The study concerned a regional hospital with no co-payment, serving a mixed rural and urban district in Denmark. The hospital provided 24-hour emergency assessment, orthopaedic surgery and internal medicine services. It furthermore had an ICU. A new orthogeriatric unit for acute patients of sixty-five years or older with various fragility fractures was opened on March 1, 2014. From that date, all patients of sixty-five years or older with fragility fractures in terms of hip and appendicular fractures were transferred directly to the new orthogeriatric unit after examination in the emergency room.
The orthogeriatric unit was staffed by an interprofessional team consisting of orthopaedic surgeons, geriatric specialists, nurses, nursing assistants, physiotherapists, occupational therapists, and dieticians collaborating on the treatment and care of patients with fragility fractures.
Each weekday, an interprofessional conference was conducted, in which treatment, training, nursing care, and discharge planning for each patient was discussed. Furthermore, on weekdays, patients were assessed in ward rounds and receiving daily physiotherapy training. Patients with severe functional challenges were offered training in daily living activities by occupational therapists. Where relevant, plans for early discharge were discussed with the patients and their families. For all patients who had previously received municipal home care, a discharge report was sent to the home care service. If major changes at home were needed, a video conference between patient, relatives, home care, and nurses from the ward was conducted. For further details on the distinction between orthogeriatric care and traditional orthopaedic care, see Fact box.
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Study design and participants
A prospective observational cohort study with a retrospective (historical) control was designed.
The participants were all patients aged 65 years or older admitted to the orthogeriatric unit with a fragility fracture during two study periods: September 1, 2013 to January 31, 2014 (the historical cohort) and between September 1, 2014 and August 31, 2015 (the orthogeriatric cohort).
Fragility fractures were diagnosed by the orthopaedic surgeon in the Emergency room by the definition: fractures occurring after minimal trauma, such as falling from a standing height or less, or after no identifiable trauma . The fragility fractures included were hip fractures, clinical vertebral fractures, and appendicular fractures, with the exception of patients with fractures of the skull, face, fingers, hands, feet, toes, or kneecaps, as these fractures were not defined as fragility fractures. Hip fractures were identified as DS72, vertebral fractures as DS22 and DS32, and appendicular fractures as DS42, DS52, DS821-9, using codes from the International Classification of Diseases, version 10 (ICD10).
The primary outcome of interest in our study was postoperative complications, defined as the proportion of patients with at least one of the following events; medical complications (cardiac, cerebral, thrombo-embolic, pulmonary, gastro-intestinal complications, urinary tract infection, delirium, pressure ulcer and subsequent fracture – new fractures during admission unrelated to the first fracture) or surgical complications (surgical site infections and surgical complications in terms of luxation) occurring at any time between operation and discharge, as recommended by Liem et al. . Adverse drug reactions (ADR) and renal complications - i.e., transient or lasting increases in serum creatinine levels—were not included, as these cases were inappropriately defined and not systematically assessed. Additionally, the number of complications per patient was assessed numerically (0, 1 or more).
We differentiated between preoperative and postoperative complications by the time the complication was recognized. A medical complication was defined as a new medical condition or a destabilization of a previously stable illness.
Neither the Confusion Assessment Method (CAM) nor the guideline-specific initiatives of delirium management were systematically employed in the prior orthopaedic organization nor implemented during our investigation. Therefore, as both criteria were not met delirium was defined as the state of a patient described being delirious in the medical record and receiving haloperidol treatment as recommended in the local guideline.
The secondary outcome of interest was readmission—defined as any admission within 30 days from discharge.
Patient and admission-related characteristics
Patient characteristics included age, gender, marital status, BMI, place of residence, use of walking aid (yes/no), mobility before fracture using a mobility score validated for hip fracture patient (the Cumulated Ambulation Score (CAS) ; only collected for hip fracture patients), and comorbidity using Carlson’s Comorbidity Index (CCI). Comorbidity data were weighted according to the Charlson protocol and an index score was calculated for each patient .
Characteristics related to admission and operation included type of fracture, number of drugs at the time of admission, polypharmacy (defined as 5 or more different medications at admission), and the American Society of Anaesthesiologists Physical Status (ASA score) - a grading system from 1 to 6 used to evaluate patients’ physical state before choosing an anaesthetic. Furthermore, we assessed preoperative complications, patient ambulation within 24 hours after operation (yes/no), pain score on the second after the operation, mobility at discharge using CAS, time to surgery (TTS), and length of stay (LOS). Time to surgery (TTS) was defined as time (hours) from recorded admission time to the time anaesthesia began, and length of stay (LOS) was defined as the number of hours for which the patient was hospitalized.
Data on age, gender, place of fall, type of fracture, TTS, and LOS were obtained from the patient administrative system, and data on ASA was sourced from the Danish Anaesthesia Database. Comorbidity data and data on readmission were collected from a national registry using diagnoses listed from all hospital discharges for a period from 1994 until 1 month after current admission . All remaining variables were collected from medical records.
The measurements of postoperative complications and readmission are expressed as proportions. Furthermore, postoperative complications and readmissions are examined using a binary logistic regression model on the individual patient level; adjusting for age and gender, and CCI or LOS, respectively. Subsequently regressions are made solely for hip fractures.
Numeric patient and admission-related characteristics are expressed as medians (quartiles) or mean values (±SDs) when appropriate; the unpaired Student’s t-test or the Mann–Whitney U-test is used depending on data distribution. When assessing categorical variables, we used proportions and the chi-squared test.
A two-sample comparison of proportions with a 1:2 patient ratio was chosen to generate more power to detect postoperative complications after implementing the intervention. On the basis of a significant 15% difference in postoperative complications in hip fracture patients assigned to multidisciplinary geriatric intervention versus the traditional orthopaedic care  and in the absence of results generated in study populations characterised by fragility fractures in general, a sample size of 183 (in the first period) and 366 (in the second period) hip fracture patients is necessary to detect a 15% decrease in postoperative complications in the intervention group, setting α at 0.05 and β at 0.9. In addition, patients with additional fragility fractures were concurrently included.
All analyses were performed using Stata 13 software (Stata Statistical Software: Release 13, 2013, College Station, TX).