general medical wards, nor ICU, during the study period our hospital provided rehabilitation for trauma patients as well as looked after patients with hip fractures presenting a risk of patient to patient transmission. In addition healthcare workers present a risk, both as an inpatient and outpatient and it is known that the incidence of SARS-CoV-2 in healthcare workers shadows the patient population that they treat and in around a third of cases it is asymptomatic.¹² This highlights that healthcare acquired SARS-CoV-2 presents a risk to patients and that, in addition to ensuring that patients do not have SARS-CoV-2 at the time of surgery, specific attention should be placed on the postoperative pathway to include minimizing inpatient stay, minimizing healthcare contacts, and recommending isolation in the immediate postoperative period.

Patients who transitioned from SARS-CoV-2 negative to positive during the study period had a mean age that was 15 years older than those who remained negative and had more medical comorbidities, as assessed by ASA and BOA Risk Assessment. Death from SARS-CoV-2 pneumonia occurred in the oldest (mean age 82 years) and most frail in the cohort, with all being ASA grade 3 or greater and assessed as high or very high risk using the BOA assessment. While increasing age and comorbidity infer an increased risk of mortality following both surgery and infection with SARS-CoV-2, the relationship between surgery and SARS-CoV-2 with respect to the impact on mortality has yet to be fully defined. Nonetheless, despite our small numbers, our study has highlighted that in addition to being more likely to acquire COVID-19 following surgery, older, more comorbid patients are more likely to have COVID-19 associated morbidity and mortality. Therefore, there should be specific consideration to the potential additional risk when considering urgent or elective surgery in this population. While the numbers were too small to permit meaningful statistical analysis anaesthetic strategy may also have an impact outcomes following surgery with patients receiving general anaesthesia having around a 50% higher incidence of SARS-CoV-2 and COVID-19 related morbidity at 30 days with all deaths occurring in the general anaesthesia group. Due the potential for confounders further data are required to confirm these findings.

There are some methodological issues that must be addressed in interpreting the results. The study represents a small cohort of patients and the results might not be generalizable to the wider population. However at present there are very few, if any, reports of orthopaedic surgery performed in patients who are COVID-19 negative prior to surgery. This study offers an important early view of the potential level of risk associated with orthopaedic surgery in this group of patients. Within the study group, screening for COVID-19 negative status was performed with a history and examination with a throat and nose swab test reserved for those who were symptomatic, for the majority of the cohort. Towards the end of the study period all admissions were tested. Therefore it is possible that some of the patients in the cohort were screened with a false negative result, either due to their asymptomatic state or failure of the test to identify them. This would mean that they were presumed COVID-19 negative because they were asymptomatic and underwent surgery, despite actually being COVID-19 positive. Testing of all patients, as currently happens in elective ‘green pathways’, may have reduced the number of false-negative cases but would not have completely excluded them.

Despite the relatively small number of cases in this study, the results offer some insight into the outcome of patients who are screened COVID-19 negative at the time of surgery. It is useful to see that in the early postoperation period, very few patients developed COVID-19-related complications. Our hospital is a specialist orthopaedic unit which does not admit patients for treatment of respiratory diseases and has no intensive care unit and as such, at the time of the study, may have been regarded as a low risk for transmission of SARS-CoV-2 within the hospital. Despite this, 4.2% of patients were SARS-CoV-2 positive on discharge. The risk may be higher for orthopaedic patients treated alongside elderly patients with medical comorbidities, respiratory disease, or Covid-19. This early evidence suggests that when planning a “safe” pathway, not only should we confirm COVID-19 negative status preoperatively, but it is also critical to establish a safe environment for patients during their recovery in hospital and rehabilitation post-discharge. This pathway should include minimizing inpatient stay and recommending isolation in the immediate postoperative period, with this combined approach potentially reducing the risk of contracting COVID infection.¹³

This study reports outcome in emergency and urgent orthopaedic cases, where there is a clear necessity to perform surgery. However, these observations also raise important questions when considering the reintroduction of primary elective orthopaedic surgery where the decision to undergo surgery is discretionary and balanced around risk and benefit. The emerging data suggest that for patients in the highest risk groups of a poor outcome, if they contract COVID-19, the increased level of risk may make the decision of proceeding with surgery more challenging and should be fully discussed as part of a shared decision making process. This re-emphasises the requirement to develop safe pre- and postoperative pathways.

In conclusion, this study establishes that orthopaedic surgery in COVID-19 negative patients carries significant risks in those patients who become COVID-19 positive after their surgery, particularly in the known high risk groups where 30-day mortality exceeds 30%. In lower risk groups, the overall risk of becoming COVID-19 positive and subsequently developing a significant postoperation COVID-19 related complication is much lower. Further research is required to define how elective surgical pathways can be optimized and more clearly establish the risks of developing COVID-19 related comorbidity after surgery.