The Norwegian Trauma Registry (NTR) is a national medical quality registry established in 2006, with web-based registrations starting in 2015. NTR´s main objective is to monitor, assess, and improve quality of trauma care. It is a collective endeavour, where 38 trauma-receiving hospitals supply information to a national database [10]. Certified personnel collect data from injury to rehabilitation, in accordance with the Utstein template [11]; classify injuries according to the abbreviated injury scale (AIS) [12]; and calculate the injury severity score (ISS) [13]and new injury severity score (NISS) [14].

NTR includes all patients admitted with trauma team activation (TTA) upon arrival at the emergency department irrespective of severity scores (ISS/NISS), as well as individuals admitted with penetrating injuries, severe head injuries (AIS ≥ 3) and NISS > 12 in the absence of TTA. Patients who succumb on the site of injury or during transportation are also included if prehospital resources were activated. However, patients with solitary chronic subdural hematoma and bodily harm without concomitant trauma are not included in the NTR [7].

Annually, the NTR retrieves information on approximately 8,000 trauma patients, of whom 1:8 have an ISS > 15. Approximately 12% of the patients with an ISS > 15 in Norway are admitted to Haukeland University Hospital (HUH) in Bergen, one of four trauma centres (TCs) in Norway and the regional TC in the western health region of Norway (Rogaland and Vestland) [10, 15]. The population in the 45,000-km2 area is approximately 1.1 million, a third of which live in the two major regional centres Bergen and Stavanger [16].

All patients registered in HUH´s local NTR database with an ISS > 15 during the period 2016–2018 were included in the study. ISS > 15 is the most common threshold when defining major trauma [17]. Exclusion criteria were the absence of fracture or dislocation in the spinal column, extremities, or pelvis. Patients with solitary cervical spine fractures, solitary penetrating injuries of the neck, or solitary hand fractures were also excluded, as these patients are treated in non-orthopaedic wards at HUH. A total of 175 patients were included in this study. Data were retrieved from the local NTR database and from the patients’ electronic hospital medical records.

From the NTR we retrieved the patient’s identification number, sex, age, preinjury physical status as defined by the American Society of Anesthesiologists (ASA PS classification) [18], ISS, NISS, mechanism of injury (MOI), whether the traumatic event was work related, highest level of treatment, length of stay (LOS) in the intensive care unit (ICU) and in-hospital LOS. Further, information about AIS codes, mortality at day 30, and, when available, cause of death were analysed.

From the patient records, we retrieved information about the main injury, number of orthopaedic injuries, localisation of the orthopaedic injuries, open vs. closed orthopaedic injury, whether the patient received operative treatment for orthopaedic injuries, and, if so, location, type of operative treatment, and time until surgery.

The patients were divided into two age groups: Group 1 (age < 65 years) and Group 2 (age ≥ 65 years). Data on the age distribution of the population in Western Norway for the study period were obtained from Statistics Norway [19].

All fractures and dislocated joints treated by the orthopaedic surgeons at HUH, were registered as orthopaedic injuries. Segmental fractures were classified as one fracture. However, if a long bone had a proximal and a distal fracture with a spared segment in between, this was recorded as two injuries if the fractures required two different types of treatment. Fractures involving connecting segments of the spine were recorded as a single injury. However, two spinal fractures separated by an uninjured segment, were considered as two injuries. Fractures involving both the radius and ulna (antebrachium fracture) were recorded as one injury, as were lower leg fractures (crus fracture), except when the fractures were located at different levels. If a patient had more than one fracture of the pelvis, it was recorded as a single injury. The sacrum was considered part of the pelvis and not the spine. Crush injury of the foot or fractures involving connecting bones in the foot, were recorded as single injuries. Solitary fractures and dislocations in the cervical spine, hand, ribcage, and head, were not considered orthopaedic injuries as they are treated by other medical specialities than the orthopaedic surgeons at HUH.

Operative treatment included both surgery and closed reduction of dislocated bones where anaesthetic procedures were employed. Some patients came to the hospital in the final hours of the day and received operative treatment the same night (< 12 h after admission). These instances were recorded as 0 days to operation, even if the actual date on which the procedure took place was one calendar day after the hospital admission date. The term “Not an option” under “External fixation” implies that the injury could not be treated with external fixation, e.g. fracture in the spinal column.

In the AIS classification system different injuries have sometimes the same severity score. Thus, to register the injury with the most severe impact on patient outcome we used discharge codes, according to the 10th version of the International Statistical Classification of Diseases and Related Health Problems (ICD-10), in an attempt to grade injuries with the same AIS severity score. The injury considered most severe based on ICD-10 codes in the patient´s medical journal was registered as the main injury. These were categorised as either injury to the ‘thorax’, ‘head’, ‘pelvis’, ‘abdomen’, ‘spinal column’, ‘extremities’, ‘neck’, or ‘burns’.

In the NTR, traffic-related injuries involving pedestrians, bicycles, motorcycles, cars, and other means of transportation are coded in different categories. These were all registered as ‘traffic-related’ in this study. The categories ‘firearm injury’ and ‘penetration by sharp or pointy object’ were both coded as ‘penetrating’. Other categories comprised ‘high-energy fall (HEF)’ (fall from a height > 1 m) and ‘low-energy fall (LEF)’ (fall from the standing position, or a height < 1 m), ‘hit by blunt object’, ‘explosion’, and ‘other’. None of our patients sustained injuries caused by an explosion, hence this category is not presented in the tables.

“Highest level of treatment” is a parameter registered in NTR to measure resource demands. The intensive care unit is considered to be the highest treatment level, followed by postoperative care unit, operating room, ward and emergency department as the lowest treatment level.

Data are shown as numbers (n) and proportions (%); means and standard deviations (SD) for continuous variables; and medians and interquartile ranges (IQR) for categorical variables. Categorical variables were analysed using the Pearson’s chi-squared test or Mann–Whitney U test, and the independent samples t-test was used to analyse continuous variables. A P-value < 0.05 (two-tailed) was considered statistically significant. Data were analysed using IBM SPSS, version 26 (IBM Corp., Armonk, New York, USA).