Is COVID-19 affecting the incidence of hip fractures?The Covid-19 pandemic is caused by the Coronavirus-2 of Severe Acute Respiratory Syndrome (SARS-CoV-2). It was first described in December 2019 in the city of Wuhan, capital of the central chinese province of Hubei, when a group of people with unknown pneumonia were reported [1] . In Europe, the first case of Covid-19 was described in France on January 25th 2020. On February 21, a large outbreak was reported in Italy, mainly in the north, near Milan [2] . The cases grew rapidly and the World Health Organization (WHO) recognized it as a global pandemic on March 11th, 2020 [3] .To prevent the spread of the virus, many governments of different nations have imposed travel restrictions, quarantines, confinements, cancellation of events and closure of non-essential establishments [4] . In Spain the government decreed the state of alarm on March 14th, which limited the free movement of citizens with little exceptions (such as basic services). In practice, this involved a period of confinement that lasted for weeks [5] .In our centre, the effect of one month of confinement was analyzed on the incidence of hip fractures in a prospective cohort of patients. The first result to highlight is the important decrease in the total number of fractures diagnosed during the confinement (32) compared to the monthly average (48,25). This is even more surprising when compared to the same period of time of the previous year (63), finding a decrease in almost half of the hip fractures diagnosed (49,2%).The 93,75% of these patients patients underwent surgery in less that 48h which is the ideal aim nowadays, moreover 73,66% of them were operated in less than 24 hours which is the next objective in our specialty [6] . The mean hospital stay was 4,98 days while in 2019 the mean hospital stay was 6,47 days. This 1.5 days of difference can be explained by the willingness of both, patients and families, to return to their homes as soon as possible, since Hospitals are a risk place for Covid-19 infection.A significant number of patients live alone or accompanied by another elderly person in their homes, which can increase the risk of falls, as these patients carry out more activities at home [7] . Among our patients 59,37% lived according to these conditions. Social alarm and fear of the coronavirus created during the state of alarm has been able to influence patients and relatives when going to the Hospital after a fall with suspected hip fracture. We surpris-ingly found that 18,75% of patients with a hip fracture (all living with a relative) were afraid of the virus and delayed a mean of 2.5 days their visit to the Hospital due to fear.

This study demonstrates that the CT obtains a higher correlation than MR when determining the size of ED.

Introduction: Periprosthetic fractures around the knee (PPF) are a devastating complication of total knee arthroplasty (TKA). Anterior femoral notching during TKA is considered a risk factor for PPF. The aim of this paper is to determine if an anterior femoral notch after total knee arthroplasty may affect the fracture pattern when a PPF appears postoperatively. Material and methods: 50 patients diagnosed in our centre of a PPF from January 2010 to December 2013 were retrospectively enrolled. 100 patients who underwent a total knee arthroplasty without fracture were randomly obtained as a control group. Evidence of the notch was searched in both groups in postoperative X-rays. In the PPF group, distance from the shield of the femoral component to the most distal (d) and proximal (D) point of the fracture were measured. Results: Two different groups were obtained: 1) d = 0 (33 out of 50 patients); the fracture is supposed to be related with the notch as it's a theoretically weaker area. 2) d > 0 (17 out of 50 patients); the fracture pattern has no relationship with the notch. Prevalence of patients suffering a fracture in the shield of the prosthesis (d = 0), was similar in both patients with notch (66,7%) and without it (68%). Conclusions: In conclusion, fracture pattern is not related with the existence of a femoral notch in the clinical setting.

Melorheostosis is a rare dysplastic bone formation disease that can also affect the joints. We present a case of a patient with knee pain that was radiographically diagnosed as melorheostosis because of "dripping wax" image. An exploratory arthroscopy was made. In the joint, we found hyperplasic synovial tissue and an increased retropatellar Hoffa pad, which was surrounding an intra-articular ossification resulting from the disease. This was removed and led to a clinical and functional improvement.

As a conclusion, obesity (BMI ≥30 kg/m²) does not have any clinical relationship with the appearance of a periprosthetic fracture around the knee (p < 0.05).