All across surgery specialties, wound or implant infections constitute rare, yet potentially severe complications of surgical procedure. It is considered, that glucose metabolism disorders, e.g. diabetes, are one of the main risk factors of such condition.

Aim of the study The aim of the study is a prospective evaluation of glucose blood level and its variability during 2 weeks before hospitalization and 2 weeks of postoperative period in patients, that will undergo elective orthopaedic surgeries, and its impact on number of cardiovascular and orthopaedic complications.

Materials and methods To this study, patients qualified for elective total knee or hip replacement in the single orthopedic center will be recruited. 100 patients will be included in this study. Every patient will be evaluated on the risk of developing diabetes mellitus in 10 years time and on the risk of death in 10 years due to the cardiovascular events. 14 days before procedure patients will have continuous glucose level measurement sensor implemented in subcutaneous tissue. After 14 days, during standard visit for stitches removal, the sensor will be removed and glycemia data will be collected. Next, patients will have their casual glucose blood level checked and surgery outcome, cardiovascular events or surgery complication risk evaluated in 3-, 6- and 12 month follow-up visits.

Expected benefits of the study Results of this study may allow to define impact of orthopaedic treatment on glycemia and possible necessity to modify treatment of hyperglycemia in perioperative period in patients with Diabetes Mellitus type 2 (DM2). Moreover it will allow to specify change of glucose levels and possibly implicating a need to monitor perioperative glycemia in patients without carbohydrate metabolism disorders. Additionally, the study will help to evaluate corelation between perioperative glucose blood level and the risk of cardiovascular events or surgical complications in 1-year after the procedure, which may decrease the risk of such incidents in the future (e.g. by adequate control and effective treatment of hyperglycemia), hence may result in reduction of mortality and lesser lowering of the quality of life in patients with DM2 or high risk of it.

In every surgical subspeciality surgical site or implants infections are not common but potentially devastating for patients health. One of the most known risk factors of such state is glucose metabolism disorders. Such pathologies, containing diabetes mellitus, are considered one of the most epidemic health-related problems in XXI century.

Diabetes is a civilization disease, caused mainly by obesity, unhealthy eating habits and lack of physical activity. It was concerning about 108 million people in 1980, while in next 40 years this number grew 4-times and is expecting to reach almost 600 million people in 2035.

Total joint arthroplasty is considered the most effective way of treating the end-stage osteoarthritis of hip and knee joints. It is estimated that every year more that one million total joint replacements are performed in Europe. It is believed that our community is getting older and that is the reason why the number of total joint replacements will be growing, as well as patients expectations towards it. Even though total knee and hip replacement have wonderful outcome and are improving significantly patients life and its quality, there are several potential side effect that might lower patients limb function.

There were several studies confirming increased risk of surgical site or implants infections in patients undergoing total joint replacements such as knee or hip, who had perioperative poor glycemic control or had treated diabetes mellitus. However, there is lack of literature concerning analysis of continuous glycemia measurements before and after hospital stay. There are some promises that glycemic disturbances during postoperative period might also increase risk of cardiovascular events in this time and more frequent periods of hypoglycemia, which might result in higher risk of unconsciousness and falls. What is more higher cardiovascular risk is corelated with higher risk of disability and death.

Results of this research will allow to investigate influence of orthopedic surgery on glycemia and possible modifications of hyperglycemia treatment in perioperative period in patients with diabetes or glucose intolerance. What is more it will allow to investigate changes of glycemia in patients with normal glycemia metabolism, potentially protecting them from hypoglycemia during hospital stay and increasing their awareness of potentially suffering diabetes mellitus in the future. Additionally, this study will allow to corelate perioperative glycemia levels with risk of cardiovascular events in one year follow-up, and its influence on surgical site and implants complications. Thanks to these findings surgeons will be able to lower the risk of such complications in the future, hence lowering mortality and quality of life, especially in patients with diabetes mellitus and from the group with high risk of developing this disorder.

Nowadays, with technological development concerning our every day life, also devices used in medicine are getting more and more sophisticated and are making patients lifes easier. One of the most prominent examples of such device are the "discs" implanted into the subcutaneous tissue which might measure patients glycemia level. Thanks to it patients no longer need to measure it with traditional glucometers, which action relayed on blood samples collected from the tip of the finger. It was associated with every day unpleasant needling. Nowadays modern solution allow patients to get the result from their devices on their smartphones by only sliding it above the place of the implanted device.

Taking into considerations, such a wide spread of diabetes mellitus in our population it is obvious, that among patients qualified for total hip or knee arthroplasty many of them will have this disease. Adding to it common risk factors of diabetes and osteoarthritis, such as obesity, it seems that number of patients with such diseases is much bigger than it seems. According to the literature mentioned above it is obvious that microangiopathic changes, as well as hyperglycemia, have negative influence on wound healing, surgery itself and might increase the risk of periprosthetic infections. It is worthy to look for ways to optimize patients care in perioperative period.

Additional good side of this study is a fact, that it contains patients without recognized diabetes mellitus to assess their glycemia fluctuations, without carbohydrate metabolism disorders. Such knowledge might improve and allow to develop the algorithm of perioperative care for the high number of patients, who in such demanding for their body period are exposed to significant glycemia fluctuations.

What is more, it must be admitted that this study has unique model (described below), in which glycemia monitoring will contain both pre- and postoperative period of every included patient. Such way of analyzing patients allows to produce "perfect control group", because every measurements after the surgery has its counterpart before the surgery.

The aim of this project is to prospectively evaluate the level of glycemia and its variability in patients undergoing elective orthopedic surgeries during one month (two weeks before the surgery and two weeks postoperatively) and its influence on the number of cardiovascular and orthopedic complications. What is more the investigators want to evaluate its influence on objective functional outcome of the surgery in one year follow-up. It seems that long bone surgery as a stress factor might increase the risk of developing diabetes or glucose intolerance, what might increase the risk of cardiovascular diseases and number of complications.

To this prospective observational study, patients qualified for elective total knee or hip replacement in the Department of Orthopedics and Rehabilitation in Miedzyleski Specialist Hospital in Warsaw will be recruited. 100 patients will be included.

There were several studies confirming increased risk of surgical site or implants infections in patients undergoing total joint replacements such as knee or hip, who had perioperative poor glycemic control or had treated diabetes mellitus. However, there is lack of literature concerning analysis of continuous glycemia measurements before and after hospital stay. There are some premises that glycemic disturbances during postoperative period might also increase risk of cardiovascular events in this time and more frequent periods of hypoglycemia, which might result in higher risk of unconsciousness and falls. What is more higher cardiovascular risk is corelated with higher risk of disability and death.

Results of this research will allow to investigate influence of orthopedic surgery on glycemia and possible modifications of hyperglycemia treatment in perioperative period in patients with diabetes or glucose intolerance. What is more it will allow to investigate changes of glycemia in patients with normal glycemia metabolism, potentially protecting them from hypoglycemia during hospital stay and increasing their awareness of potentially suffering diabetes mellitus in the future. Additionally, this study will allow to corelate perioperative glycemia levels with risk of cardiovascular events in one year follow-up, and its influence on surgical site and implants complications. Thanks to these findings surgeons will be able to lower the risk of such complications in the future, hence lowering mortality and quality of life, especially in patients with diabetes mellitus and from the group with high risk of developing this disorder.

Nowadays, with technological development concerning our every day life, also devices used in medicine are getting more and more sophisticated and are making patients lifes easier. One of the most prominent examples of such device are the "discs" implanted into the subcutaneous tissue which might measure patients glycemia level. Thanks to it patients no longer need to measure it with traditional glucometers, which action relayed on blood samples collected from the tip of the finger. It was associated with every day unpleasant needling.

Inclusion Criteria:

• Patients hospitalized in the Department of Orthopedics and Rehabilitation of Medical University of Warsaw
• Willingness to participate in the study
• Qualified for total knee or hip replacement due to the primary osteoarthritis
• Age above 18 years

Exclusion Criteria:

• No acceptance to participate in the study
• Qualified for non-surgical treatment
• Patients with other diseases but diabetes mellitus, compensated thyroid disorders and hypertension
• Patients with poorly-controled diabetes mellitus and/or poorly-controlled hypertension
• Patients with diabetes type 1
• Patients from the rest-home
• Patients who had previous lower limb surgeries
• Patients who in opinion of research team might be poorly compliant
• Patients during pregnancy
• Patients who are not fluent in polish language

Power analysis was performed to assess how many patients should be included in the study. Determining effect size was hindered by lack of literature comparing mean values and standard deviations (SD) between groups with and without complications. The effect size can be deemed "large", described numerically as 0.8 by Cohen. However, we decide to be more conservative and used effect size of 0.6, located between "medium" and "large" in Cohen's scale. Standard p value of 0.05, beta value of 0.8 and allocation ratio of 1/1 were used, resulting in total needed sample size of 90 patients. Taking into consideration that 10 % of patients might drop off the follow-up predicted number of participants is 100.