Background Pilonidal sinus is a hole in the natal cleft which may cause severe pain and become infected. The evidence base for management of pilonidal sinus is said to be poor quality, poorly focused and rapidly proliferating. We undertook a systematic mapping review to provide a broad overview of the field and support the identification of research priorities. Methods We searched MEDLINE, CINAHL, and EMBASE from inception to 22nd Nov 2020 for primary research studies focused on the management of pilonidal sinus. We extracted data on study design and categorised studies under five major headings (‘non-surgical treatment’, ‘surgical treatment’, ‘aftercare’ and ‘other’), producing frequency counts for different study designs. Gaps in research were identified from published systematic reviews and tabulated. Results We identified 983 eligible studies, of which 36 were systematic reviews and/or meta-analyses; 121 were randomised controlled trials), and 826 observational studies of various design. The majority of studies evaluated surgical techniques (n = 665), or adjuvant medical interventions (n = 98). The literature on wound care has developed most recently, and the evidence base includes 30% randomised controlled trials. Gaps analysis highlighted comparison of surgical techniques including flaps, laser depilation, and wound care interventions as potential areas for randomised controlled trials. Conclusions This mapping review summarises eight decades of research on the management of pilonidal sinus. Further research is needed to identify front-running interventions, understand variation in practice and patient values, and to prioritise future research.

Aims This paper details the impact of COVID-19 on foot and ankle activity in the UK. It describes regional variations and COVID-19 infection rate in patients undergoing foot and ankle surgery before, during and after the first national lock-down. Patients & methods This was a multicentre, retrospective, UK-based, national audit on foot and ankle patients who underwent surgery between 13 th January and 31 st July 2020. Data was examined pre- UK national lockdown, during lockdown (23 rd March to 11 th May 2020) and post-lockdown. All adult patients undergoing foot and ankle surgery in an operating theatre during the study period included from 43 participating centres in England, Scotland, Wales and Northern Ireland. Regional, demographic and COVID-19 related data were captured. Results 6644 patients were included. In total 0.53% of operated patients contracted COVID-19 (n = 35). The rate of COVID-19 infection was highest during lockdown (2.11%, n = 16) and lowest after lockdown (0.16%, n = 3). Overall mean activity during lockdown was 24.44% of pre-lockdown activity with decreases in trauma, diabetic and elective foot and ankle surgery; the change in elective surgery was most marked with only 1.73% activity during lock down and 10.72% activity post lockdown as compared to pre-lockdown. There was marked regional variation in numbers of cases performed, but the proportion of decrease in cases during and after lockdown was comparable between all regions. There was also a significant difference between rates of COVID-19 and timing of peak, cumulative COVID-19 infections between regions with the highest rate noted in South East England (3.21%). The overall national peak infection rate was 1.37%, occurring during the final week of lockdown. General anaesthetic remained the most common method of anaesthesia for foot and ankle surgery, although a significant increase in regional anaesthesia was witnessed in the lock-down and post-lockdown periods. Conclusions National surgical activity reduced significantly for all cases across the country during lockdown with only a slow subsequent increase in elective activity. The COVID-19 infection rate and peaks differed significantly across the country. Clinical relevance This paper highlights a significant regional variation in COVID-19 infection rates and peak of COVID-19 infections across the country; this data may be useful in planning response to subsequent waves. The cumulative COVID-19 infection rates suggest that the risk of contracting COVID-19 in patients undergoing foot and ankle surgery is not insignificant. The marked decrease in, and slow recovery of elective activity seen will need to be considered when planning restoration of elective foot and ankle services.